CHICAGO (AP) -- A narrowing of tiny blood vessels in the eye may be a warning sign of heart disease in women.
Some experts said the finding, while still preliminary, may one day help doctors better diagnose heart trouble in women. The connection was not found in men.
The finding came in a study of 9,648 men and women who had three eye exams over six years. Participants were ages 51 to 72. Heart attacks and other serious heart trouble occurred in 84 women and 187 men during the study.
Women with the narrowest arteries and vessels in the retina - the light-sensitive region at the back of the eye - faced nearly double the risk of developing serious heart problems, compared with women with the widest retinal arteries. The risks appeared in women with and without diabetes and high blood pressure, conditions that contribute to heart disease.
No similar increased risk was found in men.
Previous research has linked narrowed retinal arteries with high blood pressure, but the study used specialized digital photographs and measurements to detect much less obvious narrowing than can be seen in standard eye exams, said Dr. A. Richey Sharrett, a co-author and researcher at the National Heart, Lung and Blood Institute.
The results appear in Wednesday's Journal of the American Medical Association.
The study bolsters a theory that narrowing of tiny arteries and vessels - microvascular disease - plays a more prominent role in the development of heart disease in women than in men.
Other research has indicated that women with chest pain are more likely than men to have normal angiograms - imaging tests that show the size of larger arteries - and also fare worse after heart bypass surgery.
"Women are not small men. We're beginning to see investigators think a little bit further about issues of women and heart disease, instead of just applying traditional testing," said Dr. Nieca Goldberg, an American Heart Association spokeswoman.
Sharrett said the findings are too preliminary to warrant making sophisticated eye exams a part of a normal cardiac workup.
But Dr. Lynne Perry-Bottinger, a cardiologist at the New York Hospital Medical Center, said the findings suggest that women whose standard eye exams detect obvious narrowing should be checked for heart disease.
The researchers said the reason for the gender difference in the study is unclear. But Perry-Bottinger speculated that since women's arteries are generally smaller than men's, narrowing in smaller vessels would be more significant in women than in men.