Analysis on ocular biometric parameters in adult cataract surgery

Abstract

Introduction: Biometrics are crucial in calculating IOL power for best refractive advantage in cataract surgery. Regional data provides insights on corneal astigmatism and facilitates forecasts but data for Sri Lankan population is lacking.Objective: To identify ocular biometry characteristics in Sri Lankans and compare with other populations.Method: A cross-sectional retrospective study assessed ocular biometry characteristics in consecutive cataract surgery candidates at a tertiary unit in National Eye Hospital of Sri Lanka between February and August 2021. Data from 237 eyes in 237 candidates of age over 40 and under 80 years were analysed. Data on Keratometry(K), axial length(AL) and IOL power were statistically analysed through SPSS software. Sample was divided as: age between 40-60 years and 60-80years. Descriptive statistics and unpaired t-test to compare means between groups were utilised.Results: Mean Age was 62.71±7.89 years. Mean AL was 23.11±1.11mm (range 21.00-30.56)mm with majority between 22-24mm(72.6%). Mean K was 44.25±1.57mm. IOL powers most used were between 23-25D (46.3%) (range 4D,28D). Mean astigmatism was 0.82±0.78D and 26.6%, 5.9% and 1.3% had over 1.0D, 2.0D and 3.0D respectively.Discussion: In males mean K was lower (43.80±1.62 vs 44.61±1.44) (p=0.00) and AL was longer (23.31±1.20 vs 22.94±1.01) (p=0.013). The older age group had shorter AL (p=0.006) and higher astigmatism(p=0.049). AL in our sample was shorter than Caucasians but comparable with other South Asian studies. Astigmatism prevalence was lower than other studies.Conclusion: This study gives an insight of ocular biometrics, corneal astigmatism and common IOL powers in this sample. A larger sample size study may project figures for entire Sri Lankan population.