Procedure in which a surgeon cuts the cornea so that it is more spherical when it heals, thus reducing astigmatism.

Sensitivity to a substance, accompanied by sneezing, itching, watery eyes, difficulty breathing or rashes.

Also called lazy eye. Diminished sight in one eye.

Disorder characterized by the gradual loss of central vision due to a damaged macula (which is made up of retinal cones necessary for sight).

The American National Standards Institute's Practice for Occupational and Educational Eye and Face Protection; eyewear that meets this standard is considered safer than eyewear that does not.

Part of the eye behind the cornea and in front of the iris and lens.

Substance that inhibits oxidation and can guard the body from the damaging effects of free radicals. Molecules with one or more unpaired electrons, free radicals can destroy cells and play a role in many diseases. Antioxidants may help pr

Clear fluid in the eye that both provides nutrients and determines intraocular pressure.

Condition caused by an irregularly shaped cornea, resulting in two focal points (blurred vision).

Having one segment for near vision and one segment for far vision.

Corneal layer between the epithelium and the stroma.

The part of eyeglasses that extends across the nose.

Style of glasses that wraps around the ear, to keep them well-fastened.

Clouding of the natural lens of the eye, resulting in impaired vision. Cataract surgery involves removing the eye's natural lens, and replacing it with an artificial one.

Layer of blood vessels and pigments (usually brown or blue) that lies beneath the sclera (the white of the eye). Often mistakenly called the iris.

Part of the eye that contains a focusing muscle and connective tissue.

Serious eye infection usually found in those with immune problems, such as AIDS patients; symptoms include floaters, blind spots, blurry vision and vision loss.

protein in bones and connective tissue, it is also present in the eye. One type of vision correction surgery now under FDA review heats collagen around the edges of the cornea (which lets light into the eye). This procedure reshapes

Partial or total inability to distinguish specific colors.

Condition caused by prolonged computer use, and characterized by eyestrain, blurred vision, headaches and dry or irritated eyes.

A photosensitive receptor in the retina that helps you to see color.

membrane that lines the visible part of the eye and the inner surface of the eyelid.

Inflammation of the conjunctiva.

Eye drops for contact lens wearers; regular eye drops can discolor contact lenses.

The least amount of contrast that you can still see.

The clear part of the eye covering the iris and pupil; it lets light into the eye, permitting sight.

A tearing or puncture of the cornea.

Devices (such as rings or contacts) placed in the eye, usually to correct vision.

Type of vision correction surgery where a doctor inserts a tiny plastic ring into the cornea (which lets light into the eye). This ring reshapes the cornea, helping it to focus light better onto the retina so you can see better. The ring

Wound in the surface of the eye caused by injury, dryness due to lack of tear production, or infection.

Type of strabismus (a misalignment of the eyes) where one or both eyes point inward, toward the nose.

Blocked tear duct, which is characterized by a lot of tearing.

These soft contact lenses are worn every day for six months up to one year. They require daily cleaning and disinfecting, as well as a periodic enzymatic soak (usually once a week).

Corneal layer between the stroma and the endothelium.

Leaking of retinal blood vessels in advanced or long-term diabetes, affecting the macula or retina. Vision can be seriously distorted or blurred.

Unit which measures the refractive (light-bending) power of a lens; eyecare practitioners use it in eyeglass and contact lens prescriptions. A negative number refers to nearsightedness, while a positive number refers to farsightedness. For ex

Technically, this is any contact lens that is thrown away after a short period of time. Among most eyecare practitioners, "disposable" usage ranges from one day to two weeks, while "frequent replacement" lenses are discarded

Also called ptosis. Condition in which the upper eyelid(s) only sag. It can be present at birth or caused by a later problem with the muscles lifting the eyelid, called levators.

Lack of sufficient lubrication and moisture in the eye. Most dry eye complaints are temporary and easily relieved; dry eye syndrome is chronic and needs more advanced treatment by an eyecare practitioner.

The cornea's inner layer of cells.

A cleaner that removes protein deposits and other debris from contact lenses. It's recommended for use either daily, weekly, or monthly. Some enzymatic cleaners are a small tablet dropped into a solution along with the lens; others

The cornea's outer layer of cells.

Currently, these contact lenses are FDA-approved to be worn without removal for up to seven days, meaning some people will be comfortable sleeping with them in their eyes.

Optometrists (O.D.s) and ophthalmologists (M.D.s) both practice eyecare, but in different ways: O.D.s examine eyes to determine eyewear prescriptions and check for and treat many diseases such as glaucoma. M.D.s are medical docto

Also called hyperopia. To farsighted people, near objects have a geater potenial to result in blurriness and or eyestrain, while far objects are less likely to result in these same symptoms.

A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eye drops. In the U.S., these products must be approved by the FDA before they can be mar

Small specks that pass across your field of vision, these are clumps of cells inside the transparent gel filling the eyeball in front of the retina.

A depression in the retina that contains only cones (not rods), and that provides acute eyesight.

Technically, this is any contact lens that is thrown away after a moderately short period of time. Among most eyecare practitioners, "disposable" usage ranges from one day to two weeks, while "frequent replacement"

Disease characterized by excessive fluid (aqueous humor) in the eye, high intraocular pressure and vision impairment. Blindness can result.