Sex differences in ocular biometric measurements: A twin study
Han Zhang1, Jing Zhou1, Lili Yang2
1Department of Ophthalmology, Inner Mongolia Chaoju Eye Hospital, Hohhot, China.
Frontiers in Medicine
|December 5, 2022
Summary
Adolescent twins show significant differences in ocular biometrics. Girls in same-sex twin pairs (SSF) had smaller ocular measurements compared to other groups, impacting refractive development.
Area of Science:
- Ophthalmology
- Genetics
- Human Biology
Background:
- Ocular biometric measurements are crucial for understanding refractive development and potential visual impairments.
- Previous research on gender differences in ocular biometrics within twin pairs is limited.
- Twin studies offer a unique model to explore genetic and environmental influences on ocular development.
Purpose of the Study:
- To investigate gender-specific differences in ocular biometric measurements among adolescent dizygotic (DZ) twin pairs.
- To compare ocular measurements between same-sex and opposite-sex twin pairs.
- To identify potential influences of uterine environment on ocular development.
Main Methods:
- Retrospective analysis of ocular biometric data from 64 adolescent twins (32 pairs).
- Categorization into four groups: same-sex male (SSM), opposite-sex male (OSM), opposite-sex female (OSF), and same-sex female (SSF) twins.
- Measurements included axial length (AL), white-to-white (WTW) distance, lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT), and keratometry (Ks, Kf).
Main Results:
- Overall, boys exhibited higher height, AL, and WTW, but lower Ks and Kf than girls (p < 0.05).
- Adolescents in same-sex female (SSF) twin pairs showed significantly smaller ocular measurements (LT, ACD, CCT, WTW, AL) and higher keratometry readings (Ks, Kf) compared to other groups (p < 0.05).
- Specifically, SSF twins had lower ACD and higher Kf compared to opposite-sex female (OSF) twins (p < 0.05).
Conclusions:
- Significant differences in ocular biometric measurements exist between adolescent dizygotic twin pairs.
- Sharing the uterus with a twin, particularly in same-sex female pairs (SSF), is associated with smaller ocular indicator measurements.
- These findings contribute to understanding eyeball and refractive development in adolescents, highlighting potential environmental influences within the uterine environment.
