Herpes Simplex Keratitis and Vitamin D Receptor Agonist: Two Case Reports

Background: Herpes simplex keratitis (HSK) is a disease characterized by the recurrent infection of the cornea, mainly due to infection caused by herpes simplex virus type 1. The suppression of recurrence can suppress progressive corneal scarring, ulcers, and perforation. Cornea contains vitamin D receptors (VDRs). VDR agonists show antimicrobial activity.

Case Presentation: In this case report, I describe two female patients aged 76 and 85 years old in whom the administration of a VDR agonist led to the suppression of the recurrence of HSK. The former patient had repeated HSK recurrence for over 10 years after the initial infection. The latter patient developed HSK immediately after vitrectomy, and her cornea remained susceptible to infection, resulting in recurrence. Both patients were trying to suppress recurrence by applying acyclovir ophthalmic ointment, but their medication adherence was declining. So, they switched to oral treatment with 0.5 μg of the VDR agonist per day, and since then, there has been no recurrence of HSK. Oral treatment with the VDR agonist is still ongoing.

Conclusions: This report highlights the cases where ways were examined to improve medication adherence in elderly patients who had a risk of HSK recurrence. Both patients responded to VDR agonist treatment and were able to suppress recurrence.