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 “case-control” comparison study. Twenty eyes from 20 patients were analyzed: 5 with AMN and 15 with PAMM. Also, 30 healthy age-matched controls were included. We retrospectively analyzed clinical records and spectral-domain optical coherence tomography (SD-OCT) scans from patients affected by AMN and PAMM. Choroidal assessment was performed using an automated algorithm, binarized into stromal choroidal areas (SCA) and luminal choroidal areas (LCA). CVI was calculated as the ratio of LCA to total choroidal area (TCA). Sub-foveal choroidal thickness was measured too. Statistical analysis was done using non-parametric tests. Results: Patient’s median age was 52 years (IQR = 30-65.5), and 54% were female. AMN eyes showed significantly increased subfoveal choroidal thickness (SFCT), TCA, SCA, and LCA compared to PAMM and controls (p=0.041, p=0.005, p=0.006, p=0.010 respectively). No significant difference in CVI was observed between the groups (p=0.605). After disease resolution, SFCT, TCA, SCA, and LCA significantly decreased in AMN eyes (p=0.043, p=0.040, p=0.040, p=0.040 respectively), while no changes were observed in PAMM (p>0.05). Also, AMN eyes exhibited higher SFCT, TCA, SCA and LCA compared to controls and PAMM eyes (p<0.05) even after resolution. Conclusions: Increased choroidal thickness is a characteristic feature of AMN, with reduction observed after resolution. On the other hand, no changes in choroidal parameters were observed in PAMM, suggesting distinct pathophysiological mechanisms between the two conditions.