New research presented at the American Academy of Ophthalmology's annual meeting in Chicago reveals that long-term, low-dose antiviral treatment significantly reduces the risk of recurring eye disease caused by shingles. The study offers hope for patients experiencing herpes zoster ophthalmicus (HZO), a shingles-related condition that can cause vision loss and chronic pain.
Shingles occurs when the varicella-zoster virus reactivates later in life. While most cases result in painful rashes, the virus can also affect the nerves supplying the forehead and eye, leading to HZO, linked with keratitis and iritis, both of which can cause pain, vision problems, and, in severe cases, glaucoma.
Valacyclovir Reduces Eye Disease Risk
The eight-year Zoster Eye Disease Study (ZEDS) demonstrated that patients treated with the antiviral drug valacyclovir had a 26% lower risk of new or worsening eye disease over 18 months compared to those given a placebo. The study also found a 30% reduction in flare-ups at 12 months and 28% at 18 months for those receiving the antiviral therapy.
Impact on Pain and Medication Use
In addition to reducing eye inflammation, the treatment shortened the duration of pain and decreased the need for medications like pregabalin and gabapentin, which are commonly used for post-herpetic neuralgia (PHN) but may cause side effects such as dizziness.
Expert Opinions
"Our findings highlight the importance of preventive antiviral treatment in reducing not only eye disease but also the chronic pain that often accompanies shingles," said Dr. Elisabeth J. Cohen, the study's principal investigator and professor of ophthalmology at NYU Grossman School of Medicine.
"The study offers compelling evidence to support long-term, low-dose antiviral therapy as a way to mitigate HZO complications and improve patient outcomes," said co-chair Dr. Bennie Hau Jeng, chair of the Department of Ophthalmology at the University of Pennsylvania.
Study Details
The ZEDS study, funded by the National Eye Institute (NEI) and conducted at 95 medical centers across the U.S., Canada, and New Zealand, enrolled 527 participants. Each patient received either 1,000 mg of valacyclovir or a placebo daily, following a double-masked trial design to ensure unbiased results. Participants were required to have active or recent keratitis or iritis, functional immune systems, and a history of shingles rash.
Importance of Vaccination
Beyond treatment, Dr. Cohen emphasized the importance of vaccination: "While these findings represent a breakthrough in managing HZO, prevention remains paramount. Shingrix, a highly effective vaccine, has been recommended since 2018 for adults 50 and older, yet only 12% of those eligible have received it." She also highlighted the recent expansion of Shingrix guidelines to include immunocompromised adults aged 19 and older.
Implications for Clinical Practice
With support from the National Shingles Foundation and other research grants, ZEDS offers new directions for clinical practice, encouraging the use of suppressive antiviral therapy for both reducing eye disease flare-ups and limiting the need for neuropathic pain medication.
This study underscores the growing need for effective management of shingles-related complications, especially among older adults and immunocompromised individuals, as the incidence of shingles continues to rise.
