Structural profile of dome-shaped macula in degenerative myopia and its association with macular disorders

Abstract

Background: To evaluate the detailed structural profile of dome-shaped macula and its association with myopic macular complications.

Methods: This retrospective study included 147 eyes of 93 patients who were diagnosed with degenerative myopia. The height of the scleral dome and diameter of the dome base were measured via enhanced depth imaging optical coherence tomography images with 1:1 μm setting. Spherical equivalent and best-corrected visual acuity were compared in eyes with and without dome-shaped macula. In eyes with dome-shaped macula, the height and diameter of the dome were compared in eyes with and without myopic macular complications including choroidal neovascularization, myopic foveoschisis, and macular hole.

Results: Dome-shaped macula was noted in 60 eyes (40.8%) of 42 patients. The mean height of the dome in the eyes with dome-shaped macula was 126.5 ± 69.4 μm (53 to 345 μm) and the mean diameter of the dome base was 2862.1 ± 794.9 μm (1567 μm to 4886 μm). In comparing eyes with and without dome-shaped macula, eyes with dome-shaped macula had higher myopia (- 13.7 diopters vs - 12.1 diopters, P = 0.022). There was no difference in visual acuity in eyes with or without dome-shaped macula (P = 0.132). The height and diameter of the dome in eyes with and without myopic foveoschisis were 78.6 ± 20.6 μm and 134.9 ± 71.6 μm, 2499.2 ± 303.1 μm and 2969.3 ± 645.7 μm, respectively (P = 0.009 and P = 0.017). However, the height and diameter of the dome were not related to the incidence of a macular hole (P = 0.324 and P = 0.605) and choroidal neovascularization (P = 0.835 and P = 0.905).

Conclusions: The prevalence of dome-shaped macula was about 40% in the eyes with degenerative myopia. Although dome-shaped macula was associated with higher degrees of myopia, a prominent dome seemed to be protective against myopic foveoschisis.

Keywords: Degenerative myopia; Dome-shaped macula; Myopic foveoschisis.

Fig. 1

Representative vertical optical coherence tomography of the 1:1 μm setting of an eye with a dome-shaped macula. a Dome-shaped macula without inferior staphyloma (dome height = 85 μm, dome diameter = 2167 μm, subfoveal scleral thickness = 442 μm). b Dome-shaped macula with inferior staphyloma (dome height = 234 μm, dome diameter = 2716 μm, subfoveal scleral thickness = 561 μm). Both images have a short black line (measurement line for dome height) and a long black dotted line (measurement line for dome diameter). The outer scleral border is marked by white arrowheads. Note obvious subfoveal scleral thickening in the eye with inferior staphyloma

Fig. 2

a Among the 97 eyes with a measurable dome, the bar graphs show the dome height distribution in the 70 eyes first diagnosed with the dome-shaped macula. b The receiver operating curve was used to obtain the optimal cut-off value (asterisk [*] = 48.5 μm)