Contact lenses have become widely used, and advanced lens materials and care products have been introduced in recent years. However proper care still remains an expensive and time consuming process which tends to discourage potential users or causes users not to follow the recommended care procedures. Proper contact lens care should include removing foreign particles, smoke film, and other deposits such as mucous, proteins, and enzymes from the lenses and disinfection of organisms in the deposits and the lenses to prevent causing eye infections from their subsequent use. Disinfection is particularly important for the use of "soft" (hydrophilic) contact lenses which will adsorb moisture from the cleaning solution.
The conventional cleaning process includes a daily regime of scrubbing (by manual rubbing) the lenses manually with soap or a detergent, then rinsing off in water. The use of tap water is not recommended due to the presence of hard minerals in most tap water. Besides being inconvenient, the manual rubbing and handling of the lenses during cleaning can cause scratches or microscopic damage to the lenses. The lenses must then be disinfected, by soaking the lenses in a chemical solution and/or by heating for as long as six hours or overnight. The disinfection cycle is long, and the soaking solution usually contains detergents, enzyme removers, preservatives, and other chemicals which can be adsorbed into the lenses and become very irritating to the eyes and membranes. Heat disinfection is not effective for cleaning deposits from the lenses, but rather tend to bake mineral deposits onto the lens surface. Also, repeated heating of the lenses for the disinfection cycle eventually causes physical degradation of the lens material.
Some systems have been designed for disinfection of contact lenses by ultraviolet radiation to kill microorganisms, for example, as disclosed in U.S. Pat. No. 4,063,890 to N. Baron and U.S. Pat. No. 4,868,397 to P. Tittel. However, the ultraviolet radiation poses a risk of UV degradation of the lens polymer material after repeated disinfection cycles. Also, prior manual cleaning is still required, which is inconvenient and risks damage to the lenses.
USPTO Backgrounds
USPTO Backgrounds