Abstract
Purpose :
Vitreo-retinal surgery induces substantial fluctuations in intraocular pressure (IOP), which can be associated to intra/postoperative clinical complications. The aim of this study was to develop and test an intraocular monitoring system (IOMS) able to directly measure and automatically compensate real IOP variations during vitreo-retinal surgery.
Methods :
A standard 25-gauge 3-port vitrectomy was performed on an anesthetized porcine eye. A fiber optic pressure sensor was applied to measure IOP values during surgical maneuvers. The pressure sensor, with an outer diameter of 0.28 mm, was coupled with a 29-gauge chandelier and inserted into the eye through the 25-gauge valved trocar exploited for endoillumination. A peristaltic pump connected to the infusion line was used to automatically compensate positive or negative IOP variations by means of fluid aspiration or infusion. A three-way valve allowed disabling vitrector infusion when the peristaltic pump was turned on.
Results :
During standard vitrectomy, aspiration at 300 mmHg without cutting caused a IOP decrease from the setpoint value of 60 mmHg to 7 mmHg (Figure 1). When the peristaltic pump was enabled, under aspiration at 370 mmHg IOP remained within a range of about ±5 mmHg around the desired pressure level set to 25 mmHg. After scleral indentation, IOP increased up to 189 mmHg, while IOP values did not exceed 52 mmHg with the pump activated. The injection of external fluid during standard vitrectomy resulted in a rapid IOP increase to 315 mmHg in case of perfluoro and 209 mmHg in case of trypan blue, whereas pump activation allows maintaining IOP values lower than 60 mmHg under the same maneuvers.
Conclusions :
We proposed and investigated a new approach to provide real IOP data during vitreo-retinal surgery without requiring additional ocular incisions. IOMS proved effective in monitoring and compensating significant IOP variations that occur during different surgical maneuvers. The system is expected to be integrated with blood pressure data to provide the real-time estimate of ocular perfusion pressure, potentially increasing the quality and effectiveness of eye surgical treatments.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.