Glossary

A Age-related macular degeneration (AMD) A disease of the retina that can cause loss of central vision and make it difficult to recognize faces, read, drive, and perform other everyday activities. AMD appears in 2 forms: dry and wet. Untreated, wet AMD can cause the center of a person’s vision to disappear, leaving only the side vision intact. It usually does not lead to total blindness. Amsler grid A tool used to detect changes in vision. Atrophic Refers to cells, tissue, or organs that have wasted away or stopped functioning normally. Atrophy The process by which cells, tissue, or organs waste away or stop functioning normally. Back To Top C Carotenoid Any member of a group of red-, orange-, or yellow-colored fatty substances found in carrots, sweet potatoes, green leaves, and some animal tissues. Cataract A clouding of the normally clear lens of the eye, negatively affecting sight. Choroid The thin layer of blood vessels and connective tissue between the white of the eye (sclera) and the retina. Back To Top D Drusen Tiny, glassy deposits or large, yellowish fatty deposits behind the retina of the eye. Dementia The mental decline caused by physical or psychological factors. Back To Top F Fluorescein angiogram (FA) Test used to assess the health of certain blood vessels in the eye. In this test, fluorescein dye is injected into a vein in the arm and photographs are taken of the eye as the dye circulates. Fovea Central pit in the macula that produces sharpest vision. Back To Top G Glaucoma A disease caused by high pressure in the eye. If not treated, it can cause loss of vision and possibly even blindness. Back To Top I Indocyanine green (ICG) angiogram Test used to assess the health of certain blood vessels in the eye. Differs from a fluorescein angiogram in the kind of dye used. Indocyanine green dye allows leaks to be seen even under a layer of blood. Back To Top L Legal blindness A definition used to qualify individuals for certain benefits; in the U.S., best corrected visual acuity of 20/200 or less or a very narrow field of vision. Back To Top M Macula Small, specialized area of the retina responsible for central vision. Macular degeneration See "Age-related macular degeneration." Metamorphopsia Condition in which images appear distorted; a warning sign of AMD. To people with metamorphopsia, straight lines may appear wavy or bent. Back To Top N Neovascularization The abnormal growth of new blood vessels, usually in or under the retina or on the iris. Back To Top O Ophthalmoscope A device that lights up the inside of the eye and enlarges the image. Used for the detection of both early and later signs of AMD. Optical coherence tomography (OCT) A diagnostic tool that uses an infrared beam of light, a special camera, a video monitor, and a computer to get cross-sectional images of the eye. OCT is similar to ultrasound, except that it uses light rather than sound. Back To Top P Photocoagulation Procedure that uses a thermal ("hot") laser to seal off abnormal, leaky blood vessels in the back of the eye. Used in patients with wet AMD whose area of leakage is small, well defined, and outside the central area of vision. Photodynamic therapy (PDT) Uses light-activated drugs to treat a wide range of medical conditions. Some diseases in which there are fast-growing tissues, abnormal blood vessels included, can potentially be treated with this technology. Photoreceptors Retinal cells that convert light into electrical impulses for transmission of messages to the brain. Porphyria A condition that may involve an abnormal sensitivity to light. Back To Top R Retina Internal layer of the eyeball that contains the nerve necessary for receiving and transmitting visual images. Retinal pigment epithelium Pigment cell layer just outside the retina that feeds the retina’s visual cells. Retinotomy Removal of part of the retina. Back To Top S Subfoveal Beneath the fovea, the central pit in the macula that produces sharpest vision. Back To Top T Thrombus Blood clot that forms inside a blood vessel, sometimes blocking blood flow. Back To Top V Visudyne® (VIZ-u-dine) Visudyne (verteporfin for injection) therapy is a form of photodynamic therapy. It brings together a light-activated drug (Visudyne) and the use of a low-energy laser. The laser activates the drug in a targeted area of the eye. This produces a reaction that destroys abnormal, leaky blood vessels. Back To Top