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Photograph by Paul Myers
Light Sensitive: Ruth Brunner sits under a halogen lamp at her home in Saratoga. Brunner suffers from age-related macular degeneration, an eye condition that impairs vision. The halogen lamps help to correct the condition, allowing Brunner to read, cook and work at her desk.
Seeing straight can fall victim to age-related macular degeneration
By Rita Baum
Ruth Brunner was pleased that her driver's license was renewed earlier this year. The Saratoga resident has age-related macular degeneration, also known as AMD, an eye condition that impairs central vision and can interfere with driving and other activities of daily living.
Prior to renewing her driver's license, a physician specializing in low vision prescribed two new pairs of glasses for Ruth, one for driving and one for reading. She believes that the new glasses helped her get through the written test with a 100 percent score. Because she did poorly on the vision component, however, Ruth had to take the behind-the-wheel test, and her new glasses helped her pass it handily. Nevertheless, because of her vision deficit, Ruth was issued a restricted driver's license that prohibits her from driving at night or on freeways.
Ruth is not alone: Up to one-fourth of people over age 65 and one-third of those over age 80 have some signs of age-related macular degeneration. It is the leading cause of central vision loss in older adults and a major cause of visual impairment in persons age 90 and older, but total loss of vision is rare. Since AMD affects central, or straight-ahead vision, reading normal-size print--especially in low light--driving and watching television are hampered. Side vision is not affected.
The condition was once called senile macular degeneration, probably because the eye condition is virtually unknown in individuals under the age of 60. The word "macula" is from Latin, meaning "spot." This tiny spot in the middle of the retina, at the back of the eyeball, is the most light-sensitive part of the eye and responsible for central vision, which involves the ability to perceive sharp, detailed images.
Age-related macular degeneration occurs in two forms: dry and wet. About 90 percent of those with the disease have the dry form, in which the light-sensitive cells in the macula slowly deteriorate over the years, damaging and causing a slow thinning of the macular tissue. If any part of the macula deteriorates, central vision is compromised, and eventually the eye must rely on the outer portion of the retina. More often than not, the disease forms in the other eye, but if one eye is seeing clearly, central vision loss may not be noticed. There is no treatment for the less-serious, dry form of AMD, which progresses slowly and rarely causes blindness. Patients, however, are monitored for possible development of the more serious wet form and are apprised of factors that may slow the progression of the disease. The most common symptom of dry AMD is slightly blurred vision. More light may be needed for close work and reading, and faces may not be recognizable until seen at very close range. As dry AMD gets worse, a blurred spot is seen at or near the center of vision. Some words or letters on a page may be blurred. There is a dimming or graying of colors, and objects may seem smaller. Over time, the blurred spot may get bigger and darker, involving more of central vision. Neither dry nor wet AMD causes any pain, and there is no cure for either form.
Fighting Blindness: Resources for age-related macular degeneration.
Approximately 10 percent of people with the disease have the more serious wet form, which causes the most dramatic and severe vision loss. This type occurs when new blood vessels grow in the macular region behind the retina. According to San Jose ophthalmologist Dr. John Sullivan, these abnormal blood vessels almost always leak or bleed, causing rapid, irreversible damage to central vision. If the wet form develops in one eye, there is a good chance the other eye will eventually become affected. Early symptoms for wet AMD include seeing a wavy line in place of a straight one, developing a blind spot or rapid loss of central vision. Side vision is not affected. If any of these changes are noticed, an ophthalmologist should be seen immediately. Delaying treatment by only a few days may result in a profound reduction in the effectiveness of therapy, says Sullivan.
For treatment of wet AMD, new therapies, surgeries and drugs show promise of not only halting the abnormal growth of blood vessels, but restoration of vision in some cases. The most exciting and useful new treatment is photodynamic therapy with verteporfin, a procedure covered by Medicare, which involves injecting an intravenous dye that absorbs low intensity laser irradiation and destroys only the abnormal blood vessels. Other methods include conventional laser surgery, low-dose radiation and other innovative ideas and procedures that are under investigation for their potential to stop the progression of wet AMD.
The laser has replaced conventional techniques for many surgical eye procedures in modern eye care. A laser beam can be focused on a spot as small as one-millionth of a meter, the power controlled to one-thousandth of a watt, and the exposure time to one-billionth of a second. Laser surgery often does not require hospitalization or anesthesia.
The cause of AMD is unknown. The biggest risk factors are advanced age and a family history of the disease. Other risk factors include light-colored eyes, farsighted vision, smoking and excessive exposure to sunlight. Recent research has identified a possible genetic link to AMD as well. Females are more susceptible than males.
A physician can test for AMD during a routine eye exam. This includes: a visual acuity test (which measures vision at various distances); dilation of the pupils to give the physician a better look at the retina; and viewing of an Amsler grid, a line pattern on a sheet of paper that resembles graph paper with a dot in the center. If the lines in either direction look wavy or are missing, and the dot looks like an uneven splotch, this may be an indication of AMD. If the doctor suspects the wet form of AMD, the patient may need a test called fluorescein angiography, which enables the doctor to check for fluid deposits or leaking blood vessels in the macular area.
There is no cure for AMD, but the National Eye Institute is funding a number of experimental research studies to find out what causes the disease, including a study that evaluates the effects of vitamins and minerals as they influence vision.
Antioxidants vitamins A, C and E may protect tissue against oxidation damage. Studies have demonstrated that high levels of the carotenoids lutein and zeaxanthin in the blood reduce the likelihood of macular degeneration. In fact, these nutrients found in leafy greens and bright-colored fruits and vegetables, have been shown to promote good overall health. Egg yolks also supply a plentiful amount of carotenoids, and according to the American Heart Association, it is safe for people who have normal cholesterol levels to consume up to four eggs a week.
The bottom line: Don't lose sight of the good things in life. Pay attention to all vision changes, no matter how subtle, and have regular eye exams for early detection.
This article is not intended to provide medical advice, which should be obtained directly from a physician. Rita Baum has a master's degree in gerontology and has worked in the field of aging for more than 20 years.
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Campbell, California
