Eyeworld

EW FEATURE 78 World Cornea Congress highlights September 2015 by Michelle Dalton EyeWorld Contributing Writer AT A GLANCE • Herpes zoster develops in more than 1 million new cases yearly. • Treatment of herpes zoster ophthalmicus will involve long- term steroid use. • The Zostavax vaccine can reduce the risk of shingles but has not gained sufficient market penetration yet to affect the global incidence. routine question about the vaccine to the initial workup. Once a patient has developed plaques and pseudodendrites (some people believe the pseudodendrites —or dendriform keratitis as they are now also called—are caused by a live virus, Dr. Pepose noted), there can be significant neurotrophic changes. Dr. Cohen added pseudodendrites are positive for the varicella zoster virus by PCR, and "are evidence of chronic active infection, which was not known until 1995 and still not widely appreciated by ophthalmolo- gists," she said. Stromal keratitis (with or with- out ulceration), endothelial keratitis, and uveitis are among the more common ophthalmic complica- tions, Dr. Cohen said. For those who develop HZO, postherpetic neu- ralgia (PHN) will develop in about 25%, and zoster has been shown in population-based studies to be a risk factor for major depression; it is the immunity to varicella zoster virus by exposure to wild type varicella shed by infected children in the community, periodically reactivating their own latent zoster, which was associated with brief periods of vire- mia. With the reduction of chicken pox in vaccinated children, we must rely more on a zoster vaccine to substitute for the immune boost that came from natural exposure to exogenous wild type virus," he said. Understanding zoster Before the chicken pox vaccina- tion, adults continued to have their immunity against shingles boosted because of the continual exposure to the varicella virus. That continued exposure has virtually disappeared. The key now is educating older patients that they need to get vacci- nated, said Bryan S. Lee, MD, Altos Eye Physicians, Los Altos, Calif. Dr. Cohen agreed that more education is necessary on the part of primary care physicians but that ophthalmologists should add a trabeculitis and can settle with use of topical steroids. Later findings may include iris transillumination defects and poor pupil reactivity. Immune stromal keratitis and uveitis may also be late findings after HZO requiring topical steroids and a slow taper over months, with risk of recurrence." HZO can lead to acute retinal necrosis or other retinal disorders. However, Zostavax (Merck, Kenilworth, N.J.) is a live attenuated zoster vaccine that was approved almost a decade ago to prevent shin- gles in immunocompetent people over the age of 60. Studies on the vaccine showed it reduced the recurrence of zoster about 50% in people between ages 60 and 69, said Jay Pepose, MD, founder and medical director of Pepose Vision Institute, Chesterfield, Mo., and professor of clinical oph- thalmology, Washington University School of Medicine, St. Louis. "Cell mediated immunity to zoster wanes with age. Prior to chicken pox vac- cination, adults got boosts in their Understanding herpes zoster ophthalmicus Although there's a vaccine against shingles, cases of HZO are rising H erpes zoster results in more than 1 million new cases in the U.S. each year, 10–20% of those involving the trigeminal nerve. As people age, the likelihood of con- tracting zoster increases, rising from about 1 in 3 overall to more than 1 in 2 by age 85, said Elisabeth J. Cohen, MD, professor of ophthal- mology, New York University Lan- gone Medical Center, New York, but she added the greatest number of cases occurs in people in their 50s. While the disease is much more se- vere in those who are immunocom- promised, 90% of those afflicted are not immunocompromised, "leading to the number 1 misconception that healthy people are not at risk," she said. When the disorder affects the V1 distribution (herpes zoster oph- thalmicus, HZO), it can cause acute and/or chronic anterior segment dis- ease. HZO is caused by a reactivation of the latent varicella zoster virus (chicken pox), which has affected virtually everyone over the age of 40 "whether they know it or not," Dr. Cohen said. HZO typically results in a painful, unilateral, vesicular rash, and can manifest in the eye. "Pseudodendrites may be seen on the epithelium and are culture positive for HZV," said Clara Chan, MD, assistant professor of oph- thalmology, University of Toronto. "There is often decreased or loss of corneal sensation. Elevated intra- ocular pressure may occur due to a An example of an eye with dendriform keratitis Source: Elisabeth J. Cohen, MD continued on page 80

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