Abstract
Purpose :
This study aims to 1) understand IOP stability during vitreous removal with 27+Gauge (Ga) dual-cutting, 20K cuts per minute (cpm) beveled vitrectomy probes; 2) understand the operation time of vitreous removal during a vitrectomy.
Methods :
27+® HYPERVIT® beveled 20K cpm vitrectomy probes were driven by a CONSTELLATION® Vision System (Alcon Vision, LLC.) to aspirate porcine 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. For each testing, 4cc of fresh porcine vitreous was filled into the eye model. Six samples were tested under core duty cycle, vacuums of 250mmHg, 450mmHg and at 650mmHg and cut rate of 20,000cpm. Both system IOP compensation enabled and disabled were used with 30mmHg as the initial infusion pressure. Average IOP fluctuation during aspiration, final stable IOP and 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 for vacuums of 250, 450 and 650 mmHg were -0.018 ± 0.003, -0.049 ± 0.007 and -0.094 ± 0.009 mmHg/s, respectively, demonstrating significant fluctuation rate differences between each vacuum setting (p<0.05). With IOP compensation, average IOP fluctuation rates significantly decreased to 0.004 ± 0.003, 0.010 ± 0.007, and 0.011 ± 0.010 mmHg/s for the same vacuums compared with IOP off (p<0.05). No significant difference of IOP fluctuation rate was shown between each vacuum setting (p>0.05).
Without IOP compensation, the final stable IOP after removing vitreous at vacuums of 250, 450, and 650 mmHg were 23.14 ± 0.50, 16.05 ± 0.79, and 8.49 ± 0. 44 mmHg, respectively. With IOP compensation, IOP maintained at 31.32 ± 0.93, 31.33 ± 1.01, and 31.46 ± 1.09 mmHg for the same vacuums. Corresponding operation times of complete removal of 4cc vitreous were 366s, 289s, and 230s, respectively.
Conclusions :
At maximum cut rate, 27+® Ga 20K cpm probe with IOP compensation provides stable IOP and less fluctuation during vitrectomy for different vacuum levels compared to no compensation. IOP compensation is an essential feature for surgeons to efficiently control the fluidics environment during posterior segment procedures.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.