Glossary of Terms: Blindness and Visual Impairments

Access Technology — Various computers and other equipment that bridge the gap created by loss of sight.

Age-Related Macular Degeneration (AMD)—The leading cause of vision loss in people age 65 and older. It can be part of the body's natural aging process or it may be inherited. It is caused by damage to the macula, the small part of the retina that gives sharp, straight-on vision. It may cause blurred, distorted vision, often with large blank spots in the central area of sight. The two common types of macular degeneration are Wet AMD and Dry AMD. Very rarely does the disease cause total loss of sight.

Braille—A system of reading by touch developed in 1829 by Louis Braille. There are approximately 252 characters and word signs in braille. These signs are created by arrangements of one to six raised dots within a cell. Different arrangements of the dots indicate letters, numbers and punctuation. There are three grades, ranked according to the degree of contraction used.

Braille, Louis —A French scholar and teacher, blinded as a child, who developed the system of touch reading and writing, used today by an estimated 10 percent of all blind people.

Cataract—A clouding of the lens of the eye. It is estimated that 95 percent of those over 65 years of age have some degree of cataract that may or may not cause blurring of vision. If a cataract begins to cause vision loss that interferes with important activities, it can easily be surgically removed and an artificial lens implanted. This usually results in a great improvement of vision.

Diabetic Retinopathy—Associated with diabetes and is caused by the breakage of tiny blood vessels in the retina, resulting in hemorrhages on or in the retina. Untreated diabetes or poor disease maintenance greatly increase the risk of diabetic retinopathy. Depending on the severity of the disease, sight can remain near normal or can be lost entirely. Remaining vision may be blurred or distorted or the hemorrhaging may cause a deep reddish veil to form over the field of vision. Laser surgery often is effective, but the patient must cooperate by managing the diabetes through medication, diet, exercise and frequent monitoring of blood sugar.

Glaucoma—A condition in which the fluid pressure inside the eye is too high, causing damage to the optic nerve. If left untreated, vision around the edge of the eye becomes increasingly restricted, narrowing the field of vision. Eventually, total blindness can occur. If detected early enough, the damaging affects of the disease often can be treated with various drugs. Laser or conventional surgery often can relieve pressure and prevent further sight loss.

ILS (Independent Living Skills)— Class instruction to help those with sight loss develop the skills needed for everyday living, either alone or with others. Topics include identifying money, cooking safely, personal grooming and getting around town effectively.

Legal Blindness—A person is legally blind if their central vision acuity is 20/200 or less in the better eye, even with corrective lenses; or if they have central vision acuity of more than 20/200 if the peripheral field is restricted to a diameter of 20 degrees or less. Informally, those who, even with corrective lenses, cannot read the biggest letter on an eye chart are considered to be legally blind.

Library Services—Many who are blind or visually impaired—or who have reading or other physical disabilities—often cannot use printed materials, depriving them of reading materials that most take for granted. Braille Institute's Library Services—the Southern California branch of the National Library Service (NLS), provides free books, periodicals and other texts in braille and recorded formats. Patrons can select from more than 88,000 titles and 1.4 million volumes accessible from the Library's collection.

Low Vision—A visual impairment that cannot be corrected by standard eyeglasses, contact lenses, medication, or surgery, that interferes with the ability to perform everyday activities. Macular degeneration, diabetic retinopathy, glaucoma, and retinitis pigmentosa, along with many other eye diseases, are causes of visual impairment or low vision.

Low Vision Aids—Prescription and nonprescription devices that help people with low vision enhance their remaining vision. Some examples include special low vision eye glasses, telescopic lenses for driving and other distance tasks, microscopic reading glasses, magnifiers, CCTV’s (Electronic Reading Machines), large print books, check-writing guides and white canes.

Low Vision Rehabilitation Consultation—People whose vision cannot be corrected with prescription lenses often can improve their remaining sight through other techniques such as special lighting or non-prescription magnification equipment. Braille Institute provides free one-on-one consultations with Low Vision Rehabilitation specialists who determine the correct devices for your degree of vision loss. The consultants also provide demonstrations and recommendations of various assistive devices such as special lamps, nonprescription magnifiers, closed-circuit televisions (CCTVs) and other visual aids.

Macula—The tiny region of the central retina that is responsible for sharpest straight-ahead vision.

Mainstreaming—The term used by educators to designate inclusion of children who are blind or visually impaired into classrooms with sighted children.

Ophthalmologist—A medical doctor who specializes in eye and vision care. They are specially trained to provide the full spectrum of eye care, from prescribing glasses and contact lenses to complex and delicate eye surgery.

Optometrist—Doctors of optometry (ODs) are primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the eye. They prescribe glasses, contact lenses and low vision aids.

Orientation and Mobility Specialist—A person who trains people with low vision to move about safely in the home and travel by themselves.

Retina—Light-sensitive tissue at the back of the eye that transmits visual impulses to the brain via the optic nerve. It is composed of sensory elements called rods and cones that are responsible for the details, color and perspective of vision.

Retinopathy of Prematurity (ROP)—A disease of infants, usually premature ones, in which excess oxygen in their incubators causes damage or destruction of the blood vessels in the retina.

Retinitis Pigmentosa—A hereditary condition leading to chronic retinal degeneration, accompanied by abnormal deposits of pigment. The disease causes a progressive decrease in peripheral or side vision. Eventually, a person with retinitis pigmentosa can see only directly ahead, a condition known as "tunnel vision." Night vision also can be affected as can the ability to walk safely. Very rarely does the disease cause total loss of sight.

Sighted Guide Techniques—Family members and friends learn appropriate ways to help guide a blind person while in public or unfamiliar areas.

Sound Solutions—Sound Solutions is a first-of-its kind audiocassette series that presents practical information, resources and encouragement for people who are experiencing sight loss. The professional tape series uses creative scripts, testimonials, sound effects, music and humor. They are enjoyable, inspirational, practical and free.

Telephone Reader Program (TRP)—Braille Institute’s award-winning Telephone Reader Program is a free program that allows patrons to use their touch-tone telephones to listen to national and local news as well as grocery and department store ads in both English and Spanish.

Vistas Store—Braille Institute’s Vistas retail stores offer many devices that help make everyday tasks easier for people with diminished vision, such as signature guides, magnifiers, talking clocks and watches, large-print and braille games and books, kitchen aids, brailled greeting cards and much more.