Experimental and theoretical investigation of the antimicrobial effect of femtosecond laser irradiation on contact lens solutions.

Microbial contamination of contact lens solutions (CLS) can lead to eye infections, and traditional disinfectants often fail to eliminate resistant pathogens, underscoring the need for new disinfectants. We have studied the antimicrobial effects of femtosecond laser (FSL) irradiation and the combined effect of FSL irradiation and contact lens solutions (OPTI-FREE EXPRESS and CLIWEL) against common eye pathogens, methicillin-resistant Staphylococcus aureus (MRSA). The INSPIRE HF100 laser system emits FSL generated by a mode-locked Ti: sapphire femtosecond MAI TAI HP for laser exposure (400 nm, 50 mW, 15 min). The results demonstrated that each bacterial colony count was significantly reduced by FSL irradiation. The CLIWEL solution exhibited slightly higher antimicrobial activity compared to OPTI-FREE EXPRESS solution. Moreover, more inhibitory activity was demonstrated by the CLIWEL solution than that of the OPTI-FREE EXPRESS solution after FSL-exposed pathogens after 2 h. Therefore, the treatment with FSL irradiation and solution was more highly antimicrobial than FSL alone. The nonlinear theoretical logistic and Gompertz models have been applied to experimental data to interpret microbial behavior. The combination of FSL irradiation and lens solutions is a promising disinfection method that can improve the hygiene of the eye, reduce infection, and enhance ocular safety.