The blind spot. Blood vessels in the retina shown emerging from the optic disc (black). The optic disc is the part of the retina where the optic nerve carries all the visual information away from the eye and where the retinal blood vessels enter and leave the back of the eye. No light receptor cells are present here, making it a blind spot. We don't normally notice that the blind spot exists because the other eye compensates for that small area. However if you cover your right eye, look at the cross and slowly move your head towards the panel, the dot on the left will disappear.
O X Biomedical Image Awards 2006.