The eye can quickly adjust its focus between a distant point and a near one. It can be accurately directed toward an object even while the head is moving. The eye does not actually see objects. Instead, it sees the light they reflect or give off. The eye can see in bright light and in dim light, but it cannot see in no light at all.
Light rays enter the eye through transparent tissues.
The eye changes the rays into electrical signals. The signals are then sent to the brain, which interprets them as visual images.