Medical hypothesis, discovery & innovation in optometry

Abstract

Background: Keratoconus is a progressive corneal ectasia causing visual impairment, often initially managed using spectacles or rigid gas permeable contact lenses, which do not halt disease progression. Corneal collagen cross-linking (CXL) is the only treatment proven to stabilize the condition. Although its efficacy is well documented globally, data from Nepal are limited. This study evaluated visual and keratometric parameters before and after CXL in Nepali patients with varying severities of keratoconus.
Methods: This retrospective, hospital-based study analyzed visual acuity and keratometric outcomes in patients with keratoconus who underwent epithelium-off CXL at Biratnagar Eye Hospital, Biratnagar, Nepal, between January 2019 and March 2023. Secondary data were extracted from medical records. Only eyes with minimum corneal thickness greater than or equal to 400 µm were included. Patients were classified into Amsler–Krumeich stages I–IV. Pre- and 1-month post-CXL assessments included uncorrected and best-corrected distance visual acuity (UCDVA and BCDVA, respectively) both recorded in logarithm of the minimum angle of resolution, keratometry, slit-lamp biomicroscopy, corneal topography, and fundus evaluation.
Results: A total of 195 eyes from 106 patients with keratoconus were analyzed; 84.0% (n = 89) underwent bilateral CXL. The mean (standard deviation [SD]) age was 19.4 (4.9) years, with most (n = 43, 40.6%) aged 16–20 years. Male patients comprised 71.7% (n = 76) of the cohort. The mean (SD) follow-up duration after CXL was 7.5 (2.6) months. Following CXL, overall BCDVA improved, with statistically significant gains in stages I and IV (both P < 0.05). UCDVA significantly improved in stage II (P < 0.05). In stage I and II eyes, the average keratometry became flatter by –0.4 D and –0.2 D, respectively (both P < 0.05). The mean average keratometry remained comparable to baseline in stage III and IV eyes (both P > 0.05).
Conclusions: CXL is effective in stabilizing keratoconus in Nepali patients, particularly in early stages. Significant improvements in BCDVA, as well as keratometric flattening, were observed in stage I and IV and in stage I and II eyes, respectively. Although advanced-stage eyes (III and IV) showed keratometric stability without significant flattening, the results suggest that CXL can slow or halt disease progression even in later stages. These findings highlight the importance of early diagnosis and timely intervention. Further prospective, multicenter studies are warranted to optimize treatment protocols and expand the understanding of CXL outcomes in this patient population.