ITALY, Mar 14: A damaged retina is often something many people have to live with for the rest of their lives, leaving them with reduced sight or even blindness.
Even those that don’t suffer from an injury can suffer from an unfortunate condition where their retina’s photoreceptor cells die off, and their sight slowly deteriorates over time.
Delicate operations fraught with risk are occasionally used to alleviate the problems associated with a damaged or defective retina, but now, thanks to the research of those at the Italian Institute of Technology, there may soon be another way. A tiny prosthetic retina, one that is effectively a cybernetic replacement for the real thing, now exists – at least for rats.
Made of a sandwich of a thin layer of electrically conductive polymer, a silk-based substrate, and a semi-conducting polymer, it’s able to absorb photons when light sneaks in through the eye’s pupil. The photons generate an electrical current, and make their way to the back of the device and into the retinal neurons within the optic nerve.
Inserting it into the eyes of rats bred to have degenerating retinas, the team tested their pupils’ responses under a variety of low-light conditions.
When light falls on the retina under a variety of intensities, the response of the eye is to either widen the pupil (under low-light conditions) or to shrink it (under high-light conditions) in order to control the amount of light falling on the retina. Therefore, the rats with the most responsive pupils in this experiment had the most sensitive retinas – real or artificial.
Under very low-light conditions resembling that of a full Moon, the rats with implants were no more responsive than rats with damaged retinas lacking the artificial retina. However, when conditions similar to a sky at twilight arose, the augmented rats’ pupillary response were essentially no different from that of healthy rats with perfectly working retinas.
As reported in the journal Nature Materials, the implant was successful up to 10 months post-op. Perhaps most remarkably, this experiment was a bit of a shot in the dark – at this point, it’s not clear how clear an image the rats with the artificial retinas are able to process, nor is it certain how the device even works on a biological level.
“The detailed principle of operation of the prosthesis remains uncertain,” the team noted in their study.
Nevertheless, with human trials likely to follow suit later this year, it’s a remarkable step in the right direction to restoring sight to those that have lost or are losing it.