Comparative efficacies of soft contact lens disinfection systems against a fungal contaminant

The efficacies of five FDA-approved soft contact lens disinfecting solutions and heat disinfection were evaluated against the mold, Beauveria bassiana. Beauveria bassiana is a ubiquitous soil fungus with a demonstrated ability to grow into a soft contact lens matrix. A stock solution of the fungus was prepared and aliquots were added to each of the following disinfection solutions: ReNu Multi-Purpose Disinfecting Solution, Opti-Free, AOSEPT Disinfection/Neutralization Solution, Lens Plus Oxysept 1, UltraCare, and a Softmate Thermal Disinfecting Unit. Hydrogen peroxide systems were neutralized immediately using the manufacturer's recommended method. After 1 min, 5 mins, 15 mins, 30 mins, 1 hour, 4 hours, and 8 hours; samples were removed, added to neutralizing broth, and streaked onto Sabouraud's Dextrose Agar plates. Our results showed that hydrogen peroxide and heat disinfection were much more effective against Beauveria bassiana than Opti-Free or ReNu.