Corneal Degenerations
Exam-essential differences: Degeneration vs. Dystrophy
Unlike corneal dystrophies (which are typically bilateral, symmetric, and genetic), corneal degenerations are generally age-related, often asymmetric, and secondary to chronic inflammation, trauma, or environmental factors.
1. Common Degenerative Conditions
| Condition | Clinical Characteristic |
|---|---|
| Arcus Senilis | Lipid deposition in peripheral stroma; bilateral; very common in the elderly. |
| Band Keratopathy | Calcium deposition in the interpalpebral zone is often associated with chronic uveitis or hypercalcemia. |
| Salzmann Nodular Degeneration | Blue-white elevated nodules; secondary to chronic corneal disease. |
| Terrien’s Marginal Degeneration | Peripheral thinning with an intact epithelium; slow, painless progression. |
2. NEET PG High-Yield Pearls
- Band Keratopathy: Appears as a “swiss cheese” pattern due to holes in the calcium deposits where corneal nerves penetrate. Treatment: EDTA chelation.
- Arcus Senilis in Young Patients: Must investigate for underlying hyperlipidemia (Type II Hyperlipoproteinemia).
- Dystrophy vs. Degeneration:
- Dystrophy: Genetic, bilateral, symmetric, central, onset in early life.
- Degeneration: Acquired, often asymmetric, peripheral, onset in later life.