Zoster Eye Disease Study

The Zoster Eye Disease Study (ZEDS) was a multicenter, randomized, double-masked, placebo-controlled clinical trial of suppressive valacyclovir in patients with Herpes Zoster Opthalmicus (HZO). The study was conducted at 95 participating sites in Canada, New Zealand, and the United States; data collection began in November 2017 and concluded in 2024. Participant visits occurred every three months after enrollment for a total of 18 months, including 6 months after discontinuation of study medication. Participants were considered eligible if they were 18 or older and immunocompetent with a history of a typical unilateral rash at the onset of HZO anytime in the past and an episode of dendriform epithelial keratitis (DEK), stromal keratitis without ulceration (SK) or with ulceration (SKU), endothelial keratitis (EK), and/or iritis (IR) due to HZO in the year prior to enrollment.

527 participants were randomized in a 1:1 ratio to 1000 mg/d of valacyclovir or placebo, and categorized based on age at HZO onset (under 60 or 60 and over), disease duration (less than six months, which was classified as recent, or six or more months, which was classified as chronic) at enrollment. The primary endpoint was the time from randomization to development of the first occurrence of any new or worsening DEK, SK, EK, IR, or SKU due to HZO.