The Morphological Relationship Between Dome-Shaped Macula and Myopic Retinoschisis: A Cross-sectional Study of 409 Highly Myopic Eyes

PURPOSE: The purpose of this study was to analyze the clinical features of dome-shaped macula (DSM) in highly myopic eyes and its morphological relationship with myopic retinoschisis (MRS). METHODS: In this cross-sectional study, 409 eyes of 409 patients with high myopia who had spectral-domain optical coherence tomography (OCT) examinations were included. The associations of DSM with the distribution of MRS and ocular biometry were evaluated. RESULTS: Of 409 eyes, DSM was detected in 64 eyes (15.6%). The eyes with DSM were more myopic (−18.8 ± 3.9 vs. −13.4 ± 5.9; P < 0.001) and had longer axial length (31.7 ± 2.4 vs. 29.5 ± 2.5; P < 0.001) compared with those without DSM. A higher rate of extrafoveal retinoschisis (35.9% vs. 9.6%; P < 0.001) and a lower rate of foveoschisis (10.9% vs. 26.1%; P = 0.01) were detected in the eyes with DSM compared with those without DSM. In the eyes with DSM, MRS was detected in 30 eyes (46.9%). MRS predominantly affected the extrafoveal area (76.7%), especially the base of the dome (82.6%). The extrafoveal retinoschisis was most frequently distributed in the superior quadrant (52.2%). None of the eyes with DSM displayed fovea-only retinoschisis. The ratio of the height and width of the macular bulge was higher in eyes with MRS than those without MRS (0.05 vs. 0.04; P = 0.001). CONCLUSIONS: A DSM is found in highly myopic eyes with a longer axial length. MRS in eyes with DSM is more likely to affect the extrafoveal area, especially the base of the dome. A steeper macular bulge is associated with the occurrence of MRS.