title: Postmenopausal hormone therapy increases retinal blood flow and protects the retinal nerve fiber layer.
abstract: OBJECTIVE
  To investigate whether postmenopausal hormone therapy (HT) increases retinal and ONH blood flow (BF) and protects ONH topography and the function of retinal ganglion cells in postmenopausal women (PMW). The effect of estradiol (E(2)) treatment on retinal tissue perfusion was also investigated in ovariectomized rats, an animal model for menopause.
  
  
  METHODS
  Sixty-four healthy PMW were recruited, 29 of whom never used HT ( HT) and 35 of whom had used HT (+HT) continuously since the onset of menopause. Blood flow of the inferotemporal retinal artery (ITRA), peripapillary retina, and ONH rim were measured in one eye. The ONH stereometric parameters and the pattern electroretinogram (PERG) were also measured. In ovariectomized rats, the retinal tissue perfusion was assessed using the BF tracer N-isopropyl-p-[(14)C]-iodoamphetamine ([(14)C]-IMP) in rats treated with either E(2) (n = 7) or placebo (n = 5).
  
  
  RESULTS
  Compared with the HT group, the +HT group presented significantly greater BF of the ITRA (P = 0.006), greater rim volume for the entire ONH region (P = 0.032), and greater rim volume (P = 0.042), height variation contour (P = 0.011), mean thickness (P = 0.033), and cross-sectional area (P = 0.020) of the retinal nerve fiber layer for the inferotemporal region of the ONH when adjusted for age, ocular perfusion pressure, and age at menarche. In ovariectomized rats, E(2) treatment significantly increased retinal perfusion in a range of 22% to 45%.
  
  
  CONCLUSIONS
  These findings indicate that estrogens and HT increase retinal blood flow and protect the retinal nerve fiber layer.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Montréal, Montréal, Québec, Canada.
authors.forename: Micheline C
authors.initials: MC
authors.lastname: Deschênes
authors.forename: Denise
authors.initials: D
authors.lastname: Descovich
authors.forename: Michèle
authors.initials: M
authors.lastname: Moreau
authors.forename: Louis
authors.initials: L
authors.lastname: Granger
authors.forename: George A
authors.initials: GA
authors.lastname: Kuchel
authors.forename: Tomi S
authors.initials: TS
authors.lastname: Mikkola
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Fick
authors.forename: Sylvain
authors.initials: S
authors.lastname: Chemtob
authors.forename: Elvire
authors.initials: E
authors.lastname: Vaucher
authors.forename: Mark R
authors.initials: MR
authors.lastname: Lesk
mesh_terms: D000368:Aged; D000818:Animals; D001345:Autoradiography; D001783:Blood Flow Velocity; D004596:Electroretinography; D004958:Estradiol / Q000008:administration & dosage; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology*; D009898:Optic Disk / Q000098:blood supply*; D010052:Ovariectomy; D017698:Postmenopause; D011372:Progestins / Q000008:administration & dosage; D051381:Rats; D011914:Rats, Inbred BN; D012039:Regional Blood Flow; D012161:Retinal Artery / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology*
chemical_list: D011372:Progestins; D004958:Estradiol