Abstract
Purpose :
Since most commonly used syringes for intravitreal injection have not been developed for this purpose and due to the low drug volume, we decided to assess their accuracy and residual volume.
Methods :
Eight syringe models (BBraun Injekt-F 1 mL, BBraun Omnifix-F 1 mL, BD Plastipak Brazil 1mL, BD Plastipak Spain 1 mL, BD Ultra-Fine 0.3 mL, HSW Norm-Ject 1 mL, Zero Residual 0.3 mL, and Zero Residual Silicone Oil-free 0.2 mL) were tested with 2 different needle setups (TSK “The Invisible Needle”, and Zero Residual), with 2 different solutions (distilled water or glycerin) and target volumes (50 and 70 uL). Ten samples were included in each subgroup, totaling 80 samples for 7 syringe models (half with each needle model) and 40 for the BD Ultra-Fine (own staked-in needle). Syringe-needle setups were weighed with a 0.1 mg precision scale before liquid withdrawal, with it, and after its release. Additionally, the ejected volume was also weighed in an Eppendorf tube. The residual and the delivered volumes were then obtained. One-way ANOVA was used for statistical analysis. Data are presented as mean ± standard deviation as well as percentage of exceeding volume from the target.
Results :
A total of 600 syringe-needle setups were tested. BD Ultra-Fine (0.34 ± 0.28 uL), Zero Residual (1.53 ± 1.15 uL) and Zero Residual Silicone Oil-free (1.40 ± 1.16 uL) showed the lowest residual volume (p=0.000) in comparison to the others (range: 24.86 ± 1.78 uL for Injekt-F to 51.97 ± 3.37 uL for Omnifix-F). Regarding accuracy, the most accurate were: Zero Residual Silicone Oil-free (0.70% of volume excess), Zero Residual (4.49%), BD Ultra-Fine (7.83%), Injekt-F (9.42%), Norm-Ject (15.88%), Omnifix-F (16.96%), BD Plastipak Brazil (17.96%), and BD Plastipak Spain (19.41%). A pair-wise comparison showed a statistically significant difference between the ZR Silicone Oil-free to all others (p=0.000), except when compared to the Zero Residual (p=0.029).
Conclusions :
There is a remarkable difference in accuracy and residual volume across multiple syringe models employed in the real world of intravitreal injection. Increased intraocular pressure, potentially leading to severe visual loss, might be of concern as a consequence of volume excess. Additionally, drug lost to the dead space might have pharmacoeconomic implications.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.