In optical illusions, the images that are perceived by our eyes are deceptive and do not match with the actual size and shape of the object. The information on these objects is gathered by our eyes and is processed by the brain. The brain gives such a perception that actually does not match with the physical measurement of the objects. Many researchers have come out with their own visual illusions which helped in studying this concept better and researches are still going on in this field. One of the most known relative size optical illusions is the Ebbinghaus illusion. Two circles of identical sizes are placed near each other. One circle is surrounded by larger circles while the other circle is surrounded by the smaller circles than its own size. The first central circle appears smaller than the second central circle though both of them are of same size. Though this illusion has been considered as the relative sizes optical illusion but recent studies have shown that the distance of the surrounding circles is also a very important factor in this illusion. When the surrounding circles are near the central circle, the central circle seems to be larger but if the surrounding circles are apart, the central circle appears smaller. This relative size optical illusion has contributed a lot in the recent debate that there are two separated paths in the brain one for perception and the other for action.