How We See

The human eye is the organ which gives us the sense of sight, allowing us to learn more about the surrounding world than any of the other five senses. We use our eyes in almost everything we do, whether reading, working, watching television, writing a letter, driving a car, and countless other activities. Sight is the most precious of the five senses, and many people fear blindness more than any other disability. The eye allows us to see and interpret the shapes, colors, and dimensions of objects in the world by processing the light they reflect or give off. The eye is able to see in dim light or bright light, but it cannot see an object when light is absent. The eye changes light rays into electrical signals then sends them to the brain, which interprets these electrical signals as visual images. The eyeball is set in a protective cone-shaped cavity in the skull called the orbit or socket and measures approximately one inch in diameter. The orbit is surrounded by layers of soft, fatty tissue which protect the eye and enable it to turn easily. Six muscles regulate the motion of the eye. Among the more important parts of the human eye are the iris, cornea, lens, retina, conjunctiva, the macula, and the optic nerve.