Breast Cancer Medications and Vision: Effects of Treatments for Early-stage Disease

This review concerns the effects on vision and the eye of medications prescribed at three phases of treatment for women with early-stage breast cancer (BC): (1) adjuvant cytotoxic chemotherapy, (2) adjuvant endocrine therapy, and (3) symptomatic relief. The most common side effects of cytotoxic chemotherapy are epiphora and ocular surface irritation, which can be caused by any of several different regimens. Most notably, the taxane docetaxel can lead to epiphora by inducing canalicular stenosis. The selective-estrogen-receptor-modulator (SERM) tamoxifen, long the gold-standard adjuvant-endocrine-therapy for women with hormone-receptor-positive BC, increases the risk of posterior subcapsular cataract. Tamoxifen also affects the optic nerve head more often than previously thought, apparently by causing subclinical swelling within the first 2 years of use for women older than ∼50 years. Tamoxifen retinopathy is rare, but it can cause foveal cystoid spaces that are revealed with spectral-domain optical coherence tomography (OCT) and that may increase the risk for macular holes. Tamoxifen often alters the perceived color of flashed lights detected via short-wavelength-sensitive (SWS) cone response isolated psychophysically; these altered perceptions may reflect a neural-response sluggishness that becomes evident at ∼2 years of use. The aromatase inhibitor (AI) anastrozole affects perception similarly, but in an age-dependent manner suggesting that the change of estrogen activity towards lower levels is more important than the low estrogen activity itself. Based on analysis of OCT retinal thickness data, it is likely that anastrozole increases the tractional force between the vitreous and retina. Consequently, AI users, myopic AI users particularly, might be at increased risk for traction-related vision loss. Because bisphosphonates are sometimes prescribed to redress AI-induced bone loss, clinicians should be aware of their potential to cause scleritis and uveitis occasionally. We conclude by suggesting some avenues for future research into the visual and ocular effects of AIs, particularly as relates to assessment of cognitive function

Variability in Short-Wavelength Automated Perimetry Among Peri- or Postmenopausal Women: A Dependence on Phyto-Oestrogen Consumption?

Purpose:  To determine whether the hill of vision for Short-Wavelength Automated Perimetry (SWAP) is shallower for women who consume phyto-oestrogen-rich foods than for women who do not. Methods:  Visual field data were compared for two groups of healthy amenorrhoeic women 48–69 years-old with normal vision and not using hormone replacement: (1) 24 subjects who reported consuming soy and/or flax products and (2) 20 subjects who reported not consuming these products. Two types of 24-2 visual fields were measured: (1) Full Threshold SWAP and (2) a white-on-white (W/W) field obtained using a Swedish Interactive Threshold Algorithm (SITA Standard). Results:  The reduction of SWAP sensitivity from the centre of the field (4 loci, mean eccentricity = 4.2°) to the periphery (20 loci, mean eccentricity = 21.9°) was less for soy/flax consumers than for nonconsumers, both with age-referencing (mean difference = 1.7 dB, p = 0.018) and without (p = 0.012). Corresponding distinctions existed for the SWAP – W/W difference, and there was minimal effect for W/W fields alone. The peripheral age-referenced SWAP sensitivities averaged 2.5 dB higher for consumers than nonconsumers (p = 0.022). Conclusion:  The between-group distinctions are consistent with the possibility (derived from the women’s health literature) that phyto-oestrogens may counteract a decline of short-wavelength-sensitive cone-mediated response among postmenopausal women. These results suggest another potential application for SWAP outside its original intended purpose as a glaucoma test. Future studies should assess whether phyto-oestrogen consumption is most beneficial for women who are sufficiently young and/or not too far beyond menopause

The Color Appearance of Stimuli Detected via Short-Wavelength-Sensitive Cones: Comparisons with Visual Adaptation and Visual Field Data for Peri- or Post-Menopausal Women Under 70 Years of Age

Dynamics of foveal light adaptation for vision mediated via short-wavelength-sensitive (SWS) cones were compared for two groups of healthy amenorrheic (peri- or post-menopausal) women not using hormonal medication. Each subject was assigned to a group based on the color name – “lavender” (~2/3 of all subjects) or white (~1/3 of all subjects) – chosen in a forced-response paradigm to best describe a threshold-level 440-nm test presented on a larger 3.6 log td 580-nm background that had been viewed for ~5 minutes. During the first 20–30 seconds after this 3.6 log td background abruptly replaced a much dimmer background, the threshold elevations (relative to the steady-state levels measured at ~5 minutes) were significantly greater for the lavender-naming subjects than for the white-naming subjects. However, exponential rates of recovery were indistinguishable for the two groups. A viable interpretation is that the gain of the visual response at background onset is greater for lavender-naming subjects than for white-naming subjects at or distal to a site where responses from middle-wavelength-sensitive and long-wavelength-sensitive (MWS and LWS) cones oppose responses from SWS cones. In addition, the color names derived from foveal testing were related systematically to extrafoveal sensitivities measured with Short Wavelength Automated Perimetry (SWAP), in a manner suggesting that response gain and/or response speed may be greater for lavender-naming subjects in the direction of increased SWS response also. Evidence from other subject populations suggests that the choice of color name and the dynamics of visual response each can be affected by alterations (particularly reductions) of estrogen synthesis and response

Vitreo-Retinal Traction and Anastrozole Use

Purpose—This study tested a prediction stemming from the hypothesis that anastrozole users experience heightened vitreo-retinal traction. This hypothesis was based on the knowledge that menopause increases the risk of intraocular tractional events such as posterior vitreous detachments (PVDs). Methods—Retinal thickness was measured for 3 groups of amenorrheic women: (1) anastrozole users and (2) tamoxifen users undergoing adjuvant therapy for early-stage breast cancer, and (3) control subjects not using hormonal medication. Foveal shape indices were derived for subjects without PVDs. Results—For anastrozole users, the distance to the temporal side of the fovea became less than the distance to the nasal side at a sufficient height above the foveal base. This effect did not exist for control subjects; the between-group difference was appreciable. Results concerning tamoxifen users were inconclusive. Conclusions—The foveas of women using anastrozole appear to be subjected to more tractional force than are the foveas of women not using any hormonal medication

Identifying Factors Associated With Falls in Postmenopausal Breast Cancer Survivors: A Multi-Disciplinary Approach

Objective—To identify neuromuscular, balance and vision factors that contribute to falls in recently treated breast cancer survivors (BCS) and explore links between fall risk factors and cancer treatment Design—Case-control plus prospective observation Setting—Comprehensive cancer center Participants—BCS within two years chemotherapy completion and/or on adjuvant endocrine therapy (N=59; mean age: 58 yrs) Intervention—not applicable Main outcome measures—Objective measures of postural control, vision and neuromuscular function included 1) a sensory organization test (SOT), 2) a visual assessment battery, 3) muscle mass by DXA, and 4) neuromuscular function with strength by repetition maximum, power by timed stair climb, and gait speed by 4m walk. Falls were self-reported for the past year (retrospective) and monthly for six months (prospective). Results—58% of BCS reported falls in the past year. BCS with a history of falls had lower SOT scores with a vestibular deficit pattern in postural control (