According to the World Health Organisation, there are 39 million blind people, and 217 million visually impaired humans living on Earth today. Despite regular advancements in treating sight loss, there has been a distinct lack of progress on cures for blindness.
That might be about to change.
Over the last few years, both stem cell science and gene therapy have shown promise that may finally be coming to fruition. Technological developments also look set to give hope to people who have long waited for a cure.
Here is our guide to the latest blindness breakthroughs.
Stem Cell Therapy
One of the most encouraging methods to treat blindness could lie in stem cell therapy. In January this year, scientists announced that stem cell transplants restored vision in blind mice. Reprogrammed skin cells were converted into retinal tissue, which was then implanted into the eye and formed photoreceptors that made contact with neighbouring eye cells. Within one month, the mice could respond to light again!
Since the study, a Japanese man has become the first person in the world to receive skin cells from another person, which were transformed into retinal cells, and then grafted onto his retina. The aim is to stop the advancement of the patients Age Related Macular Degeneration (AMD) – a leading cause of vision loss.
A single gene that was injected into the back of a mouse eye has been shown to reverse one of the most common causes of blindness – retinitis pigmentosa – a condition that affects 1 in every 4000 people!
The research was performed by scientists from the University of Oxford, who monitored the mice for 1 year after the injection, and found that their visual improvement was maintained. In effect, the mice were cured of their blindness and could once again see light signals. Encouragingly, the study authors suggested the technique may be available to humans in as little as 5 years time!
A fascinating potential cure for blindness may be found in the body chemistry of zebrafish. These creatures have an intriguing ability to regenerate their retinas in just 28 days, and researchers wanted to know why.
Their studies could have a profound impact on a novel way to treat sight loss, as zebrafish have very similar retinas to humans!
It was found that the key to their retinal regrowth was the level of a neurotransmitter known as GABA. High amounts of GABA inactivate the stem cell repair process, yet the fish had much reduced levels, which seemed to trigger the regrowth!
If it is possible to reduce this neurotransmitter in people, then it could help to reverse AMD.
Technology, and the constant reduction in size of digital products, are leading to a wave of eye implants that can return a form of vision to previously blind people.
The Argus 2 Bionic Eye is used to treat retinitis pigmentosa and is currently the most advanced and tested implant in production. Trials of the ‘eye’ are underway, and a 56 year old man who had been blind for 20 years recently had his sight partially restored.
The bionic eye works by sending images to an implant in his eye from a tiny camera. A microcomputer then converts the images into electrical impulses, that are transmitted to electrodes in the retina. This stimulates the remaining retinal cells, giving him a new form of vision that the brain learns to interpret.
An amazing achievement that has taken years to develop!