Literature Review of Sex Hormones and Cataract Development, With Modern Implications.

Administration of exogenous testosterone and oestrogen has a number of clinical indications, with increasing use as gender-affirming hormone therapy (GAHT) in young individuals. GAHT has been associated with increasing ocular manifestations, but cataracts have not been previously reported. A literature review was conducted to assess for any associations between sex hormone administration and cataracts. Sparse data exist regarding the relationship between androgens and cataract. We also reviewed current knowledge derived from animal studies about oestrogen's effects on the lens, possible biomechanisms and correlations with observational data on cataract incidence with varying estrogen levels. Data surrounding parity, menarche, menopause and hormone replacement therapy in women generally supports a protective role of endogenous and exogenous estrogen on the crystalline lens. Such protection could be suppressed due to long-term GAHT in susceptible individuals, but no relevant studies exist regarding cataract risk in this scenario. Further research via population-based studies would be useful to identify any potential cataractogenic risk factors from GAHT.