Ophthalmology – Morning Glory Syndrome

Basics

Description

Morning glory syndrome, also called morning glory disc anomaly (MGDA), is a rare congenital malformation characterized by a distinctive funnel-shaped excavation of the optic disc and surrounding posterior fundus.

Its name comes from the resemblance of the anomalous optic nerve head to a morning glory flower.

MGDA is usually:

• Unilateral
• Congenital
• Associated with reduced vision
• Occasionally associated with serious neurologic, cerebrovascular, craniofacial, pituitary, and retinal abnormalities

Because of these systemic associations, recognition of MGDA should prompt evaluation beyond the eye.

Epidemiology

Incidence

MGDA is very rare.

An estimated incidence of approximately:

1 per 1,000,000 live births

has been reported.

Pathophysiology

MGDA is thought to result from abnormal development of the optic nerve and surrounding posterior sclera during embryogenesis.

Typical developmental abnormalities include:

• Funnel-shaped excavation of the optic nerve head
• Abnormal surrounding scleral and peripapillary tissue
• Persistent glial tissue centrally
• Abnormal retinal vascular emergence

A characteristic central glial tuft often remains over the optic disc.

Some authors have proposed that the anomaly represents a form of mesenchymal or mesodermal dysgenesis.

Myocontractile tissue has occasionally been identified histologically, and rare contractile movements of the anomalous disc region have been described clinically.

Commonly Associated Conditions

Retinal Detachment

Retinal detachment occurs in a substantial proportion of patients, historically reported in approximately one-third.

The mechanism is variable and incompletely understood.

Proposed mechanisms include:

• Peripapillary retinal breaks
• Retinoschisis-like communications
• Abnormal communication between:
• The subarachnoid space
• The anomalous optic nerve
• The subretinal space
• Vitreoretinal traction

Detachment may be:

• Localized to the macula
• Shallow and chronic
• Bullous
• Total

Rare spontaneous resolution has been reported.

Cerebrovascular Abnormalities

MGDA has important associations with abnormalities of the intracranial circulation.

These may include:

• Internal carotid artery stenosis
• Carotid hypoplasia
• Carotid aplasia
• Abnormal Circle of Willis
• Cerebral arterial stenosis

These abnormalities may predispose to:

• Stroke
• Transient ischemic events
• Seizures

Moyamoya Disease

MGDA is associated with moyamoya arteriopathy.

Moyamoya is characterized by:

• Progressive stenosis of major intracranial arteries
• Development of abnormal collateral vessels
• Increased risk of:
• Cerebral ischemia
• Infarction
• Intracranial hemorrhage

The abnormal collateral network produces the classic angiographic appearance described as a “puff of smoke.”

Because of this association, cerebral vascular imaging is an important component of evaluation in MGDA.

Midline Cranial Abnormalities

MGDA may occur with congenital midline abnormalities such as:

• Basal encephalocele
• Absent or abnormal septum pellucidum
• Corpus callosal abnormalities
• Pituitary abnormalities
• Other midline craniofacial defects

Pituitary Dysfunction

Pituitary abnormalities can be:

• Structural
• Functional
• Both

Possible manifestations include:

• Growth hormone deficiency
• Growth retardation
• Hypothyroidism
• Other pituitary hormone deficiencies

Children with MGDA should therefore have growth and endocrine development assessed carefully.

Other Associations

Less commonly reported associations include:

• Retinal arteriovenous malformations
• Renal abnormalities
• Papillorenal-spectrum disorders
• Persistent fetal vasculature
• Craniofacial abnormalities

Scattered reports have also linked MGDA with other neurodevelopmental syndromes.

Diagnosis

Diagnosis is primarily based on the characteristic funduscopic appearance of the optic nerve head.

History

Patients may present with:

• Poor vision
• Strabismus
• Failed vision screening
• Leukocoria
• Abnormal pupillary reflex
• Acute visual decline

Acute visual decline should raise concern for:

Retinal detachment

Systemic History

Ask about manifestations suggesting associated neurologic or endocrine disease.

Possible Pituitary Dysfunction

• Poor growth
• Short stature
• Delayed development
• Symptoms of hypothyroidism

Possible Cerebrovascular Disease

• Seizures
• Transient weakness
• Stroke-like episodes
• Developmental regression
• Headaches
• Syncope

Physical Examination

Visual Acuity

Visual acuity is highly variable.

It may range from:

• Nearly normal vision
• Mild visual impairment
• Severe visual impairment
• No light perception

Visual potential depends on:

• Degree of optic nerve malformation
• Macular involvement
• Presence of retinal detachment
• Refractive error
• Amblyopia

Refraction

Myopia is common.

Significant refractive error should be corrected promptly, particularly in children.

Strabismus

Strabismus is common because of unilateral visual impairment.

Most commonly:

• Esotropia
• Exotropia

may occur depending on visual function and age.

Pupillary Examination

A unilateral case may show a:

Relative afferent pupillary defect

if optic nerve dysfunction is sufficiently asymmetric.

Color Vision

Color discrimination may be reduced in the affected eye.

Characteristic Fundus Appearance

The classic features of morning glory disc anomaly include:

• Large optic disc
• Funnel-shaped excavation of the optic nerve head and surrounding posterior sclera
• Central white glial tuft
• Radial arrangement of retinal vessels
• Vessels emerging abnormally from the peripheral edge of the excavation
• Peripapillary pigmentary disturbance
• Circumferential annular ring of pigmented chorioretinal tissue

The vessels may be:

• Numerous
• Narrow
• Radially oriented

and often lack the normal central emergence pattern.

Laterality

MGDA is usually:

Unilateral

Bilateral disease is uncommon.

Retinal Examination

Carefully inspect for:

• Shallow retinal detachment
• Macular detachment
• Retinoschisis
• Peripheral retinal abnormalities

Detachment can occasionally be subtle.

Systemic Examination

Children should have:

• Height measurement
• Weight measurement
• Growth chart assessment
• Complete neurologic assessment
• Developmental assessment

Diagnostic Tests

Laboratory Evaluation

Because of the association with pituitary dysfunction, selected endocrine testing may include:

• TSH
• Free T4
• Growth hormone axis testing
• IGF-1
• Additional pituitary hormones as clinically indicated

Endocrine testing should be guided by clinical findings and pediatric/endocrinology evaluation.

Renal Evaluation

When clinically indicated:

• Serum electrolytes
• Creatinine
• Basic metabolic panel
• Urinalysis

may be obtained.

Routine renal investigations are not necessary in every patient unless the phenotype suggests a syndromic association.

Neuroimaging

A patient with MGDA should be considered for brain and cerebrovascular imaging because of the potentially serious associated abnormalities.

In children, preferred evaluation often includes:

• MRI brain
• MRA head and neck

These avoid ionizing radiation.

Imaging should carefully evaluate:

• Internal carotid arteries
• Circle of Willis
• Intracranial arterial circulation
• Midline brain structures
• Pituitary gland
• Skull base

CT / CTA

CT or CTA may be considered when:

• MRI is unavailable
• Bony anatomy needs detailed assessment
• Basal encephalocele is suspected
• Rapid vascular imaging is clinically necessary

Fundus Photography

Fundus photography is useful for:

• Baseline documentation
• Long-term comparison
• Recording optic disc morphology
• Monitoring associated retinal changes

Optical Coherence Tomography

OCT is especially useful for evaluating:

• Peripapillary architecture
• Macular anatomy
• Intraretinal splitting
• Retinoschisis-like changes
• Subretinal fluid
• Retinal detachment

OCT may help demonstrate a potential communication between abnormal peripapillary structures and the subretinal space.

Fluorescein Angiography

Fluorescein angiography may help evaluate:

• Abnormal retinal vascular anatomy
• Retinal perfusion
• Associated vascular malformations
• Areas of leakage

It is not always required for diagnosis.

Differential Diagnosis

Important differential diagnoses include:

• Optic disc coloboma
• Peripapillary staphyloma
• Posterior staphyloma
• Optic nerve coloboma
• Microphthalmia with cyst
• Congenital optic nerve excavation

Morning Glory Disc vs Optic Disc Coloboma

MGDA typically shows:

• Central glial tuft
• Radial retinal vessels
• Annular peripapillary pigmentation
• Funnel-shaped excavation

Optic disc coloboma more often shows:

• Inferior excavation
• Sharply demarcated congenital defect
• Association with other colobomatous abnormalities

Treatment

There is no treatment that can correct the congenital optic nerve anomaly itself.

Management focuses on:

• Maximizing useful vision
• Treating amblyopia
• Correcting refractive error
• Managing retinal detachment
• Detecting systemic associations
• Protecting the better eye

Refractive Correction

Correct significant:

• Myopia
• Astigmatism
• Anisometropia

as early as possible in children.

Amblyopia Therapy

Amblyopia treatment may be appropriate when useful visual potential exists.

Options include:

• Full optical correction
• Patching of the better eye
• Penalization in selected cases

However, treatment should be pursued cautiously, because the affected eye may have limited structural visual potential.

Excessive occlusion of the better eye should be avoided.

Retinal Detachment Treatment

Retinal detachment associated with MGDA is often difficult to manage.

Treatment may include:

• Pars plana vitrectomy
• Removal of vitreoretinal traction
• Internal drainage when appropriate
• Laser photocoagulation
• Long-acting gas tamponade
• Silicone oil in selected complex cases

The optimal technique depends on:

• Retinal configuration
• Presence of retinal breaks
• Macular involvement
• Vitreous traction
• Patient age

Medical Treatment

There is no specific ophthalmic medication for MGDA itself.

Systemic therapy depends on associated abnormalities.

Examples include:

• Hormonal replacement for pituitary deficiencies
• Antithrombotic or cerebrovascular management as directed by neurology/neurosurgery

Issues for Referral

Pediatric Ophthalmology

Recommended for:

• Refraction
• Amblyopia management
• Strabismus assessment
• Long-term visual development monitoring

Retina Specialist

Indicated when there is:

• Retinal detachment
• Retinoschisis
• Subretinal fluid
• Sudden visual decline

Neurology

Neurologic evaluation is appropriate because of the association with:

• Seizures
• Stroke
• Cerebral arterial abnormalities
• Moyamoya disease

Neurosurgery / Neurovascular Specialist

Referral is important if imaging demonstrates:

• Moyamoya arteriopathy
• Severe carotid stenosis
• Intracranial arterial abnormalities
• Basal encephalocele

Endocrinology

Endocrine referral is appropriate for:

• Growth retardation
• Abnormal pituitary imaging
• Growth hormone deficiency
• Hypothyroidism
• Other pituitary hormone abnormalities

Additional Therapy

Monocular Precautions

When one eye has poor vision, the better eye should be protected.

Recommend:

Polycarbonate protective spectacles

especially for:

• Children
• Sports
• Occupational activities
• Any activity with potential eye trauma

Ongoing Care

Follow-Up Recommendations

Children with MGDA generally require regular lifelong ophthalmic surveillance.

At minimum:

• Annual ophthalmic examination

More frequent follow-up is appropriate when there is:

• Amblyopia
• Significant refractive error
• Strabismus
• Retinal detachment
• Progressive retinal changes

Patient Monitoring

Parents should monitor for:

• Sudden reduction in vision
• New strabismus
• Behavioral evidence of visual loss
• New visual field complaints
• Metamorphopsia
• Micropsia

Neurologic symptoms should also prompt urgent medical assessment.

Retinal Detachment Warning Symptoms

Patients and families should be educated about:

• New flashes
• New floaters
• Curtain or shadow in vision
• Sudden visual loss

In MGDA, a shallow macular detachment may produce more subtle symptoms such as:

• Metamorphopsia
• Micropsia
• Blurred central vision

Prognosis

Visual prognosis is highly variable but is often limited because of the underlying optic nerve malformation.

Vision depends on:

• Degree of optic nerve dysplasia
• Macular involvement
• Refractive error
• Amblyopia
• Retinal detachment

Patients presenting with relatively good stable vision and no retinal detachment may retain useful vision long term.

Complications

Important complications include:

• Retinal detachment
• Retinoschisis
• Amblyopia
• Strabismus
• Severe visual impairment
• Cerebral ischemia or stroke from associated vascular abnormalities
• Seizures
• Pituitary hormone deficiency

Ophthalmology Pearls

• Morning glory disc anomaly = funnel-shaped congenital optic disc excavation with a central glial tuft and radially arranged retinal vessels.
• It is usually unilateral.
• Always think beyond the eye: MGDA can be associated with carotid abnormalities, moyamoya disease, basal encephalocele, and pituitary dysfunction.
• MRI/MRA of the brain and cerebral circulation should be strongly considered, particularly in children.
• Approximately one-third of patients have historically been reported to develop retinal detachment.
• Acute deterioration in vision in a patient with MGDA should prompt urgent evaluation for retinal detachment.
• A child with poor unilateral vision requires careful refractive and amblyopia management, but aggressive patching may be inappropriate when structural visual potential is severely limited.
• Protect the better eye with polycarbonate spectacles when visual function is markedly asymmetric.