To assess the safety and efficacy of riboflavin/ultraviolet-A-induced accelerated epithelium-off corneal collagen cross-linking (CXL) for teenagers with keratoconus.

In this case series study, 25 eyes of 18 patients with primary keratoconus who underwent riboflavin/ultraviolet-A-induced accelerated epithelium-off CXL in Zhengzhou Second People's Hospital from January 2017 to February 2018 were included, and the average age of patients was (14.4±1.3) years.The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), spherical equivalent (SE), maximum keratometry reading (K_max), thinnest corneal thickness (TCT), posterior corneal elevation (PCE) and endothelial cell density (ECD) were measured before and after CXL.The patients were followed up for one year.The complications and adverse reactions were recorded.The study adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Zhengzhou Second People's Hospital (No.KY2017002). Written informed consent was obtained from each patient and their guardian prior to the surgery.

The mean UCVA (LogMAR) was 0.96±0.35 at baseline, which was significantly improved to 0.84±0.33 at 1 year postoperatively (t=-5.765, P<0.01). The mean BCVA (LogMAR) was 0.45±0.22 preoperatively, which was significantly improved to 0.34±0.26 at 1 year postoperatively (t=-4.843, P<0.01). The mean SE was (8.66±5.11)D at baseline, which was significantly higher than (8.07±5.21)D at 1 year postoperatively (t=-3.253, P=0.003). The K_max was reduced from (58.58±9.07)D preoperatively to (56.25±9.98)D at 1 year postoperatively, with significant difference between the two time points (t=-4.357, P<0.01). The K_max was reduced more than 1 D in 17 eyes (68%), was stable in 6 eyes(24%), and was increased more than 1 D in 2 eyes (8%). The TCT was reduced from (485.0±32.5)μm at baseline to (475.3±35.5)μm at 1 year postoperatively, with significant difference between the two time points (t=-4.266, P<0.01). The differences of PCE and ECD between preoperative and postoperative 1 year were not statistically significant (t=1.023, P=0.316; t=-1.424, P=0.167). There was one eye suffering peripheral sterile corneal infiltrate 2 days postoperatively, and favorable prognosis was achieved after the topical steroids application.No complication was encountered in other subjects.

Riboflavin/ultraviolet-A-induced accelerated epithelium-off CXL is safe and effective in teenagers with keratoconus during the 1-year follow-up.The long-term effects need further observation.

Keratoconus; Corneal collagen cross-linking; Adolescent; Treatment efficacy