CONTRACEPTIVES AND GLAUCOMA

Women who have taken oral contraceptives for three or more years are twice as likely to also report a diagnosis of glaucoma, according to research presented at the 2013 Annual Meeting of the American Academy of Ophthalmology in New Orleans. The researchers caution gynaecologists and ophthalmologists to be aware that oral contraceptives might play a role in glaucomatous diseases and inform patients to have their eyes screened for glaucoma if they also have other risk factors.

The study – conducted by researchers at University of California, San Francisco and Duke University School of Medicine in the US, and Third Affiliated Hospital of Nanchang University, Nanchang, China – is the first to establish an increased risk of glaucoma in women who have used oral contraceptives for three or more years. The researchers utilised 2005-2008 data from the National Health and Nutrition Examination Survey (NHANES), administered by the US Centres for Disease Control. It included 3,406 female participants aged 40 years or older from the US.

The study found that females who had used oral contraceptives for longer than three years are 2.05 times (p=0.004, CI=1.27-3.26) more likely to report that they have the diagnosis of glaucoma.

The study also found longterm oral contraceptive use associated with the presence of visual field defects as measured by frequency doubling technology, but this association was not statistically significant.

The researchers noted that while these results do not speak directly to the causative effect of oral contraceptives on the development of glaucoma, it indicates that long-term use of oral contraceptives might be a potential risk factor for glaucoma, and may be considered as part of the risk profile for a patient together with other existing risk factors.

Previous studies in the field have shown that oestrogen may play a significant role in the pathogenesis of glaucoma. These include studies linking early menopause to higher risk of primary open angle glaucoma. A separate prospective cohort study of reproductive factors and the risk of POAG as part of the Nurses’ Health Study found a 25 per cent increase in POAG in subjects with more than five years of oral contraceptive use (Lang et al. Eye (Lond). May 2011;25(5);633-641).

“This study should be an impetus for future research to prove the cause and effect of oral contraceptives and glaucoma,” said Shan Lin MD, lead researcher and professor of clinical ophthalmology at the University of California San Francisco.

Shan Lin: lins@vision.ucsf.edu