Pellucid marginal degeneration is a corneal thinning disorder affecting the inferior periphery, leading to high irregular astigmatism. It typically presents in adulthood.
Clinical features
The central cornea often remains relatively clear and of normal thickness.
- Inferior crescent-shaped band of thinning with a “kissing dove” topography pattern
- Progressive blur and ghosting from irregular astigmatism
- Often mistaken for keratoconus but with different thinning pattern
- Risk of acute hydrops or perforation is lower than in keratoconus but still possible
Management
Treatment focuses on improving optical quality and stabilising the cornea.
- Rigid gas permeable, scleral, or hybrid lenses for visual correction
- Corneal cross-linking in selected progressive cases
- Lamellar or full-thickness transplantation when contact lenses fail
- Regular monitoring with topography to track progression
