Bilateral Acute Retinal Pigment Epitheliitis Diagnosed and Monitored Using Multimodal Imaging: A Case Report

We report a rare case of bilateral acute retinal pigment epitheliitis (ARPE) documented using multimodal imaging, with detailed sequential optical coherence tomography (OCT) findings. A woman in her 30s presented with acute bilateral visual deterioration without prodromal symptoms. Fundus examination revealed yellowish-white lesions localized to the fovea in both eyes. OCT demonstrated dome-shaped hyperreflective lesions with disruption of the ellipsoid zone (EZ) and interdigitation zone (IZ). OCT angiography, fluorescein angiography, and indocyanine green angiography showed no significant abnormalities. Based on these findings, bilateral ARPE was diagnosed. Given the bilateral visual impairment, topical betamethasone sodium phosphate was initiated to facilitate early recovery. Sequential OCT demonstrated gradual restoration of the outer retinal layers, with recovery of the external limiting membrane, followed by the IZ and EZ. Best-corrected visual acuity improved to 1.0 in both eyes within two months, and near-complete anatomical resolution was confirmed by three months. No recurrence was observed after treatment cessation. This case highlights the rare bilateral presentation of ARPE and demonstrates the value of OCT in monitoring layer-by-layer recovery of the outer retina, while emphasizing the importance of differentiating it from other white dot syndromes.