Medical News
Sight breakthrough in blind man shines light on study of optogenetics
Combination of light beams and genetic engineering also holds promise for other sensory restoration and pain relief
Recent news that a blind patient with a degenerative eye disease has had his vision partially restored in a trial is just the tip of the iceberg in the emerging field of optogenetic therapy .
It was the first reported case of such recovery using this approach in which researchers use gene therapy on one eye combined with goggles engineered to stimulate the modified genes using light .
The 5�-year-old patient , first diagnosed with a degenerative eye disease 40 years ago , was able to recognise , count , locate , and touch different objects while wearing the goggles .
The technique is part of a science that has evolved over the last fifteen years that uses a combination of genetic modification and light waves to trigger nerve reactions .
Optogenetics involves the use of light to control neurons that have been genetically modified to express lightsensitive ion channels to control the cells of the brain .
Not only can the study be applied to treatments for eye conditions , but researchers are also looking at its use for other senses , such as hearing restoration and even pain relief .
One of these is Dr Rachael Richardson , an optogenetic engineer with the Bionics Institute in Melbourne , who is looking at ways to use light to improve the way humans interact with stimulus from nerves in the ear . A breakthrough in this area would represent a major upgrade on the popular cochlear implants that rely on electrical stimulation .
While electrical stimulus of the nerves in the ear works broadly , the sounds it delivers are not precise . Light stimulus , however , is very accurate as beams can be focused more easily than sound rays , but the problem is that nerves cannot respond to them fast enough . Therefore , Dr Richardson believes that a combination of both sound and light techniques will make the next generation of cochlear implants much more effective .
“ Using electricity to activate nerves is highly efficient , but the activation spreads out , so you can ’ t be very precise . You can make light focus very precisely , but with the optogenetics and ion channels that you have to place into the nerves with your genetic modification , they ’ re quite slow to respond .
“ The nerves simply cannot follow the stimulation range , and with cochlear implants , you need it to be quite fast , so we ’ re hoping to combine electrical and optical stimulation and get the best of both worlds so we can use that highly efficient electrical stimulus and use the light to get it more precise ,” she told Global Health Asia-Pacific
Among the many other promising uses for optogenetics under development is the ability to inhibit neuroactivity to stop pain .
“ With pain , you have an abnormal firing of the nerve , so if you can silence that , you can stop the pain ,” said Dr Richardson .
�That ’ s really difficult to do with an electrical device , but with optogenetics , it ’ s a lot simpler . There are modifications you can do to the neurons where you can apply the light and it silences them , so there are applications like pain relief .”
30 AUGUST 2021 GlobalHealthAsiaPacific . com