Keratoconus causes irregular astigmatism and reduced vision. Epi-off corneal crosslinking (CXL) stabilizes the cornea but often leaves higher-order aberrations uncorrected. This randomized, parallel-group trial compares corneal wavefront guided photorefractive keratectomy (corneal wavefront guided PRK, 50 µm therapeutic ablation) combined with accelerated epi-off CXL versus epi-off CXL with epithelial removal by phototherapeutic keratectomy (PTK) using a Schwind AMARIS excimer laser, in adults with keratoconus. The primary endpoint is change in best-corrected distance visual acuity (logMAR) at 12 months. Key secondary endpoints include Kmax, corneal higher-order aberrations, manifest refraction, Scheimpflug densitometry (haze) and Fantes grade, Corvis ST biomechanics, NEI VFQ-25, and endothelial cell density by non-contact specular microscopy at 1, 3, 6 and 12 months.
Age 18-40 years
Diagnosis of keratoconus, ABCD Belin stage I-III at baseline
Minimum (thinnest) corneal pachymetry ≥ 450 µm pre-op
Written informed consent
Central corneal scars or opacities
Prior ocular surgery or trauma (exception: prior LASIK if it is the cause of post-surgical ectasia, per protocol text)
Autoimmune disease or uncontrolled diabetes mellitus
Pregnancy or lactation