Author: Ying Zhu (United States)
Co-authors: Val Kolesnitchenko, Vara Wuyyuru
Purpose
To understand intraocular pressure (IOP) compensation performance for 25 Gauge (Ga) dual-cutting, 20K cuts per minute (cpm) beveled vitrectomy probes under different system settings; to compare IOP compensation performance for 25 Ga dual-cutting, 20K cpm beveled vitrectomy probes with previous generation 25 Ga single-cutting, 10K cpm beveled vitrectomy probes.
Setting/Venue
Various laboratory bench tests
Methods
Both 25 Ga dual-cutting 20K cpm beveled and single-cutting 10K cpm beveled vitrectomy probes were driven by a dual-pneumatic vitrectomy system with IOP control to aspirate sterile irrigating solution 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 250 mmHg, 450 mmHg and 650 mmHg. Cut rate ranged from 2500 cpm to 10,000 cpm for 10K probes and 2500 cpm to 20,000 cpm for 20K probes. Both system IOP compensation enabled and disabled settings were used. The average IOP during aspiration was calculated for each test setting and statistical analyses were performed using Welch’s t-test with statistical significance level of p<0.05.
Results
Without IOP compensation, changing the cut rate did not generate a significant difference for 20K probes (p>0.05). IOP ranged from 21.80 ± 0.59 mmHg to 21.96 ± 0.60 mmHg for 250 mmHg, 13.93 ± 0.96 mmHg to 14.32 ± 1.11 mmHg for 450 mmHg and 7.19 ± 1.36 mmHg to 7.47 ± 0.98 mmHg for 650 mmHg. However, IOP level for 10K probes was statistically different when the cut rate changed. IOP ranged from 25.07 ± 0.26 mmHg to 27.63 ± 0.30 mmHg for 250 mmHg, 19.86 ± 0.29 mmHg to 24.14 ± 0.53 mmHg for 450 mmHg, and 14 .85 ± 0.41 mmHg to 17.81 ± 0.49 mmHg for 650 mmHg. When IOP control was enabled, IOP for 20K probes and 10K probes were not significantly influenced by cut rate changes. 20K probes’ IOP at maximum cut rate significantly increased to 32.32 ± 1.07 mmHg for 250 mmHg, 33.25 ± 1.55 mmHg for 450 mmHg and 37.12 ± 4.04 mmHg for 650 mmHg compared with result without IOP compensation (p<0.05). With IOP compensation, IOP of 10K probes was similar to that of 20K probes.
Conlusions
25 Ga dual-cutting 20K cpm vitrectomy probes have a more constant IOP when cut rate changes without IOP control compared to the previous generation single-cutting 10K cpm vitrectomy probes. Using IOP compensation can help surgeons to keep the eye at stabilized IOP ranges during aspiration of 25 Ga dual-cutting 20K cpm vitrectomy probes and maintain the efficiency of aspiration.
Financial Disclosure
The study is funded by Alcon Research. Ying Zhu, Val Kolesnitchenko and Vara Wuyyuru are employees of Alcon
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