New research suggests long-term, low-dose antiviral treatment reduces the risk for potentially vision-damaging bouts of shingles-related eye inflammation, infection, and associated pain.
Man with zoster eye disease. Adobe Stock.
In about 8 percent of the more than 1 million new shingles cases in the United States each year, the virus awakens in the nerve that supplies the forehead and eye, a condition called herpes zoster ophthalmicus, or HZO. Shingles causes what is known as keratitis when it affects the cornea, and iritis when it is inside the eye, with both causing pain, redness, decreased vision, and sometimes glaucoma. Repeated flare-ups are associated with chronic eye disease, scarring, and vision loss.
The new research, part of the eight-year Zoster Eye Disease Study (ZEDS) and presented at the American Academy of Ophthalmology Annual Meeting, shows that study participants treated for a year with a low dose of the inexpensive and safe antiviral drug valacyclovir (Valtrex) saw a 26 percent reduction in their risk of having new or worsening eye disease (keratitis or iritis) at 18 months. Those treated were significantly less likely than those who got a placebo to have multiple disease flare-ups, with a 30 percent reduction at 12 months and a 28 percent reduction at 18 months.
In addition, participants on valacyclovir were found to have a shorter duration of pain at 18 months and needed significantly less neuropathic pain medication. Reducing the use of such medications (e.g., pregabalin and gabapentin) was a goal of the work because they have limited effectiveness and often cause dizziness. This makes them a poor fit for older patients, who are at the greatest risk for debilitating chronic pain after shingles.
ZEDS was funded by the NEI and led by New York University Langone's Elisabeth Cohen and the University of Pennsylvania's Bennie Hau Jeng.