title: ARE INTRAVITREAL INJECTIONS WITH ULTRATHIN 33-G NEEDLES LESS PAINFUL THAN THE COMMONLY USED 30-G NEEDLES?
abstract: OBJECTIVE
  This study investigated whether pain from intravitreal injections (IVIs) can be reduced by injecting with a 33-G needle instead of the commonly used 30-G needle. Additionally, several pain-related psychological factors were explored as predictors of outcome.
  
  
  METHODS
  This randomized crossover trial included 36 patients who received injections with both needles in randomized order. After the injection, patients rated IVI pain on a 0 to 10 scale. Before injection, distress and pain expectations were assessed. Afterward, patients rated the IVI procedure and anticipated consequences. In addition, we assessed the force necessary to penetrate the sclera for both needles in porcine eyes.
  
  
  RESULTS
  The 33-G needle did not result in lower IVI pain (2.8 vs. 3.1, P = 0.758) but tended to cause less vitreal reflux (0 vs. 5 times, P = 0.054). Factors related to more pain were distress, expecting IVI pain and discomfort, dissatisfaction with the preparation procedure, anticipating negative consequences, and female gender. Patients regarded povidone-iodine disinfection as particularly unpleasant. Exploration of the needles' mechanical properties showed that 33-G needles penetrate the sclera more easily.
  
  
  CONCLUSIONS
  The thinner 33-G needle does not reduce IVI pain but may limit scleral damage. Future efforts could be aimed at optimizing patient information, reducing distress, and the use of better tolerable disinfectants.
authors.affiliation: *Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands; †Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, Leiden, the Netherlands; and Departments of ‡Medical Psychology, and §Surgery, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: Freekje
authors.initials: F
authors.lastname: van Asten
authors.forename: Henriët
authors.initials: H
authors.lastname: van Middendorp
authors.forename: Samuël
authors.initials: S
authors.lastname: Verkerk
authors.forename: Myrte B
authors.initials: MB
authors.lastname: Breukink
authors.forename: Roger M L M
authors.initials: RM
authors.lastname: Lomme
authors.forename: Carel B
authors.initials: CB
authors.lastname: Hoyng
authors.forename: Andrea W
authors.initials: AW
authors.lastname: Evers
authors.forename: B Jeroen
authors.initials: BJ
authors.lastname: Klevering
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000068258:Bevacizumab / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004867:Equipment Design; D058447:Eye Pain / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D058449:Intravitreal Injections / Q000295:instrumentation*; D008269:Macular Edema / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009339:Needles; D010147:Pain Measurement; D012170:Retinal Vein Occlusion / Q000188:drug therapy; D011795:Surveys and Questionnaires; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors*; D057135:Wet Macular Degeneration / Q000188:drug therapy
chemical_list: D020533:Angiogenesis Inhibitors; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab