Corneal ectasia refers to progressive thinning and bulging of the cornea, leading to irregular astigmatism and visual distortion. It can be primary, as in keratoconus, or secondary after surgery.
Causes and features
Post-refractive surgery ectasia is an important, though rare, complication.
- Increasing myopia and astigmatism with reduced best-corrected vision
- Topography showing steepening and thinning, often inferior or paracentral
- Associated allergy and eye rubbing in many primary cases
- Post-LASIK corneal ectasia when residual stromal bed is inadequate or biomechanically weak
Management
Goals are to halt progression and improve optical quality.
- Corneal cross-linking to strengthen collagen and slow or stop progression
- Specialist contact lenses such as rigid gas permeable or scleral designs
- Intracorneal ring segments or topography-guided laser in selected cases
- Corneal transplantation in advanced disease with scarring or contact-lens intolerance
