Only ten years ago, curing total blindness was impossible. Today, scientists are closer than ever to developing a new technology that could restore sight for the visually impaired. Artificial retinal implants have revolutionized the field of ophthalmology since their introduction in 2014, becoming a viable treatment option for patients suffering from partial or total vision loss. Through increasingly sophisticated practices, scientists have successfully engineered a retinal implant capable of processing light with shocking efficiency and utility, providing hope for millions worldwide without sight .
Many vision problems arise from damage to the retina, a light-sensitive layer of tissue at the back of the eye responsible for generating and relaying visual signals. The retina, integrated in the nervous system via the optic nerve, uses millions of light-sensing photoreceptors to generate a series of impulses that are translated into a perceivable image . Aging, excessive exposure to sunlight and eye trauma all contribute to retinal damage and degradation over time, and very often, retinal and photoreceptor damage is permanent. Available treatments, according to the Mayo Clinic, slow the progression of retinal destruction but are rarely capable of reversing damage . Scientists have attempted to counter retinal and photoreceptor damage by creating an implant that mimics the function of photoreceptors to produce artificial images in the brain.
The first retinal implant available to consumers was approved by the Food and Drug Administration (FDA) in 2014, but its comparatively crude design provided limited utility. This Argus II device, developed by the company Second Sight, consists of a video camera, a transmitter, a video processing unit (worn by the patient) and an implant with a 60-electrode array . The implant’s small electrode array, however, generates very low-resolution images that allow patients to process only basic movement and perceive large letters, according to ophthalmology professor Dr. Joshua Dunaief . Though Argus II provided groundbreaking prospects for the blind, challenges associated with improving image resolution and implant utility remained. The years 2020 and 2021 have yielded incredible technological advances that have dramatically minimized these limitations.
A 2020 research article published in Nature proves that artificial retina development has rapidly progressed since the release of Argus II: scientists have successfully developed and tested a device that functions nearly on par with a biological eye . Using a specialized electrochemical process, scientists covered a curved aluminum foil surface with a pore-filled insulating material. This surface then underwent vapor deposition and allowed researchers to “grow” nanowires in the available pores. By chemically manufacturing a studded, curved surface that could relay electrical impulses, scientists created a device that, for the first time, contained a density of receptors that is comparable to that of biological eyes. In addition to its 19-millisecond processing time (which is twice as fast as that of a human eye), the device’s curved surface generates images with very high levels of clarity, a previously significant limitation of retinal implants. Such a sophisticated device would be immensely beneficial for both patients and robotics developers who incorporate visual technologies into their creations .
While the mechanics of retinal implants continue to advance, the biotechnology firm LambdaVision is pioneering an alternative method of implant development that would occur exclusively in outer space. Through their biological approach to implant development, scientists at LambdaVision harvest a light-activated bacterial protein that functions similarly to human photoreceptor proteins and layer them into precise configurations that allow for electrical signaling associated with vision . Such specific configurations are difficult to achieve, but, according to innovation officer Jana Stoudemire at LambdaVision’s space-based research sponsor Space Tango, layering these bacterial proteins in zero gravity conditions allows for much more precise and efficient development. LambdaVision, much like the researchers developing the nanowire-based device, hopes that its technology will gain FDA approval in upcoming years for patient use.
Despite the coronavirus-stricken years of 2020 and 2021, retinal implant development has experienced immense advances in improving image resolution and implant utility. Both aforementioned technological developments, however, are challenged with ensuring their implants are applicable to a wide range of patients. While some patients may have visual impairments confined to the retinal tissue, others born with optic nerve defects may lack the neural structures necessary for relaying visual signals from the implant to the brain . The specificity of these new devices has yet to be expanded to a diverse range of patient conditions. In the meantime, these retinal devices provide valuable potential for use in robotics development. Retinal technology is rapidly progressing, and as researchers set their sights on developing suitable implants for patients, humanity can envision a more optimistic outlook on eye care in the near future.