Choroidal quantitative features in high myopia: Characteristics and association with neovascular and atrophic complications

Abstract

Aims/Purpose: To investigate the quantitative choroidal features associated with the presence of MNV or atrophy in high myopia.Methods: The study was designed as a retrospective, case series with 2‐year follow‐up. Optical coherence tomography (OCT) images were used to measure choroidal thickness (CT) and to assess the presence and subtype of dome‐shaped macula (DSM). In DSM eyes we also calculated the presence and type of choroidal deepening (CD). The eyes were categorized as Subgroup 1 (high myopia without complications), Subgroup 2 (high myopia complicated by macular neovascularization (MNV)) and Subgroup 3 (high myopia complicated by macular or posterior pole atrophy). The main outcome measures were the detection of significant CT cutoffs associated with the three subgroups of eyes and the clinical impact of DSM and CD subtypes.Results: Our study cohort (190 eyes (190 patients) affected by high myopia) was categorized as Subgroup 1 (66 eyes), Subgroup 2 (72 eyes) and Subgroup 3 (52 eyes). The mean axial length was 31.74 ± 2.01 mm (−13.0D ± 2.0D). Baseline CT values allowed to separate the subgroups with myopic‐related complications (AUC 0.85; standard error 0.04; confidence interval 0.78–0.92; p < 0.05). DSM was distributed as follows: Subgroup 1 (39%), Subgroup 2 (44%) and Subgroup 3 (29%). In Subgroup 1, vertical DSM was the most frequent (54%), with CD absence characterizing the 46% of cases. Round DSM was the most represented subtype in Subgroup 2 (49%), with 55% of sub‐dome CD subtypes; in these cases, MNV resulted always localized in the fovea. Subgroup 3 equally showed horizontal or vertical DSM (53% and 47%, respectively), with 80% of cases showing peri‐dome CD.Conclusions: Choroidal quantitative assessment can categorize three high myopia subgroups. MNV subgroup is characterized by intermediate choroidal thinning and higher prevalence of round DSM with sub‐dome CD. DSM subtypes may have a role in predicting myopic complications and MNV localization.