Riboflavin-ultraviolet a corneal cross-linking for keratoconus

ABSTRACT

To evaluate the safety, efficacy of riboflavin-ultraviolet A irradiaton [UVA] corneal cross-linking and present refractive changes induced by the treatment in cases of Keratoconus. The study includes 15 eyes of 9 patients with keratoconus with an average keratometric [K] reading less than 54 D and minimal corneal thickness greater than 420 microns. The corneal epithelium was removed manually within the central 8.5 mm diameter area and the cornea was soaked with riboflavin eye drops [0.1% in 20% dextran t-500] for 30 minutes followed by exposure to UVA radiation [365 nm, 3mW/cm[2]] for 30 minutes. During the follow-up period, uncorrected visual acuity [UCVA], best spectacle-corrected visual acuity [BSCVA], manifest refraction, slit lamp examination and topographic changes were recorded at the first week, first month, 3 and 6 months. There was statistically significant improvement of UCVA from a preoperative mean of 0.11 +/- 0.07 [range 0.05 - 0.3] to a postoperative mean of 0.15 +/- 0.06 [range 0.1 - 0.3] [P<0.05]. None of the eyes lost lines of preoperative UCVA but 1 eye lost 1 line of preoperative BSCVA. The preoperative mean K of 49.97 +/- 2.81 D [range 47.20 - 51.75] changed to 48.34 +/- 2.64 D [range 45.75 - 50.40]. This decrease in K readings was statistically significant [P<0.05]. All eyes developed minimal faint stromal haze that cleared in 14 eyes within 1 month. In only 1 eye, this resulted in a very faint corneal scar. Other sight threatening complications were not encountered in this series. Progression of the original disease was not seen in any of the treated eyes within 6 months of follow-up. Riboflavin-UVA corneal cross-linking is a safe and promising method for keratoconus. Larger studies with longer follow up are recommended