June 8, 2012
Future Eye Exams Can Possibly Prevent Strokes
Connie K. Ho for redOrbit.com
Head to toe. Top to bottom. Full body heath begins with the eyes. A recent study backs this theory and shows that an eye test could help doctors diagnose a stroke before it happens, which would help save lives. Researchers at the University of Zurich reported that a simple eye test could possibly in the future alert patients who are at risk for having a stroke.
The ocular pulse amplitude (OPA) is an exam that can help detect carotid artery stenosis (CAS), which clogs or blocks arteries from supporting the front part of the brain; this can lead to a stroke. An ophthalmologist could do the OPA test during routine visits. The findings, published in the June issue of Ophthalmology, show that those who had the lowest OPA scores ended up also having the most clogged arteries.
The research team utilized the dynamic contour tonometer, which can check the OPA of patients. 67 patients, who were thought to have CAS, were checked with the device. To find the OPA score, the difference between the two pressure levels were calculated; the occurring levels were the diastolic and systolic phases. The tonometer measures these two pressure levels, then determines the patient´s OPA score. The project found that patients who demonstrated the lowest OPA score had arteries that were the most seriously blocked. The researchers utilized ultrasound studies to double check that each patient had CAS and to look at the severity of the patient´s blockage.
"Our results show that ocular pulse amplitude is a reliable, safe screening test for carotid artery stenosis," commented lead researcher Dr. Pascal Bruno Knecht in a prepared statement. "We recommend further study to confirm the value of using OPA to detect and assess the severity of CAS and to define its use in stroke prevention."
These results are beneficial in understanding patient progress, as more and more people report strokes. Every year, around 795,000 Americans report new or recurrent strokes; of that number, over 137,000 of the people die as a result of the stroke. Furthermore, those who have severe CAS have a higher risk of suffering a stroke. However, there is currently no knowledge on the symptoms of CAS or a test that can detect the disease. As a result, it is difficult for physicians to anticipate CAS before it is diagnosed.
The U.S. Preventive Services Task Force also indicated during a research review that, if there was an effective screening test for CAS, then the number of strokes and fatalities due to strokes could be decreased. The review detailed that tests should be able to track significant CAS, which is 60 percent to 99 percent of blockage in carotid arteries. At this time, high-tech tests, like magnetic angiography and color duplex ultrasound, are available but they are expensive and not commonly used. These tests are used to help identify CAS in patients who have already shown symptoms of stroke.
The researchers believe that, apart from CAS, few diseases can have low OPA scores. During an eye exam, an ophthalmologist could determine if other diseases were significant or not significant for the patient. As well, it would be useful to perform the OPA test during a regular eye exam in the future. Ophthalmologists already use the tonometer to diagnose glaucoma.