The Association of Peripheral Refraction and Relative Peripheral Refraction with Astigmatism in Shanghai Schoolchildren's Myopia: A Cross-Sectional Study.

Purpose: Currently, no relevant studies have reported a relationship between astigmatism and peripheral refraction (PR). We aimed to describe the association between PR and relative peripheral refraction (RPR) with astigmatism in Chinese children with mild to moderate myopia, and to provide new insights into the influence of astigmatism.

Methods: Three-hundred-and-seven children (6-14 years old) from Shanghai were included in this study. The PR and RPR were measured using multispectral refraction topography (MRT). Cycloplegic refraction was measured using an autorefractor (KR-8900, Topcon), whereas axial length and ocular biological parameters were measured using Zeiss IOLMaster 700. Only data from the right eye were analyzed. Multivariate linear regression was used to explore the relationship between cylinder power and MRT parameters.

Results: Overall, the median spherical equivalent was -1.50 D (interquartile range, IQR: -2.25, -0.88), showing an apparent trend of hyperopic defocus from the macula to the peripheral retina. Astigmatism was correlated with PR rather than RPR especially at eccentrically inferior and within a 45° radius of the retina (coefficients 0.12-0.18,  < 0.05). Multivariate linear regression analysis demonstrated that the effect of astigmatism on PR tended to increase with greater lens thickness.

Conclusions: Astigmatism may be a risk factor for myopia due to its impact on peripheral refraction as opposed to relative peripheral refraction. In this cross-sectional study, we also found evidence supporting the association between peripheral hyperopia and myopia.