Glossary of Terms
Age-Related Macular Degeneration (AMD) — is a condition that primarily affects the part of the retina responsible for sharp central vision. It does not cause total blindness. There are two forms of AMD — dry AMD and wet AMD. Because AMD often damages central vision, it is the most common cause of legal blindness and vision impairment in older Americans (AMD rarely affects those under the age of 60). While there is no generally accepted treatment for dry AMD, laser therapies or injectable medications can help destroy leaking blood vessels can help reduce the risk of advancing vision loss in many cases of wet AMD. Research sponsored by the National Eye Institute has recently shown that a combination of zinc, vitamins C and E, and beta-carotene may also reduce the risk of advanced AMD by 25 percent.
Cataract — is a clouding of the eye’s naturally clear lens. Most cataracts appear with advancing age. The most important factor in cataract formation is increasing age, but there are additional factors, including smoking, diabetes, and excessive exposure to sunlight. Cataract is the leading cause of blindness in the world, and affects nearly 20.5 million Americans age 40 and older. By age 80, more than half of all Americans develop cataract. Cataract is sometimes considered a conquered disease because surgical treatment that can eliminate vision loss due to the disease is widely available. The cataract is removed surgically and a plastic lens, called an implant, is placed in the eye restoring normal sight.
Diabetic Retinopathy — is a common complication of diabetes. Retinal blood vessels can break down, leak, or become blocked, affecting and impairing vision over time. Nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime, and risk increases with age and duration of diabetes. People with diabetes are encouraged to seek annual dilated eye exams. Currently, laser surgery and a procedure called a vitrectomy are highly effective in treating diabetic retinopathy. Glaucoma — is a disease that causes gradual damage to the optic nerve that carries visual information from the eye to the brain. The loss of vision is not experienced until a significant amount of nerve damage has occurred. For this reason, as many as half of all people with glaucoma are unaware of their disease. About 2.2 million Americans age 40 and older have been diagnosed with glaucoma, and another two million do not know they have it. Most cases of glaucoma can be controlled by medication or surgery and vision loss slowed or halted by timely diagnosis and treatment. However, any vision lost to glaucoma cannot be restored.
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. Most people begin to experience difficulty with daily activities such as reading when their vision reaches 20/60 or worse and should seek out the care of a low vision specialist.
Legal Blindness — In the United States, where normal vision is considered to be 20/20, legal blindness is defined as visual acuity with best correction in the better eye worse than or equal to 20/200 or a visual field extent of less than 20 degrees in diameter. Most states use these standards to provide rehabilitation services and benefits to people who are visually impaired. Some of these benefits and services include an IRS income tax exemption, free telephone directory assistance, free Talking Book Library Services through the National Library Service and Vocational and Independent Living Services through individual state programs. Please note the term Legal Blindness does not mean that a legally blind person is blind or has no usable vision. Most people defined as legally blind have usable vision and can perform most daily tasks with the use of special glasses or low vision aids.
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. All optical low vision aids, including eyeglasses, magnifiers and telescopes, should be prescribed by either an optometrist or ophthalmologist to ensure the correct power and success of the patient.
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.
Ophthalmologist — An ophthalmologist is a medical doctor who specializes in eye and vision care. Eye M.D.’s are specially trained to provide the full spectrum of eye care, from prescribing glasses and contact lenses to complex and delicate eye surgery.
Specialist in Low Vision Rehabilitation — An optometrist or ophthalmologist who specializes in the evaluation and management of low vision rehabilitation. These doctors help their patients enhance their remaining vision with special low vision eyeglasses and microscopic and telescopic low vision aids. The doctors will also prescribe other optical and nonoptical low visions aids as well as appropriate low vision services. They help their patients perform their daily activities despite a visual impairment so that they can enjoy life and remain independent. A doctor who specializes in low vision rehabilitation does not take the place of your current optometrist or ophthalmologist. They will work in conjunction with your eye doctor to maximize your remaining vision.
Optician — A trained professional who grinds, fits, and dispenses glasses by prescription from an optometrist or ophthalmologist.
Occupational Therapist — Occupational therapists are skilled professionals who help individuals achieve independence. They can provide treatment only with the prescription of a medical doctor or a doctor of optometry. Occupational therapists who specialize in low vision rehabilitation train their clients to use optical and non-optical devices, adaptive techniques and educate in community resources.
Orientation and Mobility Specialist — A person who trains people with low vision to move about safely in the home and travel by themselves.
Vision Rehabilitation Teacher — A person who trains people with low vision to use optical and non-optical devices, adaptive techniques, and community resources.
