Cataract and Refractive Surgery
Core concepts
Know cataract types (nuclear sclerotic, cortical, posterior subcapsular), their risk factors (age, steroids, diabetes, trauma, UV), and the decision to operate based on visual function, not just density. Understand biometry (axial length, keratometry, IOL power calculation) and the difference between phacoemulsification and extracapsular extraction.
Learn refractive surgery principles: LASIK (flap), PRK (surface ablation), SMILE, and the role of corneal thickness and topography in screening. Know the complications: endophthalmitis, posterior capsule rupture, retained lens material, refractive surprise, and dry eye.
Traps
- Operating on a cataract without assessing the posterior segment and comorbidities.
- Ignoring biometry errors (e.g., prior refractive surgery alters keratometry).
- Missing posterior capsule rupture during surgery.
- Overlooking steroid response after refractive surgery.
Rule of thumb
Cataract surgery is indicated by functional visual impairment, not by density alone; and always check for prior refractive surgery before biometry.
Worked example
A patient with a dense cataract and a history of LASIK. Standard keratometry may overestimate power; use historical data or a post-refractive formula to avoid a hyperopic surprise.