Stromal Demarcation Line in Pulsed Versus Continuous Light Accelerated Corneal Cross-linking 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/cm2. 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/cm2 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 µm; 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.