The new laboratory-made corneas have shown promising results in improving the sight of patients suffering from significant vision loss, a new study found.
Damage to the cornea -- the transparent layer that covers the pupil, iris and front of the eye and is entirely made of collagen -- is the second leading cause of blindness worldwide. Corneal transplant is used to treat the condition; there is, however, a worldwide shortage of human donors.
Prosthetic corneas made from synthetic plastic are already used in patients with an unsuccessful history of donor graft transplant. These prostheses are not only difficult to implant but also associated with high risk of infection, glaucoma and detachment of the retina.
According to the study published in Science Translational Medicine, individuals who received the custom-made corneas recovered their sight without experiencing any pain or discomfort as if they had received human donor corneas.
"We were pleasantly surprised that in six patients, vision improved from about 20/400 to 20/100, meaning that these patients could see objects four times farther away than before the operation," said lead researcher May Griffith, director of the Integrative Regenerative Medicine Center at Linkoping University in Sweden.
Biosynthetic collagen-based corneal implants were able to produce normal tears. They were also reported to be sensitive to touch, similar to human corneas.
Their use, however, was not associated with any rejection problems or need for long term immune suppression, commonly noted with the use of human donor corneas. Serious complications such as calcification and retinal detachment, commonly noted in synthetic prostheses, were absent following the use of these implants.
Produced entirely from synthetic collagen, the "biosynthetic" implants can improve eye-sight through prompting the regeneration of the nerves and cells of the eye. The process is believed to be faster than it would have been following receiving a human graft.
"The patients' own cells and nerves that grow back into this prefabricated scaffold recreate a cornea which resembles normal healthy eye tissue. So essentially its stimulating regeneration," added Griffith.
"This is true cutting-edge work and brings an exciting new option to the repertoire of corneal transplant surgeons," said Mark J. Mannis, chair of the Department of Ophthalmology and Vision Science at the University of California, Davis Eye Center.
