Addition of amphotericin B to optisol-GS needs further study

(HealthDay)—Further investigation of the addition of amphotericin B to Optisol-GS, the most commonly used corneal storage medium in the United States, is warranted, according to research published online Feb. 25 in JAMA Ophthalmology.

Katherine Duncan, M.D., of the University of Maryland School of Medicine in Baltimore, and colleagues conducted an in vitro laboratory efficacy study to identify the lowest concentration of amphotericin B that could be used as supplementation in Optisol-GS to eliminate fungal contaminants. Candida albicans was used to inoculate the vials of Optisol-GS for the efficacy study. In a separate study, the potential toxic effects of amphotericin B to the corneas, with and without light exposure, were assessed.

The researchers found that concentrations of 0.06 and 0.12 µg/mL of amphotericin B added to Optisol-GS eliminated all fungal contaminants by day seven; fungal growth on day two was reduced by a mean of 3.5 colony-forming units. A concentration of 0.255-µg/mL of amphotericin B added to Optisol-GS eliminated all fungal contaminants by day two. In the safety study, no toxic effects were observed for corneas stored in Optisol-GS supplemented with amphotericin B, at any concentration, compared with paired controls. No difference was observed in the efficacy or safety of the light-exposed versus light-protected amphotericin B-supplemented Optisol-GS.

"These results do not prove that amphotericin B should be added to Optisol-GS; larger-scale studies and cost-benefit analyses need to be completed," the authors write. "Given the increasing incidence of postkeratoplasty fungal infection, however, the addition of amphotericin B to Optisol-GS deserves further investigation."