What Are Optical Illusions and How Do They Work?

Optical illusions are images or visuals that appear to us to be different what they are. To put it another way, optical illusions happen when our eyes convey information to our brains that leads us to believe something that isn't true.
 
"Illusion" is derived from the Latin word illudere, which means "to mock."
Physiological illusions exist in some cases. This indicates that they are caused by a physical mechanism in the eyes or brain.
An example of a physiological illusion is the Mach band illusion. One solid colour runs down the middle of the image. The right side of the line seems darker, while the left appears lighter, due to how the eye's retina filters the varied shades on either side of the line.

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Whether it's the renowned checker shadow illusion or the impossible triangle, we've all experienced different optical or visual illusions over time.
But how do optical illusions operate in practice?
Is it our eyes themselves that deceive us, or our eyes' perception of reality?
In this article, we'll look at three different types of visual illusions:

1. Literal Optical Illusions-

These illusions occur when our eyes perceive an image and our mind fills in gaps that don't exist, resulting in an image that isn't truly there, or when our mind focuses on specific portions of the image, causing us to "see" something that isn't there.
Because our eyes use the edges of objects to discern what they are, we can see that the elephant has a lot of legs in this example.
This can also happen when our brain sees faces in clouds or in everyday items.
 

2. Physiological Optical Illusions-

These are caused by an excessive number of stimuli (brightness, colour, flashes, etc.) for a long length of time and the effect it has on our brain or eyes.
So take a minute to look at the image below, then blink while looking at the blank spot.
The retinal photoreceptor cells in our eyes continue to produce neurological impulses to our brain long after we've stopped staring at the image, resulting in the after image.

3. Cognitive Illusions-

These are caused by our brain's "unconscious conclusions" when gazing at specific objects.
In contrast to literal illusions, the inferences we make are not based on the visual itself.
Kanizsa's Triangle is one of the most typical cognitive illusions, in which we see a dazzling white triangle where none exists.
This is because the Pac Man discs' colours and angles contrast, causing our minds to form the white triangle in the centre.
 
 
 
The most common cause of illusions is that our eyes observe items that our brain then organises.
Shape, colour, and size are all factors that influence what we see due to our neural circuitry. When our brain's normal, unconscious process of organisation clashes with our logic when we consciously look at and take in the image, we get these illusions.
For example, when we look at Kanizsa's Triangle, our eyes conjure up the image of a white triangle due to our neural circuitry, but the illusion kicks in when we consciously look at it and notice that it lacks distinct edges, resulting in a cognitive dissonance between what our brain infers and what we see.
 
 
Although these illusions are natural and prevalent, some of them can be harmful.
Whether you notice intense brightness, constant light streaking, or prominent halos surrounding certain objects, have these visual illusions investigated by professionals to see if they're an indication of something more serious.
Impaired vision can cause visual snow, floaters, and even probable hallucinations, so be sure your eyesight is fine before undergoing any type of laser eye surgery!
  Optical illusions, often known as visual illusions, are a type of visual trickery. A wide range of misleading visual illusions can be noticed due to the arrangement of images, the effect of colours, the impact of light source, or other variables.