Researchers at Newcastle University are 3D printing corneas utilizing stem cells. The process involves mixing stem cells in a bio-gel which is derived from seaweed and collagen that allows these stem cells to be cultured and printed easily and efficiently into fully functioning corneas. The cornea plays an important role in focusing light that enters the eye. Technically, blindness caused by corneal damage is easily reversible with a corneal transplant. However, there is a vast shortage of donor corneas due to general organ and tissue donation shortages. In addition, there is also a significant risk of rejection - as is the case with any donated tissue.