title: Age-Related Changes in Ocular Blood Velocity in Suspects with Glaucomatous Optic Disc Appearance. Comparison with Healthy Subjects and Glaucoma Patients.
abstract: OBJECTIVE
  To evaluate retrobulbar blood flow characteristics of glaucoma suspects with glaucomatous optic disc appearance (GODA) in comparison to healthy control group (CG) and primary open angle glaucoma patients (POAG) and assess the effect of age.
  
  
  METHODS
  145 patients from a single glaucoma clinic were enrolled and classified into two diagnostic groups (GODA and POAG). Third group of subjects consisted of 67 age matched individuals (CG). Retrobulbar blood velocity measurement in central retinal artery was performed using color Doppler imaging (CDI). CDI images were processed in custom software leading a range of parameter estimates from a continuous waveform signal. The effect of age on the estimated parameters was evaluated with the stepwise forward regression and ANCOVA in which age was used as a continuous factor. One-way ANOVA was used to test for the differences in the CDI parameters between the three considered groups. Correlation between restive index (RI) and pulsatility index (PI) was assessed with a bilinear fitting guaranteeing no discontinuities in RI intercept estimate. Fisher test was used to assess the applicability of a bilinear PI/RI relationship, while the statistics of the RI intercept estimate were evaluated using the bootstrap.
  
  
  RESULTS
  ANCOVA showed significant interaction between age and group (p<0.05) for five out of nine considered CDI parameters. The RI intercept for CG and GODA groups was 0.602±0.047, and 0.574±0.044 respectively, while the RI intercept of 0.934±0.066 was found for the POAG.
  
  
  CONCLUSIONS
  The observed similarity of CG and GODA group and dissimilarity between GODA and POAG groups in terms of PI/RI relationship is remarkable. Age may play some role in the different mechanisms occurring in blood velocity dynamics in GODA and POAG subjects but it is not a strongly determining factor.
authors.affiliation: Department of Optics & Photonics, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Asejczyk-Widlicka
authors.affiliation: Department of Ophthalmology, Wroclaw Medical University, Wroclaw, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Krzyzanowska-Berkowska
authors.affiliation: Queensland University of Technology, School of Optometry, Brisbane, Australia.
authors.forename: Beata P
authors.initials: BP
authors.lastname: Sander
authors.affiliation: Department of Biomedical Engineering, Wroclaw University of Technology, Wroclaw, Poland.
authors.forename: D Robert
authors.initials: DR
authors.lastname: Iskander
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D005123:Eye / Q000098:blood supply* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000098:blood supply* / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies