Two recent advances have brought the grail of sight restoration for all blind steps close.
The first of these is for patients with damaged corneas. Traditionally, transplant of the cornea of a donor is one of the only methods, but this can be difficult to organize, expensive and there are rarely enough corneas available. There can also be political and social difficulties in setting up units. Now, May Griffith at Linkoping University in Sweden have restored sight in people with damaged corneas by using an implant made of collagen – a material commonly found in many parts of the body (eg cartilage). The collagen was moulded to the shape of natural corneas and held by temporary sutures. After two years, the artificial corneas in all the recipients had become filled with the patients own cells anchoring them to the eye. Nerves also grew across all of the corneas – important for cell survival and to maintain the blink response. This method could be a huge advance for cornea generated blindness or low vision .
The second advance has been the insertion of a microchip into patients with retinal degeneration. The retina is the sensitive area in the back of the eye which responds to light and converts it to nerve signals. In retinal degeneration, this process slows and then ceases altogether. Eberthhart Zrenner at the University of Tubingen in Germany developed the microchip. It carries 1500 photosensitive diodes and is slid into the retina where the photreceptors would normally be. They respond to light and stimulate the nearby nerves which pass signals to the brain. At the moment an outside electrical source is needed but this is supplied by a tiny wire which is passed into the back of the eye.
Both the exciting advances could have huge implications for the blind.
Rose Charities Cambodia’s Dr Hang Vra replaces a cataract at the Rose Sight Center, Phnom Penh