Posterior Pole Shape and Its Association With Axial Length and High Myopia

Purpose To quantify retinal curvature as a geometric descriptor of posterior pole configuration and to evaluate its associations with axial length and high myopia. Methods This dual-center observational study included 142 participants (284 eyes). Retinal curvature was derived from three-dimensional reconstruction of the Bruch’s membrane surface using wide-field swept-source optical coherence tomography angiography after axial length–based magnification correction. Curvature was summarized across predefined macular regions. Eye-level associations of high myopia (HM) and axial length with retinal curvature were evaluated using generalized estimating equations adjusted for age, sex, and imaging center. Interocular analyses were performed using linear regression models relating interocular axial length differences (ΔAL) to corresponding differences in retinal curvature. Results In eye-level analyses, HM was associated with lower RC5 (β = −0.041; 95% CI, −0.071 to −0.012; q = 0.021), RC6 (β = −0.088; 95% CI, −0.114 to −0.063; q < 0.001), and superior retinal curvature (RCS; β = −0.066; 95% CI, −0.097 to −0.035; q < 0.001). Per 1-mm greater axial length, lower values were observed for RC5 (β = −0.026; 95% CI, −0.038 to −0.014; q < 0.001), RC6 (β = −0.046; 95% CI, −0.058 to −0.033; q < 0.001), RCS (β = −0.030; 95% CI, −0.043 to −0.018; q < 0.001), and RCT (β = −0.019; 95% CI, −0.032 to −0.006; q = 0.014). In interocular analyses, ΔAL was positively associated with ΔRC3 (β = 0.120; 95% CI, 0.079 to 0.160; q < 0.001) and ΔRCS (β = 0.041; 95% CI, 0.007 to 0.075; q = 0.026), but inversely associated with ΔRC6 (β = −0.087; 95% CI, −0.127 to −0.048; q < 0.001). Conclusions Retinal curvature provides a region-specific geometric characterization of posterior pole configuration. In myopic eyes, curvature demonstrates spatially heterogeneous associations with axial length and high myopia, with more pronounced variation in outer regions. These findings support the use of curvature-based metrics to describe spatial variation in posterior pole geometry.