Eye herpes, also known as ocular herpes, is a condition of the eye caused by the herpes simplex virus (HSV).

The most common type of eye herpes is called epithelial keratitis. It affects the cornea, which is the clear front portion of your eye.

In its mild form, eye herpes causes:

  • pain
  • inflammation
  • redness
  • tearing of the cornea surface

HSV of the deeper middle layers of the cornea — known as the stroma — can cause severe damage, leading to vision loss and blindness.

In fact, eye herpes is the most common cause of blindness associated with cornea damage in the United States and the most common source of contagious blindness in the Western world.

Both mild and severe eye herpes can be treated with antiviral medication, however.

And with prompt treatment, HSV can be kept under control and damage to the cornea minimized.

Typical symptoms of eye herpes include:

  • eye pain
  • sensitivity to light
  • blurry vision
  • tearing
  • mucus discharge
  • red eye
  • inflamed eyelids (blepharitis)
  • painful, red blistering rash on upper eyelid and one side of forehead

In many cases, herpes affects only one eye.

Eye herpes vs. conjunctivitis

You may mistake eye herpes for conjunctivitis, which is known more commonly as pink eye. Both conditions may be caused by a virus, though conjunctivitis can also be caused by:

  • allergies
  • bacteria
  • chemicals

A doctor can make the correct diagnosis using a culture sample. If you have eye herpes, the culture will test positive for type 1 HSV (HSV-1). Receiving a correct diagnosis can help you to receive proper treatment.

The most common type of eye herpes is epithelial keratitis. In this type, the virus is active in the thin outermost layer of the cornea, known as the epithelium.

As mentioned, HSV can also affect deeper layers of the cornea, known as the stroma. This type of eye herpes is known as stromal keratitis.

Stromal keratitis is more serious than epithelial keratitis because over time and repeated outbreaks, it can damage your cornea enough to cause blindness.

Eye herpes is caused by an HSV transmission to the eyes and eyelids. It’s estimated that up to 90 percent of adults have been exposed to HSV-1 by age 50.

When it comes to eye herpes, HSV-1 affects these parts of the eye:

  • eyelids
  • cornea (the clear dome on the front of your eye)
  • retina (the light-sensing sheet of cells in the back of your eye)
  • conjunctiva (the thin sheet of tissue covering the white part of your eye and the inside of your eyelids)

Unlike genital herpes (usually associated with HSV-2), eye herpes isn’t sexually transmitted.

Rather, it most commonly happens after another body part — typically your mouth, in the form of cold sores — has already been affected by HSV in the past.

Once you’re living with HSV, it can’t be completely eradicated from your body. The virus can lie dormant for a while, then reactivate from time to time. So, eye herpes can be the result of a flare-up (reactivation) of an earlier infection.

The risk of transmitting the virus to another person from an affected eye is low, however. Antiviral medications help minimize damage during an outbreak.

Estimates vary, but approximately 24,000 new cases of eye herpes are diagnosed every year in the United States, according to the American Academy of Ophthalmology.

Eye herpes tends to be slightly more common in men than in women.

If you have symptoms of eye herpes, see an ophthalmologist or an optometrist. These are both doctors who specialize in eye health. Early treatment may improve your outlook.

To diagnose eye herpes, your doctor will ask you detailed questions about your symptoms, including when they started and whether you’ve experienced similar symptoms in the past.

Your doctor will do a thorough eye exam to evaluate your vision, sensitivity to light, and eye movements.

They’ll put eye drops in your eyes to dilate (widen) the iris, too. That helps your doctor see the condition of the retina in the back of your eye.

Your doctor may perform a fluorescein eye stain test. During the test, your doctor will use an eye drop to place a dark orange dye, called fluorescein, onto the outer surface of your eye.

Your doctor will look at the way the dye stains your eye to help them identify any problems with your cornea, such as scarring in the area affected by the HSV.

Your doctor may take a sample of cells from your eye surface to check for HSV if the diagnosis is unclear. A blood test to check for antibodies from past exposure to HSV isn’t very helpful for diagnosis because most people have been exposed to HSV at some point in life.

If your doctor determines you have eye herpes, you’ll immediately start taking prescription antiviral medication.

The treatment differs somewhat depending on whether you have epithelial keratitis (the milder form) or stromal keratitis (the more damaging form).

Epithelial keratitis treatment

HSV in the surface layer of the cornea usually subsides on its own within a few weeks.

If you promptly take antiviral medication, it can help minimize cornea damage and vision loss. Your doctor will recommend antiviral eye drops or ointment or oral antiviral drugs.

A common treatment is the oral medication acyclovir (Zovirax). Acyclovir may be a good treatment option because it doesn’t come with some of the potential side effects of the eye drops, such as watery eyes or itching.

Your doctor may also gently brush the surface of your cornea with a cotton swab after applying numbing drops to remove diseased cells. This procedure is known as debridement.

Stromal keratitis treatment

This type of HSV attacks the deeper middle layers of the cornea, called the stroma. Stromal keratitis is more likely to result in corneal scarring and loss of vision.

In addition to antiviral therapy, taking steroid (anti-inflammatory) eye drops helps reduce swelling in the stroma.

If you’re treating your eye herpes with eye drops, you may need to put them in as often as every 2 hours, depending on the medication your doctor prescribes. You’ll need to keep applying the drops for up to 2 weeks.

With oral acyclovir, you’ll take the pills five times per day.

You should see improvement in 2 to 5 days. The symptoms should be gone within 2 to 3 weeks.

After a first bout of eye herpes, about 20 percent of people will have an additional outbreak in the following year. After multiple recurrences, your doctor may recommend taking antiviral medication daily.

This is because multiple outbreaks damage your cornea. Complications include:

  • sores (ulcers)
  • numbing of the corneal surface
  • perforation of the cornea

If the cornea is damaged enough to cause significant vision loss, you may need a corneal transplant (keratoplasty).

Although eye herpes is not curable, you can minimize damage to your eyesight during outbreaks.

At the first sign of symptoms, call your doctor. The sooner you treat your eye herpes, the less chance there’ll be significant damage to your cornea.