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 (Kmax), 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 Kmax 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 Kmax 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.
Accelerated epithelium-off corneal collagen cross-linking for teenagers with keratoconus
After disinfection, the eye speculum was placed and Oxybuprocaine Hydrochloride Eye Drops was applied in the operative eye, and the cornea was soaked with 18% ethanol for 20 seconds. When the corneal epithelium was loosened, the epithelial tissue within central 10 mm diameter of the cornea was removed. The 0.1% riboflavin eye drops was administered every 90 seconds, for a total of 10 minutes. Whether riboflavin had penetrated the whole corneal stroma and entered the aqueous humor of the anterior chamber was determine under a cobalt blue filter on the slit lamp microscope. The KXL® system, Avedro’s corneal cross-linking procedure was utilized to irradiate the cornea at a wavelength of 370 nm, and an intensity of 30 mW/cm2, for 4 minutes. Artificial tear drops were used in the process of irradiation to maintain corneal surface humidity.