Purpose: To assess the value of quantification of herpes simplex virus (HSV) DNA for the differential diagnosis of herpetic diseases of the anterior segment of the eye.
Methods: One hundred forty-four samples from 90 patients with ocular inflammatory diseases were examined for HSV DNA by real-time polymerase chain reaction (PCR) with primers set for the consensus sequence of HSV-1/2 DNA polymerase. The samples included corneal epithelial scrapings, tear fluid (200microl of eye wash), and aqueous humor.
Results: In cases of typical herpetic epithelial keratitis, a large number of copies of HSV DNA were detected (mean, 1.0 x 10(7) copies in epithelial scrapings and 3.5 x 10(5) copies in tear fluid). In atypical epithelial keratitis cases, a smaller number of HSV DNA copies were detected. In stromal keratitis cases, the number of copies of HSV DNA in the tear fluid (mean: 4.7 x 10(2) copies) was significantly smaller than in cases of epithelial keratitis. In the aqueous humor, the number of copies was small in endotheliitis cases (mean, 2.9 x 10(2) copies/microl), but the range was great, from (1.2-4.8) x 10(5)/microl in herpetic iridocyclitis. Seventeen percent of cases in which HSV was not suspected to be involved showed a small number of copies of HSV DNA, indicating the unexpected involvement of HSV in these cases.
Conclusions: Real-time PCR is an informative method of diagnosing herpetic eye diseases and evaluating the possible involvement of HSV in other inflammatory ocular diseases.