Age-related choroidal atrophy: A systematic review of multimodal imaging, clinical features, and differentiation from other forms of macular degeneration.

We conducted a systematic review on the clinical and imaging characteristics of age-related choroidal atrophy (ARCA) that distinguish ARCA from age-related macular degeneration (AMD) and geographic atrophy (GA). Studies were included if they reported on ARCA using clinical or multimodal imaging criteria and differentiated it from AMD and GA. Extracted data included subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), inner retinal layer thicknesses, and fundus findings. Risk of bias was assessed using the Joanna Briggs Institute checklists. Narrative synthesis and descriptive statistics were performed (PROSPERO (ID: CRD420251041101)). Seven studies (n = 329 patients) met inclusion criteria. ARCA was characterized by choroidal thinning (mean SFCT: 69.8-96.45 µm), preserved retinal pigment epithelium (RPE) on fundus autofluorescence, scleral visibility, and fundus features including peripapillary atrophy (83.3 %), tessellated fundus, and pseudodrusen. Compared to control, patients with ARCA had significantly thinner peripapillary nerve fiber layer (mean: 84.2 µm vs. 90.2 µm; p = 0.047) and reduced mean ganglion cell layer, macular internal plexiform layer and CVI. ARCA contrasts with AMD and GA by its distinct imaging features, less severe visual impairment, higher glaucoma prevalence (35.3 %), and more favorable response to anti-vascular endothelial growth factor agents when choroidal neovascularization is present. ARCA is a distinct clinical entity characterized by specific choroidal and retinal findings on multimodal imaging including lower CVI, thin SFCT, preserved RPE with scleral visibility, peripapillary atrophy, and inner retinal thinning. Further studies are warranted to standardize diagnostic criteria and understand long-term outcomes of ARCA.