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

Abstract

To determine the mechanism behind macular bulge height increase in eyes with dome-shaped macula (DSM). Retrospective, observational case series. 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 < 100μm) and the "classic" DSM group (DSM > 100μm). 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 ± 36.01months, mean AL increased from 26.99 ± 2.94mm to 27.12 ± 3.09mm (P= .010) and mean macular bulge height increased from 235.88 ± 282.47μm to 262.34 ± 317.15μm (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 27.66mm; P= .027), greater visual acuity (0.169 vs 0.437 logMAR; P= .002), and fewer macular complications compared to classic DSM eyes. 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 100μm) are characterized by slower evolution, better visual prognosis, and fewer complications compared to "classic" DSM.