Choroidal vascular changes in eyes with acute macular neuroretinopathy and paracentral acute middle maculopathy: new insights

Abstract Purpose To assess choroidal vasculature changes in acute macular neuroretinopathy (AMN) and paracentral acute middle maculopathy (PAMM) during the acute and resolution phases. Methods Retrospective, cross-sectional study. Twenty-eight eyes from 28 patients were analyzed: 8 with AMN and 20 with PAMM. Also, 30 healthy age-matched controls were included. Clinical records and spectral-domain optical coherence tomography (SD-OCT) scans from patients with AMN and PAMM were assessed. Choroidal assessment was performed using an automated algorithm, binarized into stromal choroidal areas (SCA) and luminal choroidal areas (LCA). Choroidal vascularity index (CVI) was calculated as the ratio of LCA to total choroidal area (TCA). Statistical analysis was performed using non-parametric tests. Results The median age was 54 years (IQR = 32-68.5), and 60.7% were female. AMN eyes showed significantly increased subfoveal choroidal thickness (SFCT), TCA, SCA, and LCA compared to PAMM and controls (p = 0.044, p = 0.007, p = 0.002, p = 0.014 respectively). No differences in CVI were observed between the groups (p = 0.535). These findings remained consistent when comparing AMN with isolated PAMM and PAMM associated with retinal vascular diseases (p < 0.05). SFCT, TCA, SCA, and LCA significantly decreased in AMN eyes (p = 0.045, p = 0.041, p = 0.040, p = 0.038 respectively) after resolution, while no changes were observed in PAMM (p > 0.05). Also, resolved AMN exhibited higher SFCT, TCA, SCA and LCA compared to controls and resolved PAMM eyes (p < 0.05). Conclusions Increased choroidal thickness is a characteristic feature of AMN, with reduction observed after resolution. On the other hand, no changes were observed in PAMM, suggesting distinct pathophysiological mechanisms between the two conditions.