title: Dynamic retinal vessel response to flicker in age-related macular degeneration patients before and after vascular endothelial growth factor inhibitor injection.
abstract: OBJECTIVE
  Retinal vessel responses to flickering light are different in various systemic and ocular diseases and can be improved after successful therapy. We investigated retinal vessel response to flickering light in age-related macular degeneration (AMD) patients before and after treatment with a single intravitreal bevacizumab (Avastin(®) ) injection.
  
  
  METHODS
  In 10 patients with exudative AMD [age: median (1.quartile; 3.quartile) 76.0 (73.5; 80.0) years], retinal vessel reactions were examined by Dynamic Vessel Analyser (DVA) before and 3 months after a single intravitreal application of bevacizumab (1.25 mg). A baseline measurement was followed by three consecutive monochromatic flicker stimulations (530-600 nm, 12.5 Hz, 20 seconds). Temporal retinal vessel reaction was analysed and compared with the reaction in healthy controls.
  
  
  RESULTS
  Mean arterial dilation at the end of flicker was not different in all groups. For veins this parameter amounted to: pre-treatment, 2.6 (1.7; 3.9)%; post-treatment, 2.9 (2.4; 4.0)%; control, 4.3 (3.2; 5.7)%; significant: pre-treatment - control (Dunnett's procedure, p < 0.05). Maximal dilation occurred in arteries at: pre-treatment, 17.5 (14.8; 32.5) seconds; post-treatment, 18.0 (16.6; 30.6) seconds; control, 14.5 (10.8; 17.3) seconds. Both AMD groups were slower (p < 0.05): in veins at 17.0 (14.5; 20.0) seconds, 12.8 (8.6; 14.8) seconds and 18.5 (17.1; 19.9) seconds, respectively; significant post-treatment - control (p < 0.05). In the post-treatment AMD group arterial constriction after stimulation occurred more slowly compared with the control group (p < 0.05).
  
  
  CONCLUSIONS
  Dynamic retinal arterial and venous reactions to flickering light are altered in AMD compared with controls. Three months after a single injection of a vascular endothelial growth factor inhibitor, the investigated retinal dynamic vascular parameters were not altered in our study.
authors.affiliation: Department of Ophthalmology, Munich University of Technology, Munich, Germany.
authors.forename: Ines M
authors.initials: IM
authors.lastname: Lanzl
authors.forename: Seid-Fatima
authors.initials: SF
authors.lastname: Seidova
authors.forename: Mathias
authors.initials: M
authors.lastname: Maier
authors.forename: Chris
authors.initials: C
authors.lastname: Lohmann
authors.forename: Arno
authors.initials: A
authors.lastname: Schmidt-Trucksäss
authors.forename: Martin
authors.initials: M
authors.lastname: Halle
authors.forename: Konstantin E
authors.initials: KE
authors.lastname: Kotliar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage*; D000068258:Bevacizumab; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011446:Prospective Studies; D012161:Retinal Artery / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab