blind spot

A blind spot, scotoma, is an obscuration of the visual field. A particular blind spot known as the physiological blind spot, "blind point", or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through the optic disc. Because there are no cells to detect light on the optic disc, the corresponding part of the field of vision is invisible. Processes in the brain interpolate the blind spot based on surrounding detail and information from the other eye, so it is not normally perceived.