FLORENCE, Italy — Continuous monitoring of mean ocular perfusion pressure during pars plana vitrectomy may preserve patients from surgery-induced visual field defect, according to one surgeon.
“Unexplained visual field loss after vitrectomy has been reported in up to 14% of patients,” Tommaso Rossi, MD, said at the FLOREtina meeting.
The underlying cause, he explained, is an unbalance between arterial pressure and IOP, resulting in reduction of mean ocular perfusion pressure and consequent ischemia.
“During surgery, IOP is significantly higher than in baseline conditions due to the bottle being above 35 mm Hg, while blood pressure tends to be lower because patients are sedated. As a result, the ocular perfusion pressure may remain below safe values for up to 50% of surgery and optic nerve function may be compromised,” Rossi said.
New software with the Optikon 2000 R-Evolution vitrectomy system processes arterial pressure and IOP data, providing continuous, real-time measurement of mean ocular perfusion pressure during surgery.
Target mean ocular perfusion pressure values are set preoperatively, and during surgery, the machine signals whether the patient is within or beyond the safety threshold. The surgeon can therefore move the bottle up or down, depending on what the arterial pressure of the patient is at each moment.
“At end of surgery you get a report telling you the percentage of surgery and the overall number of minutes the patient spent on a certain perfusion pressure, which may help you understand why some patients have visual field loss after surgery,” Rossi said. – by Michela Cimberle
Disclosure: Rossi reports no relevant financial disclosures.