Two-years evolution of two-dimensional peripheral refraction in children

Abstract

Purpose : A relative peripheral hyperopia has been suggested as a trigger on myopization in children. However, this is not fully validated yet, due to the lack of longitudinal results following the development process. To address the gap, our aim was to measure high-resolution two-dimensional peripheral refraction maps during two years of myopia progression in a group of children.

Methods : Peripheral refraction maps were measured using a peripheral sensor device (VPR, Voptica SL, Murcia, Spain) in a group of Chinese children (age 9-16 years) under cycloplegia. The maps cover a field from nasal 30° to temporal 30° of every 1°, and from superior 20° to inferior 16° of every 4°. After the study was closed, 214 children’s data were available after one year and 152 children’s data were available after two years. The participants were classified into three refraction progression groups based on their refractive change for hyperopic, emmetropic, and myopic subjects, separately. The difference of baseline peripheral defocus pattern was compared between each group by using ANOVA test. Central myopia progression as a function of peripheral defocus was investigated by simple linear regression.

Results : After the first year, a significantly different from the baseline refraction pattern was found between the various progression group in emmetropes. Baseline peripheral defocus in the central vertical field (horizontally, within ± 15°) at baseline was found to be significantly correlated with central myopic shift, especially in the superior retina [(S8°-S12°) X (N5°-T5°)]. Emmetropic subjects with more myopic defocus in the superior retina had more myopic progression (for refractive change, r=0.32, p<0.001; for axial change, r=0.42, p<0.001) (Figures a&b). In contrast, no obvious difference in baseline refraction pattern was found in the groups of hyperopes and myopes. The same tendency was confirmed after 2 years.

Conclusions : Children having the greater progression of myopia in central refraction over a two-year- period presented an initial relative myopic defocus in the superior retina. This type of relative refraction in the superior retina could be used as a predictor of central myopia. In relation, devices for keeping the superior retina emmetropic in children might be a myopia control strategy.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.