Scientists have just developed a retinal implant that is able to restore vision in rats, and are now planning to trial the procedure in human in the next semester.
The new implant, that converts light into an electrical impulse that stimulates retinal neurons, will probably help millions who suffer from retinal degeneration, in which the photoreceptor cells of the eye begin to break down, eventually leading to blindness.
The retina is located at the back of the eye, and is composed of millions of these light-sensitive photoreceptors, but any mutations on any of the human identified genes can lead to retinal degeneration, where the cells just die, besides the fact the neurons around them aren’t affected.
Due to the fact that the retinal nerves remain intact precious researches focused in implanting bionic eyes that stimulate the neurons with lights, and gene editing to try to repair the mutations.
But this new team, led by the Italian Institute of Technology, has now developed a whole new approach that implants a prosthesis into the eye that replaces the damaged retina. This implant is made from a thin layer of conductive polymer, then placed on a silk-based substrate and covered with a semiconducting polymer.
The semiconducting polymer then acts as a photovoltaic material, which absorbs photons when the light arrives at the eye, after that, electricity stimulates retinal neurons, filling then the gap left by the eye’s photoreceptors.
The researchers have implanted the device into the eyes of lab rats bred to develop a rodent model of retinal degeneration. After the healing process, which took 30 days in the rats, the researchers tested how sensitive were they to light, a test known as pupillary reflex, and compared the results to healthy rats and untreated rats suffering from the condition.
When low intensity lights of 1 lux, kind like the full moon bright, there was little to no difference between treated and untreated rats, but when they increased the value to around 4-5 lux, the pupillary response of the rats with the implant was almost indistinguishable from the healthy ones.
The rats were then tested at the 6 and 10 months’ mark, and the implant was still working fine. So, although more research is needed, we now have a viable tested solution.
“We hope to replicate in humans the excellent results obtained in animal models”, says one of the researchers, ophthalmologist Grazia Pertile from the Sacred Heart Don Calabria in Negrar, Italy.
“We plan to carry out the first human trials in the second half of this year and gather preliminary results during 2018. This [implant]could be a turning point in the treatment of extremely debilitating retinal diseases”.