Purpose: To investigate the effect of injection technique parameters on the formation of multiple gas bubbles in a porcine eye model for pneumatic retinopexy.
Methods: Three hundred twenty-four adult porcine eyes were injected with 0.4 mL of C3F8 with variations in the depth of injection, speed of injection, and size of needle bore. The number of gas bubbles in the eye was assessed with indirect ophthalmoscopy.
Results: Shallow injections resulted in a higher incidence of a single bubble than did deep injections (P < 0.001; Fisher exact and Wilcoxon rank sum tests). Slow injections were significantly advantageous in producing a single gas bubble during shallow as well as during deep injections (P < 0.001, Fisher exact and Wilcoxon rank sum tests). With a shallow needle insertion, the slow speed of injection produced a single bubble in 75.9% of the eyes, whereas moderately brisk injections resulted in one bubble in 50.9% of the eyes. During deep needle insertion, 44.4% of the eyes had one bubble if the gas was injected slowly and only 11.1% had a single bubble with moderately brisk gas injections. The bore of the needle did not significantly change the number of bubbles during deep or shallow injections.
Conclusions: The factors that were found to be important in reducing the formation of multiple gas bubbles in the eye were shallow depth of injection and slow speed of gas delivery.