Defects in the peripheral field

Localised visual field defects in the peripheral area of the eye (due to say disease or degeneration in parts of the retina) are often not perceived by the person, since the eye and brain accommodate to the problem. The video simulates how this filling-in with local colour and matching contrast obscures items until shifts of attention move their image away from the affected area of the retina. When this happens, it will seem to the viewer that the object will very suddenly resolve itself out of the background blur.