Diagnostic and Therapeutic Impact of PCR in Uveitis: Real-World Data from Intraocular Fluid Analysis

Purpose: To evaluate the diagnostic utility and clinical impact of polymerase chain reaction (PCR) analysis of aqueous humor (AH) and vitreous samples in patients with uveitis of diverse etiologies. Methods: A retrospective review was conducted on 45 eyes of 45 uveitis patients. PCR testing was performed on AH (n=24) and vitreous samples (n=21) for Herpes simplex virus (HSV), Varicella zoster virus (VZV), Cytomegalovirus (CMV), Toxoplasma gondii , and Mycobacterium tuberculosis based on clinical suspicion. Demographic characteristics, immune status, uveitis type, sampling site, PCR results, and changes between initial and final diagnosis were recorded. The contribution of PCR results to the final diagnosis was classified as “confirmed” or “changed.” Results: The mean patient age was 47.4±17.3 years, with 51.1% females. 28.9% of the patients were immunosupressed. Overall PCR positivity was 42.2 % (19/45), with a higher positivity in immunosuppressed patients (61.5%) than in immunocompetent individuals (34.4%) (p=0.094). AH samples demonstrated 50.0% positivity, whereas vitreous samples yielded 33.3%. PCR results led to a change in clinical diagnosis in 33.3% (15/45) of the patients. Positive PCR findings were significantly associated with a diagnostic certanity (p=0.006). PCR findings influenced clinical management in 80% of the patients. Conclusion: PCR analysis of intraocular fluids provides a diagnostic value in the evaluation of uveitis. Both positive and negative results meaningfully inform clinical decision making by confirming infectious etiologies or supporting non infectious diagnosis. Our findings reinforce PCR as a critical adjunct in the diagnostic work-up of uveitis, particularly in complex cases where clinical features alone are insufficient.