When you look at an image, you would expect your brain to process the information that it receives from your eyes and to give you the reality of what is in front of you. When you look at optical illusions, however, they are designed to do the opposite. You are still taking in sensory input through the eyes and transmitting that data to the brain but what the brain sees may be quite different than what you’re actually seeing.
Many people are confused as to how these types of optical illusions work. In reality, it has to do with light and the fact that you are looking at light that is bouncing off an object and entering into the eye. It is then converted to electrical impulses and the brain turns it into an image. It happens almost instantaneously, so it is impossible for your eye to focus on everything at one time.
Sometimes, your eye needs to take a shortcut and your brain may not quite get the information that it really means. That is where optical illusions come in. They trick your eye into taking one of those shortcuts and it results in something unusual that is quite difficult to believe.