Eye herpes, or ocular herpes, is caused by the herpes simplex virus (HSV). Your treatment will depend on the severity of the infection and what part of the eye it affects.

The most common type of herpetic eye infection 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
  • excessive tearing of the cornea surface

HSV of the deeper layers of the cornea — known as the cornea stroma — can cause severe tissue damage, chronic inflammation, and scarring, all of which can contribute to vision loss.

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

An experienced eye doctor can establish the correct diagnosis by collecting a thorough medical history and by performing a detailed eye examination. Careful slit lamp biomicroscopy with the use of a topical inert dye will unveil active herpetic lesions.

A sterile cotton swab can be used to collect a sample for laboratory culture. If you have ocular herpes, the culture will test positive for type 1 HSV (HSV-1). Receiving a prompt, correct diagnosis can help you receive the appropriate treatment.

The most common type of ocular herpes is epithelial keratitis. In this type, the virus is active in the thin outermost layer of cells covering the cornea, known as the corneal 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 require corneal transplantation.

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), most cases of ocular herpes aren’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. This means that even though the initial ocular herpes infection resolved with treatment, it can still recur over time due to viral reactivation.

The risk of transmitting the virus to another person from an affected eye is low, however. Antiviral medications help reduce transmission of HSV 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 instill an inert orange dye, called fluorescein, onto the outer surface of your eye.

With the use of safe, near-ultraviolet light fluorescein highlights areas of the cornea where the epithelium is unhealthy or absent. These defects produce a familiar stellate pattern on the cornea called a ‘dendrite’ that can be viewed with the slit-lamp biomicroscope.

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:

  • non-healing sores (ulcers)
  • numbing of the corneal surface
  • increased susceptibility to other infections
  • chronic inflammation and eye discomfort
  • perforation of the cornea

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

Unfortunately, for some individuals, ocular herpes is not curable, but you can still minimize potential 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.