title: Correlation among choroidal, parapapillary, and retrobulbar vascular parameters in glaucoma.
abstract: OBJECTIVE
  To study and compare the correlation among choroidal, parapapillary, and retrobulbar vascular parameters in healthy subjects, glaucoma suspects, and open-angle glaucoma (OAG) patients.
  
  
  METHODS
  Prospective observational clinical study.
  
  
  METHODS
  The study included one randomly selected eye from 21 normal subjects, 30 glaucoma suspects based on optic disc appearance, and 22 OAG patients. The pulsatile ocular blood flow (POBF), a measure of choroidal blood flow, was assessed using ocular blood flow analyzer whereas parapapillary blood flow and blood velocity of retrobulbar blood vessels were measured using scanning laser Doppler flowmetry and color Doppler imaging, respectively. All vascular parameters along with blood pressure and intraocular pressure measurements were obtained within a 2-hour period. Univariate regression analyses were used to evaluate the correlation of POBF values with parapapillary blood flow values, retrobulbar blood flow velocities, and resistive index, which represents vascular resistance, in each group. Two multiple linear regression models were created based on results of univariate analyses and included POBF, mean parapapillary blood flow, age, and mean ocular perfusion pressure; and POBF, temporal short posterior ciliary artery resistive index, age, and mean ocular perfusion pressure.
  
  
  RESULTS
  POBF was significantly associated with parapapillary blood flow (r2 = 0.54; P < .001, positive correlation) and temporal short posterior ciliary artery resistive index (r2 = 0.39; P < .001, negative correlation) in normal subjects. Results were consistent when corrected for age, intraocular pressure, and blood pressure parameters. POBF values did not correlate with parapapillary blood flow values or temporal short posterior ciliary artery resistive index in glaucoma suspects or OAG patients.
  
  
  CONCLUSIONS
  The relationships of POBF with parapapillary blood flow and calculated retrobulbar vascular resistance differs among normal subjects, glaucoma suspects, and OAG patients. This provides further evidence of vascular dysregulation in OAG.
authors.affiliation: Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, La Jolla, California 92037, USA.
authors.forename: Sunil
authors.initials: S
authors.lastname: Deokule
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Vizzeri
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Boehm
authors.forename: Christopher
authors.initials: C
authors.lastname: Bowd
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D001783:Blood Flow Velocity; D001794:Blood Pressure; D002829:Choroid / Q000098:blood supply*; D019842:Ciliary Arteries / Q000502:physiology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000503:physiopathology; D009880:Ophthalmic Artery / Q000502:physiology; D009898:Optic Disk / Q000098:blood supply*; D009915:Orbit / Q000098:blood supply*; D011446:Prospective Studies; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D012161:Retinal Artery / Q000502:physiology; D018615:Ultrasonography, Doppler, Color