الفهرس 
Epidemiology of fungal keratitisOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
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 and Triazoles as Fluconazole) and Flurinbated pyrimidines (as Flucytosine).
The recommended initial medical treatment is topical 5% natamycin once every hour, moreover topical 1% solutions of miconazole, clotrimazole, econazole, or ketaconazole have been reported to have broad antifungal activities except against Fusarium.
Ketoconazole may be given orally in daily doses of 200 to 400 mg. Amphotercin B may be used topically in a concentration of 0.15% , but systemic administration is not effective against keratomycosis.
Caspofungin (CAS) is a recently introduced antifungal with fungicidal activity in vitro against all Candida species including strains resistant to fluconazole.
Cetrimide is a new cationic surfactant of a broad antifungal spectrum with no pathological corneal effect.
Treatment of patients with fungal keratitis needs regular and close follow up for improvement or development of any complication and their management accordingly.
Conjunctival flap and penetrating keratoplasty combined with antifungal therapy may be required in severe cases not responding to medical treatment.
Corneal cross linking is a promising new technique for treating patients with fungal keratitis using the photosensitizer riboflavin and ultraviolet A irradiation at 370 nm to induce increasing corneal tissue strength and rigidity.