Cyber Eye
Scientists have restored the mouse's vision with the help of an artificial retina
The combination of gene therapy and electronic devices allowed mice with damaged retinas to gain almost 100% vision, biologists say in an article published in the journal Proceedings of the National Academy of Sciences (Sheila Nirenberg and Chethan Pandarinath, Retinal prosthetic strategy with the capacity to restore normal vision; below are pictures from this article – VM).
According to current estimates of the World Health Organization, approximately 20-25 million people live on our planet suffering from blindness resulting from damage or decay of the photosensitive elements of the retina. Scientists have developed several models of prostheses that can partially restore vision to such people. As a rule, the capabilities of such devices are extremely limited – they allow you to distinguish light sources, see the contours of objects and very large objects.
The first picture is the original. The second one was obtained from the artificial retina of mice,
the third and fourth – with the help of other developments of the artificial eye.
Sheila Nirenberg and Chethan Pandarinath from Cornell University in Ithaca (USA) have developed a fundamentally new type of eye prosthesis, which is a combination of complementary "live" gene therapy and mechanical components.
Nirenberg and Pandarinat demonstrated the first prototype of this device in 2010, but they had to spend two years recording retinal signals and deciphering the mechanisms of their operation.
The mechanical component of the prosthesis is a set of photosensitive sensors connected to a microprocessor that converts the image into a "language" of electrical impulses understandable to nerve cells. These pulses are transmitted to micro-emitters on the back of the device, which emit coded pulses of light into the eye.
Here the second component of the device comes into play – gene therapy. Nirenberg and Pandarinate have developed a special retrovirus that inserts the ChR2 gene into ganglion cells that transmit information from the retina to the brain. This gene contains instructions for the production of the protein channel rhodopsin-2, which is able to capture light and turn it into electrical impulses.
When light pulses from the mechanical component of the prosthesis reach such cells, rhodopsin is activated and causes the ganglion cell to transmit a signal to the vision centers in the brain. Since this signal was pre-encoded into a format understandable to the brain in the mechanical part of the "cyber eye", retinal cells have no problems decoding it.
Scientists tested their invention on blind mice whose photosensitive retinal cells were irreversibly damaged. According to biologists, the installation of "cyber-eyes" has successfully restored vision to their wards.
Nirenberg and Pandarinat conducted an additional test – they connected electrodes to several thousand ganglion cells in the mouse eye and recorded the signals coming from them. Then they decoded the data packet using the same algorithm that converts the image into a packet of nerve impulses, and compared it with what the rodent saw. Despite some loss in quality, the "picture from the eye" clearly showed the child the mouse was looking at.
Biologists believe that their approach makes it possible to bypass the main problem of other types of prostheses – low resolution and contrast. The authors of the article believe that their image encoding method and high-quality photosensitive elements will help people to regain full vision in the future.
Portal "Eternal youth" http://vechnayamolodost.ru13.08.2012