Persistence of vision is a phenomenon of the eye by which an image is thought to persist for about one-sixteenth part of a second on retina after the actual image is formed.

It is the ability eyes to keep seeing the object an image for a fraction of a second after the object has disappeared from view. For example, while seeing a movie which is a collection of the frame (frame my photo). Each frame (photo) is moving so fast that our eye cannot differentiate between two consecutive photos. When the speed of frames moving is reduced to below 16 frames (photo) per second, we can easily differentiate between two consecutive images.

While seeing the above moving photo our eye persist as a movie clip.