"Epithelium-on" corneal collagen cross-linking in treatment of keratoconus : non randomized retrospective study

Abstract

Purpose: To evaluate the clinical effect of Riboflavin/UVA, “epithelium-on” corneal cross-linking (CXL) on keratoconic eyes using a novel 0.5 % hypotonic Riboflavin solution.

Patients and methods: The study is designed as a retrospective study of consecutive case series of 100 eyes of 79 patients. A modified CXL-protocol without epithelial removal was applied to enhance Riboflavin penetration to stroma by use of 0.5% hypotonic- instead of ”standard” 0.1% isotonic-Riboflavin solution in addition to use of tensioactive penetration enhancers and epithelium scarification.

Results: At the final examination ≥ 12 months after surgery mean uncorrected (UDVA) and corrected (CDVA) distant visual acuity increased significantly from 20/143 and 20/36 to 20/95 and 20/27 respectively, with P < 0.01 for both. Safety index (ratio between postoperative and preoperative CDVA) was 1.35. Mean manifest cylinder (astigmatism) decreased from -4.11±2.44D (range -9.0 to -0.25) to -3.54±2.39D (range -8.75 to +2.5) (P< 0.02). Mean posterior corneal elevation over floating-best-fit-sphere (protrusion) and mean corneal surface irregularity index decreased from 82.88±43.08 µm (range 21.0 to 209.0) to 71.18±34.63µm (range 15.0 to 159.0) (P<0.01) and from 49.74±4.49 µm (range 19.0 to 174.0) to 44.97±30.41µm (range 9.0 to 174.0) (P<0.02) respectively. Mean baseline endothelial cell count decreased insignificantly to 2598±374 (P=0.31)

Conclusion: The modified “epithelium-on” CXL- protocol was safe and effective in treatment of keratoconus and the results were comparable to the results with CXL using standard “epithelium-off” protocol.