Abstract
Purpose :
1) To evaluate the vitreous flow rate of the 25+® Gauge (GA) and 27+® GA dual cutting, 20,000 cuts per minute (cpm) beveled vitrectomy probes under various system settings; 2) Compare the performance of the 20K beveled probes with previous generation 10K beveled probes.
Methods :
The 25+ GA and 27+ GA HYPERVIT® beveled20K vitrectomy probes were driven by the CONSTELLATION® Vision System (Alcon Vision, LLC.) to aspirate porcine vitreous. A precision balance (Mettler Toledo, XS) was used to chart and record mass change during aspiration over 1 min.
Flow rates were evaluated ranging from 2.5K to 20K cpm. Three duty cycles were evaluated for each cut rate: core, 50/50, and shave. Vacuum was kept constant at 650 mmHg. For each probe gauge, 6 probes were used to measure flow rate and each duty cycles’ cut rate was tested at least 3 times. Average flow rate was calculated for each setting and statistical analysis was performed using Welch’s T-Test with a statistical significance level of p<0.05.
Results :
At the maximum cut rate for the three duty cycles of core, 50/50, and shave, the 25+®GA probe flow rates were 3.52±0.26, 3.47±0.26, and 3.64±0.15 cc/min, respectively. Corresponding flow rates for the 27+®GA probes were 2.17±0.16, 2.09±0.18, and 2.07±0.22 cc/min, respectively. Statistical analysis indicated significant differences in flow rate for cut rates less than 7.5K cpm compared to the maximum cut rate under same duty cycles and vacuum (p<0.05) and no significant difference was shown between each duty cycle (p<0.05) for both probe gauges.
When operating at maximum cut rate of 20K cpm at core duty cycle, the 25+®GA and 27+®GA HYPERVIT® beveled achieved flow rates 23.61% and 19.63%, respectively, higher than the previous generation 25GA and 27GA Advanced ULTRAVIT® probe flow rates at maximum cut rate of 10K cpm, (p<0.05).
Conclusions :
The aspiration flow rate did not significantly change by duty cycle for all cut rates for both 25+®GA and 27+®GA HYPERVIT® beveled 20K vitrectomy probes. In addition, for all probes, aspiration flow rates increased as cut rate increased. In comparison with previous generation Advanced ULTRAVIT® probes, the HYPERVIT® beveled vitrectomy probes achieved higher flow rates.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.