As we follow up on last month’s column, “Fungal Keratitis: The Lessons Learned,” (November/December 2011, Review of Cornea & Contact Lenses), we realize that it is important to practice what we preach. Fungal keratitis is a condition that cannot and should not be taken lightly—left untreated, the infection may lead to permanent vision loss. Because the infection is so fast acting, even in cases that are accurately diagnosed and treated, many patients may even need a therapeutic penetrating keratoplasty. This column will present an overview of the current treatment regimens and highlight possible future therapies for the infectious disease.
Although optometrists may not necessarily be the primary eye care provider treating the fungal infection, how to prevent the disease from occurring by being aware of a patient’s lifestyle, especially in more tropical or humid climates, can play an eyesaving role in the case against fungal keratitis. Fungal keratitis is often treated by cornea specialists at tertiary care centers and eye institutes that have the ability to perform cultures and employ other diagnostic tools to test for fungal keratitis, such as confocal microscopy. However, many patients in rural areas or in lower income populations may not have access to a cornea specialist; therefore, an optometrist’s knowledge and suspicion of the disease is of crucial importance, as they may be the first to diagnose the condition. Given that fungal keratitis cases usually occur within the contact lens-wearing population, the optometrist plays a signifi cant role as more than 80 percent of contact lens wearers go to an optometrist for their eye care.
Ordinarily, it is quite rare for fungi to invade and damage a healthy eye. But when fungal eye infections do occur, it can be sight threatening. Early diagnosis is essential for the successful treatment of fungal keratitis. The importance of early identifi cation must be stressed; treatment has proven to be most effective if aggressively administered in the early stages of infection.
Suspicion is one, if not the most, important aspect of treatment and prevention. All clinicians should be especially observant in contact lens wearers. Being slow to identify and treat the disease can drastically worsen the patient’s condition. For fungal keratitis cases, systemic and topical steroids should be avoided until it is absolute that the pathogen has receded. In today’s market, natamycin 5% is the only commercially available topical agent indicated for the treatment of fungal keratitis, and has been popularly used for filamentous fungi infections. However, there are other therapeutic treatments that include both topical and oral anti-fungal medications. The two most commonly prescribed antifungal treatments are amphotericin B, which is usually used primarily to treat Candida pathogens. In addition, fl ucytosine can be an alternate treatment, used in conjunction with amphotericin B or miconazole.
More recently, however, studies have shown that triazoles—and more specifi cally voriconazole, a broad-spectrum antifungal agent effective against yeasts and molds— may be more effective than natamycin and amphotericin B against fungi. A recent study
Antifungal drugs may often have poor corneal penetration, as they are routinely administered on an hourly basis for weeks at a time, day and night. This can vastly increase non-compliance, a factor that, as mentioned above, is crucial in the steps to fi ght fungal infection. However, emerging new therapies aim to change that aspect: one new technology is a contact lens that elutes econazole, an antifungal medication of the imidazole class.
Having a wealth of knowledge concerning disease prevention, identifi cation, and consecutive treatment is of invaluable importance to an eye care practioner. Optometrists should periodically educate themselves on various diseases, no matter how rare. Furthermore, cases of Fusarium keratitis should be reported to state and local health departments or directly to the Centers for Disease Control and Prevention at 800-893-0485.