Vitreo-retinal traction and anastrozole use.
Authors: Eisner A , Thielman EJ , Falardeau J , Vetto JT 
Published: December 2010

Abstract
Abstract #1147
Background: Menopause is known to increase the risk of vitreo-retinal tractional events such as macular holes and posterior vitreous detachments (PVDs). This suggests that aromatase inhibitors (AIs), which virtually abolish estrogen synthesis in post-menopausal women, may lead to an increased degree of vitreo-retinal traction. To evaluate the hypothesis that AIs lead to heightened vitreo-retinal traction, this study tested the prediction that the foveal shapes of anastrozole users are distorted systematically.&#x2028; Material and Methods: Retinal thickness along the horizontal meridian through the fovea was measured using optical coherence tomography (OCT) for each of 3 groups of amenorrheic women ages 47-69 years: (1) anastrozole users and (2) tamoxifen users using their respective medications as adjuvant therapy for early-stage breast cancer, and (3) age-matched control subjects not using any hormonally acting medication. All subjects had 20/20 or better best-corrected visual acuity, no diabetes, and no high myopia, which itself is a risk factor for PVDs. Foveal shape indices were derived from the OCT data by normalizing each subject's retinal thickness data to her individually determined locus of minimal foveal thickness. OCT images were used to identify subjects with PVDs, which necessitated exclusion from most analyses. The information in the Results section is for subjects without PVDs.&#x2028; Results: For anastrozole users (n=13), the distance to the temporal side of the fovea was significantly less than the distance to the nasal side at a sufficient height above the foveal base. This effect did not exist for control subjects (n=24), and the between-group difference was significant (unadjusted p = .006). The data from tamoxifen users (n=19) appeared to be intermediate to the data of the other 2 groups, but the differences were not significant. At the base of the fovea, the distance to the temporal side minus the distance to the nasal side correlated significantly with the degree of myopia for the control subjects (r = -.54, p = .008) but not for the anastrozole users (r = -.23). However, the anastrozole users were observed to be significantly less myopic than the control subjects, which may have led to the negative result.&#x2028; Discussion: The foveas of women who use anastrozole are subjected to a greater amount of vitreo-retinal traction than are the foveas of women not using any hormonal medication. The data from control subjects reveal the action of an additional force that pulls on the fovea from its scleral side in the opposite direction, i.e., away from the optic nerve head, which not only anchors the vitreous but which also interferes asymmetrically with intraocular stretching related to myopia. The net result of the 2 forces may be retinal shear. The low prevalence of myopia among the anastrozole users suggests that our cross-sectional study may have excluded anastrozole users with vision change. Longitudinal studies with baseline data need to be conducted.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1147.