Women who took birth control pills for 3 years or more were twice as likely to have Glaucoma according to a recent study.

Doctors have long known that cells in the eye have estrogen receptors. But in the past few years they've started looking into whether the changes in a woman's estrogen levels as she goes through life could affect her risk of Glaucoma.

The eye disease slowly damages the optic nerve and is most common in people over 40. But the absolute risk of getting glaucoma after age 40 is still small, about 2 percent, according to the CDC. So doubling that risk would be about 4 percent.

There could be a relationship between eyesight and estrogen, though. Scientists have long thought that the hormone could have a protective effect on the eye's retina. So it makes sense that the pill, which lowers a woman's total exposure to estrogen over a month, could affect her eyes,

Women shouldn't stop using birth control pills based on this study and more research needs to be done to find out if this apparent connection is real or just a coincidence.

But women with higher risk factors for glaucoma, including African-American ethnicity, Asians and a family history of Glaucoma, history of increased IOP or existing visual field defects should be more cautious. If you've been using oral contraceptives for a long time, we recommend that you have a comprehensive analysis for glaucoma by having your eye care provider do a visual field testing, OCT analysis of the Optic nerve, along with the standard IOP measurement.