Age-Related Eye Disease Associated With High Blood Pressure
April 3, 2000 (Cleveland) -- People with high blood pressure -- especially those who are being treated with potent drugs to control the condition -- may be at higher risk of an age-related eye disease that can lead to blindness, a new study says.
The study, published in the March issue of Archives of Ophthalmology, says people with high diastolic blood pressure (the bottom number of a blood pressure reading) should be checked regularly for age-related macular degeneration (AMD).
The macula is an area of the retina, the nerve layer in the back of the eye. Its job is to distinguish details at the center of the field of vision. With age, the macula deteriorates, and the ability to focus clearly decreases. Macular degeneration is the leading cause of blindness in older people. It occurs gradually, and symptoms include difficulty reading and performing other activities that require sharp vision.
There are two forms, one that involves bleeding under the retina and one in which there is damage to the retina without bleeding. The type with bleeding, called neovascular macular degeneration (NV-AMD), is more damaging. Roughly 80% of patients with AMD have the less serious form, although it can lead to the neovascular type.
For this study, Leslie Hyman, PhD, and members of a study group used photographs to classify the eyes of 644 participants and group them according to which form of AMD they had -- neovascular (NV) or non-neovascular (non-NV) -- or into a control group that did not have the disease.
They found that people with the more serious type of AMD were more than four times as likely to have high diastolic blood pressures (greater than 95 mmHg) as those with the less serious type of the disease. The patients with neovascular AMD were more likely to be taking blood pressure medications than those with the less serious type. In addition, neovascular AMD was associated with higher dietary cholesterol intake and increased levels of HDL cholesterol (the so-called "good" cholesterol).
What this means, Hyman says, is that people with moderate to severe high blood pressure should be carefully monitored, whether or not they already have AMD.
"These findings emphasize the importance of careful follow-up in two important, chronic conditions, one that causes [death], the other that causes severe visual loss," says Hyman, an associate professor in the department of preventive medicine at University Medical Center in Stony Brook, N.Y.
"Since some patients with NV-AMD are potentially treatable and vision loss can be delayed; the identification of any high-risk groups is helpful for early detection and treatment," she says.