Optical deceptions or optical illusions are “wrongfully” perceived occurrences that often be confusing. Some illusions are caused by imperfection of our senses (eyes), and some by the way our brain functions. Optical illusions need to be differentiated from hallucinations. They are different by the fact that in the case of optical deceptions there is stimulants, but it is perceived in the wrong way, while in the case of hallucinations there is no stimulant.

Illusion is a unconscious process with which the brain groups data received from various senses and interprets them by making a logical whole. Our perception enables us to se various color smudges as certain object, and to hear many sounds as speech, and to taste the combination of sweet, sour and other types of taste as certain meal, etc.