Gender differences in higher-order aberrations and refractive error in Japanese school children: the Kyoto Childhood...

To investigate and analyze gender-related differences in myopia prevalence and factors associated with myopia progression in school-aged children.

Observational study.

This study involved 2,298 eyes (boys = 1194 eyes; girls=1104 eyes) of 1149 school children (597 boys; 552 girls) in two elementary/junior high schools in Kyoto Japan, examined from 2013 through 2022. Gender differences in all grades were evaluated in regard to subjective and objective refractive error (RE), axial length (AL), corneal keratometry, higher-order aberrations (HOAs), and a questionnaire regarding environmental factors of myopia progression.

In the girls in all grades, corneal keratometry was steeper and AL was shorter (p<0.05), coma-like and total aberration (in 6mm) corneal HOAs, coma-like, spherical-like, and total aberration (in 6mm) ocular HOAs were larger (p<0.05), in addition, only spherical aberration (in 4mm) corneal HOAs were smaller. In all grades, no gender-related differences were found in myopia prevalence (Grade 1: boys = 6.1%; girls = 6.5%, Grade 9: boys = 60.4%; girls = 65.4%) as well as RE. The questionnaire findings revealed that in all grades the girls spent more time reading and less time playing mobile-phone-app games (p<0.001).

In Japanese school children, AL was shorter in the girls than in the boys, although, no gender-related differences were observed in myopia prevalence. The steeper cornea in girls might be associated with that discrepancy, and partially with gender differences of HOAs. Gender-specific differences of AL and HOAs should be considered in the analysis of myopia progression in school-aged children.