Fungal keratitis is a serious eye infection that affects the cornea, the clear, dome-shaped outer layer at the front of the eye. Caused by various types of fungi, this infection can develop rapidly. If left untreated, fungal keratitis can lead to severe vision loss or even blindness. Prompt recognition and treatment are extremely important for preserving eye health.
How Fungal Keratitis Develops
Fungal keratitis often begins after an eye injury, especially those involving plant matter like thorns, wood, or soil. Environmental fungi, such as Fusarium and Aspergillus, are frequently found and can be introduced into the cornea during such trauma. Candida species, another common culprit, typically reside on human skin and mucous membranes.
Improper contact lens hygiene is another common cause for fungal infections to develop. Using tap water to rinse or store contact lenses, reusing old disinfecting solutions, or wearing lenses for extended periods can introduce fungi to the eye. Fungi can form biofilms on contact lenses, which are communities of microorganisms that adhere to surfaces and are difficult to remove with standard disinfection methods. Individuals with weakened immune systems or pre-existing eye conditions are more susceptible to fungal keratitis, making them less able to fight off infection.
Recognizing the Signs
Recognizing the symptoms of fungal keratitis is important for preventing severe vision complications. Common indicators include sudden eye pain and noticeable redness. Blurred vision, excessive tearing, or a discharge from the affected eye may also occur.
Increased sensitivity to light and a persistent feeling of something in the eye are also frequent complaints. These symptoms can worsen quickly, so immediate consultation with an eye care professional is advised if any signs appear. This is particularly true if the symptoms follow an eye injury, especially one involving plant material, or a history of improper contact lens care.
Identifying and Treating the Infection
Diagnosing fungal keratitis begins with a thorough eye examination by an ophthalmologist. To pinpoint the specific fungus, the doctor usually takes a small sample from the cornea by gently scraping the affected area. This sample is then sent to a laboratory for culture to identify the fungal species, though this process can sometimes take up to three weeks for definitive results. More rapid identification methods, such as molecular diagnostics like PCR, are also increasingly used to speed up the diagnosis.
Treatment for fungal keratitis involves antifungal medications, often in the form of eye drops. Natamycin 5% topical suspension is an FDA-approved antifungal eye drop, often considered the drug of choice for filamentous fungi like Fusarium species, though its penetration into deeper corneal layers can be limited. Other antifungal eye drops, such as voriconazole and amphotericin B, may also be prescribed, sometimes compounded from intravenous formulations for ophthalmic use. Amphotericin B is often preferred for infections caused by yeast species like Candida.
In addition to topical eye drops, oral antifungal medications may be necessary, especially for larger ulcers, deep infections, or if the infection spreads to other eye structures like the sclera. Systemic antifungal therapy may be continued for 6 to 8 weeks. Treatment duration for fungal keratitis is often prolonged, typically lasting several months, and requires consistent follow-up examinations to monitor progress and adjust medication. If medical treatments are not effective, surgical intervention, such as a corneal transplant, may be required to remove the infected tissue and potentially restore vision. In some severe cases, even with surgery, permanent vision impairment or blindness can still occur.
Protecting Your Eyes from Fungal Keratitis
Preventing fungal keratitis involves careful eye care practices, especially for contact lens wearers and those exposed to environmental fungi. Strict contact lens hygiene is extremely important: always wash hands thoroughly before handling lenses and use only fresh, sterile contact lens solution for cleaning and storage. Never use tap water to clean or rinse contact lenses or their storage cases, as it can contain infection-causing microorganisms. It is also important to replace contact lens cases every three months and to avoid “topping off” old solution; always discard the old solution completely before adding fresh.
Wearing protective eyewear during outdoor activities or work that could cause eye injury, such as gardening, farming, or carpentry, reduces the risk of fungal infection. Any eye injury, no matter how minor, should prompt immediate medical attention. After treatment, adhering to the prescribed medication schedule and attending all follow-up appointments is important to ensure the infection is fully cleared and minimize recurrence.