Gold nanoparticle–laden contact lenses adjust for color blindness

New contact lenses that incorporate gold nanoparticles could one day offer a safe, convenient way for people with what’s commonly known as red-green color blindness to better distinguish those colors (ACS Nano 2021, DOI: 10.1021/acsnano.0c09657). In red-green color blindness—the most common type—reds can appear green, or vice versa, because light of certain wavelengths that fall between green and red triggers both sets of light receptors in the eyes. Some people with this type of color blindness wear tinted glasses or contact lenses that block these wavelengths and can help the wearer better distinguish colors, but some people don’t like the glasses’ tinted appearance, and organic dyes used in contacts could migrate out. Ahmed E. Salih and Haider Butt of Khalifa University and their colleagues made lenses containing gold nanoparticles in place of dyes. The nanoparticles are stable and absorb light at wavelengths that depend on the particles’ size. The researchers tested nanoparticles of three diameters in lenses, identifying two sizes that filtered the targeted wavelengths as effectively as widely used commercial corrective glasses. “We will soon test the biocompatibility of the lenses and if proven successful go to clinical trials,” Salih says.