Could Hormone Replacement Therapy protect against Glaucoma? Several studies have asked this question before, with equivocal findings. The Rotterdam & Blue Mountain Eye Studies both found a reduced risk, though it didn’t reach statistical significance, while the Los Angeles Latino Eye Study found no protective effect.
This month in Jama Ophthalmology (the journal “formerly known as” Archives of Ophthalmology) researchers from the University of Michigan published a large claims-based study that included data from the records of more than 150 000 women over 50 that showed a statistically significant reduction in the risk of glaucoma in those on estrogen. There appeared to be a larger reduction in risk in those on estrogen plus progesterone, but after adjustment for age, sociodemographic factors and other health issues, this reduction in risk was not statistically significant.
The study used billing data from a managed care network, so there may have been selection bias as the study cohort may have had a disproportionately low number of racial/ethnic minorities and socially disadvantaged people. Nevertheless the study findings are interesting given previous clinical studies showing that HRT may lower intraocular pressure, and lab studies showing the presence of estrogen receptors in human retina, and a protective effect from oral estrogen on retinal ganglion cell loss (the mechanism of vision loss in glaucoma) in a rat model.
P Newman-Casey, N Talwar, B Nan, D Musch, LR Pasquale, JD Stein. The Potential Association Between Postmenopausal Hormone Use and Primary Open-Angle Glaucoma. JAMA Ophthalmol. 2014;132(3):298-303.