Purpose: To measure fluctuations in infusion pressure and intraocular pressure (IOP) during vitrectomy performed using a flow-based IOP control system.
Methods: Using 3 vitrectomized porcine eyes, the authors simultaneously measured infusion pressure and IOP during vitreous cutting and aspiration and after extraction of operative instruments in 23-gauge and 25-gauge system. The measurements were performed with the "IOP control" setting turned on or off. The efficacy of valved cannula and a built-in "IOP control limit" module in attenuation of infusion pressure fluctuation was evaluated.
Results: At set pressure of 30 mmHg and 60 mmHg, the mean infusion pressure levels were 43.7 mmHg and 78.7 mmHg in the vitreous cutting mode, 67.4 mmHg and 101.2 mmHg in the aspiration mode, and 72.8 mmHg and 115.8 mmHg after extraction of the operative instrument, respectively, when the 23-gauge system was used. Use of valved cannulas effectively attenuated fluctuations in both infusion pressure and IOP. When the IOP control limit setting was "on," the compensatory infusion pressure increase was markedly limited and similar to the set pressure level when the IOP control limit was set at Level 2. Similar results were obtained when a 25-gauge system was used.
Conclusion: Infusion pressure increased markedly during vitrectomy using a flow-based IOP control system.