Antiviral therapy found to prevent blindness, other serious effects for patients with eye shingles
Mayo Clinic has found that for patients with eye shingles, oral antiviral drugs are critical to prevent long-term consequences in the eye. Untreated, 10 percent of eye shingles patients experience a serious long-term outcome, such as severe visual loss, eyelid scarring or chronic in-turning of the eyelashes; if treated, two percent of patients experience these effects. The Mayo Clinic study refutes the findings of a previous British study of oral antivirals in patients with eye shingles.
"This is the first time its been documented that within the eye, the chance of something really bad happening is greatly reduced by administering oral antivirals," says Keith Baratz, M.D., Mayo Clinic ophthalmologist and author of the manuscript, "Herpes Zoster Ophthalmicus in Olmsted County, Minnesota: Have Systemic Antivirals Made a Difference?" to be published in the March issue of Archives of Ophthalmology, http://archopht.ama-assn.org.
This study, based on data from the Rochester Epidemiology Project, http://www.mayo.edu/research/mir/topic_1029.html, is the first long-term follow-up study and the second largest study of this medication with patients diagnosed with herpes zoster opthalmicus. The largest study completed of oral antivirals for this disease to date, by Moorfields Eye Hospital in London, found that oral antivirals did not significantly affect long-term outcome; the study was not well controlled, however, according to the Mayo Clinic researchers. Oral antiviral treatment has been controversial due to the Moorfields study as well as the cost of the medicine, which can cost several hundred dollars for a course of treatment, or approximately $13 to $22 per day.
This study compared 323 cases of eye shingles treated in Olmsted County, Minn., between 1976 and 1998. Of these cases, two-thirds, or 202 patients, were treated with oral antiviral medication, such as acyclovir, famciclovir or valacyclovir; and one-third, or 121, were not treated. In untreated patients, 8.9 percent experienced adverse outcomes five to 10 years following the onset of the illness; 2.1 percent of treated patients experienced such outcomes. Also, the group given oral antivirals was less likely to experience the complication neurotrophic keratitis, or loss of feeling in and inflammation of the cornea. Those treated, however, did experience more frequent conjunctivitis, or inflammation of the eyelid-lining membrane and sclera surface, for reasons unknown to the investigators.
Timing of treatment also affected the long-term outcome. Those who experienced long-term negative outcomes such as glaucoma, scleritis (inflammation of the white coating around the eyeball), uveitis (inflammation of the vascular middle coating of the eye), corneal edema or stromal keratitis had waited an average of 4.8 days before receiving treatment; those who did not experience these outcomes waited an average of 3.8 days prior to treatment.
"A delay in treatment with the drug negatively affected the course of the disease," says Dr. Baratz. "Getting in to your doctor quickly is an issue."
According to Dr. Baratz, receiving timely treatment for eye shingles is complicated, however, by nonspecific symptoms at the start of the disease. The origin of these early symptoms also is difficult to pinpoint.
"You can get headaches first, or a rash first or pinkeye first," says Dr. Baratz. "Very early on it can be difficult to diagnose." He adds, however, that herpes zoster ophthalmicus is very easy to diagnose once the rash starts.
Herpes zoster, or shingles, is a common condition; 20 percent of all those who have had chicken pox will get shingles, and 20 percent of those experience the disease in the eye. People at higher risk for the disease include the elderly, patients taking immunosuppressant drugs or those experiencing high stress. It may strike people of any age. The virus causing the disease, varicella zoster, can remain in the body and lie "dormant," reactivating years later in nerve cells. Factors such as stress, medications, illness and aging may prompt the reactivation.
"You can get chicken pox when youre three years old, and it can come back when youre 70," says Dr. Baratz. " Everyone who has shingles has had chicken pox before. Chicken pox usually is not a big deal; shingles is a big deal."
Herpes zoster most commonly occurs in the bodys trunk, but it also may spread along the ophthalmic portion of the fifth cranial nerve, affecting the eye. The symptoms manifest in one eye only, as shingles typically concentrate on one side of the body.
"It is very painful and can destroy your sight," says Dr. Baratz.
Lisa Copeland | EurekAlert!