Retinal Curvature at the Posterior Pole is Associated With Myopic Shift and Axial Elongation in Children

Abstract

Purpose: : Retinal curvature at the posterior pole was shown to be associated with peripheral refraction, and there exists strong evidence that peripheral refraction influences refractive development. The purpose of this study was to investigate whether retinal curvature is associated with myopic shift in children.

Methods: : Central refraction was measured in right eyes of 92 emmetropic or near-emmetropic children age 7-11 years as sphere (SPH) and sphere equivalent (SEQ) with a Shin-Nippon NVision K5001 autorefractometer at baseline and after an average of 30 months follow-up. For the estimation of retinal curvature, axial eye length was measured with a custom-made optical low coherence interferometer and subtracted from eye length measured peripherally at 20º in the temporal, superior, nasal and inferior fields. The correlation between baseline retinal curvature and shift in central refraction was evaluated with a multiple regression analysis using backward elimination.

Results: : SEQ was +0.05±0.54D (mean±SD). Shifts in SPH and SEQ, as adjusted over a 30-month interval to account for individual differences in the follow-up period, were -0.23±0.53D and -0.21±0.56D, respectively. Significant correlation was observed between baseline retinal curvature in the nasal-superior fields and myopic shift in SPH (p=0.015, R²=9.4%) and SEQ (p=0.022, R²=8.6%), steeper curvature resulting in greater myopic shift. Correlation coefficients were larger for both SPH and SEQ in subgroups that developed myopia (n=8, R²≈32%) or progressed in myopia (n=5, R²≈62%). No significant correlation was observed in the temporal-inferior fields. Myopic shift was highly correlated with axial elongation (p≤0.001), but not significantly correlated with baseline refraction. Retinal curvature did not change significantly, except in the inferior field, where it became slightly steeper (p=0.049, paired t-test).

Conclusions: : The significant correlation between retinal curvature in the nasal-superior fields and central myopic shift, with the latter being independent on baseline refraction, supports the hypothesis that eye shape at the posterior pole is one of the factors influencing axial eye growth and may be a better predictor for myopia development or progression than baseline refraction.

Keywords: myopia • refractive error development • visual development: infancy and childhood