Silicone oil microdroplets from syringes with intravitreal anti-vascular endothelial growth factor and complement...

To quantify the amount of silicone oil in intravitreal anti-vascular endothelial growth factor and complement inhibitor injections in prefilled and commercial syringes (silicone-lubricated and silicone-free).

Patients deemed clinically appropriate to receive one of five intravitreal medications received the recommended dose. Syringes were overfilled such that 0.01-0.04mL remained after injection for analysis. Aflibercept and ranibizumab were available in prefilled syringes. Pegcetacoplan, faricimab, and avacincaptad pegol were prepared with Becton Dickinson polycarbonate (BD) syringes. Faricimab was also prepared in Ocuject VitreJect® (OV) silicone-free syringes. Samples were analyzed using spectral flow cytometry.

Silicone oil was found in all syringes. The lowest amounts of silicone oil were found in the Mili-Q water in OV syringes (4.02±0.3 particles per microliter) and ranibizumab 0.5 mg prefilled syringes (8.33±3.1). Intermediate levels of silicone oil were detected in aflibercept prefilled syringes (35.5±21.8) and faricimab in OV syringes (74.6±10.1), significantly greater than Mili-Q water in OV syringes and ranibizumab. Significantly higher levels of silicone oil were found with faricimab (324.9±30), pegcetacoplan (378.1±379.6), and avacincaptad pegol (113.5±14) in BD syringes than the low or intermediate groups. The filter needles used to draw up medications from vials likely contributed to the amount of silicone oil detected in the samples.

Commonly used BD polycarbonate syringes for intravitreal injections caused significantly higher levels of silicone oil to be injected into the eye than prefilled or silicone free syringes. Repeated injections with more viscous intravitreal drugs increase the amount of silicone oil in the vitreous, leading to symptomatic floaters.