Eye alignment disorders may not be the first concern that comes to mind when weighing the risks and benefits of menopausal hormone therapy, yet a massive retrospective cohort study now suggests that hormonal exposure during menopause could meaningfully affect the muscles and neural pathways that keep the eyes coordinated. This finding invites a broader rethinking of how estrogen and progestin influence ocular motor function in midlife women.
Drawing on the Epic Cosmos database — one of the largest real-world clinical repositories in the United States — investigators tracked more than 2.15 million women diagnosed with menopause between ages 44 and 60 from 2010 through late 2025. Roughly 197,000 (9.2%) used estrogen or combined estrogen-progestin therapy for at least 90 days post-diagnosis; the remaining 1.96 million served as untreated controls. Using time-varying Cox proportional hazards models adjusted for age, diagnosis year, race, and ethnicity, MHT use was associated with an 11% higher hazard of a new strabismus diagnosis (HR 1.11, 95% CI 1.02–1.2). The study specifically excluded congenital, mechanical, neurological, paralytic, and traumatic etiologies, focusing attention on idiopathic or hormonally plausible cases.
While estrogen receptors are known to exist in extraocular muscles and the oculomotor control system, the precise biological mechanism linking exogenous hormone exposure to misalignment risk remains speculative. The effect size — an 11% hazard increase — is modest and likely clinically silent for most women, but at a population level, even small relative risks translate to meaningful absolute numbers given how widely MHT is prescribed. Importantly, this is an observational study and cannot establish causality; confounding by indication, detection bias (MHT users may simply receive more ophthalmic scrutiny), and residual unmeasured variables remain live concerns. The study does not yet report whether the risk differs by estrogen-only versus combined regimens, duration of use, or route of administration — distinctions that would be critical for clinical translation. For now, this finding is hypothesis-generating rather than practice-changing, but it establishes a compelling rationale for prospective investigation into hormonal influences on ocular motility.