How Do We See?

Ibn al-Haytham was the first to explain that vision occurs when light bounces on an object and then is directed to one's eyes. And he was the first to point out that vision occurs in the brain, rather than in the eyes.
The images we see are made up of light reflected from the objects we look at. This light enters the eye through the cornea, which acts like a window at the front of the eye. The amount of light entering the eye is controlled by the pupil, which is surrounded by the iris - the coloured part of the eye. Because the front part of the eye is curved, it bends the light, creating an upside down image on the retina. The brain eventually turns the image the right way up.
Ibn al-Haytham was also an early proponent of the concept that a hypothesis must be proved by experiments based on confirmable procedures or mathematical evidence-hence understanding the scientific method five centuries before Renaissance scientists.