Purpose: A posterior staphyloma has been reported to be present in some eyes with retinitis pigmentosa (RP), and the purpose of this study was to determine the macular curvature of non-highly myopic RP eyes. Methods: This was a retrospective, observational study. The medical charts of the right eyes of 143 patients with RP and 60 controls whose axial length ranged from 21.5 mm to 26.0 mm were reviewed. The mean curvature of Bruch's membrane within 6 mm of the central macula obtained from the horizontal optical coherence tomographic images were evaluated as the mean macular curvature index (MMCI). The relationships between the MMCI and other clinical factors were assessed. Results: The mean MMCI of RP patients (-13.73 ± 9.63 × 10-5 μm-1) was significantly lower than that of the controls (-6.63 ± 5.63 × 10-5 μm-1). This indicated a deeper concave shape of the macula in RP eyes (P < 0.001). The MMCI was significantly correlated with the age (r = 0.20; P = 0.016) and the axial length (r = -0.24; P = 0.004). Further analysis suggested a nonlinear effect of the ellipsoid zone width on the macular curvature in the RP eyes. Conclusions: There is a high incidence of steeper macular curvatures even in non-highly myopic RP eyes, and the steepness was also affected by the degree of photoreceptor degeneration.
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