The Role of Antifungal Prophylaxis After Receipt of a Positive Donor Rim Fungal Culture: The Case for Not Routinely Treating Prophylactically

Abstract

Studies conducted in the United States suggest that 1% to 2% of corneal donor rims culture positive for fungus; the fungal agent is usually Candida, and the risk of an endothelial keratoplasty recipient developing an intraocular fungal infection is approximately 7% (1 in 15) if the donor rim was culture-positive. Routine culturing of corneal donor rims is useful because a positive fungal culture alerts the surgeon to carefully monitor the keratoplasty recipient for any signs of fungal infection. However, routine implementation of antifungal prophylaxis on receipt of a positive culture is problematic because there is a lack of definitive data regarding the optimal route of administration, necessary duration of prophylaxis, and relative efficacy of different antifungal agents. The use of topical prophylaxis alone has not been proven to be effective, and the systemic agents that are effective against Candida typically involve an azole, which has many side effects, including liver toxicity and potential interactions with other drugs. The data suggest that routine antifungal prophylaxis would needlessly expose 14 patients to systemic side effects for each person who would directly benefit. Treatment of postkeratoplasty fungal infection typically involves graft replacement, but selective removal of the involved area(s) has been used successfully with Descemet membrane endothelial keratoplasty.