Purpose: To investigate the longitudinal relationship between myopia and retinal shape in Chinese children.
Methods: A total of 2471 seven-year-old Chinese children were measured for axial length, anterior corneal radius of curvature, anterior chamber depth, lens thickness, central spherical equivalent, and peripheral refractions along the horizontal meridian (±15°, ±30°) under cycloplegia. Retinal shape was fitted using vertex radius of curvature, asphericity, and an offset. The areas under the horizontal retinal curve, the nasal side of areas under the horizontal retinal curve and the temporal side of areas under the horizontal retinal curve, were calculated. Children were tested annually for 5 years from year 0 to 4, with 1123 newly developed myopes divided into eight subgroups based on relative time to myopia onset.
Results: In follow-up subgroups, vertex radius of curvature showed positive correlations with central spherical equivalent from years 1 to 4. Smaller temporal side of areas under the horizontal retinal curve was associated with negative central spherical equivalent each year. Myopic shift (Δcentral spherical equivalent) was negatively correlated with baseline central spherical equivalent and with greater change in areas under the horizontal retinal curve from year 0 to 4. The absolute change in temporal side of areas under the horizontal retinal curve (0.39 ± 1.15 mm2) was significantly larger than the absolute change in nasal side of areas under the horizontal retinal curve (0.05 ± 1.11 mm2) over the 4 years. In myopia onset subgroups, temporal side of areas under the horizontal retinal curve was significantly smaller than nasal side of areas under the horizontal retinal curve. The ratio of temporal side of areas under the horizontal retinal curve/nasal side of areas under the horizontal retinal curve was closest to 1 in the year before myopia onset and decreased as myopia developed. Vertex radius of curvature, areas under the horizontal retinal curve, and temporal side of areas under the horizontal retinal curve decreased linearly as myopia progressed.
Conclusion: A progressive steepening of the horizontal posterior retina was associated with myopia progression. Myopia shift was negatively correlated with baseline central spherical equivalent and with greater change in posterior retinal shape. As myopia progressed, the horizontal retina shape displayed increased asymmetry.
Keywords: Anyang Childhood Eye Study; children; myopia; myopic shift; retinal shape.