August 13, 2013
Your Eyes May Tell If You Are At Risk For Stroke
April Flowers for redOrbit.com - Your Universe Online
A new study, led by National University of Singapore, shows that your eyes may be a window to stroke risk. More specifically, the research team suggested that retinal imaging may someday help determine if you are more likely to develop a stroke, the nation’s fourth leading cause of disability.
"The retina provides information on the status of blood vessels in the brain," said Mohammad Kamran Ikram, MD, PhD, assistant professor in the Singapore Eye Research Institute, the Department of Ophthalmology and Memory Aging & Cognition Centre, at the National University of Singapore. "Retinal imaging is a non-invasive and cheap way of examining the blood vessels of the retina."
The results of this study were published in a recent issue of Hypertension.
The single most important risk factor for stroke globally is high blood pressure. Yet, doctors still find it impossible to predict which high blood pressure patients are most likely to develop a stroke.
The research team tracked stroke occurrence in 2,907 patients with high blood pressure for an average of 13 years. The patients had not previously experienced stroke before the study. Each participant had photographs taken of the retina at baseline. The retina is the light-sensitive layer of cells at the back of the eyeball. Damage to the blood vessels in the retina attributed to hypertension is called hypertensive retinopathy. Evidence of hypertensive retinopathy in the photographs was scored as “none,” “mild” and “moderate/severe.”
Of all the participants, 146 experienced a stroke during the follow up period caused by a blood clot. Another 15 strokes were caused by bleeding in the brain.
The scientists adjusted their findings for several stroke risk factors, including age, sex, race, cholesterol levels, blood sugar, body mass index, smoking and blood pressure readings. The team found that in patients with mild hypertensive retinopathy, the risk of stroke rose 35 percent. The risk rose 137 percent in those with moderate or severe hypertensive retinopathy.
The risk of a blood clot, even with medication and good blood pressure control, rose 96 percent in those with mild hypertensive retinopathy and 198 percent higher in those with moderate or severe hypertensive retinopathy.
"It is too early to recommend changes in clinical practice," Ikram said. "Other studies need to confirm our findings and examine whether retinal imaging can be useful in providing additional information about stroke risk in people with high blood pressure."