[Analysis of the clinical efficacy of high-ultraviolet energy epithelium-removing A-CXL in juvenile and adult keratoconus].

Abstract

Objective: To compare the 1-year clinical efficacy differences of high-ultraviolet energy epithelium-removing accelerated corneal collagen cross-linking (A-CXL) in the treatment of primary keratoconus in juveniles and adults. Methods: This is a retrospective cohort study. The data of 72 patients (110 eyes) with keratoconus who received high-ultraviolet energy epithelium-removing A-CXL in the Ophthalmology Center of Xiangya Hospital, Central South University from August 2022 to December 2023 were collected. There were 52 male patients and 20 female patients, with aged (20.3±5.5) years. According to the age, they were divided into a juvenile group (≤18 years old, 35 cases, 56 eyes) and an adult group (>18 years old, 37 cases, 54 eyes). The visual acuity (uncorrected distant visual acuity, best corrected visual acuity), corneal endothelial parameters [corneal endothelial cell density, coefficient of variation of corneal endothelial cell area (CV), hexagonal cell ratio], morphological parameters [flat corneal curvature, steep corneal curvature, maximum corneal curvature (Kmax), central corneal thickness, thinnest point corneal thickness, etc.] and biomechanical parameters [stress-strain index (SSI), horizontal Ambrósio-related thickness (ARTh), etc.] before surgery and at 1, 3, and 12 months after surgery were compared between the two groups. Results: The best corrected visual acuity of the juvenile group at 1, 3, and 12 months after surgery was changed from 0.09±0.21 before surgery to 0.20±0.23, 0.13±0.22, and 0.14±0.22 respectively (all P<0.05). The best corrected visual acuity of the adult group was only changed from 0.16±0.29 to 0.24±0.30 at 1 month after surgery (P<0.05). The CV of the juvenile group at 1 month after surgery was 29.3%±2.1%, which was significantly higher than 28.4%±2.3% before surgery (P<0.05), while the CV of the adult group remained stable (P>0.05). At 1 month after surgery, the Kmax of the juvenile group increased from (53.85±6.56) D before surgery to (55.00±6.93) D, and that of the adult group increased from (54.13±10.02) D to (56.41±8.55) D (both P<0.05), and both returned to the baseline level at 3 months after surgery. The absolute values of the changes in Kmax of the adult group at 3 months and 12 months after surgery compared with the preoperative baseline values were (1.06±2.49) D and (1.52±2.62) D respectively, which were significantly higher than (0.01±2.37) D and (0.43±2.57) D of the juvenile group (both P<0.05). Biomechanical analysis showed that the SSI of the adult group at 3 months after surgery was 0.79±0.16, which was significantly higher than 0.72±0.13 of the juvenile group (P<0.05), while the ARTh was (187.3±81.8) μm, which was lower than (235.0±117.0) μm of the juvenile group (P<0.05). By 12 months after surgery, the SSI of the adult group was still higher than that of the juvenile group (P<0.05). Conclusion: Within 1 year after high-energy A-CXL, the improvement of corneal stiffness is more significant and the changes in corneal morphology are more obvious in adult patients, suggesting that the short-term efficacy of this surgical procedure for adult keratoconus is better than that for juvenile patients.