Multimaterial 3D Printing Process for Color Blindness Correction Contact Lens Production

Multimaterial 3D printing is an emerging technology that allows for the production of 3D printed objects with controlled variations in material composition and properties. However, there have been very few studies on the use of multimaterial 3D printing for optical devices. In this work, a novel multimaterial 3D printing method is presented for the production of contact lenses with color blindness correction capabilities. The method utilizes vat-photopolymerization 3D printer and employs CAD file modifications along with a pause-material change step to enable material change within the contact lens. Using this method various dyes can be deposited at different regions within the contact lens in required patterns. Atto-565 and Atto-488 dyes were utilized for red-green and blue-yellow color blindness correction respectively. A suitable combination of hydroxyethyl methacrylate (HEMA) and polyethylene glycol diacrylate (PEGDA) served as the base resin for 3D printing. Good quality hydrogel contact lenses were obtained after 3D printing. The water absorption behavior, mechanical properties and surface quality of the contact lenses were evaluated. Good mechanical and material characteristics were observed for these lenses. Both Atto-488 and Atto-565 dyes were highly stable and did not leak from the crosslinked hydrogel matrix. Multimaterial contact lenses containing both dyes were found to be suitable for simultaneously correcting two types of color blindness. The contact lenses had light absorption spectra that closely matched commercially available color blindness correction glasses. The phenomenon of interface formation due material change was studied in detail and ways to reduce its intensity were explored. Contact lenses with dyes deposited in intricate patterns were also 3D printed, demonstrating the advanced capabilities of this technique. Multimaterial 3D printing enables the production of highly efficient aesthetically pleasing contact lenses with customizable color blindness correction capabilities.