Herpes simplex keratitis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 1, 2016
StartDiseasesHerpes simplex keratitis

Herpes simplex keratitis or herpes simplex virus (HSV) keratitis is a very common viral infection that affects the eye. The treatment is usually effective, but the disease often returns after being cleared up. If left untreated, HSV keratitis can lead to severe complications and even blindness.


Definition & Facts

Herpes simplex virus (HSV) keratitis is a viral infection of the eye. This type of eye infection affects the cornea of the eye and sometimes the iris. It can be caused by either the herpes simplex type I virus or the herpes simplex type II virus. HSV II more commonly affects the genital area while HSV I tends to be seen more often on the face, mouth, and eyes.

HSV keratitis is treatable, but it tends to recur. Recurrent episodes may be more severe than the original infection and can leave permanent scarring in the eye that can lead to blindness. HSV keratitis can occur in one or both eyes. There are more than 1.5 million cases each year worldwide.

Symptoms & Complaints

The symptoms of HSV keratitis are similar to other eye infections at first. The patient may feel like there is something in the eye that they cannot get out.

The eye may appear to be red, and it may feel itchy. In addition, the infected individual may be more sensitive to light than normal.

In some cases, small white blisters appear on the eyelid and symptoms may worsen, and vision may become blurry. The blisters will eventually burst, leaving ulcerations that heal within about a week.

The infection may appear to be gone, but it often returns when the virus is reactivated. This reactivation can happen days, weeks, or even months later, often as a result of stress, excessive sun exposure or other, unknown reasons.

The patient will typically feel similar symptoms as the first outbreak with the addition of excess watering of the eyes. Recurrent HSV keratitis usually involves the cornea and corneal epithelium, and it can result in permanent scarring and damage to the eye.


HSV keratitis is caused by either the herpes simplex type I or herpes simplex type II virus. It is most commonly caused by the first type as the second is generally found in the genital area; however, it is possible for herpes simplex type II to infect the eye.

The virus is spread through skin-to-skin contact or through contact with the secretions of an infected individual. For example, if a person has HSV keratitis and has touched her face where tears have dripped, and then she shakes hands with another person, the second person is likely to have the virus on their hand. If that person then rubs their eye, they have just introduced the virus to themselves.

Although the infection usually clears up spontaneously, it can lie dormant in the nerves of the skin or the eye and then recur at any time. There are some factors that make it more likely for the virus to come back. If a person is under a lot of stress or if she is exposed to excessive amounts of sunlight, she may have an outbreak. Additional factors that could cause a recurrent episode are fever, trauma such as injury or surgery, menstruation, and certain medications.

Diagnosis & Tests

The diagnosis of HSV keratitis can usually be made by an ophthalmologist or optometrist by clinical observation of the patient. Additionally, an inquiry into the patient's medical history including questions about whether or not the person has ever had HSV keratitis before and about possible exposures, is important in the diagnostic process.

The doctor will likely examine the eye carefully. She may use a slit lamp instrument which provides extra light and magnification for more accurate diagnosis. The appearance of a dendritic ulcer is usually enough to confirm the diagnosis of HSV keratitis, but if it is not, there are further diagnostic tools available.

Uncertain diagnoses and complicated cases may require lab testing. Laboratory tests can include the testing of a sample from the cornea and/or tears from the eye. These can be analyzed and characteristic signs will be present if HSV keratitis is the cause of the disease. DNA testing is also a fast and very reliable method of diagnosing HSV keratitis.

Treatment & Therapy

Treatment of HSV keratitis will depend upon the severity of the disease and several other factors, including the patient's overall health and medications he or she may already be taking.

Many ophthalmologists will prescribe an antiviral drug. This can take one of two forms. The medication may be in the form of a drop or an ointment that is placed directly on the eye. This could include a topical form of ganciclovir. This course of treatment is usually continued for at least 10 to 14 days. These medications are usually tolerated well by patients.

However, some doctors feel that this can lead to toxicity of the eye surface and will prescribe an oral antiviral medication such as acyclovir instead. The right oral antiviral medications appear to be just as effective as the forms that are placed directly on the eye surface. A patient must take care to take all medications exactly as directed and to finish all medications.

Along with medications, some doctors may gently scrape the cornea where the infection appears to clean it off. Corticosteroid medications are used for some eye problems, but they can be very detrimental in the case of this disease and must be carefully administered.

Prevention & Prophylaxis

The only sure way to prevent HSV keratitis is to avoid the infection. This is especially important for those individuals who have a weakened immune system. In addition, it is important for anyone who has an active cold sore not to touch the eyes for any reason to avoid spreading the disease.

Those that wear contact lenses will need to stop if they find that they are getting this infection very often. It is always important to assure proper hand washing as an essential precaution if exposure has occurred.