ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Wednesday, October 9, 1996 TAG: 9610090050
SECTION: NATIONAL/INTERNATIONAL PAGE: A-2 EDITION: METRO
DATELINE: CHICAGO
SOURCE: Associated Press
New research gives smokers one more reason to quit: Pack-a-day-or-more puffers double their likelihood of developing the most common cause of blindness among the elderly.
Age-related macular degeneration, a usually untreatable affliction, impairs the vision of an estimated 1.7 million Americans, according to the government.
Smoking already is blamed for promoting cataracts. Cataracts threaten the vision of far more people than macular degeneration but cause much less blindness because most cataract sufferers keep their sight with treatment.
The more people smoke and the longer they smoke, the higher their risk of developing macular degeneration, according to two studies in today's issue of The Journal of the American Medical Association.
``It is another reason to either not smoke, quit smoking or reduce your amount of smoking,'' said Dr. Johanna M. Seddon of the Massachusetts Eye and Ear Infirmary and Harvard Medical School.
Years after quitting, former smokers still faced up to double the risk of getting the condition, the new research found.
``Since the risks decrease very slowly - if at all - over time, it's even perhaps of greater importance not to start in the first place,'' said Dr. William G. Christen of Harvard-affiliated Brigham and Women's Hospital.
In advanced macular degeneration, which affects one of every 14 people age 75 or older, the center of the visual field deteriorates, causing a roughly circular area of blindness that grows larger gradually.
The deterioration is caused by damage to the macula, the center of the retina. The damage occurs when an insulating layer between the retina and blood vessels that nourish it breaks down.
Smoking may speed the process by increasing the number of damaging chemical compounds or reducing the number of protective nutrients delivered by the bloodstream to the eye, researchers speculate. Another theory is that smoking reduces blood and oxygen to the eye.
Seddon led researchers who looked for macular degeneration among 31,843 initially healthy women during a 12-year period beginning in 1980 in the ongoing Nurses' Health Study.
In 215 cases that developed, the disease caused vision loss; almost one-third of those cases were attributable to smoking, researchers said.
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