Herpes Keratitis, What Is It?

Herpes keratitis is usually marked by pain and redness of the eyes, as well as watery eyes.
Herpes Keratitis, What Is It?
Leonardo Biolatto

Written and verified by the doctor Leonardo Biolatto.

Last update: 27 May, 2022

Herpes keratitis is an inflammation of the cornea caused by an infection from a virus in the Herpes family. The cornea is the outermost layer of the eye that covers the iris and the pupil. When it gets damaged, it can affect the vision in that eye.

Viruses in the Herpes family are very common. To be specific, the principal cause of herpes keratitis is the Herpes Simplex type 1 virus. It’s estimated that around 90% of the world’s population is in contact with this virus from infancy.

This type of virus is able to remain in the body in a latent state and reactivate itself under certain circumstances, such as when the body’s immune defenses are weak. As a result, this means infections like herpes keratitis are very common.

Herpes keratitis is a viral infection of the eye that is easy to confuse with other eye infections, and can also reoccur various times in the same person. Read on to learn all you need to know about this virus.

What are the causes of herpes keratitis?

A close up of the herpes virus

The Herpes type 1 virus is very common and extremely contagious. It’s transmitted through contact with infected skin or saliva. Normally, people become infected during infancy, although at that point symptoms don’t usually appear. This stage is called the primary infection stage.

The virus remains in the person’s nervous system in a dormant state, in the skin and the eyes. This means that even though no symptoms appear, it’s still present in the body and can be reactivated at any time.

There are many circumstances that can cause this virus to reactivate. For example, a high stress level, overexposure to the sun, fever, or some trauma to the body that causes the body’s immune defenses to weaken can all provoke a resurgence.

Even menstruation for women or taking certain medications can cause the herpes virus to reactivate. This reactivation is what causes herpes keratitis.

How does it happen?

As we mentioned above, the virus can infect the eye for the first time in what’s called the primary infection stage. This is common in children. However, in these cases, the symptoms are usually mild and can be confused with common conjunctivitis.

But in the majority of cases, herpes keratitis occurs thanks to a reactivation of the virus that’s already present, as we noted. The virus that’s already present in the eye can cause an infection when the person’s defenses are weak.

What are the symptoms of herpes keratitis?

At the primary infection stage, the symptoms are similar to those of common conjunctivitis. The eye is usually red and very itchy. In addition to that, the eye also secretes a yellowish or green liquid, and sleep accumulates in the eyelid and eyelashes.

With a reactivation of the virus, herpes keratitis typically has more severe symptoms. Here are the most common symptoms:

  • The eyes are usually painful and red.
  • There is a sensation of a foreign object in the eye.
  • Constant weeping of the eyes.
  • Sensitivity to bright light.

The problem is that if the infection continues, the cornea can become overly inflamed and can cause blurry vision. In fact, ulcers can eventually occur in the cornea. This is serious since these can cause permanent vision loss.

Also, if herpes keratitis reoccurs several times, it can damage a large part of the cornea. It causes permanent scarring on the cornea that also diminishes vision.

A woman's red eye

Read further: 5 Eye Care Errors You Might Be Making

How do experts diagnose it?

To be able to diagnose herpes keratitis, it’s fundamental to visit your PCP or eye doctor, before symptoms appear. A professional will be able to give you a thorough eye examination.

To carry this out, they will use eye drops that have temporary colored dyes. These show up any lesions on the cornea if they exist, and make it possible to detect any damaged areas.

Sometimes, the medic will collect samples of the damaged areas of the eye to examine them in a laboratory. It’s possible to detect the presence of the virus in the eye by means of cultures of these samples.

Treatment for herpes keratitis

There are currently no treatments that exist to get rid of the herpes virus from the body completely. However, there are medications that allow you to treat infections such as herpes keratitis.

In the first place, doctors usually prescribe antiviral eye drops. These medications also come in oral or intravenous form and the most common antiviral medication for this is acyclovir.

However, when keratitis has already caused severe lesions to the cornea, then the treatment can be more complicated. A cornea transplant may be necessary in some cases. An eye specialist can choose the best treatment in each case.

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In conclusion

Herpes keratitis is a common infection of the eye. However, if not treated correctly, it can cause serious vision problems. Make sure you consult your doctor if you have any doubts or questions.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.



This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.