Understanding How Your Eyes Work
Eyesight is the most important way that we learn about the world around us. Eyes capture shapes and colors and are responsible for about 75% of what we perceive. Eyes are designed to respond to light and can sense about ten million different shades of color. With a direct link to the brain, they gather up to a billion pieces of information each second.
Components of Your Eyes
- Cornea: The cornea is the clear front window of the eye. It allows light to enter the eye. The cornea takes light rays and bends them into the eye, providing about 60% of the eyes total focusing power.
- Sclera: The sclera is the sturdy white tissue that forms the outer wall of most of the eye.
- Iris: The iris is located behind the cornea it is the part that gives color to the eye. The iris is a ring of muscles with an opening in the center called the pupil (the black center of the eye). The iris changes the size of the pupil to control the amount of light entering the eye.
- Lens: The lens is suspended directly behind the pupil by tiny elastic-like strands. The lens focuses the light that passes through it and provides about 40% of the eyes focusing power. The lens also serves to block some harmful ultraviolet light rays from entering the inner eye.
- Retina: The retina is a direct extension of the brain. It is a delicate membrane that lines the back inside wall of the eye. The retina catches rays of light that enter the eye and change the images into electrical impulses. These impulses are sent to the brain.
- Optic Nerve: The optic nerve connects the back of the eye with the brain where visual signals are interpreted. The optic nerve carries the electrical impulses from the retina to the brain.
- The Eyelids: The Eyelids protect the eye and block out light when the eyes are closed. Blinking spreads lubrication (tears) over the eye.
From Light to Sight
Light rays enter the eye through the clear cornea, pupil and lens. These light rays are focused directly onto the retina, the light-sensitive tissue lining the back of the eye.
The retina converts light rays into impulses, sent through the optic nerve to your brain. The brain decodes the impulses and vision becomes a vivid reality.