Microchips, lollipops and echolocation: New ways to help the blind see
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Two men in the United Kingdom who had lost their vision after birth due to a genetic condition called retinitis pigmentosa, wherein light-sensitive cells in the eye stop working, just received the gift of sight due to an innovative new microchip implant. Surgeons partially restored vision to both men by implanting tiny electronic chips (0.12 by 0.12 inches) in a thin sheet of tissue at the back of the men’s eyes. When switched on, the chips perform the duties of the malfunctioning photoreceptors, converting light into electrical impulses that travel to the brain. A thin cable threaded beneath the skin connects the chip to a battery back, which sits under the skin near the ear.
These chips were designed by Retina Implant AG, a medical technology company in Germany, and have been implanted in at least ten patients so far as part of clinical trials. The current implants cannot help people with glaucoma or other conditions that degrade the optic nerve, and they do not offer the blind crisp and colorful images, but rather offer blurred outlines. Even so, these indistinct images are a vast improvement over complete blindness, and with the proper training, allow patients to distinguish food, tools, and sometimes people’s faces.
Another company, California-based Second Sight, has also achieved remarkable results by combining an implant with a miniature camera mounted on a pair of glasses. These recent successes suggest that affordable retinal implants could be available within the next few years.
Other scientists are taking a different tact in seeking to help the blind see. Neuroscientist Paul Bach-y-Rita correctly hypothesized in the 1960s that we see with our brains, not our eyes. This idea is being utilized in the form of a nonsurgical new device that aims to partially restore vision for the blind and visually impaired by relying on the nerves on the tongue’s surface to send light signals to the brain. The BrainPort device collects visual data through a small digital camera about 1.5 centimeters in diameter that sits in the center of a pair of sunglasses. The data is transmitted to a handheld base unit, about the size of a cell phone. This unit converts the digital signal into electrical pulses, effectively replacing the function of the retina. From this unit, the signals are sent to the tongue via an electrode array that sits directly on the tongue. Users describe the sensation as pictures being drawn on their tongues with champagne bubbles.
This unique device may seem complicated, but researchers behind this invention insist that, although unfamiliar at first, this method of “seeing” soon becomes second nature to users. Through proper training, patients quickly learn to find doorways and elevator buttons, read letters and numbers, and pick up items without fumbling. This system is particularly interesting because it is non-invasive, unlike implants. Additionally, this device is able to help people with visual defects such as glaucoma. The BrainPort vision device is currently in the investigational stage, and has not yet been submitted to the FDA for clearance, but researchers are optimistic.
The tongue is not the only alternative source for vision – Canadian researchers are exploring the possibility of using echolocation, the preferred method of dolphins and bats, to help the blind “see.” Little research has been done on human echolocation, and nothing is known about the underlying brain mechanisms, but a few limited studies show promising results. Researchers used functional magnetic resonance imaging (fMRI) to monitor the brain activity of two blind echolocation experts, revealing that echolocation engages regions of the brain that normally process vision. The subjects use click-based echolocation on a daily basis to navigate cities, go hiking, or even play basketball.
Each of these innovations take science closer to finding viable solutions for the blind and vision impaired, and present exciting possibilities for the future of sight.