A team of researchers at University of Minnesota researchers are working on what they call “Bionic Eye” by Custom 3D Printing photoreceptors on a hemispherical surface. The process consumed hemispherical glass dome, silver particle base ink, semiconducting polymer materials and approximately one hour. With 25% efficiency, they are now planning to create prototypes that are even more efficient and could be worked upon for implantation into a real eye, thereby restoring or improving sight.
Source: https://onlinelibrary.wiley.com/doi/10.1002/adma.201803980