Retinal implant brightens future for the blind
Forty-six-year-old Miika Terho of Finland suffers from a condition called retinitis pigmentosa, a hereditary disease that causes light-sensitive cells (or photoreceptor cells) in the eye to steadily and irreversibly die off. When Terho was 16, his night vision began to fail, and by 35 he was severely blind in both eyes.
But thanks to a pioneering retinal implant, Terho and many other visually impaired patients could one day regain their sense of sight.
Terho was one of three patients who had the experimental chip inserted under part of the retina called the macula, where the highest concentration of light-sensitive cells is found.
The microchip, developed by Retinal Implant and the Institute for Ophthalmic Research at the University of Tuebingen in Germany, measures approximately 3 millimeters by 3 millimeters in size. It is loaded with 1,500 light detectors that send a grid of electrical impulses through a patient’s nerves to generate a 1,500-pixel image.
Unlike other implants that sit outside the retina, this pioneering device is implanted under the retina, directly replacing light receptors lost in retinal degeneration. It uses the eyes’ natural image-processing capabilities beyond the light detection stage to produce a visual perception in the patient that is stable and follows their eye movements.
The implant, a product of 15 years of research, converts light that enters the eye into electrical impulses. It is externally powered and in the initial study was connected to a thin wire that protruded from the skin behind the ear to connect to a battery and control box. This control box allows patients to adjust the brightness and contrast of images.