Ophthalmology – Lattice Corneal Dystrophy

Basics

Description

Lattice corneal dystrophy (LCD) is a bilateral, noninflammatory stromal corneal dystrophy characterized by deposition of amyloid within the corneal stroma. These deposits form fine, refractile, branching lines that resemble a lattice.

The major recognized forms are lattice corneal dystrophy type I and lattice corneal dystrophy type II.

Type I, also called classic lattice dystrophy or Biber-Haab-Dimmer dystrophy, is usually an autosomal dominant corneal dystrophy associated with recurrent corneal erosions and progressive visual impairment.

Type II, also called Meretoja syndrome or Finnish familial amyloidosis, produces similar corneal lattice changes but is associated with systemic amyloidosis and neuropathy.

Lattice Corneal Dystrophy Type I

Type I usually begins in the first decade of life.

Amyloid deposits develop within the central corneal stroma and gradually form branching lattice lines.

The lattice lines generally begin centrally and extend peripherally but typically do not reach the limbus.

Clinical manifestations include:

• Recurrent corneal erosions
• Eye pain
• Foreign-body sensation
• Photophobia
• Tearing
• Progressive corneal scarring
• Reduced best-corrected visual acuity

Visual impairment often becomes significant by adulthood.

Lattice Corneal Dystrophy Type II

Type II generally becomes symptomatic later, often in the third or fourth decade.

The corneal lattice lines tend to begin more peripherally and extend centrally.

Recurrent erosions may be less prominent than in type I, but reduced corneal sensation and neurotrophic epithelial problems can occur.

Unlike type I, type II is part of a systemic amyloidosis and may be associated with:

• Cranial neuropathies
• Facial weakness or drooping
• Peripheral neuropathy
• Carpal tunnel syndrome
• Autonomic dysfunction
• Cardiac arrhythmias

Epidemiology

Lattice dystrophy is among the more common stromal corneal dystrophies, although it remains relatively uncommon in the general population.

Most cases of classic LCD are inherited in an autosomal dominant fashion.

Rare autosomal recessive variants have also been described.

Risk Factors

The major risk factor is a family history of lattice corneal dystrophy.

A patient may still develop the disease without a known family history because spontaneous pathogenic variants can occur.

A family history of systemic amyloidosis is particularly important in suspected type II disease.

Genetics

Type I

Classic lattice corneal dystrophy is associated with mutations in the TGFBI gene on chromosome 5q31.

TGFBI mutations are also involved in several other stromal corneal dystrophies.

Type II

Type II is caused by mutations in the gelsolin gene on chromosome 9q34.

The mutation causes systemic amyloid deposition in addition to corneal disease.

General Prevention

There is no way to prevent the inherited disorder itself.

Genetic counseling may be useful for affected families.

Early recognition and treatment of recurrent erosions may reduce pain, infection risk, and secondary scarring.

Pathophysiology

Amyloid accumulates within the corneal stroma.

Initially, the deposits may appear as faint opacities. Over time, they develop into:

• Refractile branching lines
• Stromal haze
• Scar formation

When amyloid deposits extend toward the anterior cornea, they interfere with epithelial adhesion.

This leads to recurrent corneal erosions.

Repeated epithelial breakdown and healing eventually produce anterior stromal scarring and irregularity, which can reduce vision.

Associated Conditions

Type I

Classic LCD generally has no important systemic association.

Type II

Type II is part of systemic gelsolin amyloidosis.

Associated manifestations may include:

• Facial nerve dysfunction
• Facial drooping
• Reduced corneal sensation
• Peripheral neuropathy
• Carpal tunnel syndrome
• Autonomic dysfunction
• Orthostatic symptoms
• Cardiac rhythm abnormalities

Because of these systemic features, coordination with primary care and other specialists is important.

Diagnosis

History

Younger patients commonly present with symptoms of recurrent corneal erosion.

These include:

• Sudden foreign-body sensation
• Sharp eye pain
• Tearing
• Photophobia
• Blurred vision

Symptoms may occur in one or both eyes.

Erosions are often particularly noticeable on awakening because the eyelid may adhere to poorly attached epithelium during sleep.

Older patients may additionally report gradually worsening visual acuity from stromal scarring and irregular astigmatism.

Physical Examination

Early Disease

Slit-lamp examination may reveal:

• Fine subepithelial or anterior stromal opacities
• Faint refractile deposits near the central cornea

These findings may be subtle in young children.

Lattice Lines

As the disease progresses, characteristic:

• Thin
• Refractile
• Branching
• Interconnecting

stromal lines become visible.

They produce the classic lattice-like appearance.

In type I, these are predominantly central and usually spare the limbal region.

In type II, they may begin more peripherally and extend centrally.

Corneal Scarring

Repeated erosions can produce:

• Anterior stromal haze
• Irregular corneal surface
• Dense central scarring

This is a major cause of reduced best-corrected vision in advanced disease.

Corneal Sensation

Corneal sensation may be reduced.

This is particularly important in type II, where cranial neuropathy and neurotrophic corneal disease can lead to persistent epithelial defects.

Reduced sensation can also make corneal injuries less symptomatic despite significant epithelial damage.

Diagnostic Tests

The diagnosis is primarily clinical, based on slit-lamp findings and family history.

In atypical cases, genetic testing can be useful.

Pathological Findings

Histopathology demonstrates amyloid deposition in the corneal stroma.

Amyloid stains positively with Congo red.

Under polarized light, Congo red-stained amyloid demonstrates characteristic apple-green birefringence.

These findings confirm the amyloid nature of the deposits.

Differential Diagnosis

Important differential diagnoses include:

• Recurrent corneal erosion syndrome
• Granular corneal dystrophy
• Macular corneal dystrophy
• Amyloid corneal degeneration
• Other TGFBI-associated dystrophies

A key distinction is that lattice dystrophy shows branching amyloid lines, whereas granular dystrophy typically produces discrete crumb-like stromal deposits.

Treatment

Treatment depends on whether the main problem is:

• Recurrent erosions
• Corneal scarring
• Reduced vision
• Neurotrophic epithelial disease

Treatment of Recurrent Corneal Erosions

Lubrication

Frequent preservative-free artificial tears can reduce epithelial friction.

Lubricating ointment is particularly useful at bedtime.

Hypertonic Saline

Hypertonic sodium chloride drops or ointment may improve epithelial adhesion by reducing epithelial edema.

They are often used:

• During recurrent erosion episodes
• At bedtime for prevention

Topical Antibiotics

When an epithelial defect is present, a topical antibiotic may be used to reduce the risk of infectious keratitis.

A fluoroquinolone is commonly chosen for significant epithelial defects.

Antibiotics are not required continuously once the epithelium has healed.

Cycloplegics

Cycloplegic medication can reduce:

• Ciliary spasm
• Pain
• Photophobia

during significant acute erosion episodes.

Bandage Contact Lens

A bandage contact lens may:

• Reduce pain
• Protect regenerating epithelium
• Facilitate healing

Because an epithelial defect and contact lens together increase the risk of microbial keratitis, antibiotic prophylaxis and close follow-up are essential.

Epithelial Debridement

Loose or nonadherent epithelium may be removed to create a healthier surface for re-epithelialization.

This is particularly useful when recurrent erosions persist despite conservative treatment.

Superficial Keratectomy

For recurrent erosions with superficial scarring, superficial keratectomy may remove abnormal epithelium and anterior stromal deposits.

A diamond burr may be used to polish the underlying Bowman layer and reduce recurrence.

Phototherapeutic Keratectomy

Phototherapeutic keratectomy (PTK) can be useful when deposits and scars remain relatively superficial.

PTK can:

• Remove superficial amyloid
• Smooth the anterior corneal surface
• Improve visual acuity
• Reduce recurrent erosions

Recurrence remains possible because the genetic defect persists.

Corneal Transplantation

When stromal opacification is too deep for PTK and vision is significantly impaired, corneal transplantation may be required.

Options include:

• Deep anterior lamellar keratoplasty
• Penetrating keratoplasty

The choice depends on the depth of the disease and corneal anatomy.

Recurrence After Transplantation

Lattice dystrophy can recur in the donor cornea because abnormal amyloid-producing cells remain in the recipient tissue.

Recurrence may occur years after transplantation and can again affect visual acuity.

Delayed Epithelial Healing

Patients with lattice dystrophy may heal more slowly after corneal procedures.

Careful postoperative epithelial monitoring is therefore important.

Management of Type II

Patients with LCD II require both ophthalmic and systemic care.

Because systemic amyloidosis can cause:

• Neuropathy
• Autonomic abnormalities
• Cardiac disease

communication with primary care, neurology, and cardiology may be necessary.

Neurotrophic corneal disease may require more aggressive surface protection than classic LCD.

Referral

Referral to a corneal specialist is appropriate when:

• Erosions become frequent
• Epithelial defects persist
• Vision progressively decreases
• Corneal scarring becomes significant
• PTK or transplantation is being considered

Patients suspected of type II disease should also undergo appropriate systemic evaluation.

Follow-Up

Follow-up frequency depends on severity.

Patients with mild stable disease may be examined periodically.

More frequent review is required for:

• Active erosion
• Persistent epithelial defect
• Bandage contact lens use
• Postoperative care
• Progressive scarring

Patients who undergo transplantation require lifelong follow-up.

Monitoring After Corneal Transplantation

Patients treated with prolonged topical corticosteroids should be monitored for:

• Elevated intraocular pressure
• Steroid-induced glaucoma
• Cataract progression
• Graft rejection
• Infectious keratitis

Patient Education

Patients should understand that lattice dystrophy is:

• Genetic
• Bilateral
• Chronic
• Recurrent

There is currently no treatment that eliminates the underlying genetic defect.

However, recurrent erosions and visual impairment can usually be managed effectively.

Patients should seek urgent ophthalmic assessment for:

• Increasing pain
• Redness
• Photophobia
• Discharge
• Sudden decline in vision

because an epithelial erosion can occasionally become infected.

Prognosis

Type I

The prognosis for maintaining useful vision is generally good with proper treatment.

However, many patients eventually require procedures such as:

• PTK
• Superficial keratectomy
• Corneal transplantation

as recurrent erosions and stromal scarring accumulate.

Systemic health and lifespan are generally normal.

Type II

Patients are often less severely affected by recurrent erosions but have greater concern for systemic amyloidosis and neuropathy.

The overall prognosis therefore depends more heavily on systemic involvement.

Complications

Important complications include:

• Recurrent corneal erosions
• Corneal scarring
• Irregular astigmatism
• Reduced visual acuity
• Persistent epithelial defects
• Neurotrophic keratopathy
• Infectious keratitis
• Recurrence after corneal transplantation
• Corneal graft rejection
• Steroid-induced ocular hypertension or glaucoma

The key clinical pearl is: lattice corneal dystrophy is an inherited stromal amyloidosis characterized by refractile branching corneal lines; type I primarily causes recurrent erosions and scarring, whereas type II should prompt evaluation for systemic gelsolin amyloidosis and neuropathy.