The Role of Sex in Ocular Biometry: A Large-Scale Study of Cataract Candidates in Greece

INTRODUCTION: Accurate intraocular lens (IOL) selection in cataract surgery relies on precise ocular biometry, yet variability between patients remains a challenge in achieving optimal refractive outcomes. Sex-related differences in biometric parameters and age-related changes in corneal astigmatism may contribute to this variability. This study aimed to evaluate sex-related differences in ocular biometry and age-related astigmatic changes in Greek cataract candidates using swept-source optical coherence tomography (SS-OCT). METHODS: This retrospective observational study included 6258 eyes from 3726 adult patients. Patients were scheduled for cataract surgery between July 2024 and July 2025 at a tertiary eye hospital in Athens, Greece. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), keratometry (K1, K2), corneal astigmatism (CA), and white-to-white (WTW) were measured using the Argos SS-OCT biometer. Predicted IOL power distribution was evaluated using the Hoffer Q formula for descriptive purposes, targeting emmetropia. Sex- and age-stratified analyses were performed. RESULTS: Male eyes demonstrated longer AL (by 0.46 mm), deeper ACD (by 0.13 mm), and larger WTW (by 0.20 mm) (p < 0.01), whereas female eyes had steeper K1 (by 0.78 D) and K2 (by 0.70 D) (p < 0.01). An age-related shift from with-the-rule (WTR) to against-the-rule (ATR) astigmatism was observed in both sexes, occurring approximately one decade earlier in male eyes. Female eyes were overrepresented below the 5th (5.54% vs. 4.00%, p < 0.01) and above the 95th (4.42% vs. 2.88%, p < 0.01) percentiles of the predicted IOL power distribution. CONCLUSION: Sex-related differences in ocular biometry and age-related changes in corneal astigmatism were observed in this cohort. These findings provide population-specific data and highlight variability in biometric characteristics among patients with cataracts which may be relevant for preoperative assessment and surgery planning.