NEW YORK, July 1 | Thu Jun 30, 2011 9:33pm EDT
More than two million people over 40 in the United States alone have been diagnosed with the eye disease, which is becoming increasingly expensive to treat.
The findings in the study, a review of previous studies that was published in Opthalmology, suggest to some experts that nearsighted people — a third of all U.S. residents — may want to undergo regular eye screening.
“A conclusion might be that persons with high myopia should have regular ophthalmic examinations,” said Barbara Klein of the University of Wisconsin-Madison, who worked on one of the studies included in the review.
Glaucoma is a group of eye conditions that damage the optic nerve, causing gradual loss of vision. There are several treatments available, including drugs and surgery, but none of them can restore sight once it has been lost.
For the latest study, Nomdo Jansonius at the University Medical Center Groningen in the Netherlands and colleagues combined data from 11 previous studies that included tens of thousands of people, tracking who was nearsighted and had glaucoma.
Overall, nearsighted people were about 90 percent more likely to also develop open-angle glaucoma, with those who had higher levels of myopia appearing to be at higher risk of glaucoma as well.
The findings only show that nearsightedness and glaucoma often co-occur, not that one causes the other. Furthermore, some of the studies are hard to compare, Klein noted, because they looked at people of different ages or ethnicities, or applied different criteria for the conditions.
“The results are, in a sense, an average,” she said, adding that they may not be applicable to every group of people.
The American Academy of Opthalmology already recommends regular eye exams for all adults beginning around age 40. The group urges blacks to start even earlier, with exams every three to five years, because their risk of glaucoma is higher.