Eye infections can be caused by many different organisms, including bacteria, viruses, amoeba, and fungi. Eye infections caused by fungi are extremely rare, but they can be very serious.
Types of fungal eye infections
Fungal infections can affect different parts of the eye.
- Keratitis is an infection of the clear, front layer of the eye (the cornea).
- Endophthalmitis is an infection of the inside of the eye (the vitreous and/or aqueous humor). There are two types of endophthalmitis: exogenous and endogenous. Exogenous fungal endophthalmitis occurs after fungal spores enter the eye from an external source. Endogenous endophthalmitis occurs when a bloodstream infection (for example, candidemia) spreads to one or both eyes.
Types of fungi that cause eye infections
Many of different types of fungi can cause eye infections. Common types include:
- Fusarium – a fungus that lives in the environment, especially in soil and on plants
- Aspergillus – a common fungus that lives in indoor and outdoor environments
- Candida – a type of yeast that normally lives on human skin and on the protective lining inside the body called the mucous membrane
What Causes Fungal Eye Infections?
The most common way for someone to get a fungal eye infection is because of an eye injury, particularly if plant material such as a stick or a thorn 1 caused the injury. Some fungi that cause eye infections, such as Fusarium, live in the environment and are often associated with plant material. Fungi can enter the eye and cause infection after an injury.
Less often, infection can occur after eye surgery such as corneal transplant surgery or cataract surgery.
People who have had surgery to replace their corneas (the clear, front layer of the eye) are at higher risk of fungal eye infections. Each year, about 50,000 Americans have a corneal transplant to replace injured or diseased corneas. A small number of people who have this surgery (about 4 to 7 for every 10,000 transplants) develop a fungal eye infection.
From 2007 to 2014, endophthalmitis, or infection of the interior of the eye, became more than twice as common for people with recent corneal transplant surgery. In the past, this type of endophthalmitis was most commonly caused by bacteria. However, now fungi (most often the Candida species) cause about two-thirds of infections. CDC is working with partners to understand the reasons for this increase in fungal endophthalmitis following corneal transplant surgery and to find ways to prevent it.
Invasive Eye Procedure
Fungal eye infections could happen after an invasive eye procedure such as an injection. Some infections have been traced to contaminated medical products such as contact lens solution, irrigation solution and dye used during eye surgery, or corticosteroids injected directly into the eye.
Fungal Bloodstream Infection
Rarely, fungal eye infections can happen after a fungal bloodstream infection such as candidemia spreads to the eye.
Treatment for Fungal Eye Infections
The treatment for a fungal eye infection depends on:
- The type of fungus,
- The severity of the infection, and
- The parts of the eye that are affected.
Possible forms of treatment for fungal eye infections include:
- Antifungal eye drops
- Antifungal medication given as a pill or through a vein
- Antifungal medication injected directly into the eye
- Eye surgery
All types of fungal eye infections must be treated with prescription antifungal medication, usually for several weeks to months. Natamycin is a topical (meaning it’s given in the form of eye drops) antifungal medication that works well for fungal infections involving the outer layer of the eye, particularly those caused by fungi such as Aspergillus and Fusarium. However, infections that are deeper and more severe may require treatment with antifungal medication such as amphotericin B, fluconazole, or voriconazole. These medications can be given by mouth, through a vein, or injected directly into the eye. Patients whose infections don’t get better after using antifungal medications may need surgery, including corneal transplantation, removal of vitreous gel from the interior of the eye (vitrectomy), or, in extreme cases, removal of the eye (enucleation).