“Each dot on an array tacked to a patient’s retina is an electrode that sends visual stimuli to the optic nerve, visible as a white circle at far right. Built by the U.S. company Second Sight, the one-third-inch-wide array has 60 electrodes. An older model had just 16. As with digital camera pixels, more electrodes capture more detail. The company is now developing implants with hundreds, even thousands, of electrodes.”
