Table 1_Characteristics of cataracts in dry-hot valley-type high-altitude surgical cohort: a retrospective descriptive case series of 556 eyes from western China.docx

No individual UV exposure data were collected.</p>Results<p>Cortical opacity had the highest mean grade (3.18), followed by posterior subcapsular opacity (2.64) and nuclear (2.59). Severe opacities (C4-5, N4-5, P3-4) accounted for 35.3%, 16.7%, and 60.4% of all examined eyes, respectively. Among eyes from patients aged ≤60 years, who made up 17.3% of the total sample, 63.5% had severe posterior subcapsular opacity, and 27.1% of this younger subgroup had mature cataracts (C5 or P4 with absent fundus red reflex).

Age was significantly correlated with all three opacity types (Kendall's tau-b: cortical 0.336, P < 0.001; nuclear 0.432, P < 0.001; PSC 0.187, P = 0.004). Multivariable regression identified age (OR per year = 1.079, 95% CI: 1.051–1.107, P < 0.001) and diabetes (OR = 2.313, 95% CI: 1.149–4.656, P = 0.019) as independent risk factors for severe cortical opacity. Age was also independently associated with severe nuclear opacity (OR = 1.101, 95% CI: 1.067–1.136, P < 0.001) and severe posterior subcapsular opacity (OR = 1.035, 95% CI: 1.011–1.059, P = 0.004).

No significant gender differences were detected in any multivariable model.</p>Conclusion<p>In this surgically treated cohort from a dry-hot valley region, cataracts presented with a disproportionately high prevalence of severe opacities, particularly posterior subcapsular cataract, with evidence of early onset. The findings are hypothesis-generating and suggest that environmental factors, including intense UV exposure, may contribute.

However, individual-level exposure data are required to confirm causality. These results support the adoption of age-stratified cataract screening strategies and UV protection measures in ecologically vulnerable regions with similar environmental characteristics.</p>