Optical illusion is an illusion that occurs due to the human eye catching errors. There is conventional wisdom that there are physiological illusions and there are cognitive illusions.
Physiological illusions
Physiological illusions, such as the afterimages that occur on or impression of the image that occurred after seeing a very bright light or seeing a specific image pattern in a long time. This allegedly is the effect that occurs in the eye or the brain after a specific stimulus to excess.
Cognitive illusions
Cognitive illusions are assumed to occur because the notion of something outside the mind. In general, cognitive illusion divided into ambiguous illusions, distorting illusions, paradox illusions and fictional illusion.
In ambiguous illusion, an image or object can be interpreted differently. Examples are: the Necker cube and Rubin vase.
In the illusion of distortion, there is distortion of the size, length or nature of the curve (straight curve). An example is: illusion wall cafes and Mueller-Lyer illusion.
Paradox illusions caused by objects that paradoxical or impossible, such as the Penrose triangle or 'impossible staircase', such as shown in the graphic art of MC Escher's work, titled "Up and Down" and "Waterfall".
Fictional illusion is defined as the perception of an object completely different for someone but not for others, such as caused by schizophrenia or hallucinogenic. This is more accurately called a hallucination. Here's 7 Amazing Optical Illusions, namely:
