Intravitreal injection delivered volume under different environmental and training conditions

To evaluate the accuracy of intravitreal injection (IVI) volumes under varying environmental conditions and operator training levels.

Three syringe models (Becton-Dickinson Plastipak 1mL, Aflibercept Prefilled Syringe, and Zero Residual Silicone Oil-Free 0.2 mL) were tested with 30G needles. Distilled water was drawn against different background colors (beige, black, blue, green, and white) by a single trained operator. Later, three different operators (a medical student, an ophthalmology resident, and a vitreoretinal surgeon) performed the injections under three training conditions (no prior training, after proper training, and forced plunger depression). The 50 µl of water were expelled into Eppendorf tubes and both syringes and tubes were weighed before and after injection. The main parameters measured were the effective delivered volume and residual volume.

Significant differences were found among syringes (p < 0.001). Operator proficiency (p = 0.007) and training status (p < 0.001) also influenced volume accuracy. Post-hoc analysis revealed significant differences between clear green and black (p = 0.007), and between beige and black backgrounds (p = 0.008).

Our study revealed significant variations in IVI volumes, influenced by syringe type, operator proficiency, and background color. These findings emphasize the need to consider materials and techniques for precision in IVI.