Background/objectives: To investigate whether agitation promotes the release of silicone oil by different models of syringe used for intravitreal injection.
Methods: This lab study analyzed eight syringe models by light microscopy for the release of silicone oil under agitation (flick), without agitation, and positive controls. Fourier-Transform Infrared Spectroscopy (FTIR) was performed to identify the molecular compounds inside the syringes.
Results: A total of 240 syringes were analyzed. The presence of silicone oil droplets was observed in all positive controls. When agitated by flicking, 100% of the samples of the syringes disclosed silicone oil, except the BD Plastipak syringe, which presented 40% of positivity. Without agitation, a smaller percentage of samples with silicone oil was observed. Agitation by flicking had a 265-fold greater chance of presenting oil droplets when compared with the syringes without agitation. There was a statistically significant difference between the three conditions (P < 0.05). Analysis of the tip of the plunger rubber by FTIR indicated the presence of polysiloxane (silicone oil) in all models of syringe.
Conclusions: Agitation of the syringe promotes the release of silicone oil. It is recommended to improve the technique of injection and the manufacture of specific syringes for ophthalmological use.