• Background: It has been thought that herpes viruses may play an important role in acute retinal necrosis syndrome (herpes simplex and varicella-zoster viruses) as well as in cytomegalovirus retinitis and it would be useful to know the specificity of the methods for detecting the viruses. • Methods: Amplification of the herpetic viral genome DNA by polymerase chain reaction (PCR) in aqueous and vitreous humor was compared with Goldmann-Witmer coefficients against herpetic antigens in five patients with acute retinal necrosis syndrome and in two patients with cytomegalovirus retinitis, using vitreous samples to determine the specificity of these diagnostic methods. • Results: The varicella-zoster virus genome DNA was amplified by PCR in four of the five patients with acute retinal necrosis syndrome, and cytomegalovirus genome DNA was enhanced in both patients with cytomegalovirus retinitis. Four patients who exhibited the varicella-zoster viral genome showed marked increase of the Goldmann-Witmer coefficient against varicella-zoster virus. Conversely, the two patients with cytomegalovirus retinitis showed no remarkable changes among the antigens. • Conclusion: Our results showed that the amplification of the viral genome DNA in the samples by PCR is specific in both diseases, and that the increased level of local antibody production also is specific in varicella-zoster retinitis. In cytomegalovirus retinitis, however, antibody production against cytomegalovirus does not show increase of the Goldmann-Witmer coefficient.