Advanced macular degeneration - The loss of central vision in one or both eyes resulting from the destruction of photoreceptor cells in the macular region of the retina.
Amsler grid - A grid of straight lines resembling graph paper. A dot is printed in the center of the grid. An Amsler grid is used to test for the onset of, and progression of macular degeneration.
Antiangiogenesis - The term for one area being studied as a way to halt the growth of abnormal blood vessels (angiogenesis) in the macula that results in macular degeneration.
Antioxidants - Substances that absorb free-radical particles in the body. Damage from free-radicals is thought to lead to macular degeneration and a host of other conditions.
Atrophic macular degeneration - Characterized as "dry" AMD, it is a less aggressive and less damaging form of macular degeneration, developing slowly in the beginning.
Beta-carotene - A member of the carotenoid family of vitamins found in vegetables, such as carrots. Beta-carotene may be beneficial to eye health.
Cataract - A clouding of the lens of the eye, causing slow, progressive degradation of vision.
Central vision - That part of your vision that shows you what is directly in front of you.
Choroidal neovascularization - Characterized as "wet" AMD. It is caused when abnormal blood vessels form in the macula, and leak blood and fluids into the retina.
Cones - Light-sensitive retinal cells. They permit sharp vision in bright light and are responsible for color discrimination.
Cornea - The clear outer portion of the eye that covers the iris and allows light through the pupil.
Disciform macular degeneration - A large, scarred area in the center of the retina.
Drusen - Yellowish spots, or deposits, that form beneath the retina that are precursors of macular degeneration.
Exudative macular degeneration - Another name for wet macular degeneration.
Fluorescein angiogram - A procedure that allows visualization of retinal and choroidal vessels and abnormalities such as neovascularization.
Functional vision - Defines the ability of a visually impaired person to use their remaining vision.
Hemorrhagic macular degeneration - Wet AMD that involves bleeding in the retina.
Hyperopia - Farsightedness.
Indocyanine green angiography (ICG) - A procedure similar to a fluorescein angiogram, used to further diagnose wet AMD.
Laser therapy - A procedure in which a laser is used to seal leaking blood vessels in the retina. Scarring and blind spots are often side effects of the procedure.
Legal blindness - Having worse than 20/200 vision in your best eye with vision correction, or a field of view of 20 degrees or less.
Lens - A clear structure behind the pupil that adjusts the focus of light onto the retina.
Low vision - A visual impairment not corrected by standard eyeglasses, contact lenses, medication, or surgery that interferes with the ability to perform everyday tasks.
Lutein - A carotenoid that is found in the lens and retina, primarily in the macula. This important antioxidant acts as a blue-light filter.
Macula - That part of the retina that is responsible for central vision and seeing fine detail.
Myopia - Nearsightedness.
Ocular - Of, or, pertaining to the eye.
Ophthalmologist - A doctor who is trained in eye and vision care, and can prescribe all types of treatment from glasses to surgery.
Optical devices - Prescription and non-prescription devices that help people with low vision enhance their remaining vision.
Optometrist - A doctor of optometry who examines, diagnoses, treats, and manages diseases and disorders of the eye.
Oxidation - A chemical reaction that occurs in the body, releasing free-radical particles that can be damaging to different tissues in the body, especially to the eyes.
Partially sighted - Someone with a significant reduction in visual function that cannot be corrected to the ordinary range by ordinary means.
Peripheral vision - Your side or off-center vision.
Photoreceptors - The rods and cones of the retina that absorb light and generate vision.
Pupil - The opening in the iris that lets light into the eye and onto the retina.
Retina - The layer of tissue that lines the inside of the eye and receives the image formed by the lens.
Retinal specialist - An ophthalmologist specializing in diseases of the retina.
Rods - Retinal cells shaped like rods that allow for dim-light and peripheral vision.
Scotoma - A blind spot, which may occur in one's central vision.
Senile macular degeneration - Another commonly used term for age-related macular degeneration.
Stargardt disease - A hereditary form of macular degeneration found in younger people. It is sometimes called juvenile macular degeneration.
Subretinal neovascularization - The growth of abnormal blood vessels under the retina that occurs with wet AMD.
Supplements - Vitamin and mineral products that augment the levels of certain beneficial substances in your diet.
Visual acuity - The ability of the eye to identify objects. It is represented as a fraction, such as 20/20, 20/100, etc.
Visual disability - A condition in which a person lacks enough vision to perform certain tasks.
Vitreous - The clear gel that fills the rear portion of the eyeball, between the lens and the retina.
Zeaxanthin - A carotenoid found in fruits and vegetables. Zeaxanthin concentrates in the macula where it protects against blue light and oxidative damage.