Abstract
Purpose :
This study aims to 1) understand the IOP performance of 25+® Gauge (Ga) dual-cutting, 20K cuts per minute (cpm) beveled vitrectomy probes used for vitreous removal during a vitrectomy; 2) understand the operation time of vitreous removal during a vitrectomy.
Methods :
25+® HYPERVIT® beveled 20K cpm vitrectomy probes were driven by a CONSTELLATION® Vision System (Alcon Vision, LLC.) to aspirate vitreous in a hollow acrylic eye model. A digital transducer (OMEGA, PX409-001GUSBH) was connected to the bottom of eye model to detect IOP change during aspiration. 4cc of fresh porcine vitreous was filled into the eye model per testing. Six samples were tested under core duty cycle, vacuums of 250mmHg, 450mmHg and 650mmHg and cut rate of 20,000cpm. Both system IOP control enabled and disabled were used with 30mmHg as the initial IOP setting. Average IOP fluctuation during aspiration, final stable IOP, average operation time of vitreous removal were calculated for each test setting. Statistical analyses were performed on average IOP fluctuation rate using Welch’s t- test with p<0.05.
Results :
Without IOP compensation, the average fluctuation rate was -0.035 ± 0. 006mmHg/s for 250mmHg, -0.105 ± 0.008mmHg/s for 450mmHg and -0.175 ± 0.021mmHg/s for 650mmHg, which showed significant differences between each vacuum setting(p<0.05). After enabling IOP compensation, average IOP fluctuation rate significantly reduced to 0.001±0. 005mmHg/s, 0.004 ±0.007 mmHg/s and 0.005±0.010 mmHg/s at vacuums of 250, 450 and 650mmHg(p<0.05). There was no significant difference of IOP fluctuation rate between vacuum settings (p>0.05).
Without IOP compensation, the final stable IOPs after removing vitreous at vacuum settings of 250mmHg, 450mmHg and 650mmHg were 22.11±1.80mmHg, 15.12± 0.41mmHg and 7.11± 1.20mmHg. With IOP compensation, the IOP level maintained at 30.75 ± 0.24 mmHg, 30.72 ± 0.84mmHg, and 30.52 ± 0.92 mmHg for the same vacuums. Corresponding operation times of complete removal of vitreous were 206s, 145s and 129s respectively.
Conclusions :
During vitreous removal at the maximum cut rate, 25+® Ga 20K cpm vitrectomy probes with IOP compensation maintain IOP at improved levels with less fluctuations compared with no compensation. Using IOP compensation and 20K cpm vitrectomy probe in a 25G vitrectomy procedure can help surgeons to achieve a stable and efficient vitreous removal process.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.