oxygen transmitted to the cornea. Although silicone-hydrogel lenses almost eliminate hypoxia in patients due to their very high levels of oxygen transmissibility, they also seem to provide a more efficient platform for bacterial contamination and corneal infiltration than other conventional hydrogel soft contact lenses. One study showed that Pseudomonas aeruginosa and Staphylococcus epidermis adhere much more strongly to unworn silicone hydrogel contact lenses than conventional hydrogel lenses and that adhesion of Pseudomonas aeruginosa was 20 times stronger than that of Staphylococcus epidermidis. This might partly explain why Pseudomonas infections are the most predominant. However, another study conducted with worn and unworn silicone and conventional hydrogel contact lenses showed that worn silicone contact lenses were less prone to Staphylococcus epidermidis colonization than conventional hydrogel lenses. Besides bacterial adhesion and cleaning, micro and nano pollutants (biological and manmade) is an area of contact lens research that is growing. Small physical pollutants ranging from nanoplastics to fungi spores to plant pollen adhere to contact lens surfaces in high concentrations. It has been found that multipurpose solution and rubbing with fingers does not significantly clean the lenses. A group of researchers have suggested an alternative cleaning solution, PoPPR (polymer on polymer pollution removal). This cleaning technique takes advantage of a soft and porous polymer to physically peal pollutants off of contact lenses. Another important area of contact lens research deals with patient compliance. Compliance is a major issue pertaining to the use of contact lenses because patient noncompliance often leads to contamination of the lens, storage case, or both. However, careful users can extend the wear of lenses through proper handling: there is, unfortunately, no disinterested research on the issue of "compliance" or the length of time a user can safely wear a lens beyond its stated use. The introduction of multipurpose solutions and daily disposable lenses have helped to alleviate some of the problems observed from inadequate cleaning but new methods of combating microbial contamination are currently being developed. A silver-impregnated lens case has been developed which helps to eradicate any potentially contaminating microbes that come in contact with the lens case. Additionally, a number of antimicrobial agents are being developed that have been embedded into contact lenses themselves. Lenses with covalently attached selenium molecules have been shown to reduce bacterial colonization without adversely affecting the cornea of a rabbit eye and octyl glucoside used as a lens surfactant significantly decreases bacterial adhesion.