Stromal Demarcation Line in Pulsed Versus Continuous Light Accelerated Corneal Crosslinking for Keratoconus

Abstract

PURPOSE: To compare the stromal demarcation line depth in pulsed versus continuous corneal cross-linking (CXL) for keratoconus. METHODS: Seventy eyes underwent epithelium-off cross-linking, with 0.1 riboflavin applied during 10 minutes prior to ultraviolet irradiation at 30 mW/cm(2). Thirty-six eyes received pulsed irradiation (1 second on, 1 second off) for 8 minutes and 34 eyes underwent continuous irradiation for 4 minutes. Total fluence was 7.2 J/cm(2) for both groups. Patients were evaluated at 3 months after the procedure. RESULTS: A significantly deeper stromal demarcation line was observed in the pulsed group compared to the continuous group (201.11 +/- 27.76 vs 159.88 +/- 20.86 mu m; P < .001). CONCLUSIONS: The pulsed corneal cross-linking protocol induced a significantly deeper stromal demarcation line when compared to the 4 minutes of highly accelerated continuous CXL protocol. Neither CXL protocol induced a shallower demarcation line comparable to less accelerated CXL protocols previously reported.