The antimicrobial efficacy of multipurpose contact lens solutions on standard strains of common ocular pathogens

Objective@#To compare the antimicrobial effects of locally available multipurpose contact lens solutions (MPS) on the growth of standard strains of contact lens-related ocular pathogens and to establish the recommended duration of exposure to these solutions to achieve maximal antimicrobial efficacy.@*Methods@#This study, a single-blind controlled experiment, evaluated five locally available MPS in terms of their antimicrobial efficacy towards common contact lens-related ocular pathogens, such as P. aeroginosa, S. aureus, E. coli, F. solani, and C. albicans, using the stand alone criteria. Microbial viability counts were obtained at serial durations: after 1 hour, 3 hours, 6 hours, and 12 hours of exposure.@*Results@#MPS containing polyquaternium-1 and myristamidopropyl dimethylamine (MAPD) and polyhexamide reduced the bacterial concentrations by 3 log and fungal concentrations by 1 log, enabling them to fulfill the stand alone criteria for disinfecting solutions as mandated by ISO/CD 14729. This antimicrobial efficacy was most evident at 6 hours of exposure to the challenge organisms. MPS containing polyquaternium-1 and MAPD also have the broadest spectrum of effectivity against gram-negative and gram-positive bacteria, and C. albicans. All MPS tested have poor microbial activity against F. solani. @*Conclusion@#Multipurpose contact lens solutions demonstrated variability in their antimicrobial activity. MPS with broad spectrum efficacy and effectivity, such as those containing polyquaternum and MAPD, are preferred to prevent contact lens-related ocular infections.

A vision to remember

@#On May 1911, the Department of Eye, Ear, Nose, and Throat (EENT) of the Philippine General Hospital (PGH) was established under the able leadership of Dr. Reinhart Remebe. As part of its commitment to pursue excellence and unconditional service, the graduates of what was then the Philippine Medical School (now the University of the Philippines College of Medicine (UPCM)) had to undergo a month of comprehensive training as an orientation to the department.