NEW ORLEANS, Nov. 18 (UPI) -- Women who took oral contraceptives for three or more years are twice as likely to suffer from glaucoma, a leading cause of blindness, a U.S. researcher says.
Lead researcher Dr. Shan Lin, a professor of clinical ophthalmology at the University of California San Francisco and colleagues at Duke University School of Medicine and Third Affiliated Hospital of Nanchang University in China utilized 2005-08 data from the National Health and Nutrition Examination Survey, administered by the Centers for Disease Control, which included 3,406 female U.S. participants age 40 years or older. Study participants completed the survey's vision and reproductive health questionnaire and underwent eye exams.
The study found women who used oral contraceptives, no matter which kind, for longer than three years were 2.05 times more likely to also report a diagnosis of glaucoma.
Although the results of the study do not speak directly to the causative effect of oral contraceptives on the development of glaucoma, it indicated that long-term use of oral contraceptives might be a potential risk factor for glaucoma, and might be considered as part of the risk profile for a patient together with other existing risk factors, the researchers said.
Glaucoma risk factors include: African-American ethnicity, family history of glaucoma, history of increased eye pressure or existing visual field defects. Previous studies in the field have shown that estrogen may play a significant role in the pathogenesis of glaucoma.
"This study should be an impetus for future research to prove the cause and effect of oral contraceptives and glaucoma," Lin said in a statement. "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 findings were presented at the 117th annual meeting of the American Academy of Ophthalmology in New Orleans.