13.02.2015

Artificial corneas: New hope for the partially sighted?

Artificial corneas: New hope for the partially sighted?

Partial sightedness is an unfortunate condition which affects millions of people in the UK and across the globe. But thanks to a recent scientific breakthrough, those suffering loss of vision as a result of scarred or clouded corneas could potentially be offered a lifeline.

Canadian scientists have developed a brand new type of artificial cornea by creating a thin, transparent sliver of a collagen protein that can be placed onto the damaged eye, much like a contact lens. Once surgically attached, the implant then works to promote the eye"s natural corneal cells to re-grow, miraculously restoring the patient"s sight. Researchers hope that the breakthrough will also trim the number of partially-sighted people awaiting cornea transplants.

The new technique involves the artificial growth of collagen, an alternative substitute for human tissue, in the laboratory, before a contact lens mould is used to shape the material to precisely fit over the front of the eye. Clouded or scarred corneal tissue is then surgically removed before the biosynthetic implant is stitched in its place.

When the transplant is successful, existing corneal cells and nerves in the eye will gradually grow over the artificial matter, fully incorporating it into the natural organ. In light of strong results from the developers" first trials, the operation appears to be just as promising as live tissue transplantation, with some test patients having had their sight completely restored.

Dr May Griffiths, one of the pioneering scientists involved with the pilot study, at Linkoping University in Sweden, has expressed her delight with the outcome of trials so far, going on to suggest how the breakthrough could transform treatment for patients with this condition in the future.

"We were very excited by the results. This study is the first to show an artificially fabricated cornea can integrate with the human eye and stimulate regeneration. With further research, this approach could help restore sight to millions of people who are waiting for a donated human cornea for transplantation. There is a shortage of donors and this could solve that problem. It can also be done at a fraction of the cost," she said.

The cornea is a delicate shield protecting vulnerable parts of the eye. Consisting of three layers – the endothelium, stroma and epithelium – it plays a key role in creating the sense of vision many of us take for granted. Unfortunately, due to its fragile nature, the cornea is easily damaged by disease or scarring, which can cause blurring and even lead to a total loss of sight.

A clinical trial of ten patients with corneas inflicted with such complaints was conducted in which the subjects" eyes were operated on. With a fabricated corneal implant in place, six of the patients were reported to have noticed a significant improvement to their vision.

One of the major benefits of the breakthrough is its ability to produce replacement corneal tissue on a large scale. Currently, humans are the only source of transplants and the supply of natural donor tissue is extremely limited. In addition, the artificially-fabricated specimens could actually be more effective, as the risk of infection or rejection by the recipient"s body is almost entirely removed.

Worldwide, illnesses which lead to the clouding of corneas affect at least ten million people globally, making such diseases the leading cause of blindness. Dr Griffith and her fellow researchers first started work on the artificial creation of corneas more than a decade ago. After extensive testing within the laboratory, the scientist enlisted the help of eye surgeon Dr Per Fagerholm, based at the same university, to conduct the first human trial of biosynthetic corneas.

"We are very encouraged by these results and by the great potential of biosynthetic corneas. Further biomaterial enhancements and modifications to the surgical technique are ongoing, and new studies are being planned that will extend the use of the biosynthetic cornea to a wider range of sight-threatening conditions requiring transplantation," he explained.

Though the transplant operation has proved successful among a small sample of patients, the technique is still in its infancy. Significant trials will take place over the coming months and years before the practice is universally embraced. The initial results are promising though – and should instil hope in the millions of people affected by loss of sight as a result of damaged corneas.

by Martin Burns


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