AIM:To evaluate the antimicrobial properties of ultraviolet A (UVA) (365 nm)/riboflavin against Candida albicans and Fusarium solani.METHODS:Two fungus isolates were cultured in vitro and prepared with 10-fold serial PBS dilutions of cell concentration. For each dilution of fungus suspension, the concentration (colony-forming units/mL, CFU/mL) and the inactivation ratio of fungal cells were evaluated under 4 conditions:no treatment (control), UVA (365 nm)/riboflavin, riboflavin, and UVA (365 nm).RESULTS:The cell concentration decreased in UVA (365 nm)/riboflavin group for Candida albicans at each dilution and Fusarium solani at dilutions of 10⁴, 10³, 10² CFU/mL, when compared with that in control, riboflavin, and UVA (365 nm) groups (P<0.01). No difference of cell concentration was detected amongst the culture of control, riboflavin, and UVA (365 nm) groups for the two fungus. There is a negative correlation between suspension concentration (log-transformed) and the inactivation ratio in UVA (365 nm)/riboflavin group for Candida albicans and Fusarium solani (P<0.01).CONCLUSION: According to the standard protocol of corneal collagen cross-linking, UVA (365 nm)/riboflavin combination treatment is found to moderately inactivate the viability of Candida albicans and Fusarium solaniin vitro. The inactivation ratio was found to increase with the decrease of cell concentration under UVA (365 nm)/riboflavin condition.