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Wayne Tie, Stan Conston, Ron Yamamoto, Michael Jansen, Sepehr Bahadorani, Chelsey Krambeer, Daniel Kermany, Michael Singer; Reducing Dexamethasone intravitreal implant-related retinal injuries using a novel technique of intravitreal injection. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4445.
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© ARVO (1962-2015); The Authors (2016-present)
Dexamethasone intravitreal implant (Ozurdex) injections, while generally safe and efficacious, have been shown to cause vitreous hemorrhage and retinal injury during injection. In this experiment, by manipulating the injector using a new injection technique, the injection force of the Dexamethasone pellet is significantly reduced.
Six Dexamethasone (Dex) intravitreal implants were injected into an ex vivo water bath. Three Dex implant pellets were injected using rapid compression (within one second) of the actuator button, the Fast Injection group. Another three Dex implants were injected under the same conditions using a three-second technique to depress the actuator, the Slow Injection group.The average velocity was measured using high speed photography (240 frames per second). Impact velocity was measured at a distance 16 mm from the injector tip, representing the distance to the retina in a standard eye. Average acceleration was calculated using the difference between initial velocity and impact velocity. The impact force was calculated from the average pellet mass times the average acceleration.
The average pellet mass of the implant was 1.179 mg. In the Fast Injection group, the mean impact velocity of the pellet was 273.3 +/- 20.8 cm/sec and the mean impact force was 0.74 +/- 0.08 mN. In the Slow Injection group, the mean impact velocity was 21.7 +/- 3.6 cm/sec and the mean impact force was 0.04 +/- 0.027 mN. There was a significant reduction in velocity (p<0.0001) and impact force (p<0.0002) in the Slow Injection group compared to the Fast Injection group.
By depressing the Dexamethasone intravitreal implant injector over a longer time interval, the impact velocity and impact force of the Dex implant pellet were reduced by >90%. This injection time was reliably controlled by using a novel injection method—rolling the ball of the thumb across and down from the top of the actuator button throughout the duration of three seconds. This technique should reduce future instances of retinal damage from Dexamethasone intravitreal implant injections.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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