title: Intravitreous bevacizumab injection: an experimental study in New Zealand white rabbits.
abstract: OBJECTIVE
  To determine the effects of intraocular pressure (IOP) and needle diameter on the amount of reflux after intravitreous bevacizumab injection.
  
  
  METHODS
  Prospective randomized interventional study. Twelve New Zealand white rabbits weighing approximately 2.5 to 3.5 kg each were randomized 1:1 to group 1 or group 2. Bevacizumab stained with trypan blue was used for intravitreous injection. To lower the IOP, eyes in group 2 underwent anterior chamber paracentesis before intravitreous injection. Two eyes in each group were injected using 27-, 30-, or 32-gauge needles. If a subconjunctival bleb formed after intravitreous injection, its diameter was measured using a caliper.
  
  
  RESULTS
  The median IOP in group 1 was 17.5 mm Hg. Eyes injected using 27-gauge and 30-gauge needles showed stained subconjunctival blebs with median sizes of 3 mm and 1.7 mm, respectively; eyes injected using 32-gauge needles showed no subconjunctival bleb formation. The median IOP in group 2 was 10.3 mm Hg. Eyes injected using 27-gauge needles showed stained subconjunctival blebs with a median size of 0.7 mm, and eyes injected using 30-gauge and 32-gauge needles showed no subconjunctival bleb formation.
  
  
  CONCLUSIONS
  Decreasing the IOP before intravitreous injection and using a smaller-gauge needle reduce the risk of drug reflux after intravitreous bevacizumab injection.
  
  
  CONCLUSIONS
  Intravitreous injection is an increasingly common route of drug delivery to treat ocular diseases. Techniques that maximize bioavailability are examined in this study.
authors.affiliation: Centro de Cirugía Oftalmológica, Universidad Central de Venezuela, Caracas, Venezuela.
authors.forename: Rafael T
authors.initials: RT
authors.lastname: Cortez
authors.forename: Gema
authors.initials: G
authors.lastname: Ramirez
authors.forename: Lucienne
authors.initials: L
authors.lastname: Collet
authors.forename: Pranjal
authors.initials: P
authors.lastname: Thakuria
authors.forename: G Paolo
authors.initials: GP
authors.lastname: Giuliari
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D001682:Biological Availability; D007267:Injections; D007429:Intraocular Pressure / Q000502:physiology*; D009339:Needles; D011446:Prospective Studies; D011817:Rabbits; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014822:Vitreous Body
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab