Correlation of quantitative polymerase chain reaction with clinical characteristics of patients with viral retinitis

PURPOSE: To evaluate the correlation of quantitative real-time polymerase chain reaction (qRT-PCR) to the clinical characteristics of patients with viral retinitis. METHODS: Retrospective case series. RESULTS: Aqueous or vitreous samples of 20 out of 35 eyes showed qRT-PCR positivity for virus etiology (57.14%). Cytomegalovirus (CMV) was most commonly identified in nine eyes (45%). The mean DNA copy number was 2,68,339.65 copies/mL (range: 90–3205397). DNA copy number significantly correlated with the extent of clinical involvement (P = 0.013); however, there was no correlation between DNA copy number and presenting visual acuity (P = 0.31), macular involvement (P = 0.675), optic nerve involvement (P = 0.14), and development of retinal detachment (P = 0.73). There was a significant correlation between the number of DNA copies and the timing of sampling (P = 0.0005). Samples taken earlier in the course of the disease had higher viral copies than later ones. CONCLUSION: qRT-PCR is useful in confirming a viral etiology in over 50% of cases of suspected viral retinitis. It correlates well with the extent of clinical involvement and timing of sampling.