Purpose: To investigate the influence of hormone therapy with tamoxifen or estrogens on morphological changes in macular telangiectasia (MacTel) type 2 patients as revealed clinically in multiple imaging modalities. Methods: Patients with a history of tamoxifen or estrogen use were selected from the cohort of the MacTel Study. A race-, age- and best-corrected visual acuity-matched group of MacTel participants not under hormone therapy served as the comparison group. The frequencies of typical features of the MacTel phenotype apparent in color fundus, red-free, fluorescein angiographic and optical coherence tomographic images were graded and analyzed statistically. Results: Thirty-nine MacTel patients were included in the analyses, of whom 13 were receiving tamoxifen, 13 estrogens and 13 patients no hormone treatment. Patients treated with estrogens showed significantly fewer breaks in the ellipsoid zone on optical coherence tomography (7 eyes, 29.1%, vs. tamoxifen: 14 eyes, 53.8%, and vs. controls: 14 eyes, 53.8%, p = 0.04 in both analyses, Fisher exact test). Retinal crystalline deposits were significantly more frequent in patients receiving estrogens (12 eyes, 16.2%, vs. 2 eyes, 2.7%, p = 0.003, Fisher exact test). No significant between-group differences were apparent with regard to other features of the phenotype (extent of retinal low reflective spaces, late hyperfluorescence on fluorescein angiography or retinal thickness). Conclusions: Tamoxifen treatment does not seem to accentuate structural changes in patients with MacTel type 2. Treatment with estrogens may exhibit a neuroprotective effect as suggested by the decreased frequency of ellipsoid zone breaks in corresponding patients, although corroborative studies are warranted to confirm these exploratory data.

Keywords:
Idiopathic macular telangiectasia, MacTel Study, Neuroprotection, Estrogen, Tamoxifen
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