Long-term antiviral treatment may protect vision from shingles

Taking an antiviral medication for a year may prevent vision damage associated with shingles that affects the eye, according to new research led by faculty from the Perelman School of Medicine at the University of Pennsylvania and the NYU Grossman School of Medicine. 

"Up until now, there has been no proven long-term treatment for new, worsening, or repeated episodes of this disease, so the results of this study provide convincing evidence for using long-term, low-dose antiviral treatment," said Bennie Jeng, MD, chair of Ophthalmology at the Perelman School of Medicine at the University of Pennsylvania and the director of the Scheie Eye Institute at Penn Medicine, who co-chaired the study. 

Ocular shingles begins in the nerve connecting the brain to the eye and is present in almost 100,000 of the million people who develop shingles each year in the United States. This is called herpes zoster ophthalmicus (HZO) and can result in keratitis (inflammation of the cornea), iritis (inflammation of the iris), and inflammation in other parts of the eye. Roughly 30,000 of HZO cases result in patients' vision declining to 20/60 or worse, meaning that if a typically-sighted person could see an object clearly at 60 feet, these patients would have to move up to at least 20 feet to see it. Beyond that, approximately 10,000 patients who develop HZO experience legal blindness, meaning their vision is reduced to 20/200 or worse.

For patients who had recurrences or new findings of HZO, there was never a clear course of treatment to reliably prevent complications such as vision loss. 

Elisabeth J. Cohen, MD, a professor of ophthalmology at NYU Grossman School of Medicine and NYU Langone Health, designed the study, after she was, herself, affected by shingles-related vision loss years ago. The study examined the long-term use of the existing antiviral treatment valacyclovir, which is already used to initially treat any case of shingles, albeit only for seven to 10 days. The researchers showed that using valacyclovir for a year can decrease the risk of new or worsening eye disease by 26 percent at 18 months after initiating treatment. Patients treated with valacyclovir also were 30 percent less likely than those not receiving the treatment to have multiple HZO flare-ups at a year or a year-and-a-half later. 

We hope that our work creates a relatively simple path toward preventing vision changes that can be life-altering. With this drug already being part of the regular clinical treatment for shingles, we don't envision significant barriers to making this a standard of treatment." 

Bennie Jeng, MD, chair of Ophthalmology at the Perelman School of Medicine, University of Pennsylvania 

The research was presented at both the Cornea and Eye Banking Forum (Oct. 18) and the American Academy of Ophthalmology's annual meeting (Oct. 19). It resulted from the Zoster Eye Disease Study (ZEDS), an eight-year-long study conducted at 95 medical centers across the United States, Canada, and New Zealand. Cohen led the study with Jeng serving as co-chair. 

ZEDS ran from November 2017 until January 2023, enrolling more than 500 participants who had shingles affecting their eyes. Approximately half received daily doses of valacyclovir for a year, with the others receiving a placebo. The ZEDS study also found that this same treatment reduced a chronic nerve pain syndrome that can accompany shingles. 

"While our evidence in support of a new treatment regimen is vital, prevention is even more effective than any treatment," Cohen said. "The incidences of this are going up in persons in their 50s, and just 12 percent of that population has received the highly effective zoster vaccine. It has been recommended since 2018 for all adults age 50 and older, and, since 2022, for immunocompromised adults age 19 and older." 

Moving forward, Jeng said the ZEDS team is looking into whether the extended antiviral treatment is especially effective in reducing glaucoma, scleritis (inflammation affecting the outer eye), and other complications. Additionally, they hope to see what impact vaccination against shingles had on the patients in the study, and whether the shingles vaccine affected COVID-19 diagnosis and severity among participants. 

Other principal study investigators from NYU Langone were Andrea B. Troxel, ScD, director of the Division of Biostatistics within the Department of Population Health, and clinical trialist Judith S. Hochman, MD, the senior associate dean for clinical sciences. ZEDS was funded by NEI grant U10 EY026869 and made possible by the ZEDS network of principal investigators and study participants who volunteered.