Long-term, low-dose antiviral treatment significantly reduces the risks of vision-threatening infections, inflammation, and pain associated with shingles affecting the eye, according to new findings. The research, presented on October 19 at the American Academy of Ophthalmology (AAO) meeting in Chicago, highlights the benefits of antiviral therapy in combating herpes zoster ophthalmicus (HZO), a severe manifestation of shingles that affects the eye.

Shingles is caused by the reactivation of the varicella-zoster virus, the same virus responsible for chickenpox. This virus can remain dormant in nerve cells for decades before becoming active again, typically due to factors like age or a weakened immune system. Shingles often targets individuals over 50 and those with compromised immune systems. The virus reactivates along nerve pathways, leading to painful rashes on the skin.

In around 8% of the one million shingles cases diagnosed annually in the United States, the virus attacks the nerve that supplies the forehead and eye, resulting in HZO. When HZO impacts the cornea, it leads to keratitis, and when it affects the interior of the eye, it causes iritis. Both conditions result in significant symptoms, including eye pain, redness, and decreased vision. If untreated, repeated episodes can cause scarring, chronic eye disease, and even vision loss.

The research, part of the eight-year Zoster Eye Disease Study (ZEDS), was shared during the AAO’s Cornea Subspecialty Day. The study found that patients who received a low dose of the antiviral medication valacyclovir (Valtrex) over one year had a 26% lower risk of developing new or worsening eye disease within 18 months. Participants on valacyclovir experienced a 30% reduction in flare-ups by 12 months and a 28% reduction by 18 months compared to those who were given a placebo.

Moreover, the antiviral treatment helped shorten the duration of pain, a common and debilitating symptom of shingles, at the 18-month mark. Patients on valacyclovir also required significantly less neuropathic pain medication, such as pregabalin and gabapentin, which are known for their limited effectiveness and potential side effects, including dizziness. These medications are particularly problematic for older patients, who already face an elevated risk of chronic post-shingles pain, also known as post-herpetic neuralgia (PHN).

The study’s lead investigator, Dr. Elisabeth J. Cohen, professor of ophthalmology at NYU Grossman School of Medicine and NYU Langone Health, emphasized the significance of the findings. "Our results support changes in clinical practice, with suppressive valacyclovir recommended to reduce new, worsening, and repeated episodes of eye disease, as well as the need for neuropathic pain medication in HZO patients and those with shingles-related pain," Dr. Cohen stated. Her personal experience with HZO in 2008, which led to vision damage and the end of her career as a cornea surgeon, has driven her 16-year research focus on the condition.

The ZEDS study was supported by a grant from the National Eye Institute (NEI) and was spearheaded by NYU Langone. It explored not only the potential for long-term antiviral treatment to minimize eye disease but also its impact on reducing the chronic pain associated with shingles, particularly in older patients.

Until now, there has been no proven long-term treatment for recurring episodes of zoster eye disease, according to Dr. Bennie Hau Jeng, co-chair of the ZEDS study and chair of the Department of Ophthalmology at the University of Pennsylvania. "The results of this study provide convincing evidence for using long-term, low-dose antiviral treatment to reduce eye disease in HZO and decrease pain from shingles," he explained during the Cornea and Eye Banking Forum in Chicago.

The ZEDS study involved 527 participants from 95 medical centers across the United States, Canada, and New Zealand. From November 2017 to January 2023, participants were randomly assigned to receive either 1,000 mg of valacyclovir daily or a placebo in a double-blind setup. All participants had functioning immune systems and kidneys and were over 18. They also had a documented history of HZO rash, along with active keratitis or iritis within a year before the study’s initiation.

Dr. Cohen also stressed the importance of prevention. While the study demonstrated the effectiveness of valacyclovir, she reiterated that prevention is more powerful than any treatment. She highlighted the low vaccination rates for shingles among people in their 50s, with only 12% having received the highly effective Shingrix vaccine. "The incidence of shingles is going up in persons in their 50s, and just 12 percent of them have received the highly effective Shingrix vaccine," she noted. This vaccine, introduced in 2018, is recommended for all adults over 50 and, since 2022, for immunocompromised individuals aged 19 and above.

The study’s additional investigators included Andrea B. Troxel, ScD, from NYU Langone’s Department of Population Health, and Dr. Judith S. Hochman, senior associate dean for clinical sciences at NYU Langone. The ZEDS research was supported by NEI grant U10 EY026869 and by funding from the National Shingles Foundation and Research to Prevent Blindness.

(Input from various sources)

(Rehash/Yash Kamble/MSM)