Purpose: To evaluate the post occlusion surge characteristics of venturi and peristaltic-generated vacuum levels. Setting: University setting, Salt Lake City, Utah. Design: Experimental study. Methods: The Johnson and Johnson Veritas machine and Ellips FX handpiece with standard pack tips, with variable peristaltic and venturi settings, were used. A standard quadrant removal preset had the settings: vacuum 450mmHg, aspiration 60mmHg, bottle heights 41 cm and 81 cm. To monitor pressure changes, a rubber disk was fixed within a sealed chamber fitted with an electric sensor. The phaco tip was inserted through a small opening; the foot pedal was set to position three. The tip was in contact with the disk to replicate tip occlusion, then pulled from the disk to simulate occlusion break. Ten trials were performed for each IOP and vacuum type. Results: A significant difference ( P < .01) was observed in post-occlusion surge magnitude between venturi and peristaltic pumps at 41 cm and 81 cm bottle heights. No significant difference was observed in surge duration at either bottle height. Average duration of surge for venturi and peristaltic at 41 cm was 1.56s ± 0.75 and 2.25s ± 0.40, respectively; at 81 cm 2.27s ± 1.41 and 2.90s ± 1.10, respectively. Conclusions: Data suggest that at bottle heights of 41 and 81 cm, with indicated settings, venturi settings on the Veritas platform have a lower post-occlusion surge magnitude compared to peristaltic settings. This indicates that there may be a platform-specific lower risk of posterior capsular tear when using venturi settings in the Veritas system during cataract surgery.
Soule et al. (Tue,) studied this question.