Ophthalmology – Hypertensive Retinopathy

Basics

Description

Hypertensive retinopathy refers to characteristic retinal, choroidal, and optic nerve changes produced by systemic hypertension. The ocular findings may be divided broadly into acute changes, usually associated with severe or rapidly rising blood pressure, and chronic changes, which reflect longstanding vascular damage.

Acute severe hypertension may cause retinal ischemia, hemorrhages, cotton-wool spots, hard exudates, choroidal infarction, serous retinal detachment, and optic disc edema. Chronic hypertension produces progressive retinal arteriolar narrowing, vascular wall thickening, arteriovenous crossing abnormalities, and eventually copper- or silver-wiring of the retinal arteries.

Pregnancy Considerations

In a woman of childbearing age with severe or uncontrolled hypertension, pregnancy status should be established because hypertension may be related to preeclampsia or eclampsia. These conditions can produce marked retinal and choroidal changes and may threaten both maternal and fetal health.

Epidemiology

The frequency of hypertensive retinopathy varies between populations and depends on the definition used.

In the Beaver Dam Eye Study, approximately 6% of patients developed hypertensive retinopathy. Retinal arteriolar narrowing was noted in about 9.9%, while arteriovenous nicking occurred in approximately 6.5%.

Reported prevalence among adults older than 40 years ranges from roughly 2–15%. Some studies have found a higher prevalence among African American populations than among Caucasian populations.

Risk Factors

The principal risk factor is elevated systemic blood pressure, including both systolic and diastolic hypertension.

Diabetes mellitus increases the risk and severity of retinal vascular damage.

Other cardiovascular risk factors, particularly dyslipidemia, smoking, obesity, renal disease, and atherosclerosis, may contribute to the overall vascular burden.

Genetics

There is no single genetic cause of hypertensive retinopathy. Multiple genetic factors contribute to the development of systemic hypertension and therefore indirectly influence susceptibility to hypertensive retinal vascular changes.

General Prevention

Prevention centers on maintaining well-controlled systemic blood pressure.

Regular blood pressure monitoring, adherence to prescribed antihypertensive therapy, control of diabetes and dyslipidemia, appropriate diet, exercise, and management of other cardiovascular risk factors reduce the likelihood of hypertensive end-organ damage.

Pathophysiology

As systemic blood pressure rises, the retinal arterioles initially respond with vasoconstriction. Persistent hypertension eventually causes structural thickening of the arteriolar walls.

With more severe hypertension, the blood-retinal barrier becomes disrupted, allowing leakage of plasma, lipid, and blood into the retina.

Damage to small retinal vessels causes ischemia, producing cotton-wool spots and other manifestations of retinal infarction.

Severe acute hypertension may also compromise the choroidal circulation and optic nerve blood supply, producing choroidal infarcts, retinal pigment epithelial abnormalities, optic nerve ischemia, and optic disc edema.

Etiology

The most common cause is essential hypertension.

Secondary causes include renal disease, renal artery stenosis, endocrine disorders, pregnancy-related hypertension such as preeclampsia/eclampsia, and other systemic conditions capable of producing severe elevations in blood pressure.

Commonly Associated Conditions

Hypertensive retinopathy is associated with systemic and ocular vascular disease, including diabetes mellitus, hyperlipidemia, atherosclerosis, retinal artery macroaneurysm, retinal vein occlusion, retinal artery occlusion, stroke, and cognitive decline.

Longstanding systemic hypertension may also be associated with an increased cardiovascular risk, including coronary artery disease.

Diagnosis

History

Many patients with hypertensive retinopathy are asymptomatic and may not even know that they have hypertension.

Others have a known history of elevated blood pressure and may be receiving antihypertensive medication.

Patients should be asked about headaches, visual changes, neurologic symptoms, chest pain, shortness of breath, renal disease, pregnancy, diabetes, and medication adherence.

In acute severe hypertension, symptoms related to end-organ injury may dominate the presentation.

Physical Examination

A complete ophthalmic examination should include visual acuity, pupils, intraocular pressure when appropriate, slit-lamp examination, and a dilated fundus examination.

The retinal appearance differs substantially between acute severe hypertension and chronic hypertension.

Acute or Malignant Hypertensive Changes

Severe or rapidly developing hypertension can cause fibrinoid necrosis of the retinal and choroidal arterioles, producing ischemic and exudative changes.

Deep yellow-gray retinal pigment epithelial or choroidal lesions may be seen during the acute phase.

Later, areas of choroidal infarction can become hyperpigmented and are called Elschnig spots.

Linear hyperpigmented streaks resulting from choroidal infarction along choroidal arteries are known as Siegrist streaks.

Optic Disc Edema

Optic disc swelling may occur in very severe hypertensive disease.

It reflects significant end-organ involvement and may result from ischemic injury to the optic nerve and disruption of autoregulation.

Historically, optic disc edema was an important feature in definitions of malignant hypertension.

The presence of optic disc edema in a patient with severely elevated blood pressure should be considered a medical emergency requiring urgent systemic evaluation.

Retinal Hemorrhages

Hypertensive retinopathy may produce retinal hemorrhages of varying severity.

These may include:

Flame-shaped hemorrhages in the nerve fiber layer, deeper dot-blot hemorrhages, and occasionally more extensive pre-retinal or subretinal hemorrhage in severe disease.

Cotton-Wool Spots

Cotton-wool spots represent localized infarctions of the retinal nerve fiber layer caused by precapillary arteriolar occlusion.

They indicate significant retinal ischemia and are more likely in severe hypertension.

Hard Exudates

Breakdown of the blood-retinal barrier permits lipid-rich plasma to leak into the retina, producing hard exudates.

When arranged radially around the fovea, they may create a macular star.

Serous Retinal Detachment

Acute severe hypertension, particularly in younger patients or those with pregnancy-associated hypertension, can produce serous retinal detachment because of choroidal ischemia and retinal pigment epithelial dysfunction.

This may cause sudden visual loss.

Chronic Hypertensive Changes

Longstanding hypertension produces structural changes in the retinal arterioles.

Arteriolar Narrowing

Generalized or focal narrowing of the retinal arterioles is common.

The normal artery-to-vein caliber ratio is approximately 2:3. With chronic hypertension, the arterial component becomes progressively narrower.

Copper Wiring

As the arteriolar wall becomes thickened and sclerotic, the central light reflex broadens.

The vessel develops a reddish-brown appearance referred to as copper wiring.

Silver Wiring

With advanced arteriolosclerosis, the arterial wall becomes so thick and opaque that the blood column is difficult or impossible to visualize.

The vessel then appears pale or white, producing silver wiring.

Arteriovenous Nicking

At arteriovenous crossings, the artery and vein share a common adventitial sheath.

A thickened, rigid artery can compress the underlying vein, producing narrowing or interruption of the venous blood column.

This is termed AV nicking, or the Gunn sign.

Salus Sign

The retinal vein may be deflected from its normal course as it passes beneath a sclerotic arteriole.

This is known as the Salus sign.

Microaneurysms

Microaneurysms may develop as a consequence of chronic microvascular damage.

However, their presence should also prompt consideration of diabetes or other retinal vascular disease.

Diagnostic Tests and Interpretation

Blood Pressure Measurement

The most important initial systemic test is accurate blood pressure measurement.

If severe hypertension is found, assessment for acute end-organ damage should follow promptly.

Patients with diabetes should have careful blood pressure control because reduction of systemic hypertension decreases progression of diabetic microvascular complications.

Imaging

Routine ocular imaging is not always necessary in straightforward cases.

However, several modalities may be useful when the diagnosis is uncertain or complications are suspected.

Fundus Photography

Color fundus photography is useful for documenting the severity and progression of retinal vascular changes.

Optical Coherence Tomography

OCT may reveal macular edema, subretinal fluid, retinal thickening, or structural changes associated with severe hypertensive retinopathy.

Fluorescein Angiography

Fluorescein angiography may demonstrate:

Microaneurysms, retinal telangiectasia, retinal or choroidal ischemia, capillary nonperfusion, vascular leakage, and optic disc leakage.

It is generally reserved for cases in which additional information is needed.

Pathological Findings and Grading

A traditional grading system is the Scheie classification.

Grade 0: Normal fundus.

Grade 1: Mild generalized retinal arteriolar narrowing.

Grade 2: More obvious narrowing with focal irregularities.

Grade 3: Grade 2 changes plus retinal hemorrhages, cotton-wool spots, or exudates.

Grade 4: Grade 3 changes plus optic disc edema.

Modern clinical management places more emphasis on the presence of acute end-organ injury than on the grading system alone.

Differential Diagnosis

Important differential diagnoses include diabetic retinopathy, radiation retinopathy, retinal vein occlusion, retinal artery occlusion, retinal vasculitis, juxtafoveal telangiectasia, giant cell arteritis, and other ischemic or inflammatory retinal vascular disorders.

The patient’s systemic history and retinal distribution of lesions help distinguish these conditions.

Treatment

Treatment is directed primarily at the systemic hypertension, not the retinal lesions themselves.

The retinal changes frequently improve as blood pressure is controlled.

Medication

Chronic Hypertension

Patients with chronic hypertension generally require oral antihypertensive therapy chosen according to their overall cardiovascular and renal status.

Medication selection should be managed by the patient’s primary care physician, internist, cardiologist, nephrologist, or other appropriate clinician.

Hypertensive Emergency

Patients with severe hypertension and evidence of acute end-organ damage may require intravenous antihypertensive therapy in a monitored hospital setting.

Blood pressure should generally be lowered in a controlled manner rather than abruptly, because excessive rapid reduction can compromise cerebral, coronary, renal, and ocular perfusion.

Referral

All patients with newly recognized hypertensive retinopathy should have systemic blood pressure evaluation and appropriate medical follow-up.

Patients with severe retinal hemorrhages, cotton-wool spots, optic disc edema, choroidopathy, neurologic symptoms, or other evidence of acute hypertensive end-organ damage require urgent medical assessment.

Inpatient Considerations

Hospital admission is indicated when the patient has a hypertensive emergency, meaning severely elevated blood pressure accompanied by acute target-organ injury.

Ocular evidence of severe hypertensive damage, particularly optic disc edema together with other systemic findings, may form part of the end-organ injury picture.

Management requires controlled blood pressure lowering and evaluation for neurologic, cardiac, renal, and other systemic complications.

Follow-Up

Blood pressure should be monitored closely by the patient’s medical provider.

Ophthalmic follow-up depends on the severity of retinal findings.

Patients with mild chronic changes may be followed during routine dilated eye examinations.

Patients with acute exudative or ischemic changes should be re-examined more closely to document resolution of hemorrhages, cotton-wool spots, retinal edema, subretinal fluid, and optic disc swelling.

Diet

A diet that supports blood pressure control is recommended.

For patients with salt-sensitive hypertension, reduction of dietary sodium can contribute to improved blood pressure control.

Overall cardiovascular dietary measures should also emphasize appropriate calorie intake, fruits, vegetables, whole grains, and management of dyslipidemia and diabetes.

Patient Education

Patients should understand that hypertensive retinopathy is evidence of systemic vascular injury, not merely an isolated eye problem.

Regular blood pressure monitoring, adherence to antihypertensive medication, treatment of diabetes and hyperlipidemia, smoking cessation, and regular medical follow-up are important for preserving both vision and overall cardiovascular health.

Patients with sudden visual loss, severe headache, neurologic symptoms, chest pain, or severe blood pressure elevation should seek urgent medical care.

Prognosis

The visual prognosis is usually excellent when blood pressure is adequately controlled before permanent retinal, choroidal, or optic nerve damage develops.

Many acute retinal changes, including hemorrhages, cotton-wool spots, and edema, can improve substantially after appropriate treatment of systemic hypertension.

Longstanding vascular sclerosis may remain even after blood pressure is controlled.

Severe ischemic injury to the macula or optic nerve may result in permanent visual impairment.

Complications

Complications of systemic hypertension affecting the eye include retinal vein occlusion, retinal arterial occlusion, retinal artery macroaneurysm, optic nerve ischemia, hypertensive optic neuropathy, macular edema, choroidal infarction, and serous retinal detachment.

The presence of significant hypertensive retinopathy also serves as an important marker of increased risk for systemic cardiovascular and cerebrovascular disease.

Ophthalmology – Horner Syndrome

Basics

Description

Horner syndrome (HS) results from interruption of the oculosympathetic pathway supplying the eye and face.

The classic clinical features are:

• Miosis — due to paralysis of the iris dilator muscle
• Mild ptosis — due to denervation of Müller’s superior tarsal muscle
• Anhidrosis — variable, depending on the level of the lesion

Other findings include:

• Dilation lag in darkness
• Mild reverse ptosis of the lower eyelid
• Transient conjunctival hyperemia in acute cases
• Iris heterochromia in congenital or very early-onset Horner syndrome

Horner syndrome may be congenital or acquired.

Clinical priority: New painful Horner syndrome should raise immediate concern for internal carotid artery dissection.

Oculosympathetic Pathway

Understanding the three-neuron sympathetic pathway is essential for localizing Horner syndrome.

First-Order Neuron — Central

The pathway begins in the posterolateral hypothalamus.

Fibers descend ipsilaterally through the:

Hypothalamus → midbrain → pons → medulla → cervical spinal cord

They terminate in the ciliospinal center of Budge, approximately C8–T2.

Causes of First-Order Horner Syndrome

• Brainstem stroke
• Demyelinating disease
• Brainstem tumor
• Syringomyelia
• Cervical spinal cord tumor
• Cervical spinal cord trauma

Associated neurologic findings frequently help localize the lesion.

Second-Order Neuron — Preganglionic

Preganglionic fibers leave the spinal cord, pass over the pulmonary apex, and ascend through the cervical sympathetic chain.

They eventually synapse in the superior cervical ganglion, near the carotid bifurcation.

Causes of Second-Order Horner Syndrome

Think particularly about lesions of the chest and neck:

• Pancoast/apical lung tumor
• Neck tumors
• Mediastinal disease
• Cervical trauma
• Brachial plexus injury
• Neck or thoracic surgery
• Neuroblastoma in children

Because the pathway passes near the lung apex, an otherwise unexplained Horner syndrome may be the presenting manifestation of an apical pulmonary malignancy.

Third-Order Neuron — Postganglionic

Postganglionic fibers leave the superior cervical ganglion and travel with the internal carotid artery into the skull.

They pass through the cavernous sinus, then enter the orbit and ultimately reach:

• Iris dilator muscle
• Müller’s superior tarsal muscle

Causes of Third-Order Horner Syndrome

Important causes include:

• Internal carotid artery dissection
• Internal carotid aneurysm
• Cavernous sinus lesions
• Skull-base lesions
• Cluster headache
• Other trigeminal-autonomic cephalalgias

A cavernous sinus lesion usually causes additional cranial neuropathies rather than an isolated Horner syndrome.

High-Yield Localization

A useful anatomical framework is:

1st order: hypothalamus → brainstem → C8–T2

2nd order: spinal cord → lung apex → cervical sympathetic chain → superior cervical ganglion

3rd order: internal carotid artery → cavernous sinus → orbit

This anatomy determines both the differential diagnosis and the required imaging.

Pathophysiology

Loss of sympathetic innervation produces the characteristic ocular findings.

Miosis

Paralysis of the iris dilator leaves parasympathetic pupillary constriction relatively unopposed.

Ptosis

Denervation of Müller’s muscle causes approximately 1–3 mm of upper-lid ptosis.

Reverse Ptosis

Loss of sympathetic tone to the lower eyelid can produce slight elevation of the lower lid.

Together, upper and lower lid changes create an apparent narrowing of the palpebral fissure.

Anhidrosis

Loss of sympathetic innervation to sweat glands causes reduced sweating.

Its distribution depends strongly on lesion location.

Diagnosis

History

The most common presenting complaint is new unilateral ptosis.

Patients usually do not notice the miosis itself.

The history should establish:

• When the ptosis or anisocoria began
• Whether it was sudden or gradual
• Whether old photographs show the same findings
• Previous head, neck, or chest trauma
• Recent neck manipulation or surgery
• Previous central venous procedures
• Smoking history
• Pulmonary disease
• Previous malignancy
• Neurologic symptoms

Old photographs are particularly valuable for distinguishing a longstanding Horner syndrome from a newly acquired one.

Pain Is a Critical Red Flag

The most important associated symptom in an acute Horner syndrome is:

Head, orbital, facial, or neck pain.

A patient with:

Acute Horner syndrome + ipsilateral head/neck pain

should be considered to have internal carotid artery dissection until appropriately excluded.

The pain may be severe, but it can also be described simply as a dull ache or discomfort.

This presentation requires urgent vascular imaging.

Associated Neurologic Symptoms

Ask specifically about:

• Vertigo
• Ataxia
• Dysarthria
• Dysphagia
• Nystagmus
• Facial sensory abnormalities
• Hemisensory loss
• Limb weakness
• Diplopia

These findings may indicate a central lesion such as a brainstem stroke.

Physical Examination

Ptosis

Upper-eyelid ptosis is generally mild, approximately 1–3 mm.

This is because the major eyelid elevator—the levator palpebrae superioris supplied by CN III—remains functional.

Thus:

Horner ptosis = mild

whereas a complete third-nerve palsy can cause profound ptosis.

Reverse Ptosis

Slight elevation of the lower eyelid may occur from loss of sympathetic innervation to the inferior tarsal muscle.

The combination of:

Upper-lid ptosis + lower-lid reverse ptosis

creates an apparent enophthalmos.

The globe itself is generally not truly enophthalmic.

Miosis and Anisocoria

The affected pupil is smaller.

The key examination principle is:

Anisocoria is greater in darkness.

In bright illumination, both pupils constrict relatively normally.

In darkness, the normal pupil dilates promptly while the Horner pupil cannot dilate normally.

Therefore, the difference between the pupils becomes more obvious.

Dilation Lag

Dilation lag is characteristic of Horner syndrome.

After moving from bright illumination into darkness, the Horner pupil dilates more slowly than the normal pupil.

The anisocoria may therefore be most prominent during the first several seconds of darkness.

Dilation lag supports the diagnosis but its absence does not exclude Horner syndrome.

Pupillary Light Reaction

Because the parasympathetic pathway is intact, the Horner pupil generally has a normal direct and consensual light response.

This is an important distinction from disorders involving the parasympathetic pupillary pathway.

Anhidrosis

Anhidrosis varies according to the anatomical level of the lesion.

Central and preganglionic lesions may produce more extensive facial anhidrosis.

In many postganglionic lesions involving the internal carotid sympathetic plexus, facial sweating is relatively preserved because sudomotor fibers to much of the face travel predominantly with the external carotid artery.

Therefore:

Absence of anhidrosis does not exclude Horner syndrome.

Iris Heterochromia

Congenital or very early-onset sympathetic denervation can interfere with iris melanocyte development.

The affected iris becomes less pigmented and therefore lighter.

Thus:

Congenital Horner syndrome → lighter iris on the affected side

Heterochromia is much less useful in adult-onset disease.

Pharmacologic Confirmation

Apraclonidine Test

Apraclonidine testing is now commonly used to confirm Horner syndrome.

Chronic sympathetic denervation produces denervation supersensitivity of α₁ receptors in the iris dilator.

After apraclonidine:

• Normal pupil → little dilation or slight constriction
• Horner pupil → significant dilation

This produces a characteristic:

Reversal of anisocoria

The previously smaller Horner pupil becomes similar in size to, or larger than, the normal pupil.

The Horner ptosis may also improve temporarily.

Important Limitation in Acute Horner Syndrome

Denervation supersensitivity requires time to develop.

Consequently, very acute Horner syndrome may occasionally produce a false-negative apraclonidine test.

More importantly:

Pharmacologic testing must never delay urgent imaging when carotid dissection or another dangerous cause is suspected.

Apraclonidine in Infants

Apraclonidine requires particular caution in young children because systemic absorption can cause:

• Profound lethargy
• Bradycardia
• Hypotension
• Respiratory depression

It should generally be avoided in very young infants, with pediatric testing protocols determined by the treating specialist.

Cocaine Test

Cocaine blocks norepinephrine reuptake at sympathetic nerve terminals.

Normal Eye

Norepinephrine accumulates → pupil dilates.

Horner Eye

Little norepinephrine reaches the terminal → minimal dilation.

Thus, after cocaine:

Anisocoria increases.

Historically, cocaine was the classic confirmatory test, but practical limitations have made apraclonidine more commonly used in many settings.

Hydroxyamphetamine

Hydroxyamphetamine was historically used to distinguish preganglionic from postganglionic Horner syndrome by stimulating norepinephrine release from intact postganglionic terminals.

However, it is difficult to obtain and has important practical limitations.

Modern imaging has substantially reduced the need for pharmacologic lesion localization.

Laboratory Investigation

Routine laboratory testing is generally not necessary to establish Horner syndrome.

Laboratory studies should instead be directed toward the suspected underlying disease.

The central diagnostic priority is usually appropriate imaging.

Imaging

Imaging is determined by:

• Age
• Acute versus chronic onset
• Pain
• Associated neurologic abnormalities
• Trauma
• Suspected anatomical localization
• Whether a benign cause has already been established

Unexplained acquired Horner syndrome generally requires investigation of the relevant oculosympathetic pathway.

Acute Painful Horner Syndrome

This is the most important emergency presentation.

Suspect: Internal Carotid Artery Dissection

Urgent imaging generally involves:

• CTA head and neck, or
• MRI/MRA head and neck

The carotid arteries must be adequately visualized.

Carotid Doppler ultrasonography alone is insufficient to exclude many dissections, particularly lesions near the skull base.

Suspected Central Horner Syndrome

When associated with:

• Ataxia
• Vertigo
• Dysarthria
• Dysphagia
• Nystagmus
• Sensory abnormalities
• Other focal neurologic deficits

perform appropriate brain and brainstem MRI, often with vascular imaging depending on the presentation.

Suspected Preganglionic Horner Syndrome

Evaluate the:

• Neck
• Cervical sympathetic chain
• Thoracic inlet
• Lung apex

Chest and neck imaging is particularly important when there is:

• Shoulder or arm pain
• Smoking history
• Brachial plexopathy
• Neck mass
• Known malignancy

An apical lung tumor must be excluded when clinically appropriate.

Pediatric Horner Syndrome

The evaluation differs from that in adults.

Possible causes include:

• Birth trauma
• Neck/chest surgery
• Congenital abnormalities
• Neuroblastoma
• Other neck or thoracic masses

When there is no definite benign explanation, investigation for neuroblastoma and other mass lesions may be required.

This can include appropriate imaging of the neck, chest, abdomen, and pelvis and measurement of urinary catecholamine metabolites such as:

• VMA
• HVA

Importantly, normal urinary catecholamine metabolites do not completely exclude neuroblastoma.

Differential Diagnosis

Physiologic Anisocoria

Physiologic anisocoria is common.

Unlike Horner syndrome, there is:

• No characteristic ptosis
• No convincing dilation lag
• No pharmacologic evidence of sympathetic denervation

The degree of physiologic anisocoria is generally relatively similar under different illumination conditions, although some variability can occur.

Third Cranial Nerve Palsy

Both disorders may produce ptosis.

The key pupillary distinction is:

Horner syndrome → abnormal pupil is SMALL

Compressive CN III palsy → abnormal pupil is typically LARGE

Third-nerve palsy may additionally produce:

• Marked ptosis
• Ophthalmoplegia
• “Down-and-out” eye position

Adie Tonic Pupil

In Adie syndrome, the abnormal pupil is usually larger, particularly in bright light.

There may be:

• Poor light reaction
• Better near response
• Segmental iris sphincter palsy
• Slow redilation after near effort

Thus, it represents essentially the opposite anisocoria pattern from Horner syndrome.

Pharmacologic Anisocoria

Consider exposure to:

• Pilocarpine or other miotics
• Anticholinergic agents
• Sympathomimetics
• Scopolamine
• Certain inhaled or nebulized medications

Medication and occupational exposure history can prevent unnecessary investigation.

Treatment

There is no specific treatment required for the miosis itself.

Treatment is directed at the underlying cause.

Examples include management of:

• Carotid artery dissection
• Stroke
• Neoplasm
• Neuroblastoma
• Infection
• Inflammatory disease
• Cervical or thoracic pathology

Management of carotid dissection is individualized according to neurologic and vascular findings and generally involves specialist-directed antithrombotic therapy.

Ptosis Treatment

If the underlying disorder has been appropriately investigated and the ptosis remains cosmetically or functionally significant, surgical correction can be considered.

Options may include procedures targeting Müller’s muscle or other ptosis repair techniques depending on eyelid measurements and function.

Prognosis

The ocular manifestations of Horner syndrome themselves usually do not threaten vision.

Prognosis depends almost entirely on the underlying cause.

For example:

• Congenital or longstanding benign Horner syndrome may remain stable indefinitely.
• Horner syndrome associated with carotid dissection may improve as sympathetic function recovers.
• Tumor-associated Horner syndrome depends on the prognosis of the underlying malignancy.

High-Yield Clinical Pearls

Horner syndrome = mild ptosis + miosis ± anhidrosis.

Anisocoria is greatest in the DARK.

Dilation lag supports Horner syndrome.

The affected pupil retains a normal light reaction because the parasympathetic pathway is intact.

Apraclonidine can reverse the anisocoria because of denervation supersensitivity.

Acute Horner syndrome + ipsilateral head/neck/orbital pain = carotid artery dissection until excluded.

Preganglionic Horner syndrome → think lung apex and neck.

Central Horner syndrome + neurologic deficits → think brainstem/spinal cord disease.

Congenital Horner syndrome can cause ipsilateral iris hypopigmentation.

Unexplained pediatric Horner syndrome warrants consideration of neuroblastoma.

Do not delay urgent vascular imaging merely to obtain pharmacologic confirmation in a clinically suspicious acute painful Horner syndrome.

Ophthalmology – Homocystinuria Basics Description Homocystinuria comprises a group of inherited disorders of methionine metabolism characterized by excessive accumulation of homocysteine in the blood and urine. The classic and most common form is caused by deficiency of cystathionine β-synthase (CBS). Other metabolic defects causing homocystinuria include abnormalities of cobalamin metabolism and methylenetetrahydrofolate reductase (MTHFR) deficiency. Classic homocystinuria is a multisystem disorder affecting primarily the: Eyes Central nervous system Skeletal system Vascular system The hallmark ophthalmic manifestations are progressive high myopia and ectopia lentis. A major systemic danger is arterial and venous thromboembolism, which can cause stroke, pulmonary embolism, and premature death.

Epidemiology Classic homocystinuria is rare, although incidence varies substantially among populations because of founder mutations and consanguinity. Historically, the worldwide incidence has been estimated at approximately 1:200,000–300,000 live births, although biochemical and molecular screening suggests that it may be more common in some populations. Particularly high frequencies have been reported in Qatar and certain European populations.

Genetics Classic homocystinuria has autosomal recessive inheritance. It results from pathogenic variants in the CBS gene, located on chromosome 21q22.3. Many affected patients are compound heterozygotes, possessing two different pathogenic CBS variants. The particular variants and the amount of residual CBS enzyme activity influence disease severity and whether the patient responds to pyridoxine (vitamin B6).

Pathophysiology CBS normally participates in the transsulfuration pathway that converts homocysteine toward cysteine metabolism. CBS deficiency results in accumulation of: Homocysteine → homocystine → methionine with reduced downstream cysteine production. Elevated homocysteine has toxic effects on connective tissue and vascular endothelium. Ocularly, abnormal connective-tissue metabolism weakens the zonular fibers supporting the crystalline lens, eventually producing ectopia lentis. Systemically, increased endothelial dysfunction and platelet activation create a marked thrombotic tendency.

Ocular Manifestations Progressive Myopia Progressive myopia is often one of the earliest ophthalmic manifestations. Increasing lenticular myopia can precede obvious lens dislocation and may therefore provide an early clue to weakening of the zonules. A child developing unexplained rapidly progressive high myopia should be examined carefully for phacodonesis and early ectopia lentis.

Ectopia Lentis Ectopia lentis is the hallmark ocular abnormality of classic homocystinuria. It generally develops after infancy and becomes increasingly common with age. Progressive disruption of the zonular fibers causes the lens to become unstable and eventually subluxated or completely dislocated. Although traditionally described as inferonasal displacement, the lens in homocystinuria can actually dislocate in any direction. This is an important correction to the classic teaching.

Homocystinuria vs Marfan Syndrome Both disorders may produce a marfanoid body habitus and ectopia lentis, making differentiation particularly important. In homocystinuria, the zonular fibers tend to undergo degeneration and disruption, whereas in Marfan syndrome they are characteristically abnormal but may remain elongated. Classically: Homocystinuria → inferonasal lens displacement Marfan syndrome → superotemporal lens displacement However, lens direction alone should not be used to establish the diagnosis because homocystinuric lenses may dislocate in any direction. More useful distinguishing features are the presence in homocystinuria of developmental/intellectual impairment, osteoporosis, and especially thromboembolic disease.

Other Ocular Manifestations Additional ophthalmic abnormalities include: High myopia Irregular astigmatism Phacodonesis Cataract Pupillary-block glaucoma Retinal detachment Optic atrophy Staphyloma Amblyopia

Acute Pupillary-Block Glaucoma A markedly subluxated or dislocated lens may move anteriorly and obstruct aqueous flow through the pupil. This can cause acute pupillary-block glaucoma with: Severe ocular pain Red eye Blurred vision Markedly elevated intraocular pressure Corneal edema Possible nausea and vomiting This constitutes an ophthalmic emergency.

Systemic Manifestations Skeletal Findings Patients frequently develop a marfanoid habitus characterized by: Tall, thin stature Long extremities Scoliosis Pectus excavatum or carinatum Genu valgum Pes cavus High-arched palate Dental crowding Unlike Marfan syndrome, generalized osteoporosis is characteristic of homocystinuria.

Neurologic and Psychiatric Manifestations Neurologic manifestations vary considerably and may include: Developmental delay Intellectual disability Seizures Behavioral abnormalities Psychiatric disorders Importantly, early metabolic treatment can substantially modify neurologic outcome.

Thromboembolic Disease Thromboembolism is the major life-threatening complication of classic homocystinuria. Both arteries and veins may be affected. Complications include: Ischemic stroke Cerebral venous thrombosis Deep-vein thrombosis Pulmonary embolism Peripheral arterial thrombosis Other organ ischemia Thrombosis may occur spontaneously or be precipitated by dehydration, prolonged immobilization, surgery, anesthesia, or other physiologic stresses. This risk is particularly important when planning ocular surgery.

Diagnosis History Important questions include: Birth and Screening History Determine whether newborn metabolic screening was performed and whether abnormalities were detected. Developmental History Ask about: Speech delay Developmental delay Learning difficulties Behavioral or psychiatric abnormalities Family History Important clues include: Consanguinity Similarly affected siblings Unexplained thrombosis Stroke or thromboembolic death at a young age Ocular History Ask about: Progressive myopia Frequent spectacle changes Poor vision Monocular visual preference Ocular pain or redness Previous lens dislocation

Physical Examination General Examination Look for: Marfanoid habitus Scoliosis Pectus deformity Genu valgum Pes cavus High-arched palate Dental crowding Malar flushing Osteoporosis or history of fractures Neurologic and developmental assessment should also be performed. Ophthalmic Examination A comprehensive examination should include: Visual acuity Cycloplegic refraction in children Slit-lamp examination Intraocular pressure Assessment for phacodonesis Lens position Dilated retinal examination Particular attention should be directed toward progressive high myopia and ectopia lentis.

Diagnostic Tests Biochemical Testing Classic CBS deficiency typically produces: Markedly elevated plasma total homocysteine and usually: Elevated plasma methionine Urinary homocystine may also be elevated. Modern diagnosis relies principally on quantitative plasma amino acids, plasma total homocysteine, biochemical enzyme assessment when required, and molecular genetic testing.

Newborn Screening Newborn screening traditionally detects classic homocystinuria through elevated methionine. However, screening can miss affected infants, particularly those whose methionine concentration has not risen sufficiently when the specimen is obtained. Thus, a normal newborn screen does not absolutely exclude homocystinuria when later clinical findings are strongly suggestive.

Molecular Genetic Testing Molecular analysis of the CBS gene can confirm the diagnosis and identify the causative variants. Genetic testing is also valuable for: Family screening Carrier identification Genetic counseling Prenatal or preimplantation genetic testing when familial pathogenic variants are known

Pyridoxine Responsiveness An important component of metabolic evaluation is determining whether the patient responds to pyridoxine (vitamin B6). CBS uses pyridoxal phosphate, derived from vitamin B6, as a cofactor. Some pathogenic variants leave sufficient residual enzyme activity that pharmacologic pyridoxine substantially lowers homocysteine concentrations. Patients are therefore broadly classified as: B6-responsive or B6-nonresponsive. Responsiveness has important implications for both treatment and prognosis. High-dose pyridoxine testing and therapy should be conducted under specialist metabolic supervision because excessive doses can cause serious toxicity.

Imaging and Additional Testing Brain MRI with appropriate vascular/stroke imaging should be obtained when focal neurologic findings suggest cerebrovascular disease. DEXA scanning may be used to assess and monitor osteoporosis. Ocular imaging such as anterior-segment OCT or ultrasound biomicroscopy can occasionally help characterize severe lens displacement, although the diagnosis of ectopia lentis is usually clinical.

Differential Diagnosis Important causes of ectopia lentis include: Marfan syndrome Weill–Marchesani syndrome Familial isolated ectopia lentis Ectopia lentis et pupillae Trauma Aniridia Ocular coloboma Microspherophakia Sulfite oxidase deficiency Molybdenum cofactor deficiency Other metabolic causes of elevated homocysteine, particularly remethylation disorders such as MTHFR and cobalamin-related defects, must also be distinguished from classic CBS deficiency.

Treatment Treatment should be coordinated with a metabolic disease specialist. The principal objective is sustained reduction of plasma homocysteine to decrease the risk of thromboembolic and other systemic complications.

Pyridoxine Patients who demonstrate pyridoxine responsiveness are treated with vitamin B6, with dosage individualized by the metabolic specialist according to biochemical response. Folate and vitamin B12 status should be optimized because deficiencies can further impair homocysteine metabolism.

Dietary Therapy Patients who are insufficiently responsive to pyridoxine generally require a methionine-restricted diet. Specialized amino-acid preparations may be required to maintain adequate nutrition while restricting methionine. Dietary treatment should be managed by a metabolic dietitian because excessive protein restriction can adversely affect growth and development.

Betaine Betaine promotes remethylation of homocysteine to methionine and can substantially reduce plasma homocysteine concentrations. It is particularly useful when pyridoxine and dietary treatment do not achieve adequate biochemical control. Because betaine can increase methionine concentrations, biochemical monitoring remains important.

Ophthalmic Treatment Refractive Correction Myopia and astigmatism should be corrected promptly using: Spectacles Contact lenses when appropriate Children require careful monitoring for anisometropic or deprivation amblyopia. Amblyopia Amblyopia should be treated aggressively during the visual-development period with appropriate optical correction and, when indicated, patching or pharmacologic penalization.

Lens Surgery Lens extraction may be necessary when ectopia lentis causes: Uncorrectable visual impairment Severe progressive refractive error Amblyogenic optical distortion Lens-induced inflammation Pupillary-block glaucoma Complete lens dislocation Other significant complications Modern surgical technique is individualized according to the degree of zonular instability and associated ocular anatomy.

Perioperative Considerations Surgery in a patient with homocystinuria requires special planning because of the marked risk of perioperative thrombosis. Before elective ocular or systemic surgery, coordination with metabolic medicine, anesthesia, hematology, and the surgical team is appropriate. Important measures include: Maintaining adequate hydration Avoiding prolonged immobilization Maintaining metabolic control Assessing individual thrombosis risk Using thromboprophylaxis when indicated by the treating team The thromboembolic risk may be more clinically consequential than the ocular procedure itself.

Ongoing Care Patients require multidisciplinary lifelong follow-up involving: Ophthalmology Metabolic medicine Primary care/pediatrics Nutrition Genetics Hematology when appropriate Neurology when cerebrovascular or neurologic disease is present Ophthalmic monitoring should assess: Refraction Lens stability Intraocular pressure Amblyopia Retinal status Visual function

Patient Education Patients and families should understand the importance of lifelong metabolic treatment, even when the patient feels well. They should recognize symptoms potentially indicating thrombosis or stroke and seek emergency medical evaluation when these occur. Genetic counseling is appropriate because classic CBS-deficiency homocystinuria is autosomal recessive.

Prognosis Prognosis depends strongly on how early the disorder is recognized and how effectively homocysteine concentrations are controlled. Early treatment can markedly reduce systemic complications and may prevent or delay developmental impairment and ectopia lentis. Untreated disease carries a substantial risk of progressive ocular abnormalities, neurologic impairment, osteoporosis, and potentially fatal thromboembolism.

Complications Major complications include: Ectopia lentis Severe myopia Amblyopia Cataract Pupillary-block glaucoma Retinal detachment Optic atrophy Osteoporosis and fractures Developmental and neuropsychiatric impairment Arterial and venous thromboembolism Stroke Pulmonary embolism Premature death

High-Yield Clinical Pearls Homocystinuria + ectopia lentis + marfanoid habitus + developmental abnormalities + thrombosis = classic CBS deficiency until proven otherwise. The most dangerous complication is thromboembolism. The major ophthalmic clue is progressive myopia followed by ectopia lentis. Unlike traditional teaching, the lens in homocystinuria can dislocate in any direction. Homocystinuria vs Marfan: think thrombosis, developmental impairment, osteoporosis, and disrupted zonules in homocystinuria. Early diagnosis and metabolic treatment can prevent major ocular and systemic morbidity.

Ophthalmology – HIV/AIDS-Related Retinopathies

Basics

Description

Ocular disease is common in patients with advanced human immunodeficiency virus (HIV) infection. The two classic retinal manifestations are:

• HIV microvasculopathy (HIV retinopathy) — the most common retinal manifestation.
• Cytomegalovirus (CMV) retinitis — the most important opportunistic retinal infection and a potentially devastating cause of blindness.

Other ocular manifestations include toxoplasma retinochoroiditis, syphilitic retinitis, acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN), cryptococcosis, intraocular lymphoma, Kaposi sarcoma, and ocular surface squamous neoplasia.

CMV retinitis is a full-thickness necrotizing retinal infection. Progressive retinal necrosis can result in retinal breaks and rhegmatogenous retinal detachment.

Modern antiretroviral therapy (ART) has dramatically reduced the incidence of CMV retinitis and other opportunistic ocular infections.

Epidemiology

Before effective combination ART, CMV retinitis occurred in approximately 25–40% of patients with AIDS during their lifetime.

Its incidence has fallen dramatically in the ART era.

HIV microvasculopathy was historically reported in approximately 50–60% of patients with advanced HIV infection.

CMV retinitis remains particularly important in individuals with advanced immunosuppression, including patients who are unaware of their HIV status, are untreated, or have failed ART.

Risk Factors

The major risk factor for CMV retinitis is severe immunosuppression.

The classic setting is:

CD4 count <50 cells/µL

Risk also increases with:

• High HIV viral load
• Lack of effective ART
• Poor adherence to ART
• Treatment failure or antiviral resistance
• Other causes of profound immunosuppression, including transplantation and chemotherapy

Pathophysiology

HIV Retinopathy

HIV-associated retinal microvasculopathy is thought to result from retinal microvascular injury, immune-complex deposition, endothelial dysfunction, and altered retinal perfusion.

The characteristic lesion is the cotton-wool spot, representing focal retinal nerve fiber layer ischemia.

Unlike CMV retinitis, HIV microvasculopathy does not produce progressive full-thickness retinal necrosis.

CMV Retinitis

CMV reaches the retina primarily through hematogenous dissemination during severe immunosuppression.

The virus infects retinal vascular endothelial and retinal cells, producing:

• Full-thickness retinal necrosis
• Retinal hemorrhage
• Occlusive retinal vasculitis
• Variable choroidal inflammation

Because these patients are profoundly immunosuppressed, there is often surprisingly little vitreous inflammation despite extensive retinal destruction.

Histopathologically, infected cells may contain characteristic enlarged cells with intranuclear viral inclusions.

Etiology

Cytomegalovirus is a member of the herpesvirus family.

CMV infection is extremely common in the general population and usually remains latent after primary infection.

In immunocompetent individuals, primary CMV infection is usually asymptomatic or produces a mononucleosis-like illness.

Profound impairment of cell-mediated immunity allows CMV reactivation and dissemination, including infection of the retina.

HIV Microvasculopathy

The most characteristic finding is cotton-wool spots, particularly around the posterior pole.

Other findings may include:

• Intraretinal hemorrhages
• Microaneurysms
• Telangiectatic vascular abnormalities
• Capillary nonperfusion

Cotton-wool spots generally resolve spontaneously over several weeks.

A key distinction from CMV retinitis is that HIV cotton-wool spots are small, superficial, nonprogressive lesions, whereas CMV lesions enlarge progressively without treatment.

Diagnosis

History

CMV retinitis may be asymptomatic, particularly when disease begins in the peripheral retina.

Symptoms include:

• Floaters
• Blurred or decreased vision
• Photopsias
• Scotomas
• Peripheral visual-field loss

Central disease involving the macula or optic nerve can cause profound visual loss.

Because peripheral CMV retinitis can remain asymptomatic, patients with advanced immunosuppression require a high index of suspicion.

Physical Examination

A complete dilated retinal examination is essential.

Classic CMV retinitis consists of yellow-white areas of retinal whitening and necrosis associated with variable retinal hemorrhage.

The disease characteristically progresses along retinal vascular arcades.

The advancing edge of a lesion is the most active component.

Because of severe immunosuppression, vitritis is typically mild or absent.

Classic Patterns of CMV Retinitis

Fulminant or Hemorrhagic Pattern

This consists of dense areas of retinal whitening and necrosis associated with extensive retinal hemorrhage.

The classic descriptive term is:

“Pizza pie” or “cottage cheese and ketchup” retinopathy.

Granular Pattern

This is characterized by granular peripheral retinal whitening with relatively little hemorrhage.

It may appear less dramatic but remains progressive without treatment.

Frosted-Branch Angiitis

Marked translucent white sheathing of retinal vessels produces the appearance of frost-covered tree branches.

This represents severe retinal vasculitis and may occur with CMV infection.

CMV Retinitis vs HIV Cotton-Wool Spots

This distinction is clinically important.

HIV cotton-wool spots are generally small, superficial, and nonprogressive and resolve spontaneously.

CMV lesions are usually larger, deeper, associated with retinal necrosis and/or hemorrhage, and progressively enlarge over days to weeks if untreated.

A suspicious retinal whitening lesion in a severely immunocompromised patient should therefore be followed closely or investigated for infectious retinitis.

Diagnostic Tests

Laboratory Studies

Important systemic investigations include:

CD4 T-cell count and plasma HIV viral load.

Routine CMV antibody testing is usually unhelpful because prior CMV exposure is extremely common.

Ocular Fluid PCR

When the clinical appearance is atypical or the differential diagnosis includes other infectious retinitides, aqueous or vitreous fluid may undergo PCR testing for CMV DNA.

PCR can also test simultaneously for HSV, VZV, and Toxoplasma gondii when appropriate.

Imaging

Fundus Photography

Serial wide-field or conventional fundus photographs are extremely useful for documenting lesion borders and determining whether retinitis is progressing or responding to therapy.

Optical Coherence Tomography

OCT can document retinal structural damage and is particularly useful when the macula is involved or when complications such as cystoid macular edema or epiretinal membrane develop.

Fluorescein Angiography

Fluorescein angiography may demonstrate vascular leakage and nonperfusion but is generally not required to make the diagnosis of typical CMV retinitis.

Differential Diagnosis

Important alternatives include:

• HIV microvasculopathy/cotton-wool spots
• Toxoplasma retinochoroiditis
• Syphilitic retinitis
• Acute retinal necrosis
• Progressive outer retinal necrosis
• Intraocular lymphoma
• Other infectious or inflammatory retinitides

Progressive Outer Retinal Necrosis

PORN is another particularly severe herpetic retinitis occurring in profoundly immunocompromised patients, most often caused by varicella-zoster virus.

It typically causes rapidly progressive multifocal outer retinal whitening with relatively little hemorrhage, vasculitis, or intraocular inflammation.

Disease can progress extremely rapidly and become bilateral.

PORN carries a particularly poor visual prognosis and requires urgent aggressive antiviral therapy.

Toxoplasma Retinochoroiditis

Ocular toxoplasmosis in patients with AIDS may be unusually severe.

Unlike typical toxoplasmosis in immunocompetent individuals, lesions may be:

• Large
• Multifocal
• Bilateral
• Associated with relatively little vitritis
• Unassociated with an old chorioretinal scar

CNS toxoplasmosis should also be considered in patients with ocular disease.

Treatment

Immediate Priorities

CMV retinitis is a vision-threatening opportunistic infection requiring prompt treatment.

Management has two essential components:

anti-CMV therapy + effective systemic ART.

The choice of antiviral regimen depends on lesion location, severity, systemic disease, renal and hematologic status, previous antiviral exposure, and ability to adhere to therapy.

Valganciclovir

For many patients, oral valganciclovir is preferred because systemic treatment simultaneously treats ocular disease and protects the fellow eye and other organs from CMV dissemination.

A commonly used adult induction regimen is:

Valganciclovir 900 mg orally twice daily with food for 14–21 days

followed by maintenance therapy:

900 mg orally once daily.

Dosage must be adjusted for renal impairment.

Major adverse effects include:

• Neutropenia
• Anemia
• Thrombocytopenia
• Other bone-marrow suppression
• Renal toxicity

CBC and renal function require monitoring.

Sight-Threatening CMV Retinitis

Lesions immediately threatening the macula or optic nerve require especially rapid control.

Current NIH guidance recommends systemic therapy plus an intravitreal injection of ganciclovir or foscarnet for immediate local antiviral concentrations when lesions are immediately sight-threatening.

Systemic treatment remains necessary because an intravitreal injection treats only the injected eye and does not protect the fellow eye or prevent extraocular CMV disease.

Alternative Antiviral Therapy

Alternatives include:

Intravenous ganciclovir — useful when oral treatment cannot be used or absorption is unreliable; major toxicity is bone-marrow suppression.

Foscarnet — useful particularly when ganciclovir resistance or intolerance is suspected. Important adverse effects include nephrotoxicity and electrolyte disturbances, which can occasionally precipitate seizures.

Cidofovir has anti-CMV activity but is now used much less commonly because of substantial toxicity, particularly nephrotoxicity and ocular complications such as uveitis and hypotony.

Antiretroviral Therapy

Effective ART is fundamental.

Immune recovery markedly decreases:

• New CMV retinitis
• Progression and recurrence
• Fellow-eye involvement
• Other opportunistic infections
• Overall morbidity and mortality

ART should be coordinated with clinicians experienced in HIV management.

Maintenance Therapy

Following successful induction, maintenance anti-CMV treatment is continued until sufficient immune recovery has occurred.

Current NIH guidance allows discontinuation of maintenance therapy when CMV lesions have been treated for at least 3–6 months, are inactive, and the CD4 count has remained ≥100 cells/mm³ for at least 3–6 months in response to ART, following consultation with an ophthalmologist.

Maintenance treatment should be restarted if immune function subsequently deteriorates substantially.

Follow-Up

During active CMV retinitis, patients require frequent dilated retinal examinations to document regression of the active borders and detect new lesions.

Serial fundus photography is particularly useful.

Even after immune recovery, ophthalmologic monitoring remains important because complications can occur after the infectious retinitis becomes inactive.

Immune Recovery Uveitis

Immune recovery uveitis (IRU) is an inflammatory complication that may occur after ART restores immune function in a patient with previously treated CMV retinitis.

As the recovering immune system reacts to residual CMV antigens within the eye, patients may develop:

• Anterior uveitis
• Vitritis
• Floaters
• Decreased vision
• Cystoid macular edema
• Epiretinal membrane

Additional complications can include posterior subcapsular cataract and proliferative vitreoretinopathy.

This differs fundamentally from recurrent CMV retinitis: IRU represents inflammation associated with immune recovery rather than uncontrolled viral replication.

Retinal Detachment

CMV causes full-thickness retinal destruction.

As necrotic retina heals, it becomes thin and atrophic, predisposing to multiple retinal breaks and rhegmatogenous retinal detachment.

This was a major cause of visual loss in the pre-ART era and remains an important complication of extensive disease.

Retinal detachment requires prompt vitreoretinal evaluation and frequently surgical repair.

Prognosis

The prognosis of HIV-associated ocular disease has improved dramatically with modern ART.

Visual outcome in CMV retinitis depends heavily on:

• Location and extent of retinal involvement
• Macular or optic nerve involvement
• Speed of diagnosis and treatment
• Degree of immune suppression
• Response to ART
• Development of retinal detachment or IRU

Peripheral disease diagnosed and treated early may preserve excellent central vision.

Disease involving the macula or optic nerve can cause irreversible severe visual loss.

Complications

Major complications include:

• Permanent retinal atrophy
• Macular destruction
• Optic nerve involvement
• Retinal breaks
• Rhegmatogenous retinal detachment
• Bilateral CMV retinitis
• Immune recovery uveitis
• Cystoid macular edema
• Epiretinal membrane
• Cataract
• Proliferative vitreoretinopathy
• Permanent visual-field defects
• Severe irreversible visual loss

High-Yield Clinical Pearls

CD4 <50 cells/µL + retinal whitening/hemorrhage → strongly consider CMV retinitis.

CMV retinitis = full-thickness necrotizing retinitis with surprisingly little vitritis in a profoundly immunosuppressed patient.

Cotton-wool spots are common in HIV retinopathy but are small and nonprogressive; CMV lesions enlarge without treatment.

Macula- or optic nerve-threatening CMV → systemic therapy + intravitreal antiviral treatment.

ART is essential for long-term control.

New inflammation after immune recovery does not necessarily mean recurrent CMV—consider immune recovery uveitis.

Retinal detachment is an important late complication of CMV-induced retinal necrosis.

Ophthalmology – Herpes Zoster Ophthalmicus

Basics

Description

Herpes zoster ophthalmicus (HZO) results from reactivation of latent varicella-zoster virus (VZV) within the ophthalmic division of the trigeminal nerve. It classically produces an acute, painful, unilateral vesicular eruption involving the V1 dermatome.

Ocular inflammation may involve the eyelids, conjunctiva, episclera, sclera, cornea, anterior chamber, iris, retina, optic nerve, or ocular motor nerves.

Occasionally, ocular VZV disease occurs without the characteristic skin eruption. This presentation is called zoster sine herpete.

HZO is clinically important because ocular complications can arise during the acute eruption or weeks to months later, and some may cause permanent visual loss.

Epidemiology

The risk of herpes zoster increases substantially with age because of declining VZV-specific cellular immunity.

HZO represents reactivation involving the ophthalmic division of the trigeminal nerve and occurs more often in older adults and immunocompromised individuals.

Risk Factors

The strongest risk factor is increasing age.

Other important risk factors include impaired cellular immunity due to HIV infection, malignancy, organ transplantation, immunosuppressive medication, chemotherapy, or other causes of immunodeficiency.

General Prevention

Vaccination is the principal preventive measure.

Current CDC recommendations use the recombinant zoster vaccine, Shingrix, rather than the older live Zostavax vaccine. Two doses of Shingrix are recommended for immunocompetent adults 50 years and older and for adults 19 years and older who are or will be immunodeficient or immunosuppressed. Previous herpes zoster does not eliminate the indication for vaccination. Zostavax is no longer available in the United States. 

Vaccination is preventive and is not a treatment for an active episode of HZO.

Pathophysiology

After primary varicella infection, VZV establishes latency within sensory ganglia.

HZO occurs when latent virus reactivates in the trigeminal ganglion, particularly along the ophthalmic division of cranial nerve V.

The virus travels along sensory axons toward the skin and ocular structures, producing a combination of direct viral injury, vascular inflammation, and host immune-mediated tissue damage.

Declining VZV-specific cellular immunity with increasing age helps explain the rising incidence of zoster in older adults.

Diagnosis

History

The illness may begin with a prodrome consisting of fever, malaise, headache, fatigue, and neuropathic pain within the affected dermatome.

Pain may precede the rash by several days and can be described as:

burning, aching, stabbing, lancinating, itching, or hypersensitivity to touch.

The characteristic rash is unilateral and respects the midline.

Patients should be questioned about visual blur, photophobia, ocular redness, diplopia, floaters, reduced vision, and severe eye pain.

Skin Findings

The V1 rash evolves from erythematous macules and papules into vesicles, followed by pustules and eventually crusting.

The forehead, scalp, upper eyelid, and periocular skin may be involved.

Lesions involving the tip, side, or root of the nose suggest involvement of the nasociliary branch of V1 and increase concern for ocular involvement. This is traditionally called Hutchinson sign, although ocular disease can still occur when the sign is absent.

Ophthalmic Examination

All patients with HZO should undergo careful ocular assessment, particularly when ocular symptoms are present. Contemporary reviews recommend ophthalmologic evaluation because potentially serious ocular disease may accompany or follow the rash. 

Examination should include visual acuity, pupils, slit-lamp examination, intraocular pressure, corneal sensation, ocular motility, and dilated fundus examination when indicated.

Early Ocular Findings

Eyelids

The eyelids may show edema, erythema, vesicles, crusting, and temporary ptosis.

Marked swelling may occasionally make examination difficult.

Conjunctiva

Conjunctival involvement may cause hyperemia, follicular or papillary reaction, petechial hemorrhages, vesicular lesions, or pseudomembranes.

Episclera and Sclera

Patients may develop episcleritis, scleritis, sclerokeratitis, or posterior scleritis.

Cornea

Early corneal manifestations include punctate epithelial keratitis and pseudodendrites.

Unlike the classic dendrites of herpes simplex, VZV pseudodendrites are typically elevated epithelial lesions and generally do not have the same classic terminal bulbs.

Later stromal involvement may produce nummular keratitis, stromal inflammation, endothelial disease, or disciform edema.

Anterior Uveitis

HZO can cause a granulomatous or nongranulomatous anterior uveitis with anterior chamber cells, keratic precipitates, and elevated intraocular pressure.

A characteristic late finding is sectoral iris atrophy, caused in part by ischemic damage to iris vessels.

Secondary ocular hypertension or glaucoma may result from trabeculitis, chronic inflammation, synechial changes, or corticosteroid treatment.

Late Corneal Disease

Ocular complications may begin or recur after the skin eruption has resolved.

Late manifestations include delayed pseudodendrites, mucous plaque keratitis, neurotrophic keratopathy, persistent epithelial defects, stromal scarring, chronic edema, lipid deposition, band keratopathy, and corneal ulceration.

Reduced corneal sensation is particularly important because it may result in severe epithelial disease with surprisingly little pain.

Neurotrophic Keratopathy

Damage to trigeminal sensory innervation can substantially reduce corneal sensation.

The resulting neurotrophic cornea may develop:

• Persistent epithelial defects
• Sterile ulceration
• Stromal melting
• Secondary infection
• Corneal perforation

Patients with reduced corneal sensation require particularly careful long-term follow-up.

Retina and Optic Nerve

Serious posterior segment complications include retinal vasculitis, optic neuropathy, acute retinal necrosis (ARN), and progressive outer retinal necrosis (PORN).

ARN is a rapidly progressive necrotizing retinitis accompanied by retinal vasculitis and inflammation.

PORN is particularly associated with profound immunosuppression and may progress extremely rapidly with relatively little intraocular inflammation.

Both require urgent retina specialist evaluation and systemic plus local antiviral therapy.

Neuro-Ophthalmic Manifestations

HZO may affect ocular motor nerves and produce transient or persistent diplopia and ophthalmoplegia.

Cranial nerves III, IV, and VI may be involved.

Rarely, multiple cranial neuropathies may occur in association with orbital apex inflammation, vasculitis, or brainstem disease.

Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is persistent neuropathic pain after the acute rash has healed.

Symptoms may include:

• Constant burning or aching
• Sudden electric or lancinating pains
• Allodynia, where light touch causes pain
• Persistent itching or dysesthesia

Risk increases considerably with age.

Diagnostic Tests and Interpretation

Laboratory Testing

Typical HZO with a characteristic dermatomal rash is primarily a clinical diagnosis, and routine laboratory confirmation is unnecessary.

Testing for an underlying immunodeficiency, including HIV, should be considered when disease occurs in an unusually young patient, is severe or disseminated, or when other clinical features suggest immunosuppression.

PCR

When zoster sine herpete is suspected or when the cause of anterior uveitis, retinitis, or other ocular inflammation is uncertain, PCR of aqueous or vitreous fluid for VZV DNA can help establish the diagnosis.

Differential Diagnosis

Important differential diagnoses include herpes simplex infection, orbital cellulitis, contact dermatitis such as poison ivy exposure, bacterial skin infection, other causes of anterior uveitis, and other necrotizing retinitides.

Treatment

Systemic Antiviral Therapy

Systemic antiviral treatment is the cornerstone of HZO management.

Therapy should be initiated as soon as possible, ideally within 72 hours of rash onset. Early treatment reduces viral replication and is associated with faster rash resolution and fewer ocular complications. Because HZO itself carries a high risk of complications, antiviral treatment may still be appropriate when a patient presents after 72 hours, particularly if new lesions are appearing or ocular disease is present. 

Common oral regimens in immunocompetent adults include:

Valacyclovir 1,000 mg three times daily, famciclovir 500 mg three times daily, or acyclovir 800 mg five times daily, generally for approximately 7–10 days depending on clinical circumstances. Renal adjustment is required when appropriate. 

Treatment should not be delayed while awaiting ophthalmology evaluation.

Renal Considerations

Acyclovir, valacyclovir, and famciclovir require dose adjustment in patients with impaired renal function.

Older adults are particularly vulnerable to drug accumulation, acute kidney injury, and neurotoxicity when renal function is reduced or hydration is inadequate.

Skin Care

Crusted or secondarily infected skin lesions may be treated with appropriate local wound care.

Topical antibiotic ointment may be used when there is concern for secondary bacterial infection of open or crusted lesions.

Ocular Surface Treatment

Lubricating artificial tears and ointment may help when ocular surface irritation or dry eye is present.

Patients with reduced corneal sensation require more aggressive lubrication and close observation for epithelial breakdown.

Topical Corticosteroids

Topical corticosteroids may be appropriate for stromal keratitis, endotheliitis, scleritis in selected circumstances, or anterior uveitis, but they should be used under ophthalmologic supervision and generally with adequate systemic antiviral treatment.

Steroids should not be used indiscriminately for epithelial disease.

Patients receiving corticosteroids require monitoring of intraocular pressure.

Cycloplegia

Cycloplegic agents may be used for significant anterior uveitis to reduce ciliary spasm, relieve pain, and prevent posterior synechiae.

Secondary Glaucoma

Elevated intraocular pressure should be treated with appropriate pressure-lowering medication.

Persistent or difficult-to-control glaucoma may require referral to a glaucoma specialist.

Postherpetic Neuralgia Treatment

Management of PHN may involve agents used for neuropathic pain, such as gabapentin or pregabalin, selected antidepressants, topical lidocaine, and other analgesic strategies.

Persistent or severe neuralgia may warrant referral to neurology or a pain specialist.

Neurotrophic Corneal Disease

Management depends on severity and may include preservative-free lubrication, autologous serum tears, protective contact or scleral lenses in selected cases, amniotic membrane, punctal occlusion, tarsorrhaphy, or other ocular surface procedures.

Corneal thinning or melting requires urgent corneal specialist management.

Acute Retinal Necrosis and PORN

Suspected ARN or PORN is an ophthalmic emergency.

Treatment generally requires aggressive systemic antiviral therapy and frequently intravitreal antiviral therapy.

Immediate retina specialist involvement is essential because progression can be rapid and may lead to retinal detachment and profound vision loss.

Surgery and Other Procedures

A tarsorrhaphy may be necessary for persistent neurotrophic epithelial defects or ulceration that fails conservative treatment.

Small corneal perforations may sometimes be managed with tissue adhesive and protective measures.

Amniotic membrane transplantation or conjunctival flap procedures may be considered for persistent epithelial defects, thinning, or neurotrophic ulceration.

Corneal transplantation may eventually be necessary for visually significant scarring or structural failure, although surgery in a severely neurotrophic eye carries increased risk.

Inpatient Considerations

Hospital admission may be necessary for patients with disseminated zoster, severe immunosuppression, inability to take or administer oral medication, serious neurologic complications, severe posterior segment involvement, or need for intravenous antiviral therapy.

Airway, neurologic, systemic, and ocular complications should be addressed according to severity.

Follow-Up

The timing of follow-up depends on ocular involvement.

Patients with active ocular disease frequently require reevaluation within several days, followed by visits determined by corneal, uveitic, retinal, and intraocular pressure findings.

Long-term follow-up may be necessary because keratitis, uveitis, glaucoma, neurotrophic keratopathy, and retinal disease can develop or recur after the cutaneous rash has resolved.

Patient Education

Patients should understand that the skin eruption may improve while ocular complications continue to develop.

They should seek urgent assessment for new blurred vision, photophobia, increasing redness, worsening eye pain, diplopia, floaters, flashes, or sudden loss of vision.

Patients should also be informed about vaccination after the acute illness has resolved. Current CDC guidance recommends Shingrix even for people who have previously had shingles. 

Prognosis

In otherwise healthy individuals, formation of new skin lesions generally stops within several days and the rash subsequently crusts and heals.

The ocular prognosis varies with the structures involved.

Patients with uncomplicated epithelial disease may recover well, while those developing stromal scarring, glaucoma, neurotrophic keratopathy, optic neuropathy, or necrotizing retinitis can sustain permanent visual loss.

Complications

Important ophthalmic complications include corneal scarring, chronic keratitis, neurotrophic ulceration, corneal perforation, secondary bacterial keratitis, cataract, glaucoma, chronic anterior uveitis, retinal necrosis, retinal detachment, optic neuropathy, ocular motor nerve palsies, and permanent visual impairment.

Systemic and neurologic complications include postherpetic neuralgia and an increased risk of cerebrovascular events after herpes zoster.

The combination of early systemic antiviral treatment and appropriate ophthalmic follow-up is central to reducing preventable morbidity.

Ophthalmology – Herpes Simplex Keratitis

Basics

Description

Herpes simplex keratitis (HSK) is a corneal infection caused most commonly by herpes simplex virus type 1 (HSV-1). Primary HSV infection usually occurs in childhood and may be mild or even clinically inapparent. After the initial infection, the virus becomes latent within sensory ganglia, particularly the trigeminal ganglion, where it can remain dormant for years before reactivation.

Reactivation can produce several forms of ocular disease. Superficial epithelial infection may begin with conjunctival inflammation, punctate epithelial keratitis, or small corneal vesicles that evolve into the classic dendritic epithelial ulcer. A dendritic lesion can enlarge and become a broader geographic ulcer.

Deeper forms of HSV keratitis involve the corneal stroma or endothelium. Stromal disease may be immune-mediated, necrotizing, or associated with anterior uveitis. Disciform keratitis, now generally considered a form of HSV endotheliitis, produces localized stromal edema because of inflammation involving the corneal endothelium.

Repeated episodes can lead to corneal scarring, thinning, irregular astigmatism, reduced corneal sensation, and permanent visual loss. Rarely, severe stromal disease can result in perforation.

Epidemiology

HSV is one of the most important infectious causes of corneal blindness worldwide.

Primary systemic HSV-1 infection is very common, but only a minority of infected individuals develop ocular disease.

Herpetic keratitis may occur as an initial episode or as recurrent disease. Recurrences are particularly important because repeated stromal inflammation is a major cause of permanent corneal scarring and visual impairment.

Risk Factors

Reactivation has historically been associated with events such as febrile illness, upper respiratory infection, ocular trauma, psychological stress, menstruation, and contact lens wear, although not all proposed triggers have been consistently proven.

Prior episodes of ocular HSV are the strongest clinical predictor of future recurrence.

Genetics

Genetic susceptibility probably contributes to the likelihood and severity of HSV ocular disease, but no single genetic pattern explains most cases.

General Prevention

Long-term oral antiviral prophylaxis can reduce recurrent ocular HSV in selected patients, particularly those with previous recurrent stromal keratitis or multiple clinically significant episodes.

Pathophysiology

After primary infection, HSV travels along sensory nerves and establishes latency within the trigeminal ganglion.

During reactivation, infectious virus can travel back down sensory axons toward the eye and produce epithelial disease.

Epithelial keratitis is caused primarily by active viral replication within corneal epithelial cells.

Stromal and endothelial disease have a more complicated pathogenesis. They may involve a combination of viral antigen, persistent or recurrent viral activity, and a host immune response that damages corneal tissue.

Repeated inflammation can cause progressive stromal scarring and loss of corneal transparency.

Commonly Associated Conditions

Patients with ocular HSV may have a history of herpes labialis or vesicular lesions around the mouth, nose, eyelids, or periocular skin.

However, the absence of a history of cold sores does not exclude ocular HSV.

Diagnosis

History

Patients may report ocular irritation, foreign-body sensation, pain, redness, photophobia, tearing, or blurred vision.

Blurred vision is more likely when the lesion involves the visual axis or when stromal edema is present.

A previous episode of unilateral red eye, dendritic keratitis, unexplained corneal scarring, or recurrent herpetic disease can be diagnostically helpful.

Physical Examination

A careful slit-lamp examination is essential.

Vital dyes such as fluorescein and, when appropriate, rose bengal or lissamine green can help delineate epithelial lesions.

Corneal sensation should also be assessed because reduced corneal sensitivity is common after recurrent HSV disease.

Epithelial Herpes Simplex Keratitis

The classic lesion is a dendritic ulcer.

It consists of a branching epithelial defect with terminal bulbs.

The central ulcerated portion stains with fluorescein, while the swollen epithelial borders may stain with rose bengal or lissamine green.

Dendrites can enlarge and merge into a broader irregular geographic epithelial ulcer, particularly in patients who have received inappropriate topical corticosteroids.

Stromal Herpes Simplex Keratitis

Stromal disease may be non-necrotizing immune stromal keratitis or necrotizing stromal keratitis.

Immune stromal disease causes stromal haze, edema, and sometimes vascularization without a major epithelial defect.

Necrotizing stromal keratitis is more severe and may involve active viral infection, stromal ulceration, marked inflammation, thinning, and risk of perforation.

HSV Endotheliitis / Disciform Keratitis

HSV can produce endothelial inflammation resulting in disc-shaped stromal edema, keratic precipitates, and sometimes anterior chamber inflammation.

This has historically been termed disciform keratitis.

The corneal epithelium may initially remain intact.

HSV Anterior Uveitis

HSV can also cause anterior uveitis.

Possible findings include keratic precipitates, anterior chamber cells and flare, iris atrophy, and elevated intraocular pressure.

The combination of unilateral anterior uveitis, increased IOP, and sectoral iris atrophy should raise suspicion for herpetic disease.

Diagnostic Tests and Interpretation

Laboratory Testing

Typical dendritic epithelial keratitis is usually diagnosed clinically and generally does not require laboratory confirmation.

When the presentation is atypical, recurrent, severe, or involves deeper structures, laboratory testing can be useful.

PCR of corneal, aqueous, or other ocular samples may detect HSV DNA and can help distinguish HSV from VZV, CMV, and other causes.

Viral culture is less commonly required.

Imaging

Routine imaging is not generally necessary for uncomplicated HSV keratitis.

Anterior-segment photography or OCT may occasionally be useful for documenting severe or chronic corneal disease.

Pathological Findings

Corneal biopsy is rarely necessary.

When tissue is examined, findings vary depending on whether disease involves the epithelium, stroma, or endothelium and may include epithelial necrosis, inflammatory infiltration, stromal scarring, and viral cytopathic changes.

Differential Diagnosis

Important differential diagnoses include herpes zoster keratitis, Acanthamoeba keratitis, fungal keratitis, bacterial keratitis, Epstein-Barr-associated disease, neurotrophic epithelial defects, and other causes of persistent or atypical corneal ulceration.

HSV dendrites should also be distinguished from pseudodendrites, particularly those caused by herpes zoster.

Treatment

Treatment depends on which corneal layer is involved.

Epithelial Keratitis

Active epithelial HSV disease is treated with antiviral therapy.

Topical options include ganciclovir gel or, in some settings, trifluridine.

Oral antivirals such as acyclovir or valacyclovir are also effective and are often used because they are convenient and avoid topical epithelial toxicity.

Topical corticosteroids should not be used for active epithelial dendritic or geographic keratitis unless there is a specific specialist-directed indication with adequate antiviral coverage.

Stromal Keratitis

Immune-mediated stromal keratitis is treated with topical corticosteroids combined with antiviral coverage.

Steroids are tapered slowly according to clinical response because rapid withdrawal can precipitate recurrence.

Oral antiviral therapy is often used during steroid treatment.

Necrotizing Stromal Keratitis

Necrotizing disease requires aggressive antiviral therapy and specialist management.

Topical corticosteroids may be used cautiously when indicated, but only with adequate antiviral coverage because active viral replication may be present.

Endotheliitis and Uveitis

HSV endotheliitis and anterior uveitis are commonly treated with topical corticosteroids plus systemic or topical antiviral therapy.

Elevated intraocular pressure should be treated appropriately.

Because prolonged steroid therapy may be necessary in some cases, careful monitoring for glaucoma and cataract is required.

Long-Term Antiviral Prophylaxis

Suppressive oral antiviral therapy can be considered in patients with recurrent disease, especially those with recurrent stromal keratitis, previous corneal transplantation for HSV, or frequent vision-threatening recurrences.

Long-term prophylaxis reduces the risk of recurrent ocular HSV while therapy is continued.

Surgery

Severe corneal scarring, irregularity, thinning, or perforation may eventually require surgical treatment.

Penetrating keratoplasty or selected lamellar corneal transplantation procedures may be used for visually significant scarring or structural compromise.

Active inflammation should ideally be controlled before elective corneal transplantation because recurrent HSV can affect the graft.

Antiviral prophylaxis is commonly used around and after keratoplasty in patients with prior HSV disease.

Follow-Up

Patients with active dendritic keratitis require serial slit-lamp examinations until the epithelial defect has healed.

Stromal keratitis, endotheliitis, and uveitis usually require longer and closer follow-up, particularly during corticosteroid tapering.

Patients with recurrent disease may require lifelong intermittent ophthalmic monitoring.

Patient Monitoring

Monitoring should include visual acuity, corneal epithelial integrity, stromal inflammation, corneal thickness, corneal sensation, intraocular pressure, and anterior chamber inflammation.

Patients receiving topical corticosteroids should be monitored for steroid-related ocular hypertension and cataract.

Patient Education

Patients should understand that HSV remains latent in the nervous system and may recur even years later.

They should be instructed not to self-treat recurrent red eye with leftover steroid drops because steroids can worsen active epithelial HSV dramatically.

Any recurrence of unilateral redness, pain, photophobia, or decreased vision should prompt an early ophthalmic examination.

Pediatric Considerations

Infants and children can develop ocular HSV after maternal antibodies decline.

Because herpetic epithelial disease may worsen rapidly with corticosteroids, topical steroids should not be used empirically for an unexplained red eye in a child without appropriate ophthalmic examination.

Children also require careful monitoring for amblyopia if corneal scarring or irregular astigmatism develops.

Prognosis

The prognosis is generally good for an initial episode of epithelial dendritic keratitis when promptly treated with antiviral therapy.

The prognosis becomes more guarded with recurrent stromal keratitis, endotheliitis, corneal neovascularization, thinning, or scarring.

Repeated stromal episodes are the major cause of permanent visual morbidity.

Complications

Complications include recurrent epithelial keratitis, neurotrophic keratopathy, stromal scarring, corneal neovascularization, irregular astigmatism, corneal thinning, secondary glaucoma, cataract, and rarely corneal perforation.

The greatest risk of substantial long-term vision loss comes from recurrent stromal HSV disease rather than from a single uncomplicated dendritic epithelial episode.

Ophthalmology – Hemangioma in Children

Basics

Description

Infantile hemangioma is a benign vascular tumor of infancy that can involve the eyelids, orbit, or surrounding periorbital tissues. It characteristically undergoes a phase of rapid postnatal growth followed by gradual spontaneous involution.

The main ophthalmic concern is not the tumor itself but its ability to interfere with visual development. A periocular hemangioma can obstruct the visual axis, induce astigmatism or anisometropia, produce ptosis, or cause proptosis, all of which can lead to amblyopia.

Epidemiology

Infantile hemangiomas occur in approximately 1–2.6% of newborns. They are among the most common benign vascular tumors of infancy.

Most lesions become apparent during the first few weeks of life and enlarge rapidly during the first several months.

Risk Factors

Important risk factors include female sex, Caucasian race, prematurity, and a positive family history. An association with chorionic villus sampling has also been reported.

Genetics

Most infantile hemangiomas are sporadic and have no clear hereditary basis.

Rare familial forms have been reported with an autosomal dominant pattern with variable expression, including linkage to chromosome 5q31–33.

Genetic counseling may be appropriate in clearly familial cases or when the child has features of a syndromic vascular disorder.

Pathophysiology

During the proliferative phase, hemangiomas show increased endothelial cell growth and high expression of vascular endothelial growth factor (VEGF) and other proangiogenic factors.

As the lesion enters its involutional phase, angiogenic signaling decreases and endothelial cells undergo apoptosis, allowing the vascular tumor to progressively regress.

Etiology

Infantile hemangiomas represent a benign proliferation of blood vessels. They are often described as hamartomatous vascular growths, although modern classification considers infantile hemangioma a true benign vascular tumor with a characteristic growth and involution cycle.

Commonly Associated Conditions

Large or segmental facial hemangiomas may be associated with PHACE syndrome, which includes posterior fossa abnormalities, large facial hemangiomas, arterial anomalies, cardiac abnormalities including coarctation of the aorta, eye abnormalities, and sternal or ventral developmental defects.

Very large vascular tumors associated with thrombocytopenia and consumptive coagulopathy require urgent evaluation. Importantly, classic Kasabach-Merritt phenomenon is generally associated with kaposiform hemangioendothelioma or tufted angioma rather than typical infantile hemangioma.

Other vascular or developmental syndromes that may enter the differential include Maffucci syndrome and Klippel-Trenaunay syndrome.

Diagnosis

History

The characteristic history is of a vascular lesion that appears shortly after birth and undergoes rapid growth during the first several months of life.

A lesion may initially appear as a small red macule or may not be obvious at birth.

Growth is usually most rapid during infancy. Spontaneous involution begins later, often during the second year of life, and may continue for several years.

Parents should be asked about feeding or breathing difficulty, noisy breathing, skin lesions elsewhere on the body, bleeding, bruising, and any change in fixation behavior.

Physical Examination

A complete ocular examination is required.

Superficial lesions are typically bright red, whereas deeper subcutaneous lesions may have a bluish-purple appearance.

Hemangiomas are generally compressible and may blanch with pressure. They may enlarge or become more violaceous during crying, straining, or dependent positioning.

The size and location of the lesion should be documented, preferably with serial photography.

Particular attention should be paid to whether the lesion obstructs the visual axis, induces ptosis, or causes an abnormal head posture.

Visual Development

Cycloplegic refraction is important because periocular hemangiomas can induce significant astigmatism, anisometropia, or myopic shift.

Even a lesion that does not directly cover the pupil can produce amblyopia through corneal distortion.

Fixation preference, ocular alignment, and age-appropriate visual acuity should therefore be monitored closely.

Orbital Involvement

The examination should assess for proptosis, globe displacement, optic nerve compromise, restricted ocular motility, or fullness of the temporal fossa.

An afferent pupillary defect or reduced vision raises concern for optic nerve compression or another serious orbital complication.

Diagnostic Tests and Interpretation

Laboratory Testing

No laboratory testing is necessary for a typical isolated lesion.

A complete blood count with platelet count may be appropriate in a child with a very large vascular tumor, petechiae, bleeding, or concern for a consumptive coagulopathy.

Ultrasound

Ultrasonography can demonstrate a compressible vascular lesion with internal blood flow.

Doppler imaging can help confirm the vascular nature of the mass.

MRI

MRI is preferred when deeper orbital involvement, extensive facial disease, PHACE syndrome, or possible intracranial extension is suspected.

It provides excellent visualization of the lesion’s extent and relationship to the orbit, brain, and vascular structures without ionizing radiation.

CT

CT may demonstrate associated bone changes but is generally avoided when MRI can provide the necessary information because of radiation exposure in infants.

Biopsy

Biopsy is rarely needed when the clinical appearance is typical.

It may be considered when an atypical rapidly growing orbital mass raises concern for rhabdomyosarcoma or another neoplasm.

Pathological Findings

During the proliferative phase, lesions show dense proliferation of small capillary-sized vessels lined by plump endothelial cells, often accompanied by pericytes and other stromal cells.

During involution, endothelial proliferation declines and vascular tissue is progressively replaced by fibrofatty tissue.

Differential Diagnosis

Important differential diagnoses include rhabdomyosarcoma, lymphatic malformation, venous malformation, congenital vascular malformation, port-wine stain, arteriovenous malformation, neuroblastoma metastasis, encephalocele, and dacryocystocele.

A port-wine stain differs from an infantile hemangioma because it is a capillary malformation present at birth that generally grows proportionally with the child rather than undergoing a rapid proliferative phase followed by spontaneous involution.

Treatment

Many periocular hemangiomas can be observed if they do not threaten vision, cause significant disfigurement, ulcerate, or produce other functional complications.

Treatment becomes necessary when there is risk of amblyopia, visual axis obstruction, rapidly progressive orbital disease, significant astigmatism or anisometropia, optic nerve compression, ulceration, or major cosmetic deformity.

Amblyopia Management

Amblyopia should be treated aggressively when present.

Management may include full spectacle correction, patching of the better-seeing eye, or atropine penalization, depending on the child’s age and the degree of visual asymmetry.

Correction of refractive error is essential even when tumor-directed therapy is being used.

Beta-Blocker Therapy

Propranolol is now the standard first-line systemic treatment for most vision-threatening infantile hemangiomas.

It can produce rapid softening, color change, and shrinkage of the lesion.

Treatment is usually coordinated with pediatrics or another clinician experienced in infantile hemangioma therapy because propranolol can cause bradycardia, hypotension, bronchospasm, and hypoglycemia, particularly in young infants.

Dosing and initiation protocols vary according to age, weight, comorbidities, and local practice.

Contraindications or important precautions include significant bronchospastic disease, certain cardiac abnormalities, and some cerebrovascular abnormalities, particularly in patients being evaluated for PHACE syndrome.

Topical Timolol

Topical timolol may be useful for selected small, superficial periocular hemangiomas.

Because systemic absorption can occur, especially in infants, it should still be used with appropriate caution and monitoring.

Deep orbital lesions generally require systemic rather than topical therapy.

Corticosteroids

Systemic corticosteroids were historically the principal treatment before the widespread use of propranolol.

They may still be considered when beta-blockers are contraindicated or ineffective.

Potential complications of prolonged systemic corticosteroid therapy include growth suppression, adrenal suppression, immunosuppression, hypertension, and Cushingoid changes.

Intralesional corticosteroid injection is now used much less often because of serious potential complications, including retinal artery occlusion, skin necrosis, depigmentation, and subcutaneous fat atrophy.

Other Medical Therapies

Interferon alfa is rarely used today because of significant neurologic and systemic toxicity.

Other systemic agents may be considered for unusually aggressive or treatment-resistant vascular tumors under specialist guidance, but these are not routine first-line therapies for typical infantile hemangioma.

Laser Treatment

Laser therapy can be helpful for selected superficial residual or ulcerated lesions, particularly when treatment is directed primarily at surface components.

Pulsed dye laser is generally more relevant than older destructive laser techniques.

Laser therapy is not usually sufficient for a deep orbital hemangioma.

Surgery

Surgery is rarely required during the proliferative phase because many lesions respond well to medical therapy and later involute spontaneously.

Partial or complete excision may be considered for sight-threatening lesions resistant to medical treatment, lesions producing persistent mechanical problems, or residual deformity after involution.

Reconstructive or cosmetic surgery is often best deferred until involution has substantially completed when possible.

Referral

Urgent otolaryngology evaluation is indicated when an airway hemangioma is suspected.

Genetics evaluation is appropriate for suspected PHACE syndrome, familial disease, or other syndromic findings.

Hematology evaluation is required if there is thrombocytopenia or concern for a consumptive coagulopathy.

Neurology, neurosurgery, cardiology, or vascular anomaly specialists may be required when there is intracranial, arterial, cardiac, or extensive orbital involvement.

Inpatient Considerations

Hospitalization may be appropriate for infants with airway compromise, severe systemic disease, or significant cardiorespiratory risk during initiation of systemic beta-blocker therapy.

Whether propranolol is started as an inpatient or outpatient depends on the child’s age, medical status, treatment protocol, and local practice.

Follow-Up

Close ophthalmic follow-up is essential during the proliferative phase.

Monitoring should include visual acuity or fixation behavior, cycloplegic refraction, ocular alignment, lesion size, ptosis, globe position, and optic nerve function.

Rebound growth can occur after discontinuation of beta-blocker or corticosteroid therapy, so follow-up should continue after treatment is stopped.

Once active growth has ceased, follow-up can be adjusted according to residual refractive error, amblyopia, and cosmetic concerns.

Patient Monitoring

The two principal ophthalmic monitoring targets are vision and refraction.

Children with periocular hemangiomas are particularly vulnerable to amblyopia from astigmatism, anisometropia, ptosis, or direct visual-axis obstruction.

Psychosocial effects of a visible facial lesion should also be considered as the child grows.

Patient Education

Parents should understand that many hemangiomas eventually involute spontaneously, but lesions near the eye require closer observation because visual development can be permanently affected.

They should seek prompt medical attention for wheezing, stridor, feeding or breathing difficulty, sudden lesion enlargement, bleeding, petechiae, reduced fixation, or increasing eyelid closure.

Families should also understand that even after the lesion shrinks, refractive error and amblyopia may persist and require continued treatment.

Prognosis

The overall prognosis is very good.

Many infantile hemangiomas undergo substantial spontaneous involution during childhood.

The visual prognosis depends mainly on whether amblyopia is prevented or treated early.

Periocular hemangiomas frequently induce astigmatic or anisometropic refractive errors, and untreated refractive asymmetry can result in permanent reduction of vision.

Complications

Potential complications include amblyopia, induced astigmatism, anisometropia, ptosis, proptosis, optic nerve compression, corneal exposure, residual eyelid deformity, skin atrophy, scarring, hypopigmentation, facial asymmetry, and psychosocial distress.

The most important preventable ophthalmic complication is permanent amblyopia from untreated visual deprivation or refractive error.

Ophthalmology – Hard Exudates

Basics

Description

Hard exudates are yellow-white retinal deposits composed mainly of lipid and protein that leak from incompetent retinal, choroidal, or optic disc vessels. They usually accumulate in the outer plexiform layer of the retina, although in more severe disease they may extend into other retinal layers or even the subretinal space.

Hard exudates are not a disease themselves. They are an ophthalmoscopic sign of underlying vascular leakage, most commonly associated with retinal vascular disorders.

Epidemiology

The true incidence is difficult to quantify because hard exudates occur as a manifestation of many different ocular and systemic diseases.

Risk Factors

Important risk factors include systemic vascular conditions such as diabetes mellitus, hypertension, and dyslipidemia.

These conditions increase the likelihood of retinal vascular leakage and therefore the development of hard exudates.

General Prevention

Good control of blood glucose, blood pressure, and serum lipid levels reduces the risk and severity of several diseases associated with hard exudates.

These include diabetic retinopathy, hypertensive retinopathy, retinal vascular occlusions, and retinal arterial macroaneurysms.

Pathophysiology

Hard exudates form when retinal or choroidal vessels become abnormally permeable.

Breakdown of the vascular barrier allows lipoproteins, serum proteins, and fluid to escape into the surrounding retinal tissue.

The fluid component may eventually be resorbed, while the lipid-rich material remains behind as visible yellow-white deposits.

For this reason, hard exudates are commonly associated with retinal or macular edema.

Etiology

A wide variety of retinal vascular and inflammatory disorders can produce hard exudates.

Common causes include diabetic retinopathy, hypertensive retinopathy, retinal vein occlusion, retinal arterial macroaneurysm, radiation retinopathy, Coats disease, retinal capillary hemangioma, neuroretinitis, and choroidal neovascularization, including that associated with age-related macular degeneration.

Commonly Associated Conditions

Macular edema is one of the most important associated findings.

When hard exudates are present near or within the fovea, vision may be significantly reduced.

Diagnosis

History

Patients may be asymptomatic if the deposits are outside the macula.

When the macula is involved, they may complain of blurred or decreased central vision.

A detailed medical history should assess for diabetes, hypertension, hyperlipidemia, vascular disease, previous radiation treatment, and other conditions associated with retinal vascular leakage.

Physical Examination

Dilated fundus examination reveals discrete yellow-white retinal deposits, usually most prominent in the posterior pole.

Their configuration may vary.

They may appear globular, linear, clustered, circinate, or confluent.

A circinate pattern refers to a ring or partial ring of hard exudates surrounding a leaking microaneurysm or other vascular abnormality.

When exudates form a radial pattern around the macula, a macular star may be present. This is classically associated with neuroretinitis and may also occur in severe hypertensive retinopathy.

Diagnostic Tests and Interpretation

Hard exudates are usually diagnosed clinically during fundus examination, but imaging is often useful for determining their cause and associated complications.

Optical Coherence Tomography

OCT is particularly useful for identifying and quantifying macular edema, subretinal fluid, and structural retinal changes associated with the exudates.

Hyperreflective foci corresponding to lipid deposits may also be visible.

Fluorescein Angiography

Fluorescein angiography can help identify the source of vascular leakage, such as microaneurysms, retinal neovascularization, macroaneurysms, or other abnormal vessels.

The hard exudates themselves generally do not leak; rather, the associated abnormal vessels demonstrate leakage.

Differential Diagnosis

Hard exudates should be distinguished from other yellow or white retinal lesions.

Important alternatives include cotton-wool spots, myelinated retinal nerve fibers, drusen, retinitis, chorioretinal atrophy, Hollenhorst plaques, and crystalline retinopathies.

Cotton-wool spots are typically softer, fluffier, and located in the retinal nerve fiber layer, whereas hard exudates are more sharply defined and yellow.

Drusen are located beneath the retinal pigment epithelium rather than within the neurosensory retina.

Treatment

Treatment is directed at the underlying cause of vascular leakage, not at the hard exudates themselves.

As vascular permeability and edema improve, the exudates may gradually be resorbed.

Systemic Treatment

Patients with diabetes, hypertension, or dyslipidemia require appropriate systemic control.

Improved management of these conditions can reduce further leakage and limit progression.

Diabetic Retinopathy and Diabetic Macular Edema

Diabetic retinopathy is one of the most common causes of hard exudates.

When hard exudates are associated with diabetic macular edema, treatment of the edema may include intravitreal anti-VEGF therapy, and in selected situations laser photocoagulation or intraocular corticosteroid therapy.

Successful treatment of the underlying leakage frequently results in gradual reduction of the hard exudates.

Other Causes

Retinal vein occlusion, choroidal neovascularization, retinal arterial macroaneurysm, Coats disease, and other vascular disorders should be treated according to their specific underlying pathology.

For example, anti-VEGF therapy may be appropriate for vascular leakage associated with retinal vein occlusion or choroidal neovascularization.

Surgery and Other Procedures

Surgical removal of hard exudates is rarely performed.

Historically, submacular surgery has been attempted in selected cases of massive subfoveal lipid deposition, particularly in severe diabetic disease, but this is not routine management.

Ongoing Care

Follow-up should focus on the underlying retinal disorder and the presence or progression of macular edema.

Serial fundus photography and OCT can be useful for documenting changes in exudation and retinal thickness.

Systemic vascular risk factors should also be reassessed regularly.

Prognosis

The visual prognosis depends primarily on the underlying disease and the location of the exudates.

Hard exudates outside the macula may have little effect on vision.

When they accumulate within or beneath the fovea, especially in association with chronic edema, permanent photoreceptor damage and reduced central vision may result.

Complications

The most important associated complication is macular edema.

Long-standing dense lipid deposition in the central macula may lead to permanent visual impairment even after the vascular leakage has been controlled.

In neuroretinitis, an afferent pupillary defect may occur during the acute phase, although it can improve as the underlying optic nerve inflammation resolves.

Ophthalmology – Visual Hallucinations

Basics

Description

Visual hallucinations are visual perceptions that occur without a corresponding external visual stimulus. They are not a diagnosis by themselves, but rather a symptom that may arise from ophthalmic, neurologic, metabolic, toxic, medication-related, or psychiatric conditions.

Hallucinations may be simple, such as flashes, colored lights, sparkles, geometric shapes, or patterns, or complex, such as seeing people, animals, faces, flowers, or complete scenes.

An especially important ophthalmic form is Charles Bonnet syndrome (CBS). In CBS, patients with significant visual impairment experience vivid, often complex visual hallucinations while retaining insight that the images are not real. Cognition is otherwise relatively preserved.

Epidemiology

The frequency of visual hallucinations varies considerably depending on the patient population and underlying disorder.

They are common in patients with dementia, delirium, metabolic encephalopathy, severe visual impairment, and certain neurologic disorders.

Among ophthalmic populations, visual hallucinations are particularly associated with older age and substantial reduction in visual acuity. Charles Bonnet syndrome is probably underrecognized because many patients are reluctant to report hallucinations for fear of being considered psychiatrically ill.

Risk Factors

Important risk factors include significant visual loss, advanced age, social isolation, dementia, psychiatric disease, alcohol or illicit drug use, medication exposure, and metabolic illness.

Women have been reported to experience visual hallucinations somewhat more frequently in some populations.

Pathophysiology

The mechanism depends on the underlying cause.

In patients with severe visual impairment, reduced sensory input to the visual cortex may produce a release phenomenon or deafferentation phenomenon. Normally, continuous external visual input suppresses internally generated visual imagery. When visual input is markedly reduced, previously suppressed visual cortical activity may emerge as hallucinations.

This mechanism is believed to contribute to Charles Bonnet syndrome.

In epilepsy, abnormal electrical activity affecting the occipital or temporal cortex can produce ictal visual hallucinations.

Migraine aura is related to cortical spreading depression, a wave of neuronal activation followed by suppression that commonly spreads through the visual cortex.

Hallucinogenic drugs and other toxic agents may alter serotonergic, limbic, and cortical pathways.

Etiology

Visual hallucinations can arise from several major categories of disease.

Ophthalmic Causes

Severe visual impairment from conditions such as advanced cataract, glaucoma, retinal disease, optic neuropathy, or loss of an eye can produce release hallucinations and Charles Bonnet syndrome.

Neurologic Causes

Neurologic causes include epilepsy, migraine, narcolepsy, Parkinson disease, Alzheimer disease, dementia with Lewy bodies, brainstem disease, thalamic disease, occipital or temporal lobe lesions, stroke, and other structural brain disorders.

Toxic and Metabolic Causes

Hallucinations may occur with drug intoxication, medication adverse effects, alcohol intoxication or withdrawal, metabolic encephalopathy, hypoxia, organ failure, and delirium.

Psychiatric Causes

Psychotic illnesses such as schizophrenia can include visual hallucinations, although auditory hallucinations are more typical.

Commonly Associated Conditions

Important associations include visual deprivation, dementia, Parkinson disease, dementia with Lewy bodies, delirium, delirium tremens, psychosis, substance use, medication toxicity, seizures, and migraine.

Diagnosis

History

A detailed description of the visual experience is essential.

Patients should be asked about:

• What exactly they see
• Whether the images are formed or unformed
• Whether the images move
• How long they last
• How often they occur
• Whether they affect one or both visual fields
• Whether they occur with eyes open, closed, or both
• Whether the patient knows the images are not real
• Associated headache, weakness, confusion, seizure activity, sleep disturbance, or other neurologic symptoms
• Visual impairment or recent worsening of vision
• Current medications
• Alcohol and illicit drug use
• Recent withdrawal from alcohol or other substances

Patients may avoid mentioning hallucinations unless asked directly because they fear being labeled as mentally ill.

That makes direct, nonjudgmental questioning especially important in patients with significant visual impairment or dementia.

Physical Examination

A full ophthalmic and neurologic examination is appropriate.

The eye examination should include visual acuity, pupillary responses, visual fields, ocular motility, anterior segment examination, and fundus examination.

The neurologic examination should assess mental status, cranial nerves, motor function, sensation, coordination, gait, and signs of focal neurologic disease.

Diagnostic Tests and Interpretation

Testing should be directed by the suspected cause rather than performed routinely in every patient.

Laboratory Testing

When toxic or metabolic disease is suspected, laboratory testing may include metabolic studies, toxicology testing, medication levels, and other investigations guided by the clinical presentation.

Electroencephalography

EEG may be useful when seizure activity or encephalopathy is suspected.

Brief, stereotyped, recurrent hallucinations, particularly when accompanied by altered awareness or other seizure manifestations, increase suspicion for an epileptic cause.

Neuroimaging

MRI of the brain is appropriate when a structural brainstem, thalamic, temporal, or occipital lesion is suspected.

Acute presentations may require urgent neuroimaging depending on associated neurologic findings.

Differential Diagnosis

Visual hallucinations must be distinguished from several related phenomena.

Delusions

A delusion is a fixed false belief that the patient believes to be true. It is not a sensory perception.

Confabulation

Confabulation refers to fabricated or distorted memories, often occurring in patients with memory impairment.

Visual Illusions

An illusion is a distorted perception of something that is actually present.

Examples include metamorphopsia, polyopia, palinopsia, or misinterpretation of real objects.

Hallucinations

A hallucination occurs when a person sees something without any corresponding external object.

Simple Visual Hallucinations

Simple hallucinations consist of elementary visual phenomena such as:

flashes, sparkles, colored lights, geometric shapes, patterns, halos, or phosphenes.

They are more often associated with occipital cortex dysfunction, migraine, retinal disease, or seizure activity.

Complex Visual Hallucinations

Complex hallucinations include formed images such as:

people, animals, faces, buildings, flowers, or complete scenes.

They may occur with Charles Bonnet syndrome, temporal lobe disorders, dementia, delirium, or brainstem disease.

Charles Bonnet Syndrome

Charles Bonnet syndrome consists of recurrent, often vivid and detailed visual hallucinations occurring in a person with significant visual impairment but without primary psychosis or major cognitive impairment.

Patients typically retain insight and recognize that the images are not actually present.

The hallucinations are often nonthreatening and may include people, animals, buildings, patterns, or scenery.

CBS is associated with a wide range of causes of reduced vision, including macular degeneration, glaucoma, cataract, diabetic eye disease, retinal degeneration, and optic neuropathy.

Reassurance is especially important because many patients fear that hallucinations indicate dementia or psychiatric illness.

Ictal Hallucinations

Visual hallucinations caused by seizures tend to be brief, stereotyped, and recurrent.

Occipital seizures usually produce simple unformed visual phenomena, whereas temporal lobe seizure activity is more likely to produce complex formed images.

Peduncular Hallucinosis

Peduncular hallucinosis consists of vivid, colorful, often highly detailed visual hallucinations associated with lesions involving the midbrain, pons, or thalamus.

Patients may maintain insight.

The mechanism is thought to involve disruption of pathways regulating visual sensory processing and arousal.

Migraine Aura

Migraine aura frequently causes transient visual phenomena such as:

flashing lights, scintillating scotomas, zigzag lines, fortification patterns, or expanding areas of visual disturbance.

These phenomena usually evolve over minutes rather than appearing instantaneously.

Alice in Wonderland Syndrome

Alice in Wonderland syndrome is a rare perceptual disturbance often associated with migraine, particularly in children.

Patients may experience metamorphopsia, altered body image, changes in perceived object size, or distortion of spatial relationships and perspective.

Hypnagogic Hallucinations

Hypnagogic hallucinations occur while a person is falling asleep.

They can be vivid and dreamlike and are particularly associated with narcolepsy, although they can occur in otherwise healthy individuals.

Dementia-Related Hallucinations

Visual hallucinations are common in several neurodegenerative disorders.

They are especially characteristic of dementia with Lewy bodies, where recurrent detailed visual hallucinations may occur together with progressive cognitive impairment, fluctuating attention, parkinsonism, and REM sleep behavior disorder.

Patients with Lewy body dementia can be highly sensitive to antipsychotic medications, an important management consideration.

Visual hallucinations also occur in Parkinson disease and Alzheimer disease.

Pediatric Considerations

In children, possible causes include seizures, migraine, sleep disorders, medication effects, substance exposure, psychiatric disease, and night terrors.

Alice in Wonderland syndrome is particularly associated with childhood migraine.

A careful neurologic and medication history is important.

Geriatric Considerations

Older adults may experience visual hallucinations because of visual impairment, dementia, delirium, medication toxicity, Parkinson disease, or Lewy body dementia.

Seeing people, animals, or detailed scenes is particularly common in both Charles Bonnet syndrome and dementia-associated hallucinations.

Distinguishing between these conditions requires assessment of cognition, insight, visual function, and neurologic status.

Treatment

Treatment depends entirely on the underlying cause.

There is no single medication appropriate for all visual hallucinations.

Charles Bonnet Syndrome Treatment

The main treatments for CBS are reassurance and optimization of vision.

Patients should be told that the hallucinations can occur as a consequence of visual deprivation and do not by themselves imply psychosis or dementia.

Correctable causes of visual impairment should be treated when possible.

Improving environmental lighting, increasing social engagement, and changing visual fixation or blinking may sometimes interrupt episodes.

Medication is rarely required unless hallucinations are persistent and severely distressing.

Seizure-Related Hallucinations

Hallucinations caused by epilepsy should be treated with appropriate antiseizure therapy under neurologic supervision.

Migraine

Migraine-associated visual phenomena are treated according to standard migraine management when attacks are frequent or disabling.

Delirium and Metabolic Disease

When hallucinations occur in delirium or metabolic encephalopathy, the priority is correction of the underlying medical abnormality.

Potential causes include infection, electrolyte disturbance, organ failure, hypoxia, medication toxicity, or withdrawal states.

Psychiatric Disease

Antipsychotic treatment may be appropriate when hallucinations arise from psychotic illness, severe agitation, or certain dementia syndromes.

Medication choice must be individualized according to the patient’s diagnosis, previous treatment response, comorbidities, potential drug interactions, and adverse-effect profile.

Dementia With Lewy Bodies

Mild hallucinations that are not distressing may require no drug treatment.

Cholinesterase inhibitors may improve hallucinations and cognitive symptoms in some patients.

Extreme caution is required with antipsychotic drugs because patients with dementia with Lewy bodies can develop profound neuroleptic sensitivity, including worsening parkinsonism, altered consciousness, or potentially life-threatening reactions.

Management should therefore be coordinated with neurology, geriatrics, or psychiatry.

Referral

Referral depends on the suspected cause.

An ophthalmologist should evaluate patients with significant visual loss or suspected ocular disease.

A neurologist should evaluate suspected seizures, migraine with unusual features, structural neurologic disease, Parkinsonism, or focal neurologic findings.

A psychiatrist may be appropriate when primary psychiatric disease is suspected or hallucinations are severely distressing and require psychotropic treatment.

Inpatient Considerations

Hospitalization may be required when hallucinations occur in the setting of delirium, severe metabolic disturbance, intoxication or withdrawal, severe agitation, or dangerous behavior.

Treatment should focus on correcting the underlying metabolic or toxic abnormality and ensuring patient safety.

Patients with severe agitation require careful monitoring to prevent injury to themselves or others.

Follow-Up

Follow-up should be tailored to the underlying condition.

Medication lists should be reviewed regularly because medications can trigger or worsen hallucinations.

Patients with Charles Bonnet syndrome benefit from periodic ophthalmic follow-up to optimize remaining visual function.

Patients with neurologic or psychiatric causes require appropriate specialist follow-up.

Patient Education

Reassurance is particularly important in patients with Charles Bonnet syndrome.

Patients should be informed that visual hallucinations associated with visual impairment are a recognized neurologic response to reduced visual input.

They should also be encouraged to report hallucinations openly rather than concealing them.

New hallucinations associated with confusion, weakness, severe headache, seizure activity, fever, or sudden neurologic changes require urgent medical evaluation.

Prognosis

The prognosis depends on the underlying cause.

Hallucinations caused by a reversible metabolic or toxic abnormality may resolve when the abnormality is corrected.

Charles Bonnet hallucinations may decrease with reassurance or improved visual function, but they can persist for months or years in some patients.

Hallucinations associated with chronic neurodegenerative disorders may recur or progress over time.

Complications

Visual hallucinations themselves may cause fear, anxiety, sleep disruption, social withdrawal, or unsafe behavior.

Patients may conceal symptoms because of fear of psychiatric stigma.

In delirium or dementia, hallucinations can contribute to agitation, falls, or self-injury.

The most important clinical task is therefore to distinguish relatively benign phenomena such as Charles Bonnet syndrome from hallucinations caused by potentially serious neurologic, metabolic, toxic, or psychiatric disease.

Ophthalmology – Gyrate Atrophy

Basics

Description

Gyrate atrophy of the choroid and retina is a rare, progressive autosomal recessive chorioretinal dystrophy caused by deficiency of the enzyme ornithine aminotransferase (OAT).

The disease typically begins during the first decade of life with:

• Nyctalopia
• Progressive loss of peripheral vision
• High myopia
• Progressive visual-field constriction

Characteristic sharply demarcated areas of peripheral chorioretinal atrophy gradually enlarge and coalesce. With advancing disease, the atrophy progresses toward the posterior pole, eventually resulting in loss of central vision.

Epidemiology

Gyrate atrophy is rare worldwide.

The highest reported prevalence is in Finland, where its frequency has been estimated at approximately 1 in 50,000.

Clinical manifestations usually begin during the first decade of life.

Risk Factors

The principal risk factor is inheritance of pathogenic mutations affecting ornithine aminotransferase.

Although the disorder occurs worldwide, a particularly large number of affected patients have historically been reported in Finland.

Genetics

Gyrate atrophy has an autosomal recessive inheritance pattern.

The responsible OAT gene is located on chromosome 10q26.

Numerous pathogenic variants have been identified.

Genetic counseling is appropriate for affected patients and their families.

Pathophysiology

The fundamental abnormality is deficiency of ornithine aminotransferase (OAT), a mitochondrial enzyme involved in ornithine metabolism.

OAT deficiency produces a dramatic elevation in circulating ornithine.

Plasma ornithine concentrations are typically approximately 10–20 times normal.

The markedly elevated ornithine concentration is believed to exert a toxic effect on the retinal pigment epithelium (RPE) and associated chorioretinal structures.

Progressive degeneration consequently involves:

• Retinal pigment epithelium
• Choriocapillaris
• Photoreceptors
• Other retinal structures as disease advances

The result is progressive chorioretinal atrophy and deterioration of retinal function.

Etiology

The disease results from OAT enzyme deficiency caused by pathogenic variants in the OAT gene.

The resulting hyperornithinemia is central to the development of retinal degeneration.

Commonly Associated Conditions

Although the ophthalmic manifestations dominate the clinical picture, systemic abnormalities have occasionally been reported.

These include:

• EEG abnormalities
• Hair abnormalities
• Skeletal muscle abnormalities demonstrated by CT or MRI
• Cerebral white-matter abnormalities
• Cerebral atrophy on MRI

Diagnosis

History

First Decade

Patients usually initially develop:

• Night blindness
• Decreased peripheral vision
• Myopia
• Astigmatism

Nyctalopia is frequently among the earliest manifestations.

Second Decade

During adolescence, patients commonly develop posterior subcapsular cataracts.

Later Disease

Progressive retinal degeneration causes increasingly severe constriction of the visual field.

Central visual acuity is initially relatively preserved but gradually deteriorates as the chorioretinal atrophy advances toward the posterior pole.

Significant central visual loss commonly develops by middle age.

Physical Examination

Refractive Error

Virtually all affected patients are myopic.

The degree of myopia may be substantial, historically reported in the approximate range of:

−4.00 to −20.00 D

Astigmatism is also common.

Lens Findings

Posterior subcapsular cataracts commonly become apparent by adolescence or early adulthood.

They may contribute substantially to visual deterioration but do not account for the progressive peripheral visual-field loss.

Fundus Findings

The funduscopic appearance is highly characteristic.

Early disease demonstrates multiple, sharply demarcated, round areas of chorioretinal atrophy involving the peripheral and midperipheral retina.

The abnormalities are typically:

• Bilateral
• Relatively symmetric
• Well circumscribed
• Initially separated by areas of relatively preserved retina

With time, individual areas of atrophy enlarge and coalesce.

The boundary between normal and atrophic retina characteristically develops a scalloped or gyrate appearance, giving the disease its name.

As the disorder progresses, chorioretinal atrophy extends centripetally toward the posterior pole.

In advanced disease, most or essentially all of the fundus may become involved.

Diagnostic Tests and Interpretation

Plasma Ornithine

Measurement of plasma ornithine concentration is a key diagnostic investigation.

Levels are generally approximately 10–20 times above normal.

Marked hyperornithinemia in a patient with the characteristic fundus appearance strongly supports the diagnosis.

Molecular genetic testing of the OAT gene can provide definitive genetic confirmation.

Fluorescein Angiography

Fluorescein angiography typically demonstrates hyperfluorescence corresponding to areas of chorioretinal atrophy.

There may also be leakage near the transition between preserved and atrophic retinal tissue.

Optical Coherence Tomography

OCT is useful for evaluating the macula and documenting structural complications.

Potential findings include:

• Progressive retinal thinning and atrophy
• Cystoid macular edema
• Epiretinal membrane
• Outer retinal and RPE abnormalities

Electroretinography

ERG abnormalities develop early.

Initially, both:

• Scotopic responses
• Photopic responses

are reduced.

This indicates dysfunction involving both rod and cone systems.

As retinal degeneration progresses, ERG amplitudes continue to decline.

In advanced adulthood, ERG responses may become nondetectable.

Differential Diagnosis

The major differential diagnosis is choroideremia.

Choroideremia

Choroideremia also produces progressive degeneration of the choroid, RPE, and retina with nyctalopia and peripheral visual-field loss.

However, it is typically X-linked, primarily affecting males, whereas gyrate atrophy is autosomal recessive.

The characteristic scalloped lesions and markedly elevated plasma ornithine strongly support gyrate atrophy.

Other inherited retinal/choroidal dystrophies may also enter the differential diagnosis depending on the phenotype.

Treatment

There is currently no treatment that reliably reverses established chorioretinal atrophy.

The primary therapeutic strategy is to reduce plasma ornithine concentrations in an attempt to slow retinal degeneration.

Dietary Treatment

Low-Arginine Diet

A low-protein, arginine-restricted diet is the principal long-term treatment.

Arginine restriction reduces the amount of substrate available for production of ornithine and consequently lowers plasma ornithine concentrations.

Long-term dietary treatment may slow progression of chorioretinal degeneration, particularly when initiated early.

Evidence from affected siblings suggests that patients beginning dietary restriction at a younger age may experience slower progression than siblings beginning treatment later.

However, retinal degeneration may continue despite excellent dietary compliance.

Because substantial protein restriction can have nutritional consequences, dietary therapy should be supervised by clinicians and dietitians experienced in metabolic disease.

Pyridoxine Therapy

Some patients demonstrate biochemical responsiveness to vitamin B6 (pyridoxine).

Pyridoxine acts as a cofactor for ornithine aminotransferase and may increase residual enzyme activity in responsive mutations.

However, most patients are not pyridoxine responsive.

A therapeutic trial may therefore be considered with monitoring of plasma ornithine levels to determine whether a meaningful biochemical response occurs.

Cataract Treatment

Visually significant posterior subcapsular cataracts may be treated with cataract extraction.

Patients should be counseled that cataract removal addresses only the lenticular component of their visual impairment.

Postoperative visual potential may remain substantially limited by the underlying retinal and choroidal degeneration.

Ongoing Care

Follow-Up Recommendations

Gyrate atrophy is a lifelong progressive disease.

Regular ophthalmic follow-up should assess:

• Visual acuity
• Refraction
• Visual fields
• Cataract progression
• Macular status
• Extent of chorioretinal atrophy
• Development of cystoid macular edema or epiretinal membrane

Serial retinal imaging and functional testing can help document progression.

Patient Monitoring

Plasma ornithine levels should be monitored when dietary or pyridoxine therapy is being used.

Patients undergoing significant dietary protein and arginine restriction require appropriate nutritional supervision to ensure adequate growth and general health, particularly during childhood.

Patient Education

Patients and families should understand that gyrate atrophy is a hereditary and progressive retinal disease.

Early recognition is important because dietary reduction of ornithine may slow progression, particularly when treatment begins during childhood.

Genetic counseling should be offered to affected individuals and their families.

Low-vision rehabilitation should be considered as visual impairment progresses.

Prognosis

The long-term visual prognosis is generally poor.

The typical progression is:

Nyctalopia in childhood → peripheral chorioretinal atrophy → progressive visual-field constriction → posterior pole involvement → central visual loss

Despite treatment, retinal function usually continues to decline, although early and sustained reduction of plasma ornithine may slow the rate of progression.

Key Ophthalmology Points

Gyrate atrophy = OAT deficiency + hyperornithinemia + progressive scalloped chorioretinal atrophy.

The classic diagnostic combination is childhood nyctalopia, high myopia, sharply demarcated scalloped areas of peripheral chorioretinal atrophy, and plasma ornithine levels approximately 10–20 times normal.

Treatment centers on early arginine restriction, with a trial of pyridoxine in potentially responsive patients.