The future of 3D printing and medicine is coming into focus.

Scientists at Newcastle University in the UK say they've created the first 3D-printed human corneas. Using a combination of their unique "bio-ink" and cornea stem cells, they can print the corneas in under ten minutes.

If their methods gain medical approval, 3D-printed corneas could greatly benefit the millions of people in need of corneal transplants and those suffering from vision impairment due to corneal injury.

The cornea is the eye's outermost lens, protecting it from harmful matter as well as providing a majority of the eye's focusing power. Corneas are resilient, but injury can cause pain and vision impairment. The infectious eye disorder Trachoma can also affect the cornea, causing blindness.

A 2016 survey of corneal transplants globally found that only one cornea transplant was available for every 70 needed. The study's authors concluded that bioengineering could be an "essential" part of relieving this need. That's where 3D printing comes in.

The Newcastle scientists created a "bio-ink" made of the substances alginate and collagen. They mix this with human cornea stem cells. They then print the corneas in concentric circles, at which point the stem cells grow around the bio-ink.

"Many teams across the world have been chasing the ideal bio-ink to make this process feasible," study co-author Professor Che Connon said in a statement. "Our unique gel — a combination of alginate and collagen — 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."

However, the study's authors said it will likely take years for patients to actually start receiving 3D-printed corneas. This study was essentially a proof-of-concept. But a really nifty one.