ConditionEyes & vision
Keratitis (Corneal Inflammation)
Keratitis is inflammation of the cornea, the clear dome at the front of the eye. It causes eye pain, redness, light sensitivity, watering and blurred vision. It can be infectious, caused by bacteria, viruses (especially herpes simplex), fungi or the amoeba Acanthamoeba, or non-infectious, from dry eye, injury or overwearing contact lenses. Contact lens wear is the biggest risk factor for infectious keratitis. Because infections can scar the cornea and cause permanent vision loss, keratitis needs prompt assessment by an eye professional.
Also called: Corneal inflammation, corneal infection, infectious keratitis, contact lens keratitis
At a glance
- What it is
- Inflammation of the cornea, infectious or non-infectious.
- Biggest risk factor
- Contact lens wear, especially sleeping in lenses or exposing them to water.
- Symptoms
- Eye pain, redness, light sensitivity, watering, blurred vision, a white spot on the cornea.
- Diagnosis
- Slit lamp exam with fluorescein dye, and corneal scrapings for culture.
- Treatment
- Antibiotic, antiviral, antifungal or anti-amoebic drops depending on the cause.
When to get help
Call 911 or go to the ER
- Sudden severe eye pain with significant vision loss, or an eye injury with a sharp or high-speed object
- A chemical splash: rinse with clean water for at least 15 to 20 minutes, then go to the ER
See a doctor within a day or two
- Eye pain, redness and light sensitivity in a contact lens wearer: remove the lenses, do not put them back, and see an eye doctor the same day
- A white or gray spot on the clear part of the eye
- Blurred vision with a painful red eye
- Eye pain after an injury with plant material, such as a branch
- A painful red eye in someone with a history of herpes eye disease
Book a routine appointment
- Recurring gritty, red, irritated eyes, especially with contact lens use
Usually safe to manage at home
- Mild dryness or irritation without pain or blurred vision in a non-lens wearer, eased by lubricating drops
Why keratitis is serious
The cornea focuses light into the eye and must stay clear for good vision. Infection or inflammation can make it cloudy, cause an open sore (corneal ulcer), and leave a scar. Severe infections can perforate the cornea. Early treatment usually prevents lasting damage, which is why same-day care is recommended.
Types and causes
Infectious keratitis
| Type | Cause | Typical clues |
|---|---|---|
| Bacterial keratitis | Pseudomonas, Staphylococcus and others | Rapid onset, pain, discharge, white infiltrate. Most common in contact lens wearers |
| Herpes simplex keratitis | Herpes simplex virus | Often recurrent, one eye, branching (dendritic) ulcer on dye testing, reduced corneal sensation |
| Herpes zoster keratitis | Shingles virus | Shingles rash on the forehead or tip of the nose |
| Fungal keratitis | Fusarium, Aspergillus, Candida | After injury with plant matter, warm climates, slower onset |
| Acanthamoeba keratitis | A free-living amoeba in water and soil | Contact lens wearers exposed to tap water, pools or hot tubs. Pain often severe and out of proportion to signs |
Non-infectious keratitis
- Overwearing or sleeping in contact lenses (lack of oxygen)
- Severe dry eye and incomplete eyelid closure
- Minor injuries and corneal abrasions
- UV light exposure from welding or snow ("snow blindness")
- Autoimmune conditions such as rheumatoid arthritis
- Reactions to eye drops or preservatives
Risk factors
- Contact lenses: sleeping in them, wearing them too long, poor cleaning, topping up solution, rinsing lenses or cases with tap water, swimming or showering in lenses
- Eye injuries, particularly with organic material
- Weakened immune system
- Long-term steroid eye drops
- Previous herpes eye infection
- Eye surgery
Symptoms
- Eye pain, from mild to severe
- Redness
- Sensitivity to light
- Excess tearing or discharge
- Blurred or reduced vision
- A feeling of something in the eye
- Difficulty opening the eye
- A visible white or gray spot on the cornea
Keratitis differs from conjunctivitis, which causes redness and discharge but usually only mild discomfort and normal vision. Pain, light sensitivity and blurred vision point to the cornea.
Diagnosis
- Slit lamp examination: a microscope view of the cornea.
- Fluorescein dye: shows scratches, ulcers and the branching pattern of herpes.
- Corneal scraping and culture: for moderate to severe infections, to identify the organism and guide treatment.
- Contact lens and case culture in some cases.
- Confocal microscopy and PCR testing for Acanthamoeba and fungi in specialized centers.
Treatment
- Bacterial keratitis: frequent antibiotic eye drops, sometimes every hour at first, then tapered.
- Herpes simplex keratitis: antiviral eye gel or drops, or antiviral tablets. Long-term antiviral tablets reduce recurrences in some people.
- Fungal keratitis: antifungal drops such as natamycin, sometimes with oral antifungals. Treatment lasts weeks.
- Acanthamoeba keratitis: specialized anti-amoebic drops for months.
- Non-infectious keratitis: stop contact lens wear, lubricating drops and ointment, treat the underlying cause.
- Pain relief: oral pain relievers and sometimes dilating drops.
- Corneal transplant if scarring severely affects vision, or the cornea perforates.
Do not use leftover steroid eye drops for a red eye. Steroids can make herpes, fungal and Acanthamoeba infections much worse. Do not wear contact lenses until your eye doctor says the cornea has healed, and discard the lenses and case used during the infection.
Prevention for contact lens wearers
- Wash and dry your hands before handling lenses.
- Do not sleep in lenses unless they are specifically prescribed for overnight wear, and even then, the risk is higher.
- Never rinse lenses or cases with tap water, and never use saliva.
- Remove lenses before swimming, showering or using a hot tub.
- Use fresh solution every time. Do not top up old solution.
- Replace your lens case at least every 3 months.
- Replace lenses on schedule.
- Keep backup glasses and remove lenses if your eyes become red or painful.
Frequently asked questions
What are the symptoms of keratitis?
Symptoms include eye pain, redness, sensitivity to light, watering or discharge, blurred vision and a feeling that something is in the eye. A white or gray spot may be visible on the cornea. Contact lens wearers with these symptoms should remove their lenses and see an eye doctor the same day.
What causes keratitis?
Infectious keratitis is caused by bacteria, viruses such as herpes simplex, fungi or Acanthamoeba. Non-infectious keratitis results from contact lens overwear, dry eye, injury, UV exposure or autoimmune disease. Contact lens use is the most important risk factor for infection.
Is keratitis serious?
It can be. Infections can create ulcers that scar the cornea and permanently reduce vision, and severe cases can perforate the eye. With prompt treatment, most people recover well. Same-day assessment by an eye professional is recommended.
How long does keratitis take to heal?
Mild bacterial keratitis often improves within days and heals over 1 to 2 weeks. Herpes keratitis may take a couple of weeks and can recur. Fungal and Acanthamoeba keratitis can take months of treatment. Healing time depends on the cause and how early treatment starts.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Ophthalmology: Bacterial Keratitis Preferred Practice Pattern; Keratitis
- CDC: Contact lens health and keratitis
- National Eye Institute: Keratitis and corneal conditions
- MedlinePlus: Keratitis
- American Optometric Association: Keratitis