High blood pressure’s effect on the eyes

High blood pressure's effect on the eyes

Q: My ophthalmologist told me that I have early signs of eye
damage that is probably the result of my high blood pressure. I’m
worried about losing my sight. How do I prevent this problem from
becoming worse?
Q: My ophthalmologist told me that I have early signs of eye damage that is probably the result of my high blood pressure. I’m worried about losing my sight. How do I prevent this problem from becoming worse?

A: High blood pressure can narrow the small arteries in the retina, the light-sensitive tissue that lines the back of the inside of the eye. Your doctor can see the narrowed arteries during an eye exam. Although the changes usually don’t disturb vision, they are an early warning sign – one you can do something about.

Very high blood pressure for long periods or brief spikes of super-high pressure can force arteries in the retina to balloon out and leak. The narrowed vessels can also block veins in the retina and create areas of dead or dying tissue caused by lack of blood flow. These areas appear as fluffy white “cotton wool” spots. Another possible result is swelling of the optic nerve, the nerve that sends visual signals from the eye to the brain. These more drastic changes can interfere with vision. The changes are called hypertensive retinopathy (ret-in-OP-ethy).

The changes your eye doctor saw indicate that high blood pressure threatens your health in two ways. Besides putting your vision at risk, the changes seen in your eyes indicate that other key organs are also at risk.

Four large studies that included almost 20,000 volunteers have shown that people with changes in their retinal blood vessels are two to four times as likely to have a stroke as those without such changes. Other studies have found that people with hypertensive retinopathy have double the risk of having a heart attack, as well as a higher risk of heart failure.

If you have diabetes, you could be at risk of losing your vision because the combination of uncontrolled high blood pressure and diabetes can be especially damaging to your eyes. Diabetes is one of the leading causes of vision loss and blindness among Americans. Like high blood pressure, diabetes damages blood vessels, especially small ones in the eyes and kidneys. These damaged vessels leak blood and fluid into the center of the eye, blurring vision. The damage releases growth factors that cause new blood vessels to grow on the surface of the retina or optic nerve. This new growth can cause further bleeding and may seriously increase pressure inside the eye if the new blood vessels grow in the front of the eye where fluid usually drains.

What can you do about hypertensive retinopathy? You and your doctor need to work hard to be sure your blood pressure is adequately treated, with both medicines and lifestyle changes. With modern medicines, blood pressure can almost always be controlled. Controlling your blood pressure is especially important if you have heart disease, atherosclerosis of the arteries to the brain, or diabetes.

And if you also have diabetes, you and your doctor need to work hard to control your blood sugar. Again, with modern medicines and lifestyle changes, this is almost always possible.

If you suffer eye damage from uncontrolled high blood pressure or high blood sugar, laser treatment and surgery often can reduce vision loss. People with diabetes should have yearly eye exams. And while there are no specific guidelines for eye exams in people with high blood pressure, having your eyes checked regularly is a good idea. That’s especially true if you have trouble keeping your blood pressure in check or have a ministroke or stroke, or if you have trouble seeing.

Submit questions to the Harvard Medical School Adviser at www.health.harvard.edu/adviser.

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