title: Intraocular Pressure Reduction Is Associated with Reduced Venous Pulsation Pressure.
abstract: OBJECTIVE
  To explore whether alterations in intraocular pressure (IOP) affect vein pulsation properties using ophthalmodynamometric measures of vein pulsation pressure.
  
  
  METHODS
  Glaucoma patients had two retinal vein pulsation pressure (VPP) measurements from upper and lower hemiveins performed by ophthalmodynamometry at least 3 months apart. All subjects had VPP and IOP recorded at two visits, with standard automated perimetry, central corneal thickness (CCT) recorded at the initial visit. Where venous pulsation was spontaneous ophthalmodynamometry could not be performed and VPP was considered equal to IOP. Change in VPP was calculated and binarized with reduction in pressure scored 1 and no change or increase scored as 0. Data analysis used a mixed logistic regression model with change in VPP as response variable and change in IOP, visual field loss (mean deviation), CCT and time interval as explanatory variables.
  
  
  RESULTS
  31 subjects (20 females) with mean age 60 years (sd 11) were examined with change in VPP being significantly associated with change in IOP (odds ratio 1.6/mmHg, 95% CI 1.2 to 2.1 in the glaucoma patients but not suspect patients (p = 0.0005).
  
  
  CONCLUSIONS
  Change in VPP is strongly associated with change in IOP such that a reduced intraocular pressure is associated with a subsequent reduction in VPP. This indicates that reduced IOP alters some retinal vein properties however the nature and time course of these changes is not known.
authors.affiliation: Lions Eye Institute, University of Western Australia, Nedlands, Australia.
authors.forename: William H
authors.initials: WH
authors.lastname: Morgan
authors.affiliation: Lions Eye Institute, University of Western Australia, Nedlands, Australia.
authors.forename: Philip H
authors.initials: PH
authors.lastname: House
authors.affiliation: Statistics and Bioinformatics Group, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Martin L
authors.initials: ML
authors.lastname: Hazelton
authors.affiliation: Statistics and Bioinformatics Group, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Brigid D
authors.initials: BD
authors.lastname: Betz-Stablein
authors.affiliation: Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Balwantray C
authors.initials: BC
authors.lastname: Chauhan
authors.affiliation: Moorfields Eye Hospital, City University, London, United Kingdom.
authors.forename: Ananth
authors.initials: A
authors.lastname: Viswanathan
authors.affiliation: Lions Eye Institute, University of Western Australia, Nedlands, Australia.
authors.forename: Dao-Yi
authors.initials: DY
authors.lastname: Yu
mesh_terms: D000368:Aged; D003315:Cornea / Q000098:blood supply* / Q000473:pathology; D063171:Corneal Pachymetry; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009884:Ophthalmodynamometry; D011673:Pulsatile Flow; D012169:Retinal Vein / Q000503:physiopathology; D014065:Tonometry, Ocular; D014794:Visual Fields
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