Herpes Keratitis The HSV type I virus is known to affect approximately 85 to 95% of the adult population... Herpes simplex keratitis is an eye infection caused by the herpes simplex virus (HSV) which is the same virus that causes cold sores and fever blisters near the mouth and nose. The HSV type I virus is known to affect approximately 85 to 95% of the adult population although the virus usually lies dormant in a nerve that supplies the eye and skin. The virus may be “activated” by a mild injury to the eye exposure to excessive sunlight stress or an illness or fever.
Once an infection has started it may run its course and disappear just like cold sores do. But the herpes infection tends to recur and recurrences are prone to complications. One complication is a type of corneal ulcer called a dendritic corneal ulcer.
Keratitis means an infection of the cornea (the cornea is the clear front surface of the eye) an ulcer is a small break or pit in the surface and dendritic means branched like a tree which is how the ulcer looks under magnification.
At first a herpes eye infection may look or feel like the common pink eye (conjunctivitis-red watery scratchy and uncomfortable as though there is a grain of sand in your eye. If you have an ulcer you won’t be able to see it in the mirror because it is only about 1/25 of an inch in length. Other symptoms can include light sensitivity pain and decreased vision.
A complete eye examination will include a check of your best correct vision and a slit lamp (clinical microscope) evaluation of the cornea. The herpetic corneal ulcer has a characteristic shape that can be easily identified especially after a drop of yellow fluorescein dye is instilled onto the cornea. Sometimes corneal sensitivity is tested (it is reduced in herpes simplex). Additional clinical and laboratory tests may be necessary to confirm the diagnosis.
The best way to avoid complications is to begin treatment as early as possible. Several medications may be prescribed. You will probably need anti-viral eyerops which must be used very frequently at first sometimes hourly; a lubricating ointment usually for night use; and possibly eyedrops to dilate (enlarge) the pupil. Herpes is contagious so it is important that you always wash your hands after touching your eye. You must not share your eyedrops with anyone else or touch the tip of the dropper to either eye.
Sometimes in spite of the best treatment the virus does not respond. It may infect the deeper tissues of the cornea or you may get deep ulcers forming. If this occurs other medications will be added to the treatment routine which may go on for weeks of months. Rarely and only in extreme cases corneal scarring will develop and may require a corneal transplant to restore vision.
HOW TO PREVENT A RECURRENCE
Sometimes herpes simplex keratitis seems to be cured only to recur months or even years later in the same spot just as cold sore keeps coming back on the lip. While it may run the same course as it did initially it may also be more resistant to treatment. You can help prevent a recurrence by protecting your eyes with sunglasses whenever you are in bright sunlight seeing the doctor right away if your eye starts to “act up” or behave like pinkeye and making sure every doctor who treats your eyes knows that you previously had herpes keratitis. It is especially important to avoid eyedrops containing steroids that have not been prescribed for you and without first having your cornea examined with a slit lamp.
WHAT ABOUT OTHER KINDS OF HERPES?
A number of years ago it became evident that there were several other types of herpes simplex viruses. One is transmitted primarily through sexual activity with a person who has the disease; it has been identified as herpes type II. The virus that typically affects the eyes and face is herpes type I.
A different herpes virus called herpes zoster is identical to the chickenpox virus. This virus sometimes affects the cornea but it does so in a different way has a different course and requires different management from herpes simplex infections.