Looking for a long amount of time at changing patterns,a certain color, or a certain degree of brightness also can affect what We "see." Staring at a certain color of a certain amount of brightness tires our eyes, and as a result, We may perceive things differently. In Short, the tiring of our eyes following an excessive exposure to a certain kind of visual can cause optical
illusions. These are called physiological optical illusions. An example of a physiological illusion is an "afterimage." Have you ever looked at a light stayed in your eyes after you looked away? This optical illusion is mostly the result of the operation of the "cones" in one's eyes.