Once a topic of science fiction and lore, the idea of restoring eyesight is finally becoming an approachable reality. Today, the idea of building visual prosthesis has become less the subject of science fiction and more the pursuit of numerous and intense scientific researches. According to the World Health Organization, there are at least 2.2 billion visually impaired individuals worldwide. Out of these, about 1 billion are people whose blindness could have been treated or was avoidable. Research on possible solution is underway. Companies like Science and Gensight are currently experimenting with methods to restore vision. Science, a startup company, has claimed of designing a visual prosthesis that could restore vision, only to limited degrees, in people with retinis pigmentosa. All of these companies have based their work on a research tool in neuroscience called optogenetics. It is a tool that delivers opsins through injection into the eye to boost light sensitivity of the cells in the retina. How optogenetics works In a normal eye vision, light enters the eye through the lens and finally forming an image on the retina. The retina is made of several different types of cells, mainly photoreceptors. Photoreceptors are the light-sensing cells which are shaped like rods and cones and contain opsins. Normally, photoreceptors convert light into electrical signals that travel to the retina’s ganglion cells, which in turn transmit those electrical signals via the optic nerve into the brain. That’s how we naturally see. In the case of one contracting retinitis pigmentosa, the rods and cones in the photoreceptors die down. First the peripheral vision goes, and people develop tunnel vision. They would have to turn their heads just to view the world around them. Blindness follows after this. The breakdown of the photoreceptors, however, doesn’t diminish the brain’s ability to process electrical signals. So, basically, the ganglion cells remain intact. Optogenetics seeks to go about this process by delivering opsins directly into ganglion cells. There are two elements of the Science Eye developed by the company Science. The first is an implant containing a wireless power coil and an ultrathin Micro-LED array that’s applied directly over the retina through a complex surgery. The second element is a pair of frameless glasses, shaped into regular prescription glasses that contain miniature infrared cameras and inductive power coils. So, the first step would be to inject opsins into the ganglion cells of the eye. The second step is to install the implant which leads to the final step of the glasses that activate the modified ganglion cells by wirelessly communicating information from the world. The new light sensitive ganglion cells, in turn, transmit the information received through the glasses to the optic nerve to the brain. Through this process, the eye is not receiving an image anymore but rather digital information. GenSight Biologics uses the optogenetics-plus-glasses approach to intensify the light that genetically edited ganglion cells can decode. According to the clinical trial results that were published in 2021 in the Nature Medicine journal, this method was able to help a man in locating objects on a table. The patient was 58 year-old during the trial and was blind since 18 years of age, diagnosed with retinis pigmentosa. Despite such a technology, questions have been raised on various limitations of the Bionic Eye. The insertion of opsins into retina is a feasible approach to storing vision. However, the potential immune response of the human retina to microbial opsins is a challenge. Another concern is that the light intensity of optogenetic stimulation is very high. Issues arise too when a company suddenly stops their development and research in the field. Some years back, Second Sight suddenly stopped making Argus II bionic eye to focus on brain implants instead. Hundreds of people who depended on the technology were left with an uncertain future because the technology they relied on was halted. Despite the concerns and the potential of optogenetics still to be determined, the steps towards its application are already underway. The Science Eye seeks to help countless people and its clinical trials are expected to be started in around 18 months.