Herpes Keratitis

The term "keratitis" refers to an inflammation of the cornea (clear covering at the front of the eye). When you look at the color of a person's eye, you are looking through the clear cornea to the colored iris, which is inside the eye. The cornea is an extremely sensitive tissue. This is why you immediately blink when something touches your eye, or even if you think something is going to touch your eye.

One of the most common forms of keratitis is produced by the herpes virus. There are different types of herpes infections. Herpes Simplex Virus 1 (HSV-1) usually causes cold sores and eye infections. HSV-2 is usually, but not always, the cause of sexually transmitted herpes infections. There is another type of herpes virus called Herpes Zoster, which is the cause of a painful rash known as "shingles."

When shingles affects the face, there may be an associated herpes infection or inflammation in the eye on the same side as the rash. This makes it very important to have your eye checked, but this is typically not a herpes keratitis infection.

Most people, at one time or another, have had some form of herpes virus in their system. Stress, fatigue, sunlight, surgery, illness, the use of certain drugs like steroids, and certain foods are all factors that may make the herpes virus flare up again, causing a herpes-related illness.

One of the places that the virus can cause inflammation is on the surface of the cornea. For this reason, if you have an active herpes infection, such as a cold sore, it is very important to avoid contact to your eyes with your fingers, since the virus may spread.


Herpes keratitis almost always occurs in only one eye at a time. Herpes keratitis causes:

  • Pain in the affected eye.

  • Extreme light sensitivity.

  • Eye is typically red and inflamed.

  • Vision may be blurred.

  • Eye may tear excessively.


Herpes Keratitis has a very specific pattern of inflammation on the cornea. It is so typical that an eye specialist can tell almost immediately what is wrong, by simply looking at the eye with a special microscope and with a small amount of special green dye placed in the eye. Herpes keratitis forms a branch-like pattern of inflammation known as a "dendrite." For this reason, it is also called "dendritic keratitis."


Without treatment, herpes keratitis can cause scarring of the cornea and loss of vision. It can come back even after it has been successfully treated. This usually happens during a generalized illness, when all herpes viruses are prone to flare up. The inflammation can also spread to the inside of the eye, causing scarring. The side effects of such scarring can result in complications and such conditions as glaucoma and cataracts.

It is very important to know exactly what type of keratitis you have, and to know the cause of any red eye. This is because certain medicines, which are commonly used as eye drops, can make a herpes keratitis infection much worse very fast. Steroid drops (prednisone) for instance, can rapidly make a herpes infection worse, if used at the wrong time, while the virus is still active.


Medicines are available for the treatment of herpes keratitis. The medicines used will depend on how much of the eye is involved. It may also depend on whether there is live virus still in the eye.

Your caregiver may want you to have a complete physical examination, to be sure that nothing else is going on in your body that allowed the herpes virus to flare up. Even after successful treatment, one third of people with herpes virus will have a recurrence.


  • Take all medicines as instructed. Take pain medicines only as prescribed by your caregiver. Do not self medicate with eye drops, unless instructed to do so.

  • Keep all appointments as instructed. Remember, this illness is a leading cause of blindness.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.