Herpes Simplex Eye
Herpes is a very common virus to which the vast majority of us become exposed in our early years. This virus infects the skin, mucous membranes and nerves. Type I herpes generally causes disease above the belt; Type 2 herpes is below the belt. By age 15 over 90% of American have circulating antibodies to Type I herpes, which is the one we are concerned with in ophthalmology.
What Is Herpes Simplex Eye Disease?
Following primary infection, the herpes virus remains dormant in our systems within nerve clusters behind the eyes and elsewhere. From these reservoirs, the virus can make several trips to the surface of the skin, as evidenced by recurrent infections on the lips in the form of cold sores and in the eyes as recurrent corneal ulcers and intraocular inflammation.
The most common symptoms of the primary disease are fever, enlarged lymph nodes, conjunctivitis (pink eye or inflammation of the mucous membrane that covers the white of the eye), keratitis (infection of the cornea), and a general sense of "feeling awful". Often confused with the common cold or flu, primary herpes infections usually occur in childhood and go undiagnosed.
Recurrent ocular herpes is the form of the disease with which we are most concerned. It is a recurrent eye infection of the cornea (the clear front window of the eye) which can potentially threaten sight. This causes true corneal ulceration, lid blisters, and intraocular inflammation, almost always involving only one eye. Once a patient experiences ocular herpes, the chances of recurrence are about 40%, despite appropriate therapy. Some patients can identify "trigger mechanisms" that tend to precede such recurrences. These include fever, fatigue, becoming "run down", emotional upsets and exposure to ultraviolet light (when in high altitudes, for instance).
The disease usually begins on the surface of the cornea. The eye turns red, is uncomfortable, teary, light sensitive and may have a scratchy sensation, as if something were in the eye. Pain may also be a prominent complaint. The process may go deeper into the cornea and cause permanent scarring or inflammation inside the eye. Chronic ulcers which are sometimes very difficult to heal, may also develop on the cornea. After several bouts, patients learn to detect the earliest signs and symptoms of the disease. Spreading the infection to another person is unlikely.
Treatment has improved greatly over the past 10 years. We now have excellent drugs that will destroy the virus ability to multiply Itself, thereby, curing the infection. It is most important to treat early in the course of the recurrence. If left untreated, scars may form and significantly impair vision. Eye drops are very effective. Sometimes we will literally scrape the herpes virus and ulcer from the eye and allow it to heal with the assistance of drops or ointments.
Our immune system makes antibodies to the herpes virus, and sometimes these antibodies create a "battlefield" on the surface of the eye, leaving scars and reducing vision. This problem can and should be treated vigorously, yet cautiously. It is very important to consult an ophthalmologist before beginning any treatment since some medications may actually make the disease worse.
Rarely is corneal transplantation needed to eliminate the scars of ocular herpes, but it remains an alternative in severe cases.