Sunday, January 15, 2006

vision

As an individual ages, light does not reach the retina as readily due to decreased pupil size, loss of lens transparency, and the thickening of the lens and lens capsule. Thus, a 65-year-old needs twice as much illumination to see as does a 20-yearold, and the 75-year-old needs three times as much. If the eyes adapt slowly to changes in illumination, wearing dark glasses until the person just steps into the doorway will enable him or her to overcome this problem. A small pocket flashlight will enable him or her to read restaurant menus or theater programs. If the person has decreased side vision, he or she should turn his or her head further to the right or left, especially when driving or crossing streets. Visual acuity, the ability to see details at a distance, has a more rapid decline in the sixties and seventies. Most elderly people need glasses to correct this loss of vision. When decreased vision occurs, it is helpful to simplify the environment. Suggest that the person discard items that are not needed in cupboards, bookshelves, and closets. Small bright red, pressure-sensitive markers can be put on items that are hard to see and often needed.
Increased far-sightedness, or presbyopia, occurs due to the loss of elasticity of the lens of the eye. If not corrected with eyeglasses, near objects will not be in focus. The lens of the eye also tends to yellow with increasing age, affecting color discrimination. Blue and violets are filtered out and are more difficult to identify than colors at the red end of the color spectrum.
In almost 95 percent of the people over 65 years of age, opacification of the lens, a cataract, occurs. If the cataract causes sufficient visual difficulty to interfere with the patient's lifestyle, it can be removed in a surgical procedure done as an outpatient. The vast majority of patients have an artificial lens implanted at the time of surgery, thus avoiding the difficulties and inadequacies of cataract glasses or contact lenses. Impairments such as macular degeneration, diabetes mellitus, multiple sclerosis, or a stroke greatly affect the eyes. Often, rehabilitative services are needed to enable the patient to cope with the effects of these changes. Low-vision clinics and numerous private and public agencies work with the ophthalmologist and other professionals to assist the visually handicapped. Some aids that are available include lighted magnifiers, large-type print, talking books, as well as assistance in filing for special Social Security benefits and tax benefits.
See also CATARACT; MACULAR DEGENERATION; PRESBYOPIA.
Reichel, W. M. Clinical Aspects of Aging. Baltimore: The Williams & Wilkins Co., 1979.
Steinberg, F. U. Care of the Geriatric Patient, 6th ed. St. Louis: C. V. Mosby Co., 1983.

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