Eye herpes, also known as ocular herpes, is an infection of the eye by the herpes simplex virus (HSV). The most common type is called epithelial keratitis, and it affects the cornea, the clear front portion of your eye. In its mild form, eye herpes causes:
- tearing of the cornea surface
HSV infection of the deeper, middle layers of the cornea, known as the stroma, can cause severe damage leading to vision loss and blindness.
Both mild and severe eye herpes can be treated with antiviral medication.
Eye herpes is the most common cause of blindness associated with cornea damage in the United States and the most common source of infectious blindness in the Western world. But 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
- mucus discharge
- red eye
- inflamed eyelids (blepharitis)
In many cases, herpes infects only one eye.
Eye herpes vs. conjunctivitis
You may mistake eye herpes for conjunctivitis, which is known commonly as pink eye. Both conditions may be caused by a virus, though conjunctivitis can also be caused by bacteria, allergies, or 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 diagnose 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.
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 the cornea enough to cause blindness.
Eye herpes is caused by an HSV infection of the eyes and eyelids. It’s estimated that up to 90 percent of adults have been exposed to HSV by the age of 50. In eye herpes, HSV-1 infects these parts of the eye:
- 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)
Eye herpes isn’t sexually transmitted, but is picked up from direct contact with the skin or fluids of a person with active HSV-1. Genital herpes is usually associated with type 2 HSV and is sexually transmitted.
Once infected with HSV, you can’t completely eradicate it from your body. The virus can lie dormant and then reactivate from time to time. The risk of transmitting the virus to another person from an infected eye is low, however. Antiviral medications help to minimize damage during an outbreak.
Estimates vary, but approximately 20,000 new cases of eye herpes are diagnosed every year in the United States. Including recurrences, the total number of annual infectious episodes is 48,000. Eye herpes is slightly more common in men than in women.
If you have symptoms of eye herpes, see an ophthalmologist or an optometrist, 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 to 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 from the HSV infection.
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 infection in the surface layer of the cornea usually subsides on its own within a few weeks. Promptly taken antiviral medication 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 all 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 infection 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 to reduce swelling in the stroma.
For treatment with eye drops, you may need to put the drops in as often as every two hours, depending on the medication your doctor prescribes. You’ll need to keep applying the drops for up to two weeks. With oral acyclovir, you’ll take the pills five times a day.
You should see improvement in two to five days. The symptoms should be gone within two to three weeks.
After a first bout of eye herpes, about 20 percent of people will have an additional outbreak of eye herpes in the following year. After multiple recurrences, your doctor may recommend taking antiviral medication daily.
Multiple outbreaks damage the 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 get treated, the less your chances of significant damage to your cornea.