Visual Illusions are also referred to as optical illusions. This is when what we see with our eyes is different from what we perceive or what is interpreted by the brain. Normally what we see is then processed by the brain before we can understand the figure or objects that are in front of us. When objects that are in reality differ from what we understand is what is called an optical illusion. However, when you miss out some parts of an image or impression and conclude a different thing is not considered as an optical illusion. In the informal context, people will refer it as an optical illusion when for example something seems difficult to you yet your friends can figure it out. This is used to joke around but is not a formal way of telling people that they do not understand a thing.
Types of Visual Illusions
Physiological illusion is when the brain cannot interpolate the after images that follow after you have been used to certain patterns for quite some time. This type of illusion is said to be caused by change stimuli and are mostly associated with light intensities, size, movements and color. Contrast and change in patterns in a manner that the brain is not adapted to causes some problems with internalizing the objects and this may cause as change in the perception.
Pathological illusion is the other form. This may not be taken well and is in most of the cases associated with certain diseases. It is when the brain cannot clearly perceive a real external stimulus. It may be known as hallucinations it is when you see thing or stimulus where there is none.
The last type of illusion is called cognitive illusions. They are said to arise from assumptions that we make during the physical interactions with the world or nature. This leads to unconscious or unsure inferences just because we have had some vague assumptions about the word. It is divided into paradox, distortion and ambiguous illusions.
Aspects used to create Visual Illusions
In all cases, illusions are just tricks that mess with your brain and impair your judgment on how you see and deduce things. Whatever information gathered by the eyes is used to create an impression that what the brain interpolates is different from what we see. Color, dimensions, patterns, tone, light and location are the major aspects that are used in creating of Visual Illusions.