Contact Lens Keratitis: What Every Lens Wearer Should Know
Understanding Contact Lens Keratitis
Keratitis means inflammation or infection of the cornea. When caused by a microorganism, it is called microbial keratitis, and contact lens wear is the leading risk factor for this condition in adults. A corneal ulcer, which is a painful open sore on the corneal surface, is one of the most serious outcomes of untreated lens-related infection.
When a lens rests on the cornea for hours at a time, it can reduce the eye's natural defenses. Tears normally wash microorganisms off the surface of the eye, but a contact lens can trap germs against the cornea and allow them to grow. Small breaks in the corneal surface, which can happen even without obvious injury, give those germs an entry point.
Contact lens wearers face a significantly higher risk of corneal infection compared to people who do not wear lenses. The risk is greater among people who sleep in lenses, wear lenses longer than recommended, or do not follow proper hygiene. Each year in the United States, lens-related eye problems account for a large number of doctor and emergency room visits, many of which involve infections that could have been prevented.
Bacteria are the most common cause of contact lens keratitis. Pseudomonas aeruginosa is particularly associated with lens wear and can cause rapid, aggressive damage to the cornea. Staphylococcus and Streptococcus species are also common culprits.
Fungal infections, caused by organisms like Fusarium and Aspergillus, tend to progress more slowly but are harder to treat. Acanthamoeba, a microscopic organism found in tap water, swimming pools, and hot tubs, can cause one of the most painful and difficult-to-treat forms of keratitis. Exposure to tap water while wearing lenses is a primary risk factor for Acanthamoeba infection.
Habits That Raise Your Risk
The majority of contact lens infections are connected to specific habits that can be changed. Knowing which behaviors carry the most risk helps you take real steps to protect your eyes every day.
Sleeping in lenses, even those marketed as extended-wear, significantly increases the risk of infection. During sleep, tear production decreases and the eye cannot flush away microorganisms as effectively. Unless your Cornea Specialist has specifically prescribed overnight wear for your situation, removing lenses before sleep is the safest approach.
Hands carry bacteria from everyday surfaces directly onto the lens and into the eye. Washing hands thoroughly with soap and water and drying them with a clean, lint-free towel before touching lenses or a lens case is one of the most effective ways to reduce infection risk.
The lens case is a common source of contamination that is easy to overlook. Rinsing the case with tap water is not safe, since tap water can introduce Acanthamoeba. Cases should be rinsed with fresh contact lens solution, then left open and face-down to air dry. Replacing the case at least every three months further reduces the buildup of harmful microorganisms.
Topping off means adding fresh solution to old solution that is already in the case rather than emptying and refilling completely. This practice dilutes the disinfecting strength of the solution and allows microorganisms from the old solution to survive. Always empty the lens case completely and refill it with fresh solution each time.
Tap water, shower water, pool water, and hot tub water all carry microorganisms that can cause serious corneal infections. Lenses should be removed before showering, swimming, or using a hot tub. If a lens does come into contact with water, it should be discarded rather than rinsed and reinserted. Wearing well-sealed goggles during water activities can offer some protection if lens removal is not possible.
Warning Signs That Require Immediate Attention
Contact lens keratitis can progress quickly, sometimes within hours, making early recognition and prompt care critical to preserving vision. Knowing which symptoms are serious helps you act before an infection causes lasting damage.
A healthy eye should not be painful when a lens is in place. Sharp, aching, or persistent pain is the most important warning sign of a corneal infection. Remove the lens immediately and contact our office if the pain does not ease within a short time. Acanthamoeba keratitis in particular is known for causing pain that feels far worse than what is visible on examination, so pain should never be dismissed simply because the eye looks only mildly red.
Redness that remains or worsens after removing a lens needs to be evaluated the same day. Sensitivity to light, called photophobia, is another warning sign that the cornea may be inflamed or infected. These symptoms should not be managed with artificial tears or ignored in hopes they will clear on their own.
Blurry vision that does not improve with glasses, a white or gray spot visible on the cornea, or thick yellow or green discharge from the eye are all serious symptoms requiring same-day evaluation. A visible white spot on the cornea often indicates an active ulcer. Each of these signs means infection may already be present and treatment should begin as soon as possible.
If you experience any combination of pain, redness, light sensitivity, blurred vision, or visible changes to the cornea, seek eye care that same day. Do not wait to see if symptoms improve overnight. If our office is closed, an emergency room with ophthalmology coverage is the appropriate next step. Delay in treating corneal infections increases the risk of permanent scarring and vision loss.
How Corneal Infections Are Diagnosed and Treated
Prompt, accurate diagnosis is the foundation of effective treatment. The type of organism causing the infection determines which medications will work, and identifying it early guides the entire course of care.
Your Cornea Specialist will examine your eye under a slit lamp, a specialized microscope used in eye care. A dye called fluorescein may be used to highlight any damage to the corneal surface. For larger, deeper, or centrally located ulcers, a small sample of material from the ulcer may be collected and sent to a laboratory. Culture results take one to two days and help ensure that treatment is matched precisely to the germ responsible.
Most bacterial cases are treated with prescription antibiotic eye drops, often from a class called fluoroquinolones. In the early phase of treatment, drops may need to be used very frequently, sometimes every thirty to sixty minutes around the clock. For more severe infections, your Cornea Specialist may prescribe two types of specially compounded antibiotic drops, called fortified drops, that work through different mechanisms. As the infection responds to treatment, the frequency of drops is gradually reduced.
Fungal keratitis requires antifungal eye drops and typically heals more slowly than bacterial infections, sometimes requiring months of treatment. Acanthamoeba infections require a specific type of drop containing an antiseptic agent. Both conditions are challenging to treat and require close follow-up with a Cornea Specialist. Letting your care team know if your lenses were ever exposed to tap water or pool water is important information that helps direct testing from the very beginning.
After treatment begins, you will be seen frequently, often several times in the first week, so your Cornea Specialist can monitor healing, adjust medications, and check for complications. A bandage contact lens may be placed after the active infection clears to support the healing corneal surface. All lenses, lens cases, and opened solution used at the time of infection should be discarded. When the eye has fully healed, our team can help fit you with new lenses and guide you through safer habits going forward.
Frequently Asked Questions
The following questions address practical decisions that lens wearers commonly face when trying to understand their risk or manage symptoms.
Daily disposable lenses eliminate the need for a storage case and solution, which removes two of the most common sources of contamination. Because a fresh lens is opened each morning and discarded each night, there is no opportunity for organisms to build up over time. For patients who have had a previous infection or who struggle with consistent hygiene routines, daily disposables are often a strong option to discuss with our optometry team.
No. Tap water should never contact lenses or lens cases under any circumstances. Tap water can carry Acanthamoeba and other organisms that cause serious infections, and these organisms are resistant to many standard disinfectants. If you run out of solution, the safest choice is to discard the lens rather than rinse it. Keeping a travel-size bottle of solution in a bag or at work is a simple habit that prevents this situation.
Redness without pain can still indicate a problem, including early infection, a reaction to lens solution, or mechanical irritation from the lens. While pain is the most alarming symptom, painless redness that does not clear after removing the lens should still be evaluated promptly. Some infections in the early stage or in certain parts of the cornea may not yet be causing significant discomfort, and waiting for pain to develop before seeking care can allow the infection to advance.
Most patients who receive prompt treatment do not require a corneal transplant. A transplant becomes necessary only when deep scarring from a healed infection significantly blocks vision or when the cornea becomes structurally compromised. The earlier an infection is treated, the lower the risk of the kind of deep scarring that might eventually require surgical intervention. If scarring does develop, our Cornea Specialists, including Jane Cook, M.D., Elliot Perlman, M.D., and Christopher Newton, M.D., are experienced in the full range of corneal transplant options.
Teenagers can wear contact lenses safely when consistent hygiene habits are in place. Daily disposable lenses are a practical option for younger wearers because they simplify the routine and eliminate case care. Parents should watch for signs that lenses are being slept in, lenses are being kept beyond their replacement schedule, or that any redness or discomfort is being dismissed. Any pain, redness, or change in vision in a young lens wearer warrants a prompt exam rather than a wait-and-see approach.
Yes. Mascara, eyeliner, and eyeshadow can carry bacteria, especially after they have been opened for several weeks. The recommended practice is to insert lenses before applying makeup so that cosmetics do not transfer onto the lens surface, and to remove lenses before cleansing makeup at night. Replacing eye makeup every three months and avoiding sharing cosmetics with others reduces the risk of introducing bacteria near the ocular surface.
Care for Your Cornea at Rhode Island Eye Institute
Our Cornea Specialists bring fellowship-level training and decades of combined experience to the diagnosis and treatment of contact lens-related infections and complex corneal conditions. Whether you need guidance on safer lens habits, same-day evaluation of a concerning symptom, or advanced care for a serious corneal infection, our team is here to support you with the depth of expertise you deserve. We welcome patients from across Rhode Island and southeastern Massachusetts and are committed to protecting your vision at every stage of care.