PurposeTo compare the clinical findings in patients with anterior uveitis (AU) caused by herpes simplex virus (HSV), varicella zoster virus (VZV), and cytomegalovirus (CMV).MethodsWe retrospectively analyzed the clinical profiles of HSV-AU (14 patients), VZV sine herpete (ZSH-AU: 21 patients), and CMV-AU (17 patients) diagnosed by the detection of corresponding viral DNA in aqueous humor samples by polymerase chain reaction. Further, five patients with Posner–Schlossman (P–S) syndrome were selected as controls for CMV-AU.ResultsPatients with CMV-AU were predominately male or older in age, and all cases were unilateral except for three patients with CMV-AU. Mutton-fat keratic precipitates (KPs) were found mostly in patients with HSV-AU and ZSH-AU. Severities of AU and viral load were the highest in ZSH-AU, followed by HSV-AU and CMV-AU. Iris atrophy was observed in HSV-AU (50%) and ZSH-AU (76%), with typical morphology of round type and sector type, respectively. In patients with CMV-AU, a ring-shaped KP was found in 53% patients, 76% of whom showed a decreased number of corneal endothelial cells. CMV was not detected in the aqueous humor of patients with typical P–S syndrome.ConclusionClinical findings of HSV-AU and VZV-AU were similar; however, more inflammatory findings were observed in VZV-AU. Iris atrophy morphologically differed in HSV-AU and VZV-AU. Inflammatory findings in CMV-AU were mild, and clinical features of iritis differed from those of the two former groups. A difference in the etiology between CMV-AU and P–S syndrome was observed.