Objectives: Using PCR to to identify HSV, HSV in the aqueous samples from patients with PSS syndrome. Patients and Methods: the study was done on 38 eyes of 38 patients with PSS who were examined and followed in VNIO from September 2011 to August 2012. After the clinical had been made the aqueous samples were taken in sterile condition and sent to Gene-Protein Center, Hanoi Medical University, for analysis. Results: PSS tended to occur in males than in females, most frequently at the age group 2140 year olds (50 percent). The disease usually. presented in acute attacks which were most frequently seen in Spring-Summer time (from February to May). 8 out of 38 cases were positive for CMV accounting for 21.1 percent. HSV was not found in any cases. Conclusions: CMV may be one of causes of PSS syndrome.