Microwave disinfection of soft contact lenses.

We evaluated the effectiveness and convenience of microwave irradiation as a method of disinfecting soft contact lenses. Soft contact lenses from each of the four Food and Drug Administration (FDA) categories were placed in sterile vials and immersed in 2 ml of saline which had been contaminated with one of three common species of bacteria. The contaminated lens vials were placed in a standard 600 W microwave oven and exposed to microwave irradiation times ranging from 30 to 180 s. Significant reductions in bacteria colony counts were found after 30 s of microwave irradiation. Few of the bacteria survived 60 s of microwave exposure and none survived 90 s. Our findings indicate that microwave disinfection can be an effective and rapid means of killing bacteria on soft lenses and in the storage solution. However, further studies are necessary to determine the minimum exposure time required, the effect of microwave disinfection on other microorganisms, and the effect of microwave irradiation on contact lens polymers and lens dimensions.