Purpose: To evaluate the efficacy of trans-epithelial cross-linking (TE-CXL) and to compare the visual and topographic outcomes of TE-CXL versus epithelium-off cross-linking (CXL) in adult keratoconus (KC).
Design: A prospective non-randomized open case series.
Methods: The study enrolled 27 KC eyes of 15 patients treated by TE- CXL (group I) and 35 KC eyes of 20 patients treated by epithelial-off CXL (group II). In group I, riboflavin 0.1% solution in 15% Dextran T500 with sodium EDTA 0.01% and trometamol (Ricrolin TE) was used with intact corneal epithelium. In group II, the epithelium was removed. Then, riboflavin 0.1% solution (10 mg of riboflavin 5-phosphate in a 20% dextran T-500 10-mL solution (Ricrolin) was applied. Ultraviolet, A irradiation, was occurred using UVA system (CBM X-linker, at 3 mW/cm2). Preoperative and postoperative assessment included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal astigmatism, maximum keratometry (K max), central corneal thickness (CCT), thinnest corneal thickness, and spherical aberration using Wavelight oculyzer –pentacam HR. All included patients had at least one-year follow-up.
Results: In both groups, there was a significant improvement in visual and topographic outcomes at 6 months postoperative. Furthermore, in the TE-CXL group; the vision and keratometric readings gradually deteriorated at the end of one year follow- up. Comparison of postoperative changes at 12 months between two groups demonstrated the epithelial-off CXL group had statistically better results concerning UCVA, BCVA, corneal astigmatism, and K max (p=0.03, 0.002, 0.001, and <0.001 respectively).
Conclusions: Functional and clinical regression in TE-CXL group to the preoperative status after an initial improvement could conclude that TE-CXL cannot stabilize KC for a long term. Conventional CXL is superior on TE-CXL in KC stability after 12 months of follow-up.
Keywords: Keratoconus, cross-linking, epithelial-off, trans-epithelial, ricrolin-TE