Researchers at the University of Zurich have discovered the test called ocular pulse amplitude (OPA) can reliably detect carotid artery stenosis (CAS), a condition that clogs or blocks the arteries that feed the front part of the brain. It’s a known risk factor for stroke.
The researchers used a dynamic contour tonometer to check the OPA of 67 patients who were assumed to have CAS. They calculated the OPA score by finding the difference between the two pressure levels that occur inside the eye during the two phases of the heartbeat – the systolic and diastolic. When blood flow to the eye is blocked by CAS, there is not much difference between the two pressure levels, so the OPA score is low.
The study confirmed that patients with the lowest OPA scores also had the most seriously blocked arteries. The researchers used ultrasound exams to corroborate that each study participant had CAS and to detail the severity of his or her blockage.
The study was published in the June issue of Ophthalmology.
