From the American Academy of Ophthalmology

Using a large, nationwide health care claims database including more than 150,000 women age 50 or older, investigators evaluated the association between different classes of postmenopausal hormone therapies and development of primary open-angle glaucoma. Subjects were in the plan for at least four years had at least two visits to an eye care provider during the eight-year period studied.  After adjustment for age and other possible confounding factors, each additional month of hormone therapy containing estrogen only was associated with a 0.4 percent reduction in glaucoma risk, while women prescribed estrogen plus progesterone had a 0.6 percent per month reduction. JAMA Ophthalmology, March 2014