In an effort to find an alternative to the rinse-and-rub method for cleaning contact lenses, researchers recently demonstrated that a polymer-on-polymer pollutant removal method is as effective for larger particles, such as pollen, and more effective for extremely fine particulate pollutants, including microplastics and nanoparticles. The polymer method uses the elastic properties of polydimethylsiloxane (PDMS) to remove contaminants from contact lens surfaces through non-adhesive unpeeling.

A team evaluated three different setting agent to polymer PDMS ratios (1:30, 1:40 and 1:50) and compared them against the rinse-and-rub control method with a commercial multi-purpose lens cleaning solution. They used three simulated pollutants of different sizes—pollen (25μm to 40μm), microbeads (1μm to 5μm) and nanoparticles (5nm to 10nm)—to test the effectiveness of both cleaning methods.

The investigators found that PDMS 1:40 was the optimal ratio for lens cleaning using the polymer method. For larger particles (>10μm), the researchers didn’t observe a difference between the control method and the proposed polymer method. However, they added that the polymer method was significantly better at removing small particles (<2.5μm) compared with the rinse-and-release method, specifically for microbeads and nanoparticles.

“This method offers a potentially more efficient cleaning protocol that could enhance the safety, health and comfort of contact lens users, especially those living in regions with significant air pollution,” the study authors concluded in their paper.

Burgener K, Bhamla MS. A polymer-based technique to remove pollutants from soft contact lenses. Cont Lens Ant Eye. May 19, 2020. [Epub ahead of print].