title: Estrogen-replacement therapy: effects on retrobulbar hemodynamics.
abstract: OBJECTIVE
  Estrogen-replacement therapy causes vasodilation and increased blood flow in major peripheral arteries. We examined the role that estrogen may play in enhancing perfusion within the watersheds of several major and minor retrobulbar arteries.
  
  
  METHODS
  Postmenopausal women receiving estrogen-replacement therapy (n = 16) were compared with both age-matched women not receiving estrogen (n = 16) and with young women (n = 20). Studies involved color Doppler imaging analysis of flow velocities measured in the ophthalmic, central retinal, and nasal and temporal posterior ciliary arteries.
  
  
  RESULTS
  In the ophthalmic artery, young women and postmenopausal women receiving estrogen exhibited reduced resistance indexes as compared with postmenopausal women not receiving estrogen (each P <. 001). In contrast, flow velocities in the central retinal artery were similar among the three groups of women. In the posterior ciliary arteries, a different pattern emerged: young women, as compared with either group of postmenopausal women, showed greater peak systolic and end-diastolic velocities at similar resistance index (each P <.05).
  
  
  CONCLUSIONS
  Estrogen-replacement therapy in postmenopausal women apparently helps reduce vascular resistance distal to the ophthalmic artery to levels matching those of young women. However, estrogen replacement has little impact on flow velocities in the posterior ciliary arteries. In those vessels, aging per se may reduce perfusion, potentially contributing to the age-dependent risk of major eye diseases, such as glaucoma and age-related macular degeneration.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5133, USA.
authors.forename: M
authors.initials: M
authors.lastname: Harris-Yitzhak
authors.forename: A
authors.initials: A
authors.lastname: Harris
authors.forename: Z
authors.initials: Z
authors.lastname: Ben-Refael
authors.forename: D
authors.initials: D
authors.lastname: Zarfati
authors.forename: H J
authors.initials: HJ
authors.lastname: Garzozi
authors.forename: B J
authors.initials: BJ
authors.lastname: Martin
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure; D019842:Ciliary Arteries / Q000502:physiology*; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy; D005123:Eye / Q000098:blood supply*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008593:Menopause / Q000502:physiology; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D017698:Postmenopause / Q000502:physiology; D011374:Progesterone / Q000627:therapeutic use*; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
chemical_list: D011374:Progesterone