Abstract
Until the 1990s, scant attention was paid to effects of estrogen on the brain outside the reproductive axis. However, perspectives have evolved for numerous reasons. For example, (1) improved technologies have revealed the presence of estrogen receptors throughout the brain, (2) non-circulating estrogens now are known to be synthesized and utilized locally, and (3) estrogens are derived from androgens, are present in both sexes, and have been shown to act genomically and non-genomically. The visual system is an especially accessible part of the CNS, amenable to controlled non-invasive assessment. Plus, there is abundant evidence that estrogen receptors are present retinally. I will present data from distinct subject populations collectively demonstrating that changes in estrogenic activity can impact vision mediated via SWS cones. The following results all were for postmenopausal women. First, three separate studies revealed that about 1/3 of healthy women perceived a threshold-level, short-wavelength, test stimulus square-wave modulated on a yellow adapting background as white rather than bluish and/or reddish. Second, this color perception effect was related systematically: (a) to the degree of desensitization induced by onset of the yellow background, and (b) to the steepness of the hill of vision measured with short-wavelength-automated-perimetry (SWAP). Third, adjuvant endocrine therapy for early-stage breast cancer significantly affected these color percepts, but differently for women using the selective-estrogen-receptor-modulator (SERM) tamoxifen than for women using an aromatase inhibiter (which abolishes estrogen synthesis). These and other results (including some from reproductive-age women) present a host of implications and possibilities, both basic and clinical.