The human eye

The human eye works very much like how a camera works, camera lens focus light on to a photosensitive surface, just like how our eye focus light onto the retina. The first human eye evolved around 500 million years ago, scientists have theorized that the first human eye could only see light and dark and distinguish the two. Their is a lens that covers our eyes which is called a cornea, it is transparent and protect the eye against gems UV rays, if the cornea is damaged a persons vision will become blurry as its like trying to look through a cracked window. Human actually see things upside down as a result of a curved cornea the light enters our eyes an is refracted causing the image to be flipped upside down but our brains automatically fix this.