The results held true even after researchers took into account traditional risk factors for stroke such as smoking and high blood pressure, according to the study published in the October 11, 2005 issue of Neurology, the scientific journal of the American Academy of Neurology.
The study involved 3,654 Australians age 49 and older. Researchers took special photographs of the retina of the eyes of the participants and examined them for changes suggestive of small blood vessel damage, or retinopathy. These small vessel changes can be seen in the early stages of the condition, well before eyesight is affected.
"The blood vessels in the eyes share similar anatomical characteristics and other characteristics with the blood vessels in the brain," said Paul Mitchell, MD, PhD, of the University of Sydney in Australia. "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."
The researchers followed the participants for seven years, tracking which participants had strokes or transient ischemic attacks, also called mini-strokes. For those who died during the study, researchers examined the cause of death to determine whether stroke was involved.
Those with eye blood vessel damage were 70 percent more likely to have a stroke during the study than those without the damage. The risk was higher in those with small vessel signs in the eye but without severe high blood pressure; they were 2.7 times more likely to have a stroke than those without eye signs. The risk was also higher for those with more than one type of blood vessel lesion. (Because diabetes can cause this type of eye damage, these results did not include participants with diabetes, which is also a risk factor for stroke.)
The signs of damage include tiny bulges in the blood vessels, or microaneurysms, and hemorrhages, or tiny blood spots where the microaneurysms leak blood.
The American Academy of Neurology, an association of nearly 19,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, epilepsy, Parkinson's disease, multiple sclerosis, and stroke. For more information about the American Academy of Neurology, visit www.aan.com.
Editor's Note: Stroke affects more than 700,000 people in the United States per year. Nearly 25 percent of people who recover from their first stroke will have another stroke within five years. The warning signs of stroke include:
- Sudden numbness or weakness of face, arm, or leg, especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking, dizziness, loss of balance or coordination
- Sudden severe headache with no known cause