title: Ocular blood flow parameters after pars plana vitrectomy in patients with diabetic retinopathy.
abstract: BACKGROUND
  Whereas the anatomic result of vitrectomy in patients with vitreoretinal complications due to diabetes is usually satisfying, the functional outcome is sometimes poor. The authors investigated whether this may be related in part to effects of vitrectomy on ocular perfusion.
  
  
  METHODS
  Ocular hemodynamics were measured before vitrectomy and 1 and 4 weeks postoperatively in 13 consecutive diabetic patients. Pulsatile choroidal blood flow was assessed with laser interferometric measurement of fundus pulsation amplitude. In addition, mean blood flow velocity and resistive index in the ophthalmic artery, the central retinal artery, and the posterior ciliary arteries were measured with color Doppler imaging.
  
  
  RESULTS
  Fundus pulsation amplitude was significantly reduced after surgery as compared to baseline (baseline: 3.7 +/- 1.0 microm; 4 weeks: 3.1 +/- 0.8; P < 0.001). Postoperatively, mean blood flow velocity in the central retinal artery (P = 0.009) and the posterior ciliary arteries (P = 0.0006) was significantly reduced, whereas resistive index was increased in the central retinal artery (P = 0.028) but not in the posterior ciliary arteries.
  
  
  CONCLUSIONS
  The current data suggest that vitrectomy induces significant reductions in ocular blood flow in patients with diabetic retinopathy. Whether this may affect the visual outcome after vitrectomy or whether this reflects improved retinal oxygenation after vitrectomy remains to be established.
authors.affiliation: Department of Ophthalmology, University of Vienna, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Krepler
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Polska
authors.forename: Andreas
authors.initials: A
authors.lastname: Wedrich
authors.forename: Leopold
authors.initials: L
authors.lastname: Schmetterer
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D003930:Diabetic Retinopathy / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012039:Regional Blood Flow; D012161:Retinal Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color; D014821:Vitrectomy