New research suggests taking oral contraceptives for over three years doubles the risk of glaucoma, which can cause blindness.
Glaucoma affects about 60 million people globally and is the leading cause of blindness in the world, an American Academy of Ophthalmology news release reported.
The academy urged both gynecologists and ophthalmologists to remain aware of these risk factors. They also recommended women on birth control who have other glaucoma risk factors should undergo regular screenings.
The study was the first-ever to confirm a link between glaucoma and birth control use for three or more years.
The researchers looked at 3,406 U.S. female patients that were over 40 years of age. All of the participants took the study's vision and reproductive health questionnaire and received an eye exam.
The team concluded females that had taken any type of oral contraceptives were 2.05 times more likely to be diagnosed with glaucoma than those who had not.
Although the team was not able to find a causal link between oral contraceptives and glaucoma, it does indicate birth control use could be a risk factor for the condition.
"This study should be an impetus for future research to prove the cause and effect of oral contraceptives and glaucoma," Shan Lin, M.D., lead researcher and professor of clinical ophthalmology at the University of California San Francisco., said in the news release. "At this point, women who have taken oral contraceptives for three or more years should be screened for glaucoma and followed closely by an ophthalmologist, especially if they have any other existing risk factors."
The study was conducted by "researchers at University of California, San Francisco, Duke University School of Medicine and Third Affiliated Hospital of Nanchang University, Nanchang, China."
"Glaucoma is not just one eye disease, but a group of eye conditions resulting in optic nerve damage, which may cause loss of vision. Abnormally high pressure inside your eye (intraocular pressure) usually, but not always, causes this damage," MayoClinic reported.
Symptoms of glaucoma can include: a "gradual loss of peripheral vision; tunnel vision; eye pain; nausea and vomiting; blurred vision; reddening around the eyes; and seeing halos.
