Do you know what is an optical illusion? Today I will tell you about optical illusion and share a cool video on this also. Actually, optical illusion refers to visually perceived images that differ from objective reality. The information gathered by the eye is processed and the brain to give a percept that does not tally with a physical measurement of the stimulus source. Optical illusions are divided into three categories. First one is literal optical illusions which create images that are different from the objects that make them, secondly we have physiological illusions that are the effects on the eyes and brain of excessive stimulation of a specific type – brightness, tilt, color, movement, and the third is cognitive illusion where the eye and brain make unconscious inferences. Now watch out this cool video on optical illusions.