Seeing Stroke Through the Eyes

Stroke risk among patients with high blood pressure may be predicted by retina imaging

(RxWiki News) Looking deep into a person’s eyes may hold clues about his or her cardiovascular health. Retinal imaging could become a tool for predicting which patients may have a stroke.

Managing high blood pressure (hypertension) is the single most important thing an individual can do to lessen stroke risk, according to the American Heart Association. Some patients with high blood pressure, however, may be more susceptible to stroke than others.

Scientists have recently discovered that a technique for imaging the eyes may be able to predict which hypertensive patients are more likely to suffer a stroke.

"Lower high blood pressure to decrease stroke risk."

Mohammad Kamran Ikram, MD, assistant professor in the Singapore Eye Research Institute, the Department of Ophthalmology and Memory Aging & Cognition Centre, at the National University of Singapore, collaborated on this study following 2,907 patients with high blood pressure who had not had a stroke before.

Dr. Ikram and colleagues tracked stroke occurrence among these participants over the course of 13 years.

At the beginning of the study, the researchers took photographs of the retina, the light-sensitive layer of cells at the back of the eyeball.

High blood pressure can damage blood vessels in the retina. When the scientists imaged patients' eyes, they evaluated any damage to blood vessels (called hypertensive retinopathy) as none, mild or moderate/severe.

Dr. Ikram told dailyRx News that generalized narrowing of the arteriole (small blood vessel) in the retina is a feature of mild hypertensive retinopathy. More severe lesions, such as small bleedings in the retina, are signs of moderate to severe hypertensive retinopathy.

As the study progressed, 146 participants had a stroke caused by a blood clot and 15 by bleeding in the brain.

After accounting for other possible risk factors, the researchers found that the chance of stroke was 35 percent greater in those with mild hypertensive retinopathy and 137 percent higher in those with moderate or severe hypertensive retinopathy.

The study authors noted that patients who were on medication and kept their blood pressure under control still had a high risk of stroke if they already had retinal blood vessel damage. In these individuals, the risk of a blood clot was 96 percent higher in those with mild hypertensive retinopathy and 198 percent higher in those with moderate or severe hypertensive retinopathy.

Christopher Quinn, OD, president at Omni Eye Services in Iselin, New Jersey, and a member of the medical staff at Robert Wood Johnson University Hospital, told dailyRx News, “Eye doctors have known for some time that important cardiovascular risks could be unveiled during the course of eye examination and this study serves to confirm that changes observed in the eye can be a harbinger of important health events such as stroke.”

He added that the most sensitive form of “retinal imaging” remains the observation of the retinal vasculature obtained during an examination by an experienced eye doctor who can easily detect the earliest stages of hypertensive retinopathy.

“Retinal photography and newer forms of retinal imaging can supplement the direct examination of the retina and may have a role in helping doctors identify those patients at greatest risk,” said Dr. Quinn.

Dr. Ikram said that retinal imaging may be an inexpensive and non-invasive way to assess risk, but at this stage it is too early to recommend changes in clinical practice.

He told dailyRx News, “Other studies need to confirm our findings and show that retinal imaging provides additional information on predicting the risk of stroke in persons with a high blood pressure.”

This study was published August 12 in the American Heart Association journal Hypertension. The National Heart, Lung, and Blood Institute funded the study.

Review Date: 
August 13, 2013