A corneal inflammation due to a herpes virus - either herpes simplex or herpes zoster virus.
Keratitis is an inflammation of the cornea — the clear, dome-shaped tissue on the front of your eye that covers the pupil and iris. Keratitis is sometimes caused by an infection involving bacteria, viruses, fungi or parasites. Non-infectious keratitis can be caused by a minor injury, wearing your contact lenses too long or other noninfectious diseases.
- Corneal inflammation
- Red eye
- Eye irritation
- Reduced visual acuity
- Eye pain
- Eye tearing
- Light sensitivity
Causes of herpetic keratitis may include:
- Contaminated contact lenses. The cornea may become contaminated when the lens is in your eye, resulting in infectious keratitis.
- Viruses. Viruses such as the herpes viruses (herpes simplex and herpes zoster) and the virus that causes chlamydia may cause keratitis.
Bacteria, fungi and parasites in water — particularly in oceans, rivers, lakes and hot tubs — can enter your eyes when you're swimming or bathing and result in keratitis. If you're exposed to these microorganisms, a healthy cornea is unlikely to become infected. But if you've experienced some previous breakdown of the corneal epithelium, such as from wearing a contact lens too long, your cornea may be vulnerable to infection.
Factors that may increase your risk of keratitis include:
Contact lenses. Wearing contact lenses increases your risk of both infectious and noninfectious keratitis. The risk typically stems from not disinfecting lenses properly, wearing contact lenses while swimming, wearing them longer than recommended, or using water or homemade solutions to store and clean lenses.
Keratitis is more common in people who use extended-wear contacts, or wear contacts continuously, than in those who use daily wear contacts and take them out at night.
- Reduced immunity. If your immune system is weakened due to disease or medications, you're at higher risk of developing keratitis.
- Warm climate. If you live in a warm, humid climate, your risk of keratitis is increased, particularly if plant material gets into your eyes. Plant material can scratch the corneal epithelium and chemicals from the plant can cause an inflammation, which may then lead to an infection.
- Corticosteroids. Use of corticosteroid eyedrops to treat an eye disorder can increase your risk of developing infectious keratitis or worsen existing keratitis.
- Eye injury. If one of your corneas has been damaged from an injury in the past, you may be more vulnerable to developing keratitis.
Some forms of viral keratitis, such as herpetic keratitis (caused by the herpes virus), can't be completely eliminated. But the following steps may control viral keratitis recurrences:
- If you have a cold sore or a herpes blister, avoid touching your eyes, your eyelids and the skin around your eyes unless you've thoroughly washed your hands.
- Don't use corticosteroid eyedrops unless they have been prescribed by a specialist knowledgeable about viral keratitis and the need for careful monitoring. Corticosteroid drops can increase your risk of developing viral keratitis and, if a viral infection does occur, these drops can make it more severe.
- If you wear contact lenses and have multiple recurrences of viral keratitis, discontinuing your use of contact lenses may decrease your risk of recurrences. Discuss this option with your eye doctor.
Diagnosing keratitis typically involves the following:
- Eye exam. Your doctor will perform a general examination of your eye. It may be uncomfortable to open your eye for the exam, but it's important that your doctor be able to examine your eye. The exam will include an effort to determine how well you can see (visual acuity), usually using standard eye charts.
- Penlight exam. Your doctor may examine your eye using a penlight, to check your pupil's reaction, size and other factors. Your doctor may apply a stain to the surface of your eye, to help identify the extent and character of surface irregularities and ulcers of the cornea.
- Slit-lamp exam. Your doctor may examine your eyes with a special instrument called a slit lamp, which provides a bright source of light and magnification. This instrument uses an intense line of light — a slit-like beam — to illuminate your cornea, iris, lens, and the space between your iris and cornea. The light allows your doctor to view these structures with high magnification to detect the character and extent of keratitis, as well as the effect it may have on other structures of the eye.
- Laboratory analysis. Your doctor may take a sample of tears or some cells from your cornea for laboratory analysis to determine the cause of keratitis and to help develop a treatment plan for your condition.
If not treated, potential complications of keratitis include:
- Chronic corneal inflammation
- Chronic or recurrent viral infections of your cornea
- Open sores on your cornea (corneal ulcers)
- Corneal swelling and scarring
- Temporary or permanent reduction in your vision
If a virus is causing the infection, antiviral eyedrops and oral antiviral medications may be effective. But these medications may not be able to eliminate the virus completely, and viral keratitis may recur.
Refer to Research Publications.