Evolution of Dome-shaped Macula Is Due to Differential Elongation of the Eye Predominant in the Peri-dome Region.

Purpose: To determine the mechanism behind macular bulge height increase in eyes with dome-shaped macula (DSM).
Design: Retrospective, observational case series.
Methods: Eyes presenting with DSM followed up for a minimum of 1 year were examined using ocular biometry and spectral-domain optical coherence tomography at baseline and at end of follow-up. Axial length (AL), DSM bulge height, and central and peripheral choroidal thickness (nasal, temporal, superior, and inferior quadrants) were reported. Eyes were categorized into 2 groups for comparison: the "mini-DSM" group (DSM < 100 μm) and the "classic" DSM group (DSM > 100 μm).
Results: Fifty-eight eyes (33 patients) were studied: 32 (55%) were classic DSM and 26 (45%) mini-DSM. During the mean follow-up of 51.76 ± 36.01 months, mean AL increased from 26.99 ± 2.94 mm to 27.12 ± 3.09 mm (P = .010) and mean macular bulge height increased from 235.88 ± 282.47 μm to 262.34 ± 317.15 μm (P < .001). DSM height change was significantly higher than AL change (P < .001). Mean peripheral choroidal thickness significantly decreased nasally (P = .008), temporally (P = .026), and inferiorly (P < .001). Mini-DSM eyes exhibited shorter AL (26.17 vs 27.66 mm; P = .027), greater visual acuity (0.169 vs 0.437 logMAR; P = .002), and fewer macular complications compared to classic DSM eyes.
Conclusions: Macular bulge increase in DSM is associated with eye elongation and overall thinning of the peripheral choroid. DSM might result from differential elongation of the eye predominant in the peri-dome region. Mini-DSM (ie, inferior to 100 μm) are characterized by slower evolution, better visual prognosis, and fewer complications compared to "classic" DSM.
(Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)