Abstract
Purpose :
As IOP maintenance during vitrectomy surgery is a critical parameter, the study aims to 1) understand the IOP performance of 25+Gauge (Ga) dual-cutting, 20K cuts per minute (cpm) beveled vitrectomy probes under different system settings, and 2) help surgeons to optimize their system settings during surgery.
Methods :
25+® HYPERVIT® beveled 20K cpm vitrectomy probes were driven by a CONSTELLATION® Vision System (Alcon Vision, LLC.) to aspirate sterile irrigating solution (BSS®) 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. Six samples were tested under core duty cycle and vacuums of 250mmHg, 450mmHg and 650mmHg. Cut rate ranged from 2500cpm to 20,000cpm. Both system IOP compensation enabled and disabled were used. Average IOP during aspiration was calculated for each test setting and statistical analyses were performed using Kruskal-Wallis test with statistical significance level of p<0.05.
Results :
At 450mmHg, without IOP compensation, the IOP ranged from 13.93 ± 0.96 to 14.32 ± 1.11mmHg when the cut rate changed from 2500cpm to maximum cut rate of 20,000cpm. When IOP compensation was enabled, IOP ranged from 33.21± 1.06 to 33.25 ± 1.55mmHg for cut rates from 2500cpm to 20,000cpm. Statistical analysis indicated that there was no significant difference between results using various cut rates for both IOP compensation enabled and disabled (p>0.05).
At the maximum cut rate and without IOP compensation, IOP was 21.96 ± 0.60 mmHg under 250mmHg, 14.32 ± 1.11mmHg under 450mmHg and 7.47 ± 0.98mmHg under 650mmHg. Corresponding average flow rate was 6.54 ± 0.13 cc/min under 250mmHg, 10.64±0.1 cc/min under 450mmHg and 14.08 ± 0.09 cc/min under 650mmHg. When IOP compensation was enabled, IOP at maximum cut rate significantly increased to 32.32 ± 1.07mmHg (47% improvement) for 250mmHg, 33.25 ± 1.55mmHg (132% improvement) for 450mmHg, 37.12± 4.04 mmHg (397% improvement) for 650mmHg compared with result without system’s intervention (p<0.05).
Conclusions :
25+® Ga Dual-Cutting 20K cpm vitrectomy probes have constant IOP performance under different cut rates. IOP compensation keeps the eye at improved IOP ranges during aspiration. 25+® Ga 20K cpm vitrectomy probe using IOP compensation offer surgeon flexible operation settings as well as a controllable and efficient process.
This is a 2021 ARVO Annual Meeting abstract.