Vitreo-retinal traction and anastrozole use

Abstract

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.

Figure 1

Graph of the height above the minimal foveal thickness (i.e., of the degree by which the thickness of the fovea at a given locus exceeds the minimal thickness) vs. the lateral distance from the locus of minimal thickness to the foveal slopes in the nasal (left) and temporal (right) directions. Squares (□) represent median data of anastrozole users, circles (○) represent median data of control subjects, and crosses (×) represent median data of tamoxifen users. Connecting lines are unbroken for the anastrozole users and control subjects, and are dashed for the tamoxifen users. Although heights vary along the ordinate and the distances vary along the abscissa, distance is the dependent variable. Data at a height of 90 μm are not included since the maximal height on the temporal side was < 90 μm for 10 of 56 subjects. All units are in microns (μm). Note that the scales on the two axes differ. The locus of minimal thickness itself defines a height of 0 μm. Non-PVD subjects only.

Figure 2

Graphs of the lateral distance to the nasal side of the fovea at a height of 70 μm minus the corresponding distance to the temporal side at the same height vs. the component distance to the nasal side (left) and to the temporal side (right). Same symbols as for Fig. 1 except that the filled square (■) signifies data from the one anastrozole user with outlying data. When this subject was retested ~2.5 years later (at age 54 years), her acuity had decreased from 20/20 to 20/25 and her nasal-temporal profile had become asymmetric in the opposite direction, more like that of most anastrozole users, for whom the distance to the temporal side of the fovea was less than the distance to the nasal side. All units are in microns (μm). The scales on the two axes are the same. Non-PVD subjects only.

Figure 3

Graph of the lateral distance to the nasal side of the fovea at a height of 10 μm minus the corresponding distance to the temporal side at the same height. vs. the spherical equivalent refractive error. Non-PVD control subjects only. The straight line is the least-squares linear regression line. The spherical equivalent refractive error is defined as the spherical refractive error plus one-half the cylindrical refractive error. The ordinate is in units of microns (μm), and the abscissa is in units of diopters.

Figure 4

The mean spherical refractive error ± the standard error of the mean (SEM) for the anastrozole users, control subjects, and tamoxifen users. Units are diopters. Data from non-PVD subjects only.