A 22-year-old contact lens wearer is diagnosed with keratoconus based on inferior corneal steepening of 51 D, I-S value > 1.5 D, and a skewed radial axis on Placido disk topography. Simulated keratometry (SimK) is 50 D / 47 D. The progression is confirmed over 6 months. Spectacle-corrected visual acuity is 6/18. The most appropriate next step is:
- A Penetrating keratoplasty (PK) immediately
- B LASIK to improve vision in the keratoconic eye
- C Corneal collagen cross-linking (CXL) to halt progression ✓
- D Phakic intraocular lens (pIOL) implantation
Explanation
Confirmed progressive keratoconus in a young patient is the primary indication for corneal collagen cross-linking (CXL) — the Dresden protocol using riboflavin 0.1% drops with 370 nm UV-A irradiation (3 mW/cm² for 30 min). CXL increases corneal biomechanical rigidity by inducing covalent bonds between collagen fibrils, halting or stabilising progression in 90%+ of cases. It does not restore lost vision but prevents further deterioration. PK is reserved for advanced stage with poor corrected acuity despite rigid contact lenses — not yet reached here. LASIK is absolutely contraindicated in keratoconus as it further weakens the cornea. pIOL addresses refractive error, not progressive ectasia.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.