Acute Retinal Necrosis versus Progressive Outer Retinal Necrosis

This review aims to provide a comprehensive comparison between acute retinal necrosis (ARN) and progressive outer retinal necrosis (PORN), two sight-threatening manifestations of herpetic viral retinopathies emphasizing how immune status shapes presentation, diagnosis, management, and prognosis. Recent studies suggest that ARN and PORN represent a spectrum influenced largely by host immune status rather than distinct diseases. Ultra-widefield imaging improves detection of far-peripheral lesions, while PCR of aqueous or vitreous enables rapid etiologic confirmation. In ARN, high-bioavailability oral antivirals, often with adjunct intravitreal injections, accelerate lesion regression and reduce fellow-eye involvement. In PORN, monotherapy performs poorly; combined intensive intravitreal and systemic therapy improves local control but vision remains limited in advanced immunosuppression. Prompt differentiation based on inflammatory signs, lesion morphology, and host immunity directs therapy. ARN generally responds to systemic agents yet carries substantial detachment risk; PORN progresses quickly with worse outcomes despite aggressive care. Early diagnosis coordinated medical–surgical management, and close surveillance are critical; priorities include optimal dosing and duration of antiviral therapies as well as adjunctive anti-inflammatory strategies.