Collagen Cross-linking for Advanced Progressive Keratoconus

Purpose: Collagen cross-linking (CXL) is a safe and effective procedure to stop progression of keratoconus. However, corneas with a maxK of more than 55 to 58 diopters (D) have been suggested to have an increased failure rate. We report results of CXL for progressive keratoconus in corneas with a maxK of 55 D or more. Methods: Retrospective follow-up. Twenty-eight eyes of 22 patients from 12 to 38 years were treated with CXL for progressive keratoconus. All patients had a preoperative maxK of at least 55 D. Patients were examined on 2 or more occasions after treatment, with a mean follow-up of 22 months. At all visits, patients received routine clinical examination with slit-lamp biomicroscopy, determination of corrected distance visual acuity (CDVA), and Pentacam tomography. Results: The average preoperative maxK was 61.2 ± 3.7 D. After CXL, maxK significantly decreased to 59.5 ± 3.7 D at the last recorded visit. In 27 eyes, keratoconic progression seemed to have stopped, and in 14 eyes maxK improved with more than 2.0 D decrease, whereas 1 eye showed an increase in maxK of more than 2.0 D. The average CDVA remained unchanged after CXL treatment, although 11 eyes improved and 2 eyes had an unexplained loss of CDVA. Conclusions: CXL treatment in eyes with advanced progressive keratoconus prevented further progression in 27 of 28 eyes. Progression in cases with advanced keratoconus should not exclude CXL as a treatment to preserve visual acuity or as a supplement to other treatment modalities to delay or avoid keratoplasty.