The implant was given to those who suffer from diseased corneas, the outermost and transparent layer of the eye, an issue that affects millions of people worldwide. .
A 2016 study found that an estimated 12.7 million people are on waiting lists for cornea transplants, which are the only curative treatment for corneal blindness, and that only one in 70 is able to get the surgery.
The newly bioengineered corneas were given to 14 people in Iran and India who were already blind and six others who were on the verge of losing their sight.
Along with limited donor availability, the typical treatment, which requires doctors to surgically replace a cornea and sew it into place, also risks graft rejection, healing complications, infections, astigmatism and the need for long-term support.
"The operations were free from complications; the tissue healed fast; and an eight-week treatment with immunosuppressive eye drops was enough to prevent rejection of the implant," a press release for the study states.
By the end of the study, all 14 people who had once been blind had fully regained their vision – including three who ended up having perfect 20/20 vision.
"Bioengineering implantable tissue is the key to addressing the global burden of corneal blindness," the study says.