title: EXPERIMENTAL VISUALIZATION AND QUANTIFICATION OF VITREOUS CONTAMINATION FOLLOWING INTRAVITREAL INJECTIONS.
abstract: OBJECTIVE
  To detect and quantify vitreous contamination after intravitreal injection using an experimental vitreous contamination model.
  
  
  METHODS
  Enucleated porcine eyes served as a Type 1 experimental vitreous contamination model with fluoresbrite carboxylate microspheres applied to the conjunctival surface. Saline solution (0.05 mL) was injected using a 27-, 30-, or 32-gauge (G) needle. Injection procedures were monitored using an intraocular fiber catheter. Condensed microspheres were applied to an excised sheet of porcine sclera (Type 2 experimental vitreous contamination model). Saline solution (0.05 mL) was injected from the top of an applied condensed microsphere through the sclera using a needle of one of the aforementioned gauges, and samples were then collected. The fluorescence strength of samples was measured using fluorophotometry.
  
  
  RESULTS
  We visually detected fluorescent microspheres in 10/10, 9/10, and 9/10 eyes injected with 27-G, 30-G, and 32-G needles, respectively. In the experimental quantification study, values at all needle gauges were significantly higher than those of controls (P < 0.01). Fluorescence strength was significantly higher in the 27-G group than in the 30- (P < 0.01) and 32-G (P < 0.01) groups.
  
  
  CONCLUSIONS
  Intravitreal injection carries the risk of introducing contamination directly into the eyes even when a 32-G needle is used. Furthermore, the 27-G needle carries the highest contamination risk.
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakashizuka
authors.forename: Jun
authors.initials: J
authors.lastname: Shoji
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimada
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Yuzawa
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D009877:Endophthalmitis / Q000382:microbiology; D004866:Equipment Contamination; D015353:Eye Enucleation; D015590:Fluorophotometry; D058449:Intravitreal Injections / Q000009:adverse effects*; D008863:Microspheres; D009339:Needles / Q000382:microbiology*; D013552:Swine; D014822:Vitreous Body / Q000382:microbiology*