The eyes are complex organs, with many parts that must work together to produce clear vision. Here is a basic overview of eye anatomy:
This is a layer of clear tissue at the front of the eye that helps focus light.
Located at the corner of each eye, tear ducts produce tears to keep the cornea lubricated and clear of debris.
Iris & Pupil
The colored part of the eye is the iris. It is a muscle that controls the pupil, the opening in the middle of the eye that controls the amount of light coming in.
Lens & Retina
The lens is behind the pupil and focuses light onto the retina, the light-sensitive cells on the back of the eyeball. Acting much like the film in a camera, the retina converts images into electrical signals that are sent to the optic nerve.
The optic nerve is a thick bundle of nerve fibers attached to the back of the eye that transmits visual information from the retina to the brain.
When Things Go Wrong
Problems or malfunctions in any of eye parts cause many common eye conditions.
When light is not focused properly, it causes blurry vision. Refractive errors can usually be corrected with glasses, contacts, or surgery. They include:
- myopia (nearsightedness), which is when far-away objects look blurry;
- hyperopia (farsightedness), which is when close-up objects look blurry
- astigmatism, which can result in blurry vision because the cornea is not perfectly shaped to direct light into the eye.
- presbyopia, which is the inability of older people to focus on close-up objects.
Glaucoma is increased pressure of the fluid inside the eye, which can cause optic-nerve damage. Glaucoma is a common cause of blindness, particular in diabetic patients.
Cataract is a clouding of the lens, causing blurry or color-tinted vision. People with cataracts often report