Analysis of ocular biometrics in cataract patients aged 40 and above in Suzhou, China

Purpose This cross-sectional study investigated the distribution of ocular biometric parameters in cataract patients aged ≥40 years from East China, with a specific focus on age- and sex-related differences and their correlations. Given the paucity of large-sample reference data for this population, we aimed to establish a localized framework to support precise surgical planning in refractive cataract surgery. Methods This retrospective study consecutively enrolled patients aged ≥40 years who underwent cataract surgery at Lixiang Eye Hospital of Soochow University between January 2019 and September 2022. Axial length (AL), anterior chamber depth (ACD), corneal curvature (K1, K2), corneal astigmatism, intraocular lens (IOL) power, and intraocular pressure (IOP) were assessed. Non-parametric tests, Spearman correlation analyses, and multivariable linear regression were applied using SPSS 22.0 (IBM Corp.). Results A total of 3,311 cataract patients (1,458 males, 1,853 females) were included. Female eyes had shorter AL and shallower ACD, but steeper corneal curvatures (K1, K2) compared to male eyes (all P < 0.001). With-the-rule astigmatism was significantly more prevalent in females, whereas against-the-rule astigmatism predominated in males. AL and ACD decreased with advancing age, and IOP was also negatively correlated with age. Corneal curvatures K1 and K2 increased with age, while corneal astigmatism showed a U-shaped pattern: initially decreasing before rising again after age 60–69. AL was positively correlated with ACD and negatively correlated with corneal curvature. Multivariable regression confirmed that age and sex were independently associated with all examined biometric parameters (all P < 0.05). Quantitatively, each additional year of age was associated with a 0.080 mm decrease in AL and a 0.182 D increase in IOL power. Conclusion This study provides comprehensive, large-sample reference data on ocular biometric parameters for cataract patients in East China. We identify distinct age- and sex-specific patterns, particularly the non-linear age-related changes in corneal astigmatism and the sex-specific differences in astigmatism axis distribution. These findings offer actionable benchmarks for preoperative IOL selection, astigmatism management strategies, and patient counseling, thereby contributing to optimized refractive outcomes in cataract surgery.