Detection of Herpes Simplex Virus in Corneal Buttons with Clinical Diagnosis of Corneal Scarring

Purpose: The evaluation of the presence of Herpes Simplex Virus (HSV) in corneal scars by realtime polymerase chain reaction (PCR) and comparison of the results with histopathologic findings and clinical diagnoses Methods: Eighty-seven corneal scar samples obtained after penetrating keratoplasty (PK), were selected after reviewing the records from 2006 to 2010. Nucleic acid was extracted from paraffin embedded corneal samples and PCR-amplified for HSV DNA. Results: Among 87 samples, four samples were excluded because internal controls were negative. HSV infection was established in 9.6% (8/83) of all patients. The prevalence of HSV infection in patients with no clinical suspicion of herpetic keratitis was 7.3%. Histopathologic evaluation revealed that among samples with positive PCR results, 100% had evidence of inflammation, 62.5% had giant cells, 37% had necrosis, 62.5% had vascularization, 62.5 % had ulcer and all of them had inclusion bodies. Conclusion: Because some of the patients with no clinical suspicion of herpes infection were found positive, we suggest that HSV keratitis to be considered as one of the underlying etiologies in any patient with corneal scar. Therefore, performing further diagnostic methods, including PCR and histopathology, are mandatory to rule out the infection.