The Blind Spot

Each normal human eye has a blind spot where the optic nerve exits the retina and photoreceptors are absent. The retina sends no visual signal from that patch. Yet we do not normally see a permanent dark hole: the other eye’s view covers it in binocular vision, and during monocular viewing the visual system can perceptually fill it using surrounding color and texture. The mechanism of this filling-in is still being studied.