Corneal Dystrophy
👁️🗨️ Corneal Dystrophies
🔍 Definition
Corneal dystrophies are a group of inherited, typically bilateral, progressive, non-inflammatory disorders of the cornea characterized by abnormal deposition of material in one or more layers of the cornea.
🧠 These are genetic disorders — not caused by infection or trauma.
🧬 Key Features
| Feature | Description |
|---|---|
| Genetic origin | Often autosomal dominant inheritance |
| Bilateral & symmetric | Usually affects both eyes symmetrically |
| Layer-specific | Affects different corneal layers depending on type |
| Non-inflammatory | No redness or pain (unless recurrent erosion) |
| Progressive | Slowly worsens over years |
🌈 Types of Corneal Dystrophies (by layer affected)
1. Epithelial & Subepithelial
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Map-Dot-Fingerprint Dystrophy (aka Epithelial Basement Membrane Dystrophy, EBMD)
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Irregular basement membrane
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Causes recurrent corneal erosions
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Map-like, dot-like, or fingerprint patterns
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2. Bowman’s Layer
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Reis-Bücklers Dystrophy
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Early onset (childhood)
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Subepithelial fibrosis and opacities
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Painful erosions and visual loss
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3. Stromal Dystrophies
These are the most common and important dystrophies:
| Type | Deposits | Description |
|---|---|---|
| Granular dystrophy | Hyaline | White, crumb-like opacities; discrete lesions |
| Lattice dystrophy | Amyloid | Refractile, branching lines (like lattice) |
| Macular dystrophy | Mucopolysaccharides | Grayish, ill-defined opacities; severe vision loss |
🧠 Remember:
Granular = clear spaces between
Lattice = lines
Macular = most visually impairing
4. Descemet’s Membrane / Endothelium
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Fuchs Endothelial Dystrophy
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Most common in elderly
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Progressive loss of endothelial cells → stromal edema
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Symptoms: blurred vision (worse in morning), glare, halos
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Guttata seen on slit-lamp (beaten metal appearance)
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Advanced cases → bullous keratopathy
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Posterior Polymorphous Corneal Dystrophy (PPCD)
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Vesicle-like endothelial lesions
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Usually asymptomatic; rarely leads to edema
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🔬 Diagnosis
| Test | Purpose |
|---|---|
| Slit-lamp exam | Identifies specific corneal changes |
| Specular microscopy | Evaluates endothelial cells (Fuchs) |
| Corneal topography | Maps irregularities in shape |
| Genetic testing | Optional in atypical or early-onset cases |
💊 Management
| Stage / Severity | Treatment |
|---|---|
| Mild cases | Observation, lubricating eye drops |
| Recurrent erosions | Hypertonic saline drops, bandage lenses, epithelial debridement |
| Significant visual loss | Lamellar or penetrating keratoplasty (corneal transplant) |
| Fuchs dystrophy | DSEK or DMEK (endothelial keratoplasty) |
🧠 Mnemonic: "FAM-G" for stromal dystrophies
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Fuchs (endothelial)
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Amyloid = Lattice
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Mucopolysaccharide = Macular
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Granular = Hyaline
📋 Quick Comparison Table
| Dystrophy | Layer Affected | Key Feature | Inheritance |
|---|---|---|---|
| EBMD (Map-dot) | Epithelium | Recurrent erosions, fingerprint pattern | Autosomal dominant |
| Reis-Bücklers | Bowman’s | Subepithelial haze, erosions | Autosomal dominant |
| Granular | Stroma | Crumb-like opacities | Autosomal dominant |
| Lattice | Stroma | Branching refractile lines | Autosomal dominant |
| Macular | Stroma | Diffuse opacities, severe vision loss | Autosomal recessive |
| Fuchs Endothelial Dystrophy | Endothelium | Guttata, morning blur, corneal edema | Sporadic / dominant |
| PPCD | Endothelium | Vesicles, asymptomatic | Autosomal dominant |
🛡️ Prognosis
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Most dystrophies are slowly progressive
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Fuchs and macular have higher risk of significant visual impairment
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Transplants usually successful when needed
💡 Would You Like:
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Visual diagrams of each dystrophy?
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A flashcard-style revision set?
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A printable comparison chart?
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