Recent Advances in Diagnosis and Management of Fungal Keratitis.

Abstract

Fungi are opportunistic organisms that are recognized more frequently as ocular pathogens in rural tropical countries than in developed world. For clinical purposes, fungi can be classified on morphological basis into filamentous, yeast and dimorphic forms. Major risk factor for fungal keratitis include: ocular trauma (mainly by vegetable matter), topical steroid use, contact lens wear, and history of surgical procedures including mainly photorefractive keratectomy and LASIK. Fungal keratitis is a diagnostic and therapeutic challenge to ophthalmologist. Proper diagnosis and treatment is required to conserve visual outcome and avoid serious complications. Diagnosis of fungal keratitis starts with clinical suspicion, based on its specific characters, including elevated slough with 'hyphate' lines that were reported to be extending beyond the ulcer edge into the normal cornea with multifocal granular (or feathery) grey- white 'satellite' stromal infiltrate, immune ring , endothelial plaque and hypopyon formation.

Clinical suspicion should be followed by corneal scrapings for culture (mainly Sabouraud dextrose agar), and staining with various stains including gram, giemsa, KOH 10% or calcoflour white using fluorescent microscopy, whereas scraping should be vigorous and should include samples from the edge and the base of the ulcer. Polymerase chain reaction (PCR) is a promising mean to diagnose fungal keratitis and offers some advantages over culture. Another technique that may provide a new modality for quick and accurate identifying the agent of corneal infection is the use of Confocal Microscope. Antifungal agents can be mainly classified into three main categories: Polyenes (as Amphotericin and Natamycin), Azoles (including Imidazoles as Miconazole