In a giant step in vision recovery technology, doctors have been able to drastically improve the sight of patients suffering from significant vision loss by using corneas that were produced entirely in the laboratory. The news is important because doctors were able to accomplish this by using synthetic collagen, thereby eliminating the need for donor tissue, for which there is a worldwide shortage.
The findings, published in Science Translational Medicine, represent the first time that vision had been restored in this way, which works by encouraging the regeneration of nerves and cells in the eye. The cornea is vital to our sight because it is responsible for properly refracting light that focus images on the retina, and damaged corneas are the second leading cause of blindness in the world, affecting nearly 10 million people.
In the study in questions, 10 patients who were awaiting human donor tissue were enrolled. Diseased or damaged tissue in the eyes of the patients were removed. Researchers then used yeast and human DNA to create synthetic version of human collagen. These "biosynthetic" products created in the laboratory were implanted in the hopes that they would mimic the cornea.
Doctors then closely monitored the patients after surgery in order to keep track of how well the tissue grafts were being taken by the eye. What they observed was that sight was restored in all 10 patients, and in 6 out of 10, vision was improved enough (20/400 to 20/100) for them to see objects that were four times further away than before the surgery.
In fact, it was determined that the improvement in vision was as good, and maybe even a bit better, than if human donor corneas had been used. Not only was recovery faster, but none of the patients experienced rejection nor did they require long term immunosuppression, both of which can have serious detrimental side effects.
Furthermore, the laboratory corneas were able to produce tears. This is a necessary part of visual function because the cornea has no blood supply and therefore receives oxygen from tears. Also absent were problems related to plastic corneal implants, which include infection and glaucoma.
According to the researchers, the success of the operation is rooted in the ability of the eye tissue to re-grow, with the collagen acting as a scaffolding that stimulates regeneration of the damaged tissue. The initial goal of the experiment was to first test the safety of the implants; that real benefits to vision were observed was considered a surprising but significant bonus.