A ‘contact lens’ loaded with stem cells could be a way to naturally repair or retain sight. Scientists hope the biodegradable implant loaded with stem cells that then multiply, will allow the body to heal the eye naturally. Stem cells are the building blocks of tissue growth. They can transform into any other type of cell the body is built from and so should be able to repair everything from the brain to the heart. The scientists at the University of Sheffield who developed the implant now hope the new technique could help millions of people across the world retain or even regain – their sight. The technology has been designed to treat damage to the cornea, the transparent layer on the front of the eye, which is one of the major causes of blindness in the world. With the new implant, by mimicking structural features of the eye, the researchers have developed a new method for producing very delicate thin membranes to help graft stem cells onto the eye itself. Using a series of complex techniques, the researchers are able to make a disc of biodegradable material that can be fixed over the cornea. The disc is loaded with stem cells that then multiply, allowing the body to heal the eye naturally. Standard treatments for corneal blindness are corneal transplants or grafting stem cells onto the eye using a donated human membrane as a temporary carrier to deliver these cells to the eye. But for some patients, the treatment can fail after a few years as the repaired eyes do not retain these stem cells, which are required to carry out repair of the cornea. A key feature of this new disc is that it contains small pockets to house and protect the stem cells, to keep them in the eye and also grouped together. ‘The disc has an outer ring containing pockets into which stem cells taken from the patient’s healthy eye can be placed,’ said Dr Ílida Ortega Asencio, from Sheffield’s Faculty of Engineering. ‘The material across the centre of the disc is thinner than the ring, so it will biodegrade more quickly allowing the stem cells to proliferate across the surface of the eye to repair the cornea.’ Without this constant repair, thick white scar tissue forms across the cornea causing partial or complete sight loss. The researchers said another advantage of the disc is that it is biodegradable and made from the same material already used in sutures, so it will not cause a problem in the body. Laboratory tests have shown that the membranes will support cell growth. As a result, clinical trials are expected to begin shortly in India, as the Sheffield scientists are working in conjunction with researchers at the LV Prasad Eye Institute in Hyderabad. Commenting on the disc, Dr Frederick Claeyssens, lecturer in biomaterials at the University of Sheffield, said: ‘We also believe that the overall treatment using these discs will not only be better than current treatments, it will be cheaper as well.’ The research is published in the journal Acta Biomaterialia.