Association between Retinal Steepness and Central Myopic Shift in Children

Abstract

Retinal steepness at the posterior pole was shown to be associated with peripheral refraction, and there exists strong evidence that peripheral refraction influences central refractive development. The purpose of this study was to investigate whether retinal steepness is associated with central myopic shift in children. Central refraction was measured in OD of 140 children aged 7 to 11 years as central sphere equivalent refraction (CSER) and central sphere refraction at baseline and after ~30 months. For the estimation of retinal steepness, relative peripheral eye length (RPEL) was determined in OD by measuring length axially with a custom-made optical low coherence interferometer and subtracting it from eye length measured peripherally at 20° in the nasal, inferior, temporal, and superior fields. Association between baseline RPEL at the various locations and shift in central refraction was evaluated with a Structural Equation Modeling analysis. CSER at baseline measured +0.05 ± 0.54 diopters (D) (mean ± SD). Shift in CSER, as standardized over a 30-month interval to account for individual differences in the follow-up period, was -0.21 ± 0.56 D. A weak, but significant, correlation was observed between baseline RPEL in the temporal retina and myopic shift in CSER (r = 0.207, p = 0.049), steeper retinas displaying greater myopic shifts. Myopic shift was correlated with axial elongation but not correlated with baseline refraction. Analyses were performed for both CSER and central sphere refraction with near-identical results. RPEL did not change significantly. The significant correlation between temporal RPEL and central myopic shift, with the latter being independent of baseline refraction, supports the hypothesis that eye shape at the posterior pole is one of the factors influencing visually guided axial eye growth, possibly through associated peripheral defocus. Its predictive value for refractive development and limitation to the temporal retina require further investigation.