To report a case of unilateral varicella zoster virus (VZV) retinal vasculitis aspect in an immunocompetent child without systemic infection. Clinically, no signs of retinal necrosis or frosted branch vasculitis were present. This is an observational case report. Quantitative PCR was performed on the aqueous humor (AH) using primers specific for herpes virus (cytomegalovirus, Epstein-Barr virus, herpes simplex virus 1-2, and VZV). The patient was treated with intravenous acyclovir, intravitreous ganciclovir, and oral valacyclovir. A positive quantitative PCR result was found for VZV DNA (1.72 x 10(6) viral copies/ml) in the AH. After 6 months, PCR of the AH was negative. Herpes viruses are involved in the pathogenesis of isolated retinal vasculitis. This case demonstrates that quantitative PCR is useful to detect viral DNA in AH and to monitor the viral activity and the therapeutic response.