Electroretinogram as an Early Diagnostic Biomarker for Acute Retinal Necrosis: A Multicenter Comparative Study

Acute retinal necrosis (ARN) is a rare but severe ocular condition that often results in significant visual impairment or blindness. We aimed to determine whether ARN exhibits a distinct electroretinogram (ERG) waveform compared with other infectious and non-infectious uveitis forms.

This retrospective observational multicenter study included a total of 73 patients; 21 with ARN, 9 with bacterial endophthalmitis, 16 with other types of infectious uveitis, and 27 with non-infectious uveitis. Full-field electroretinography was performed at the initial examination to evaluate retinal function. Additionally, initial and post-treatment visual acuity were recorded. The a- and b-wave amplitudes were measured and compared between the groups.

Patients with ARN had significantly reduced a- and b-wave amplitudes than the other types of infectious and non-infectious uveitis at the first visit (p < 0.01). Receiver operating characteristic analysis showed that an a-wave amplitude reduction of more than 73% discriminated ARN from other infectious uveitis with 75% sensitivity and 90% specificity (area under the curve [AUC] = 0.84), while a reduction greater than 49% discriminated ARN from non-infectious uveitis with 89% sensitivity and 76% specificity (AUC = 0.83). Pre-treatment visual acuity was the strongest predictor of visual prognosis.

ERG response is significantly reduced in the early stages of ARN. Therefore, ERG may serve as a valuable diagnostic tool for ARN, particularly when specialist examination or definitive diagnosis based on clinical findings is delayed. Given that early treatment improves the prognosis of ARN, this finding highlights the critical role of early diagnosis in preventing vision loss.