THERAPY OF OCULAR FUNGAL INFECTIONS

Abstract

Therapy of ocular fungal infections represents a challenge for the ophthalmic clinician. Although ocular fungal infections are relatively uncommon in developed countries compared with bacterial infections, the need for improved antifungal therapy is emphasized by the potentially poor clinical outcomes in patients with severe ocular mycoses. An increased number of fungal infections of the eye have been reported in the past few decades, in part, because of increased clinical awareness and improved laboratory techniques. The increase reflects more significantly the widespread use of antibiotics, immunosuppression, chemotherapy, and ocular prosthetic devices. Although the number of cases of ocular mycoses have increased, the number of antifungal agents available for therapy are few, given the number of fungal pathogens capable of infecting the eye. Current treatment for systemic fungal infections is not always sufficiently effective for ocular mycoses. The slower research and development progress in antifungal therapy compared with antibacterial therapy stems from the fact that fungal cells, unlike bacteria, are eukaryotic, so any drug that is toxic to fungal cells could potentially exert similar effects on mammalian cells. There also has been less financial incentive for pharmaceutical companies to invest in the development of ocular antifungal agents. Fungal infections can involve various regions of the eye and periocular tissues, including the lacrimal apparatus, conjunctiva, eyelids, and bony orbit. The two most common sites for fungal infections of the eye are the cornea and retina or vitreous. Successful medical treatment of fungal keratitis and endophthalmitis depends not only on the spectrum of antifungal activity of the particular drug but also on the pharmacokinetic properties of the agent (i.e., its ability to achieve therapeutic concentrations in the cornea or vitreous). This article reviews the antifungal agents currently available and under development for use in therapy of ocular fungal infections.