Transepithelial Corneal Cross-linking With Supplemental Oxygen in Keratoconus: 1-Year Clinical Results.

PURPOSE: To evaluate the efficacy and safety of transepithelial corneal cross-linking (CXL) with supplemental oxygen. METHODS: This was a prospective, non-comparative, pilot cohort study conducted at the National Reference Center for Keratoconus (Toulouse, France) on patients with progressive keratoconus. Transepithelial, pulsed, accelerated CXL was performed in an oxygen-rich atmosphere. Oxygen goggles were applied to the eyes to maintain a high level of oxygen during treatment. The main efficacy outcome was the mean change from baseline in maximum keratometry (Kmax) and the secondary outcomes were the mean changes in flat keratometry (K1), steep keratometry (K2), mean keratometry (Km), corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), and demarcation line depth. The safety outcomes were the incidence of adverse events, the mean change in pachymetry, and endothelial cell count. RESULTS: Thirty-four eyes of 34 patients were included. At 12 months postoperatively, the Kmax decreased by 1.56 ± 1.71 diopters (D) (P < .0001) and CDVA improved by 0.093 ± 0.193 logMAR (P < .02). The K2 and Km decreased by 0.51 ± 1.03 D (P < .02) and 0.40 ± 0.78 D (P < .01), respectively. There was no change in K1 and UDVA. The most frequent adverse event was corneal haze (64.78%). There were neither cases of infectious keratitis or loss of more than two lines in CDVA nor changes in pachymetry or endothelial cell count. CONCLUSIONS: Transepithelial CXL performed in an oxygen-rich atmosphere results in improved Kmax and CDVA with good safety. These promising findings suggest that this procedure could be safe and capable of halting the progression of keratoconus. [J Refract Surg. 2021;37(1):42-48.].

Transepithelial photorefractive intrastromal corneal crosslinking versus photorefractive keratectomy in low myopia.

PURPOSE: To compare the outcomes of transepithelial photorefractive intrastromal corneal crosslinking (CXL) and photorefractive keratectomy (PRK) in eyes with low myopia. SETTING: Purpan Hospital, Toulouse, France. DESIGN: Prospective case series. METHODS: Myopic patients with a manifest refraction spherical equivalent (MRSE) of -1.00 to -2.50 diopters (D) and a cylindrical component of plano to -0.75 D were included. The dominant eye had PRK (PRK eyes). The nondominant eye had transepithelial photorefractive intrastromal CXL with riboflavin (ParaCel Part 1 and 2), 30 mW/cm2 pulsed ultraviolet-A irradiation centered on the pupil (Mosaic System) for 16 minutes and 40 seconds, and a supplemental oxygen delivery mask (CXL eyes). The primary outcome measure was the change in the MRSE. Other outcome measures were the uncorrected (UDVA) and corrected (CDVA) distance visual acuities, mean keratometry, and endothelial cell count (ECC) over a 6-month follow-up. Adverse events were assessed. RESULTS: Nineteen patients were included. By 6 months, the mean MRSE had decreased by 0.72 D ± 0.42 (SD) in CXL eyes and by 1.35 ± 0.46 D in PRK eyes (P < .001). The mean change in UDVA was -0.35 ± 0.21 logarithm of the minimum angle of resolution (logMAR) in CXL eyes and -0.66 ± 0.19 logMAR in PRK eyes (P < .001). No complications were reported. The change in the ECC and CDVA was not statistically significant. CONCLUSIONS: Photorefractive keratectomy provided better visual and refractive outcomes than transepithelial photorefractive intrastromal CXL. Transepithelial photorefractive intrastromal CXL, however, showed the potential refractive effect of CXL but with a limited magnitude of myopic correction.