PCR-based detection of viral and parasitic etiologies in anterior uveitis: a cross-sectional study from Iran

Anterior uveitis (AU) is a significant cause of visual morbidity, with viral etiologies requiring precise diagnosis for effective management. This cross-sectional study evaluated polymerase chain reaction (PCR) analysis of aqueous humor in 80 patients with 81 eyes affected by unilateral AU in Isfahan, Iran, from 2015 to 2020. Clinical suspicion was based on unilateral presentation, sectoral iris atrophy, keratic precipitates, ocular hypertension, and poor response to steroids. PCR identified viral pathogens in 66.7% (54/81) of cases: varicella-zoster virus (VZV, 27/54, 50.0%), herpes simplex virus (HSV, 25/54, 46.3%), and cytomegalovirus (CMV, 2/54, 3.7%). All samples were negative for Epstein-Barr virus (EBV) and Toxoplasma gondii. Multivariate logistic regression, adjusted for age and gender, identified iris atrophy (adjusted odds ratio [aOR], 2.12; 95% CI, 1.1–4.0; P = .01) and a borderline association with ocular hypertension (aOR, 2.88; 95% CI, 0.9–8.7; P = .06) as predictors of PCR positivity. PCR sensitivity was 72.2%, specificity 77.8%, positive predictive value (PPV) 86.7%, and negative predictive value (NPV) 58.3%. The low NPV suggests PCR cannot reliably rule out viral AU, requiring clinical correlation. Treatment was modified in 24.7% of cases. PCR positivity varied by clinical form: chronic (75%), acute (60%), recurrent (65%) . VZV and HSV are primary causes of AU in Iran, with PCR guiding targeted therapy. However, PCR is an adjunct to clinical diagnosis, limited by moderate sensitivity, prior treatment, and small sample size. Iris atrophy and ocular hypertension guide testing, addressing a regional knowledge gap.