The United States typically defines someone as legally blind when the person’s central vision has degraded to 20/200, or the person has lost peripheral vision so that he sees less than 20 degrees outside of central vision. Normal vision is 20/20, and people can usually see up to 90 degrees with their peripheral vision. An estimated 1.1 million people in the United States are considered legally blind.
This has led to companies like Nano-Retina to develop a sophisticated and elegant solution intended to restore the sight of people who lost their vision due to retinal degenerative diseases. The miniature Nano Retina device, the NR600 Implant, replaces the functionality of the damaged photoreceptor cells and creates the electrical stimulation required to activate the remaining healthy retinal cells. NR600 consists of two components; a miniature implantable chip and a set of eyeglasses worn by the patient.
Very interesting technology for those that are always sitting in front of the computer like myself, hopefully it will not be needed by me, but it’s great that companies are advancing for those that suffer this debilitating illness.
Many groups around the world are working on bionic vision systems to replace lost photoreceptors. Most use a camera that communicates to an implanted chip, but vary in the number of electrodes in the chip and how deep the chip is placed inside the retina. Yet others eschew the camera for light-sensitive diodes in the chip.
German company Retina Implant, for example, recently completed human tests with its 1,500-pixel implant that does not depend on a camera but instead directly harvests light and transmits that data to remaining neurons. A photodiode array replaces the photoreceptors.
Some people with artificial retinas can read large letters, see slow-moving cars, or identify tableware. Other patients experience no benefit. The variation can be ascribed in some cases to the exact placement of the neuron-stimulating array in the tissue-paper-thin retina as well as the state of the remaining neurons and pathways in each individual’s eye. How well people can learn to use the device and retrain their brain is also important.