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Eye Health Glossary

Achromatopsia: A hereditary condition in which people lack certain receptors in their retinas, causing them to be nearly or completely colorblind and to have poor visual acuity.

Alpha-2 agonists: A medication used to treat glaucoma that helps by inhibiting the production and increasing the drainage of aqueous humor, thereby reducing the pressure inside the eye.

Recommended Related to Eye Health

Night Vision Problems: Halos, Blurred Vision, and Night Blindness

Are you having problems with night vision? Millions of Americans do. Poor night vision may simply be an early sign of progressive cataracts. Problems with night vision -- or at the extreme, night blindness -- may be treatable or could be a sign of a congenital problem such as retinitis pigmentosa or other more serious conditions.

Read the Night Vision Problems: Halos, Blurred Vision, and Night Blindness article > >

Amblyopia: Also known as "lazy eye," amblyopia is a condition that starts in childhood in which vision has not developed properly in one eye or the other. If amblyopia is left untreated, a child's vision will not develop correctly, and as the brain matures, one eye will remain with poor vision.

Aqueous humor: The clear, watery fluid between the lens and the cornea.

Astigmatism: A condition in which blurred vision is caused by the cornea being shaped more like a football than spherical like a basketball. Astigmatism may be compensated for through eyeglasses or contacts, or it can be corrected through refractive surgery.

Beta-blocker: A medication used in the treatment of glaucoma, beta-blocker eye drops help reduce the pressure within the eye by reducing the production of aqueous humor.

Carbonic anhydrase inhibitor: A type of medication used to treat glaucoma. Carbonic anhydrase inhibitors work by reducing the production of aqueous humor, thereby reducing pressure inside the eye.

Choroid: The layer of blood vessels between the retina and the sclera.

Choroiditis: A form of uveitis that causes an inflammation of the layer beneath the retina. It may also be caused by an infection such as tuberculosis.

Conjunctiva: A thin layer of tissue that lines the inside of the eyelids as well as the outer surfaces of the sclera.

Conjunctivitis: Inflammation of the conjunctiva, also called "pinkeye."

Cornea: The clear outer layer of the eye. It covers the iris.

Cryotherapy: A surgical procedure in which abnormal cells are destroyed by freezing them.

Cyclitis: A form of uveitis that causes inflammation of the middle portion of the eye and may affect the muscle that focuses the lens. Cyclitis may develop suddenly and last several months.

Dilation: Expansion of the iris with medicated eye drops.

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