Incidence of Presumed Silicone Oil Droplets in the Vitreous Cavity After Intravitreal Bevacizumab Injection With Insulin Syringes.

Importance: Intravitreal bevacizumab is a frequently used antivascular endothelial growth factor medication in the United States, but its off-label use is associated with risks associated with the compounding preparation.

Objective: To determine the incidence of presumed silicone oil droplets after intravitreal bevacizumab was prepared in insulin syringes by a compounding pharmacy.

Design, Setting, and Participants: A retrospective review was conducted of 60 patients who experienced intravitreal silicone oil droplets in the eye after intravitreal bevacizumab injections from a single specialist practice from October 1, 2015, to November 30, 2016. Bevacizumab, 1.25 mg/0.05 mL, was delivered in insulin syringes with a 31-gauge needle.

Main Outcomes and Measures: Small, round clear spheres in vitreous on dilated biomicroscopic retinal examination.

Results: Over a 14-month period involving 6632 intravitreal bevacizumab injections, 60 cases (35 [58%] women) of intravitreal silicone droplets were identified. Mean [SD] age of the patients was 80 [12] years; the population comprised 48 white, 9 Asian, and 3 Hispanic patients. The incidence of silicone oil droplet injections was 0.03% (1 of 3230) from October 2015 to April 2016 and 1.7% (59 of 3402) from May to November 2016 (Fisher exact test, P < .001; odds ratio [OR], 57; 95% CI, 9.8-2260). From May to November 2016, nonpriming the syringe before the intravitreal injection had a higher risk of intravitreal silicone oil droplets compared with priming the syringe (6.4% [47 of 739] vs 0.5% [12 of 2627]; Fisher exact test, P < .001; OR, 15.1; 95% CI, 7.9-33.4). Among the 60 cases, 41 patients (68%) were symptomatic, and the main symptom was floaters with spots of light. Among the patients with floaters, 36 (88%) improved over time (range, 2-8 months) despite the silicone droplets still being present on ophthalmoscopic examination.

Conclusions and Relevance: An increase in intravitreal silicone oil associated with bevacizumab prepared with insulin syringes was documented. Priming the syringe before injection was associated with a lower frequency of this complication. These findings suggest that physicians should counsel their patients on the risk of floaters with intravitreal bevacizumab preloaded in insulin syringes.