The role of lens in early refractive development: evidence from a large cohort of Chinese children

Abstract

Purpose : To document longitudinal changes in spherical equivalent refraction (SER) and related biometric factors during early refractive development.

Methods : This was a prospective cohort study of Chinese children with baseline examinations in 2018, and subsequent annual follow-ups. At each visit, children received cycloplegic autorefraction and ocular biometry measurements following a standard protocol. Lens power (LP) was calculated using Bennett’s formula. Children were divided into eight age groups based on their baseline age: the 3-year-old, 4-year-old, 6-year-old, 7-year-old, 9-year-old, 10-year-old, 12-year-old, and 13-year-old age groups.

Results : This study included right-eye data from 5826 children. The 3- and 4-year-olds demonstrated an inflection point in longitudinal SER changes at a mild hyperopic baseline SER (+1 to +2 D), with children with more myopic baseline SER showing hyperopic refractive shifts while those with more hyperopic baseline SER showing myopic shifts. The hyperopic shift in SER was mainly attributed to rapid LP loss. Hyperopic shifts were rarely seen in the older age groups. Axial elongation accelerated in the premyopia stage, accompanied by a partially counter-balancing acceleration of LP loss. For children aged 3 to 7 years, the baseline SER of those with annual SER changes less than 0.25 D all fell in a mild hyperopic range (mean: 1.23 D, 95%CI: 1.20 to 1.27 D).

Conclusions : Our findings suggest that during early refractive development, refractions cluster around or above +1.0D. There is a pushback process in which increases in the rate of LP occur in parallel with increases in axial elongation.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.