Objective To characterize age-related cataract (ARC) morphology and subtype distribution across Yunnan (China), Vietnam, and Sri Lanka, and to assess associations with region, age, sex, and preoperative best-corrected visual acuity (BCVA). Methods We reviewed 390 patients (657 eyes) who underwent phacoemulsification with IOL implantation at tertiary eye hospitals in Yunnan, Vietnam, and Sri Lanka from 2019–2024. Exclusions: traumatic, congenital, metabolic, or secondary cataracts (e.g., post-uveitic), and combined procedures (e.g., cataract–glaucoma surgery). ARC subtypes were classified using LOCS III as pure cortical (CC), nuclear sclerotic (NSC), posterior subcapsular (PSC), or mixed (e.g., CC/NSC, CC/PSC). We collected demographics, preoperative BCVA (decimal notation), ocular comorbidities, and surgical indications. Regional differences were tested with ANOVA or Kruskal–Wallis; correlations used Spearman’s rank test (α = 0.05, two-sided). A sensitivity analysis used one eye per patient—selected as the more advanced cataract—to address bilateral inclusion. Results ARC subtype distribution differed significantly by region (χ2 = 105.33, df = 12, p < 0.001). CC/PSC was most common in Yunnan (34.7%) and Vietnam (56.6%); Sri Lanka had the highest proportion of pure CC (31.9%) and CC/NSC. Mean preoperative BCVA was better in Yunnan (0.43 ± 0.23), intermediate in Sri Lanka (0.25 ± 0.25), and worse in Vietnam (0.19 ± 0.24); all pairwise differences were significant (ANOVA F = 36.65, p < 0.001; Kruskal–Wallis H = 79.58, p < 0.001). Females comprised 60–68% of cases across regions. Age correlated positively with NSC (r = 0.37, p = 0.008) and CC/NSC (r = 0.47, p = 0.001). BCVA correlated inversely with mixed cataracts (r = − 0.67, p < 0.001) and pure PSC (r = − 0.32, p = 0.021). All key findings held in the single-eye sensitivity analysis (p < 0.001 for both BCVA and subtype distribution). Conclusion ARC morphology differs markedly across Yunnan, Vietnam, and Sri Lanka—CC/PSC dominates in Yunnan and Vietnam; pure CC and CC/NSC predominate in Sri Lanka. These patterns may reflect regional differences in UV exposure, nutrition, healthcare access, or genetic background. As a retrospective observational study, causal inference is limited—but the findings provide clear, testable hypotheses for future prospective research.

Latitudinal variation in morphological patterns of lens opacity among patients with cataracts

期刊论文
发表日期：

2026年7月13日

查看全文

Yali Feng,
Li Zhang,
Zisuo Li,
Jianfeng Zhao,
Yu Geng

摘要

Objective

To characterize age-related cataract (ARC) morphology and subtype distribution across Yunnan (China), Vietnam, and Sri Lanka, and to assess associations with region, age, sex, and preoperative best-corrected visual acuity (BCVA).

Methods

We reviewed 390 patients (657 eyes) who underwent phacoemulsification with IOL implantation at tertiary eye hospitals in Yunnan, Vietnam, and Sri Lanka from 2019–2024. Exclusions: traumatic, congenital, metabolic, or secondary cataracts (e.g., post-uveitic), and combined procedures (e.g., cataract–glaucoma surgery). ARC subtypes were classified using LOCS III as pure cortical (CC), nuclear sclerotic (NSC), posterior subcapsular (PSC), or mixed (e.g., CC/NSC, CC/PSC). We collected demographics, preoperative BCVA (decimal notation), ocular comorbidities, and surgical indications. Regional differences were tested with ANOVA or Kruskal–Wallis; correlations used Spearman’s rank test (α = 0.05, two-sided). A sensitivity analysis used one eye per patient—selected as the more advanced cataract—to address bilateral inclusion.

Results

ARC subtype distribution differed significantly by region (χ² = 105.33, df = 12, p < 0.001). CC/PSC was most common in Yunnan (34.7%) and Vietnam (56.6%); Sri Lanka had the highest proportion of pure CC (31.9%) and CC/NSC. Mean preoperative BCVA was better in Yunnan (0.43 ± 0.23), intermediate in Sri Lanka (0.25 ± 0.25), and worse in Vietnam (0.19 ± 0.24); all pairwise differences were significant (ANOVA F = 36.65, p < 0.001; Kruskal–Wallis H = 79.58, p < 0.001). Females comprised 60–68% of cases across regions. Age correlated positively with NSC (r = 0.37, p = 0.008) and CC/NSC (r = 0.47, p = 0.001). BCVA correlated inversely with mixed cataracts (r = − 0.67, p < 0.001) and pure PSC (r = − 0.32, p = 0.021). All key findings held in the single-eye sensitivity analysis (p < 0.001 for both BCVA and subtype distribution).

Conclusion

ARC morphology differs markedly across Yunnan, Vietnam, and Sri Lanka—CC/PSC dominates in Yunnan and Vietnam; pure CC and CC/NSC predominate in Sri Lanka. These patterns may reflect regional differences in UV exposure, nutrition, healthcare access, or genetic background. As a retrospective observational study, causal inference is limited—but the findings provide clear, testable hypotheses for future prospective research.