Biometric description of 34 589 eyes undergoing cataract surgery: sex differences

Abstract

Purpose To describe gender differences in the biometric parameters of a large sample of cataract patients. Cataract surgery has evolved from a vision restoration to a refractive procedure, and population-based studies are vital to optimise normative databases and post-surgical outcomes. Setting Miguel Servet University Hospital, Zaragoza, Spain. Design Retrospective single-centre observational study. Methods The study included 34589 eyes (20004 cataract patients). Biometric data was obtained from IOL Master 700 and Pentacam HR. Linear mixed models were used to account for inter-eye correlation. HofferQST formula was used to calculate the hypothetical distribution of IOL power (arbitrary lens; A=119.2). Results Most biometric variables showed significant differences between sexes (p<0.0001), such as 0.53mm shorter eyes found in females, of which 0.16mm are explained by shorter aqueous depth. Steeper anterior keratometries (∼0.75D) were found in females, to end up in no difference on anterior astigmatism magnitude, but different orientation (p<0.0001). The distribution of IOL power differed between sexes (p<0.001), with the interquartile range shifting one dioptre towards more powerful lenses in females and odds ratio (power>26D) = 2.26, p<0.0001 (Fisher’s). Conclusions Large sample size studies provide smaller margin of error, higher power, and controlled risk of reporting false (negative or positive) findings. Highly significant differences between sexes in ocular biometry were found; this supports the idea that including sex as a parameter in IOL calculation should be explored and may improve results. Additionally, the distribution of IOL powers was provided, which may be useful for manufacturers and hospital stock planning.