Herpetic Eye Disease

What is herpetic eye disease?

Herpes simplex (the cause of "cold sores" or "fever blisters" on the lips and face) and herpes zoster (the cause of chickenpox or shingles) are two viruses that can occasionally affect the eyes. When this happens, the condition is known as herpetic eye disease.

Most people are exposed to these viruses during their childhood and carry the dormant (inactive) viruses in their bodies their entire lives. (In 1995 most children in the United States started receiving the herpes zoster vaccine so they will not carry the dormant virus.)

These two viruses are not the same virus that causes genital herpes (which is herpes simplex type 2) and herpetic eye disease is not regarded as a sexually transmitted infection.

• Varicella zoster virus: When this virus affects the eye, it is called herpes zoster ophthalmicus.
• Herpes simplex type 1: In the eye, it usually causes an infection of the cornea. This infection is called herpes simplex keratitis.

Although both of these problems are caused by a herpes virus, different medications are sometimes needed to treat the appearances of the disease.

How does herpetic eye disease develop?

Like many viruses, the herpes simplex 1 and varicella zoster viruses are actually present in most adults. The viruses in the herpes family usually live around the nerve fibers in humans without ever causing a problem. Occasionally, the viruses will start to multiply, or they will move from one area of the body to another, and that is when herpetic disease breaks out. This often happens when the immune system of the body is weakened by some other health problem.

How is herpetic eye disease diagnosed?

The two different types of herpetic eye disease have different symptoms. One thing they have in common, however, is that they can both be very painful because they affect the nerves directly.

The problem may be caused by herpes zoster ophthalmicus if your doctor finds some or all of these symptoms:

• Pain in and around only one eye
• Redness, rash or sores on the eyelids and around the eyes, especially on the forehead (and sometime on the tip of the nose). Its appearance is similar to poison ivy blisters that turn into scabs over 1 to 2 weeks. The rash is subtle in younger people and more severe in older.
• Redness of the eye
• Swelling and cloudiness of the cornea
• Flu-like symptoms (low-grade fever, generally feeling unwell)
• Tingling/numbness in forehead before the rash appears

The problem may be caused by herpes simplex keratitis if your doctor sees these symptoms:

• Pain in and around only one eye
• Redness of the eye
• Decreased vision
• Feeling of dirt or "grit" in the eye
• Overflowing tears
• Pain when looking at bright light
• Swelling or cloudiness of the cornea

Many other conditions can display these symptoms, so it is necessary for a doctor to perform a full examination of the eye to learn the cause. Your doctor might want to use special tests if it looks like herpetic eye disease might be present. He or she will probably check the pressure inside the eye, for example. There is also a special dye called fluorescein that the doctor might put into the eye. This dye glows under ultraviolet light and can help to show the doctor if the virus is causing problems on the surface of the eye.

How is herpes zoster ophthalmicus treated?

Because herpes is a virus, antibiotics such as penicillin are not an effective treatment. The only drugs that will work against herpes infections are antiviral medications.

Depending on how serious the herpes zoster ophthalmicus is and what part of the eye is affected, your doctor will recommend antiviral eye pills, drops or both. No matter what kind of medicine is recommended, it is important to keep using the medicine for as long as your doctor recommends. Even though the eye might start to look or feel better, the infection could come back if you stop taking your medicine too soon.

If the infection is affecting the cornea, another kind of eye drops called corticosteroids might also be recommended. Corticosteroids can help control the inflammation caused by the disease, but in some patients they can also raise the pressure in the eyes. If corticosteroids are being used, it is important for the patient to come back to the doctor's office so the pressure can be checked. In some cases, a drop that dilates the pupil may be prescribed to prevent damage to the iris (the colored part of the eye) caused by inflammation.

Unfortunately, herpetic eye disease can be painful even after several days of treatment when the eye is starting to look better. This can be discouraging, but it does not mean that the treatment is a failure. The medicines are working, and the pain will go away eventually. (For some people, post-herpetic neuralgia [chronic pain] may persist from nerve damage from the infection. In rare cases, long-term medications may be necessary to treat symptoms.)

How is herpes simplex keratitis treated?

The same types of eye drops and pills are prescribed to treat herpes simplex keratitis. It is also just as important to use the medicines as recommended, and to keep all appointments with your doctor.

Is there a cure for herpetic eye disease?

At present, there is no "cure" for the infections caused by herpes viruses, only treatments to suppress the infection and reduce inflammation. When treated properly, vision loss can usually be avoided, but it is important to continue to follow up with your doctor at the recommended intervals. In some cases, long-term antiviral pills may be recommended to reduce the chance of repeated episodes of infection. These medications are usually well-tolerated and have very few side effects. Only your doctor can tell you if long-term medication is recommended for your condition.