Observational study of clinical characteristics of dome-shaped macula in Chinese Han with high myopia at Zhongshan Ophthalmic Centre

Purpose To evaluate the prevalence of dome-shaped macula (DSM) in highly myopic eyes among Chinese Han and to detect the correlation with myopic maculopathy and macular complications. Methods A total of 736 Chinese Han patients (1384 eyes) with high myopia (refractive error <= 6.0 diopters or axial length >= 26.5 mm) are reviewed based on information entered into a high-myopia database at Zhongshan Ophthalmic Centre. Subfoveal choroidal thickness (SFCT) and parafoveal choroidal thickness (PFCT) are measured. The prevalence of DSM in patients with myopic maculopathy is categorised from C0 to C4. Clinical features, including macular complications, SFCT and PFCT, are compared between myopic eyes with and without DSM. Results Among the 1384 eyes, 149 (10.77%) show DSM. In highly myopic eyes without macular complications, the best corrected visual acuity is significantly worse in patients with DSM (p=0.002), and the ratio between subfoveal and parafoveal choroidal thickness (S/PCT) is significantly elevated in patients with DSM (p=0.021). The proportion of foveal schisis (17.24% vs 62.86%) is much lower in eyes with DSM compared with those without DSM. However, the proportions of extrafoveal schisis (39.66% vs 5.37%), foveal serous retinal detachment (SRD) (5.17% vs 0) and epiretinal membrane (ERM) (24.14% vs 10.74%) are much higher in eyes with DSM. The proportion of DSM was lower in C0 and C1, but higher proportion of DSM was found in C3 and C4. Conclusions DSM is found in 10.77% of highly myopic eyes among Chinese Han. DSM might be a protective mechanism for foveal schisis and a risk factor for extrafoveal schisis, SRD and ERM.