Comparative insights into the role of sex hormones in glaucoma among women and men

Baseline differences in sex hormone levels between males and females influence tissues including the brain and eye. To investigate the effects of estrogens and androgens on ocular physiology and glaucoma, we review the current literature on the influence of primary sex hormones on ocular function, glaucoma incidence and related parameters like intraocular pressure (IOP) at physiologic levels and related to hormone therapies in men and women. These articles reveal activity of estrogen, testosterone, and progesterone within ocular tissues including the retinal pigment epithelium and ciliary epithelium where they likely influence glaucoma pathophysiology through effects on ocular blood flow and aqueous outflow. A growing body of evidence demonstrates a protective role of estrogen in glaucoma. With fluctuations across a woman's lifetime through menstrual phases, pregnancy, and menopause, the general association seen is a lower risk of glaucoma and lower IOP with higher estrogen. Exogenous hormones in the form of oral contraceptive pills and hormone replacement therapy also appear to affect glaucoma risk, although published findings are inconsistent. Few studies have reported a positive association between IOP and serum testosterone, and men treated with androgen deprivation therapy have shown a reduced risk of glaucoma while masculinizing hormone therapies at supra-physiologic testosterone levels have significantly increased IOP. Sex hormone perturbations affect components of glaucoma pathogenesis including IOP and ocular blood flow and overlap with known risk factors like age and sex. Standardized studies are needed to further elucidate the roles of estrogen and testosterone in glaucoma risk and progression.