The group of DU Xuemin has developed a contact lense made from a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel matrix which features periodic nanostructures, resulting in bright, tunable structural colors ranging from red to green to blue. The spacing of periodic nanostructures within the pHEMA hydrogel are sensitive to changes in moisture and pressure, leading to real-time color changes. Based on these features, the ‘smart’ contact lens can monitor xerophthalmia and high intraocular pressure. Under normal conditions, its color will not change over time, while its color changes from red to blue in the xerophthalmia-simulation condition in about 25 minutes. In addition, a linear decrease in the wavelength of the reflectance peak of the “smart” contact lens is observed when human intraocular pressure changes in the pathological range.
CAS news release, February 19, 2020