It had been thought that because hypertension ensures that blood can enter the eye, it could counteract the high eye pressure that causes glaucoma. However, this study of short-term (one hour) and long-term (four weeks) hypertension in rats with elevated eye pressure indicates that chronic hypertension increases the risk of glaucoma.
“When we raised blood pressure…for four weeks, we didn’t get the same protection against eye pressure elevation as in the [one-hour] case,” study author Bang Bui, PhD, from the department of optometry and vision sciences at the University of Melbourne in Australia, said in a journal news release. “What this means is that having high blood pressure for a longer time has compromised the eye’s capacity to cope with high eye pressure,” Bui explained. “It seems that hypertension might damage the blood vessels in the eye so that they can’t compensate for changes in blood flow when eye pressure increases.”
These findings may help doctors treat people with glaucoma. Instead of regarding hypertension as benefiting patients with the eye disease, it should be considered a risk factor for glaucoma, Bui said. Further research is needed to determine the best way to treat people with hypertension who also develop glaucoma, according to the researchers.