The varicella-zoster virus, which is the herpes virus famous for causing childhood chickenpox, can be reactivated in adult years as herpes zoster, commonly known as shingles. Herpes zoster accounts for 1 percent of all visits to dermatologists. “As we have become an older population, the incidence of herpes zoster has increased,” said Vincent P. de Luise, MD, assistant clinical professor at Yale University
There are one million new cases of zoster each year in the United States, and between 25 percent and 40 percent of all cases have ophthalmic complications. In most cases, herpes zoster ophthalmicus is mild, and usually results in short-term inflammation, such as a temporary keratitis, which usually resolves without topical antiviral treatment.
However, a minority of patients can go on to develop recurrent iritis, and are at risk for secondary glaucoma, cataracts, corneal scarring or retinitis that can be sight-threatening. People who are immunocompromised, such as those with HIV or those undergoing treatment with chemotherapy, are especially at risk for serious complications of zoster ophthalmicus.
Zoster can affect the eye when the trigeminal nerve is involved in the infection. Typically, the virus manifests in an initial painful eruption of vesicles on the forehead, the side of the nose, upper eyelid and eye.
The most problematic aspect of zoster is the development of chronic and persistent pain, called postherpetic neuralgia (PHN). In zoster ophthalmicus, PHN usually affects the forehead as well as the eye. The pain of PHN can be severe and disabling, and can so affect patients’ quality of life that they can develop secondary depression and even, rarely, become suicidal. “When PHN develops from the trigeminal nerve, it can be very severe around the eye, and the pain can be incapacitating,” Dr. de Luise said. “It can be devastating.” Nerve damage can also result in a neurotrophic cornea, in which the lack of sensation can lead to future ulcers, scarring or thinning. This often requires aggressive medical or surgical intervention to prevent permanent corneal damage
The best treatment for shingles or zoster is the shingles vaccine. We encourage all of our patients who are candidates to have this vaccine before this disease develops. You should verify with your primary medical doctor whether you are eligible for the vaccine.
Once it occurs, the treatment of herpes zoster includes oral and/or topical antivirals, administered ideally within the first 72 hours of onset. These medications decrease pain, shorten the duration of viral shedding, and decrease the incidence of keratitis or iritis. Unfortunately, they do not affect the incidence or severity of postherpetic neuralgia. Our patients with severe neuralgia are often managed in conjunction with a neurologist or pain management specialist.
(C) 2011 American Academy of Ophthalmology. Used by Permission