Multifunctional and multimaterial contact lenses: tailored solutions for tunable color filtering and tear pH sensing

Colour vision disorders, pose challenges in perceiving and distinguishing specific colours. To address these challenges, technologies such as colour-filtering glasses and contact lenses have been developed. However, customisation of eyewear for individual patients remains a challenge. This research aims to design multifunctional contact lenses combining colour filtering and pH sensing capabilities for personalised colour vision correction. A pH-responsive, Neutral red dye-doped hydrogel was developed and optimised for the vat photo polymerization-based 3D printing process. A novel in-house multimaterial 3D printing technique was employed for printing lenses exhibiting both colour filtering and pH sensing capabilities. 3D printed samples contained outer radial rings, made from porous and pH-responsive polymer. The optically tunable dye-doped resin was also applied to the central part of the lenses to achieve customised wavelength blockage. The lenses demonstrate potential for customised colour vision correction and pH monitoring of the tear film.