COMPARATIVE STUDY BETWEEN EPITHELIUM ON AND EPITHELIUM OFF COLLAGEN CROSS LINKING WITH RIBOFLAVIN AND UVR IN TREATMENT OF EARLY KERATOCONUS

Document Type : Original articles: include clinical trials, interventional research, Basic researches and clinically relevant laboratory investigations

Authors

Ophthalmology dept., Faculty of Medicine, AL-Azhar Univ., Assuit, Egypt

Abstract

Objective: To compare the safety and efficacy epithelium on versus epithelium off collagen cross
linking with riboflavin and UVR in treatment of early keratoconus.
Patients and Methods: The
present study was a prospective, randomized study. 40 eyes from 25 patients with a mean age of 24
years (range: 15–35 years) were included. There were 15 males and 10 females, and all of them
underwent corneal CXL using riboflavin and ultraviolet-A light at the Tipa Eye Hospital, Assuit.
Results: Among the included samples, 20 eyes underwent epithelium-on corneal collagen CXL, and
20 eyes underwent epithelium-off corneal CXL. The incidence of postoperative pain was lowered by
about 20% in the trans-epithelial group as compared with the epithelial-off group in the first postoperative week. In addition, the incidence of postoperative corneal haze was lowered by about 50% in
the transepithelial group as compared with the epithelial-off group in the first postoperative week. It
was also noticed that the CXL was formed in the upper-third of the corneal stroma, 20-30 μm
beneath bowman membrane in the transepithelial CXL technique, while in the classic debridement
technique; it was formed much deeper in the stoma. In group I, after 3 and 6 months, there was a
non-statistically significant corneal thinning. In group II, none statistically significant corneal thinning
was detected after 3 months, but after 6 months there was some regression in the form of corneal
thinning by nearly 5-10 μm in 20% of cases.
Conclusion: Both epithelium-off CXL and the epitheliumon CXL were effective in stabilizing the progression of keratoconus at least for 6 months; however,
the epithelium-off CXL appeared to be much more effective in improving the refractive best-corrected
visual acuity and topographic outcomes in keratoconic eyes compared with the epithelium-on CXL.


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