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Updated: Mar 23, 2026
Intravitreal Injection and Quantitation of Infection Parameters in a Mouse Model of Bacterial Endophthalmitis
Published on: February 6, 2021
EXPERIMENTAL VISUALIZATION AND QUANTIFICATION OF VITREOUS CONTAMINATION FOLLOWING INTRAVITREAL INJECTIONS
Hiroyuki Nakashizuka1, Jun Shoji, Hiroyuki Shimada
1Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
Purpose:
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.
Conclusion:
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.
