title: Lack of spontaneous venous pulsation: possible risk indicator in normal tension glaucoma?
abstract: OBJECTIVE
  Recently, the absence of spontaneous venous pulsation (SVP) has been suggested as a vascular risk factor for primary open-angle glaucoma (POAG). As the mechanism behind this phenomenon is still unknown, the authors have studied this vascular component using colour Doppler imaging (CDI).
  
  
  METHODS
  A total of 236 patients were divided into three diagnostic groups: healthy controls (81), POAG (86) and normal tension glaucoma (NTG; 69). All subjects were submitted to CDI studies of the retrobulbar circulation, intraocular pressure measurements and assessment of SVP existence. Mann-Whitney, chi-square contingency tables and Spearman correlations were used to explore differences and correlations between variables in the diagnostic groups.
  
  
  RESULTS
  Eighty-two percent of healthy controls had SVP (66/81), while a smaller numbers were registered in both glaucoma groups: POAG - 50% (43/86); NTG - 51% (35/69). In NTG patients, but not in POAG patients, the prevalence of the SVP phenomenon decreases with increased glaucoma damage (p = 0.04; p = 0.55, respectively). Overall glaucoma patients from both groups had lower central retinal vein (CRV) velocities than the healthy controls (p < 0.05). NTG patients with SVP had less severe visual field defects (mean defect -6.92 versus -11.1, p < 0.05), higher [correction added after online publication 21 September 2012; the word 'higher' has been inserted to replace the word 'lower'] peak systolic and mean flow velocities in the central retinal artery (p < 0.01; p < 0.05, respectively) as well as higher [correction added after online publication 21 September 2012; the word higher has been inserted to replace the word lower] maximal velocities and RI of the CRV (p < 0.02; p < 0.05, respectively).
  
  
  CONCLUSIONS
  Glaucoma patients have a decrease in CRV velocities. SVP is less prevalent in glaucoma patients than in healthy individuals. This phenomenon apparently reflects different hemodynamic patterns in the central retinal vessels. This variable may be of particular importance in NTG patients, where it may be associated with more advanced functional damage.
authors: Department of Ophthalmology, Centro Hospitalar de Lisboa Central, Portugal.
authors: Luís
authors: L
authors: Abegão Pinto
authors: Evelien
authors: E
authors: Vandewalle
authors: Eline
authors: E
authors: De Clerck
authors: Carlos
authors: C
authors: Marques-Neves
authors: Ingeborg
authors: I
authors: Stalmans
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005902:Glaucoma, Open-Angle / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D057066:Low Tension Glaucoma / Q000503:physiopathology*; D008875:Middle Aged; D009915:Orbit / Q000098:blood supply; D012039:Regional Blood Flow / Q000502:physiology; D012169:Retinal Vein / Q000503:physiopathology*; D012307:Risk Factors; D014065:Tonometry, Ocular; D018615:Ultrasonography, Doppler, Color; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields