Women on menopausal hormone therapy (MHT) may face a surprising side effect: a higher risk of strabismus (eye misalignment). A large retrospective study found MHT users had an 11% greater chance of a new strabismus diagnosis and a 76% higher risk of needing surgery. Researchers also detected estrogen receptors in human eye muscle tissue, hinting at a biological mechanism behind the link.
Women on menopausal hormone therapy (MHT) may face a surprising ocular side effect: a significantly higher risk of developing strabismus, or eye misalignment. A large retrospective study of over 2.15 million women diagnosed with menopause between ages 44–60 found that those who received estrogen-only or combined estrogen-progestin therapy faced notably worse eye alignment outcomes compared to those who didn't.
Timing also matters — women who started MHT 3 to less than 10 years after menopause had a 29% higher risk of strabismus diagnosis compared to those who started within 3 years, with each additional year of delay adding a 7% increased risk. Adding a potential biological explanation, researchers detected estrogen receptor alpha in human extraocular (eye-moving) muscle tissue from a donor, suggesting hormones may directly influence eye muscle function.
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Why it matters: Strabismus in adults can significantly impair vision and quality of life. These findings raise important questions about the ocular risks of MHT — a therapy used by millions of women — and suggest that clinicians should factor in eye health when counseling patients on hormone therapy timing and use.
