Project BlindZero - 03/08/2023 Hope for patients with eye diseases: human cornea from 3D printers Thousands of cornea transplants are performed every year. However, donors are rare and the procedure is not always without complications. Researchers at the University of Heidelberg are developing an innovative technique in the project BlindZero. It involves ‘printing’ human corneas directly onto patients’ eyes using 3D bioprinting. The reprogrammed genetically engineered cells used for this purpose are not expected to cause a rejection reaction.