When Dr. William White shines a bright light in his patient's eye, he's looking for more than just vision problems.
He's searching for clues indicating the effects of high blood pressure, or hypertension, and what he finds could help prevent heart attacks, strokes and other serious health problems far beyond the eye.
"We can see changes due to vascular conditions caused by diabetes or hypertension," said White, an optometrist with Baylor Scott & White Health in Temple, Texas. "The blood vessels in the retina can become a little more stiff and hardened. They'll push on each other and cross, like two hoses in a confined space.
"When it gets really bad, we'll see some of the blood vessels start to leak, we'll see some hemorrhaging. And that can cause a whole range of vision issues."
Vision symptoms may not show up for years. But ultimately, high blood pressure can result in hypertensive retinopathy, blood vessel damage causing blurred vision or loss of sight; choroidopathy, a buildup of fluid under the retina that can distort or impair vision; or optic neuropathy, a blood flow blockage that can kill nerve cells and cause vision loss.
Similarly, high blood pressure may not reveal itself for decades before causing a heart attack or stroke, which earns its grim description as the "silent killer."
That is why detecting high blood pressure early – and treating it with diet, exercise and medication – is crucial, and why White says eye doctors are on the front lines of the battle.
"Sometimes people will say, 'I'm just here to get my glasses. Why are you checking my blood pressure?'" he said. "We try to inform them about the unique opportunity we have to look at these blood vessels in the eye."
A 2013 study reported in the journal Hypertension underscored the point. Researchers checked about 2,900 patients with high blood pressure for hypertensive retinopathy, then tracked them for an average of 13 years. They found that those with a mild form of the condition had a 35 percent greater risk of stroke. That increased risk leaped to 137 percent for those with moderate or severe hypertensive retinopathy.
Although more research is needed to confirm the findings regarding stroke risk, White has no doubt about the crucial role of eye doctors to educate patients about the need to control blood pressure.
"You're not just a pair of eyeballs walking into an exam room," he said. "We have to look at the entire person and the whole picture. These are things that can impact their lives significantly, and we have a responsibility for their overall health."
But doesn't every medical checkup start with a blood pressure check? And doesn't every pharmacy have a machine to measure it yourself?
White said many people would be surprised how many of his patients rarely see another doctor, or if they do, don't always follow medical advice or don't take their blood pressure medication.
"Some people don't go for a routine checkup every year," he said. "They tell me, 'Look, I just don't like going to the doctor.' But their eyes are a problem, so they'll come to us."
Knowing the risks of high blood pressure, White said, keeps him vigilant.
"It's so important because of the silent nature of this problem," he said. "People can feel absolutely fine, but high blood pressure has a cumulative effect. If it's uncontrolled over years, it's going to cause damage later in life."
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