The aim of this study is to investigate the clinical characteristics of age-related cataract (ARC) patients in ultraviolet-irradiated areas and the role and mechanism of glutathione peroxidase (GPX) content in aqueous humor.

From July 2024 to July 2025, 140 ARC patients (140 eyes) who visited Peking University Third Hospital (Beijing), Tibet Autonomous Region People′s Hospital (Lhasa), Chifeng Songshan Hospital (Chifeng), Kezuo Banner Hospital (Tongliao) and Xilinhot Xilingol League Central Hospital were enrolled. Among them, there were 83 patients (83 eyes) female and 57 male (57 eyes) with a mean age of (69.7±9.3) years (ranging from 51 to 89 years ). According to the mean annual accumulated ultraviolet radiation from 2011—2014, subjects were classified into low-ultraviolet groups, medium-ultraviolet groups, and high-ultraviolet groups. According to age, patients were divided into the 50 to <65, ≥65 to <75, ≥75 to <85, and ≥85 groups. All ARC patients underwent routine preoperative cataract examinations before enrollment, including best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp microscopy, and fundus examination. History of high myopia, diabetes, hypertension, and cardiovascular/cerebrovascular disease was queried and recorded. Continuous variables that passed tests for normality (age, BCVA, IOP, GPX, etc.) are described as ±s, between-group comparisons were performed using one-way ANOVA, and when differences were statistically significant, pairwise comparisons were further performed using the Bonferroni method. Comparisons between two groups for binary variables used the Mann-Whitney U test; comparisons among multiple groups for ordinal variables used the Kruskal-Wallis H test. Categorical data such as sex and laterality are presented as counts and percentages and compared using the chi-square test. Correlations between continuous variables and ordered categorical variables were assessed with Spearman′s correlation coefficient; correlations between continuous variables were assessed with Pearson′s correlation coefficient. Multivariate linear regression was used to explore factors influencing GPX.

The proportions of patients with cortical opacity >3 scores in the low, medium, and high UV groups were 23.2%, 29.2%, and 44.4%, respectively; the proportions with posterior subcapsular opacity scores >3 were 32.1%, 58.3%, and 75.0%, respectively. The distributions of cortical opacity grading and posterior subcapsular opacity grading differed significantly (H= 6.45, 15.74; P<0.05), whereas nuclear opacity grading showed no significant difference (H=3.78, P> 0.05). The BCVA in the low, medium, and high UV groups were (0.84±0.78) logarithmic minimum angle of resolution (logMAR), (1.53±0.85) logMAR, and (1.81±0.86) logMAR, respectively, with significant differences among groups (F=17.46, P<0.05); pairwise comparisons between low vs. medium and low vs. high UV groups were both statistically significant (adjusted P<0.05). Aqueous humor GPX levels in the low, medium, and high UV groups were (332.19±187.74) U/ml, (292.98±177.55) U/ml, and (183.76±144.06) U/ml, respectively, with significant differences among groups (F=8.16, P<0.05). Pairwise comparisons of low vs. high and medium vs. high UV groups were both significant (adjusted P< 0.05). There was no significant difference in IOP among the low, medium, and high UV groups (F=1.89, P>0.05). The proportion of patients with ≤ 3 scores in 50 to <65 group, ≤ 65 to <75 group, ≤ 75 to <85 group and ≥ 85 group were 74.4%, 72.5%, 54.5% and 30.8%, respectively; The proportion of patients with of 3 to 5 scores in 50 to <65 group, ≤ 65 to <75 group, ≤ 75 to <85 group and ≥ 85 group were 20.9%, 17.6%, 33.3% and 38.4%, respectively; The proportion of patients with ≥ 5 scores in 50 to <65 group, ≤ 65 to <75 group, ≤ 75 to <85 group and ≥ 85 group was > 4.7%, 9.8%, 12.1% and 30.8%, respectively. There were statistically significant differences in the grading distribution of nuclear opacity in arc patients at different ages ( H=12.11, P<0.05). GPX level was significantly negatively correlated with UV grading, cortical opacity grading, nuclear opacity grading, posterior subcapsular opacity grading, and BCVA (r= -0.33, -0.36, -0.18, -0.27, -0.27; P<0.05), and showed no significant correlation with age or IOP (r= 0.007, -0.005; P>0.05). Multiple linear regression showed that UV grading and cortical opacity grading were independent negative predictors of aqueous humor GPX level (β= -50.45, -62.87, 95%CI: -90.60 to -10.31, -109.14 to -16.60; t=-2.49, -2.69; P<0.05), whereas nuclear opacity grading and posterior subcapsular opacity grading did not significantly affect aqueous humor GPX level (β=16.56, -18.40, 95%CI: -35.20 to 68.32, -59.03 to 20.02; t=-0.63, -0.98; P>0.05).

Long-term exposure to UV radiation reduces aqueous humor GPX levels in ARC patients, impairs ocular antioxidant stress capacity, and is closely associated with aggravated cortical and posterior subcapsular opacities and visual acuity decline. UV radiation grade and cortical opacity grading are key factors affecting aqueous humor GPX levels.