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Eyes may be known as the window to the soul, but a new study suggests they may also provide a porthole to the brain and reveal future stroke risk.

Researchers found people with changes in the small blood vessels in their eyes were more likely to suffer a stroke than people without these changes, even after accounting for traditional stroke risk factors like high blood pressure and smoking.

"The blood vessels in the eyes share similar anatomical characteristics and other characteristics with the blood vessels in the brain," says researcher Paul Mitchell, MD, PhD, of the University of Sydney in Australia, in a news release. "More research needs to be done to confirm these results, but it's exciting to think that this fairly simple procedure could help us predict whether someone will be more likely to have a stroke several years later."

Strokes occur when a blood vessel leading to the brain bursts or becomes blocked by a blood clot, resulting in damage to the affected area of the brain.

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Eyes May Reveal Stroke Risk

In the study, which appears in the journal Neurology, researchers examined the relationship between changes in the blood vessels in the eyes and the risk of stroke in more than 3,500 Australian adults age 49 and over.

Researchers took special photographs of the retina of the eyes of the participants at the start of the study and followed them for five years. During the follow-up period researchers noted any changes in the retina suggestive of small blood vessel damage, known as retinopathy.

Because diabetes can also cause this type of blood vessel damage in the eyes, people with diabetes were excluded from the study.

The results showed that people with evidence of blood vessel damage in the eyes were 70 percent more likely to have a stroke during the study than those without such damage.

In addition, the risk of stroke was nearly three times higher in people who had small blood vessel damage in the eye but did not have severe high blood pressure, a common risk factor for stroke.

Finally, researchers found that the risk of stroke was higher in people who had more than one type of blood vessel damage.

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By Jennifer Warner, reviewed by Louise Chang, MD

SOURCES: Mitchell, P. Neurology, Oct. 11, 2005; vol 65; pp 1005-1009. News release, American Academy of Neurology.