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Eye and Vision Care

Glossary

Cataract: When the normally clear lens inside the eye becomes cloudy or dark and causes blurred vision which is not correctable by ordinary glasses.

Computer eyestrain: Ocular alignment and/or focusing problems associated with the use of a computer monitor.

Diabetes mellitus: Patients with this disease have a high amount of sugar in their blood (which is known as hyperglycemia); they can become permanently blind from swelling, bleeding, and/or abnormal blood vessel growth in the back of their eyes.

Diabetic retinopathy: One of many ocular complications from the disease known as diabetes, in which permanent damage occurs to the tissue in the back of the eye (retina) and the blood vessels that nourish it.

Dry eye(s): A lack of adequate tears (moisture) in the eye(s). Tears are critically important for healthy eyes and clear vision.

Eye safety: Optical devices (i.e., shatter-resistant lenses), information (i.e., avoidance of hazardous chemicals in and around the eyes), and personal conduct (i.e., proper behavior modification) which minimize the possibility of eye injuries and associated loss of vision.

Functional Vision Loss: Blurred vision, or a loss of vision, that results from a non-disease condition of the eye. This is contrasted with organic causes of blurred or lost vision, such as cataract or glaucoma.

Glaucoma: Permanent loss of vision as a result of damage to the optic nerve in the back of the eye. Treatment for this eye disease is directed toward lowering the eye's pressure by medications, laser treatment, and/or surgery.

Hypertension: Also known as high blood pressure, this disease can cause swelling and/or bleeding in the back of the eye which, if not diagnosed and treated, can lead to permanent loss of vision.

Low Vision: When a patient cannot be corrected to normal 20/20 vision with ordinary glasses, he or she is said to have "low vision." This condition can result from inheritance, trauma, disease, or aging. Optometrists can use special optical aids to compensate for, but not to correct, the patient's permanent loss of sight.

Macular degeneration: Damage or breakdown of the macula, which is an area in the back of the eye that controls central vision. It may be caused by injury or aging; and while it does not progress to total blindness, patients with macular degeneration require special optical aids to enlarge distant and near objects. In the elderly, this is known as Age-Related Macular Degeneration (ARMD).

Ocular alignment: Both eyes directed at the same target simultaneously. If patients do not have good ocular alignment, they may experience blurred or doubled vision, headaches, and/or excessive tearing and redness.

Presbyopia: The normal loss of near focusing ability that occurs with increasing age. Most people recognize this change in their early 40's, and then need reading glasses or bifocals to compensate for it.

Refractive error: Distance focusing difficulties in an otherwise healthy eye, such as nearsightedness (myopia), farsightedness (hyperopia) and slanted or distorted vision (astigmatism).

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Last Reviewed: Aug 05, 2009

Robert D Newcomb, OD, MPH, FAAO Robert D Newcomb, OD, MPH, FAAO
Professor Emeritus of Clinical Optometry
College of Optometry
The Ohio State University