We understand by optical illusion all those images or visual representations of reality that suppose some alteration of it according to the normally accepted parameters. Optical illusions are generated from the modification of the common elements of certain images and therefore, the eye receives certain information that the brain cannot understand as logical and then they attract attention or generate some kind of surprise.
Optical illusions, as the name implies, are always visual. This means that the only way to know and recognize optical illusions is through sight, not through any of the other senses such as touch, taste, smell or hearing. Optical illusions can be very varied and generate different sensations according to each person since each individual captures and apprehends them in a particular and subjective way.
There are two main types of optical illusions: those that involve an alteration of the image at a physical level, that is, that the image is altered based on parameters such as brightness, light, darkness, color (for example, an image possessing a particular light and makes it appear to human eyes that that light is a divine apparition). Then, we can also talk about optical illusions that have to do with the previous existence of certain knowledge about reality, which makes us realize when the image is not correct or true as a representation of reality (for example, when a staircase is infinite and space is altered in terms of gravity).
Optical illusions can be voluntarily generated from art or from planned image modification. However, the mental alteration that a person may suffer occasionally or permanently can also cause involuntary optical illusions such as the famous mirages to appear by wrongly capturing everything that surrounds the individual.
