Sight and Vision, What is the Difference?
This photograph shows that even though you can see clearly, you may not understand what you see. This is called visual perception.
Children may pass a school screening with 20/20 vision but be unable to learn to read, due to such visual perceptual skills as understanding different forms, sizes, shapes, colors, directions, being unable to distinguish between small differences, inter-relationships of forms, visual memory, visual span (how much they can visually bite at one time), and integrating vision with hearing, hands, movement and balance.
Mouse over the picture to see what is really there.
There is a lot more to vision than how clearly you see.