Abstract
BackgroundIntravitreal silicone oil droplets have been found in the vitreous. The aim of this study is to compare the rates of silicone oil released by different brands of commonly used syringes for intravitreal injection after agitation by flicking.MethodsThree models of two brands of syringes were analyzed for their rates of silicone oil release: Saldanha Rodrigues (SR) 1 mL insulin syringe (SR, Brazil, syringe 1), Becton–Dickinson (BD) Plastipak 1 mL insulin syringe (Brazil, syringe 2), and BD Safety-Glide 1 mL insulin syringe (USA, syringe 3). All syringes were tested under four different conditions: positive control (fluid with addition of silicone oil) without agitation (group 1, n = 5); positive control with agitation (group 2, n = 3); fluid only without agitation (group 3, n = 5); and fluid only with agitation (group 4, n = 5). Masked graders performed all analyses using light microscopy.ResultsAll syringes (1, 2, and 3) released silicone oil droplets in the positive control group regardless of the agitation status (groups 1 and 2). When no oil was added and the syringes were not agitated, only syringe 1 released silicone oil droplets (40% of samples). After agitation, syringes 1 and 3 released silicone oil droplets in all samples. Quantitative analysis showed a significantly (P = 0.011; 11.2 ± 2.9 vs. 0.6 ± 0.9, respectively) higher mean number of silicone oil droplets released by syringe 1 after agitation compared to no agitation. Syringe 1 also had significantly (P = 0.002, 11.2 ± 2.9 vs. 0.0 ± 0.0 vs. 2.2 ± 0.8, respectively) more droplets than syringes 2 and 3 after agitation.ConclusionsSyringes commonly used for intravitreal injections frequently release silicone oil droplets when agitated by flicking, especially the SR insulin ones. We recommend that they not be agitated at the time of intravitreal injection and that the manufacturers consider producing syringes adapted for intraocular use.
Highlights
Intravitreal silicone oil droplets have been found in the vitreous
The current study showed that flicking the syringes that are commonly used for intravitreal injections leads to a relevant release of silicone oil droplets
We performed this study for three major reasons: (1) some studies have shown that silicone oil was observed in the vitreous of patients treated with intravitreal injections [6,7,8, 14]; (2) we observed that patients who received injections with certain brands of syringes tended to have more oil droplets especially after the syringes were agitated; and (3) we speculated that a large amount of silicone oil released by syringes used to administer aflibercept might be associated with development of inflammation already reported [11,12,13,14]
Summary
The aim of this study is to compare the rates of silicone oil released by different brands of commonly used syringes for intravitreal injection after agitation by flicking. The number of indications for treatment has increased throughout the years when it became clear that intravitreal injections can slow, halt, or improve disease, leading to improved visual acuity. This treatment is important for vision and for quality of life and work productivity. Current on-label indications for intravitreal injections are AMD, macular edema secondary to diabetes and retinal vein occlusions, myopic choroidal neovascularization, and proliferative diabetic retinopathy [4, 5]
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