New-onset herpes simplex virus epithelial keratitis following corneal transplantation: Clinical characteristics and exploration of viral origin.

PURPOSE: To investigate the clinical characteristics, treatment, outcomes, and potential etiologies of new-onset herpes simplex virus (HSV) epithelial keratitis after corneal transplantation. METHODS: This retrospective study included 1028 eyes of 1006 patients who underwent corneal transplantation from 2015 to 2023, with a minimum follow-up of 1 year at Qingdao Eye Hospital. Clinicodemographic data of patients with new-onset postoperative HSV epithelial keratitis were analyzed. Donor corneas were screened for HSV-1 DNA using reverse transcription-quantitative polymerase chain reaction, and recipient corneas were tested for HSV-1 antigens through immunohistochemistry. RESULTS: New-onset HSV epithelial keratitis was observed in 20 eyes (1.9%). The primary indications for transplantation included fungal keratitis (45%, 9/20), bacterial keratitis (25%, 5/20), adherent leukoma (10%, 2/20), and other isolated lesions. Surgical procedures included penetrating keratoplasty (85%, 17/20) and anterior lamellar keratoplasty (15%, 3/20). Onset varied from 19 days to 5 years postoperatively, with 50% (10/20) occurring within the first 3 months. All patients improved with antiviral therapy; however, 30% (6/20) experienced recurrence. The HSV-1 antigen was identified in 88.9% (16/18) of recipient corneas, but all donor grafts tested negative for HSV-1 DNA. CONCLUSION: Reactivation of latent HSV is a likely cause of new-onset epithelial HSK after corneal transplantation. Given the risk of rapid onset and potential for progression, patients should be informed preoperatively about the potential for HSK, and prophylactic treatment should be considered in high-risk individuals.