Preparation of Antioxidant Hydrogel Contact Lenses Based on Hindered Amine Light Stabilizer

In this work, we prepared antioxidant hydrogel contact lenses based on a hindered amine light stabilizer (HALS) which is 1,2,2,6,6-pentamethylpiperidin-4-yl methacrylate. The synthesis of the antioxidant hydrogel contact lenses was performed via the copolymerization of HALS monomer, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate. Three contact lenses were prepared by varying the weight ratio (3, 5, 7%) of HALS monomer. Although the HALS group was incorporated in the hydrogel contact lenses, the prepared lenses exhibited visible light transmittance and water content similar to conventional hydrogel contact lenses without HALS group. The antioxidant activities of the HALS-based lenses were evaluated using 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Consequently, the antioxidant lenses showed more than 25% higher radical scavenging activities than that (52.2%) of a control lens without HALS group. These values are more than 80% of the antioxidant activity of ascorbic acid, which is well-known as an antioxidant.