https://techcrunch.com/2018/05/31/researchers-create-the-first-3d-printed-corneas/

Researchers at Newcastle University have been able to 3D-print a biocompatible corneal framework using a new gel formulations that “keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer.”

There is a significant shortage of corneas available to transplant, with 10 million people worldwide requiring surgery to prevent corneal blindness as a result of diseases such as trachoma, an infectious eye disorder,” wrote the researchers. “In addition, almost 5 million people suffer total blindness due to corneal scarring caused by burns, lacerations, abrasion or disease.”