Experimental Application of Piezoelectric Actuator-Driven Pulsed Water Jets in Retinal Vascular Surgery

To report on the effectiveness and safety of an ophthalmic piezoelectric actuator-driven pulsed water jet (ADPJ) system adapted for intraocular use.

First, we determined the highest ADPJ flow rate that did not cause an unsafe rise in intraoperative intraocular pressure (IOP) in rabbits (n = 4). Next, we determined the most effective ADPJ frequency (in hertz) at that flow rate. Finally, we visualized the ADPJ stream, measured its pressure, and determined the minimum voltage and distance between the ADPJ needle and retinal veins to induce intravenous displacement of the blood column (DBC) through massage of the outer retinal vessels (n = 3) while not causing retinal tearing or hemorrhage.

We found that a 0.05 mL/min ADPJ flow rate caused IOP to rise above 40 mm Hg after 1 minute, but that at 0.025 mL/min, IOP stayed below 40 mm Hg even after 3 minutes. Moreover, we found that a 0.025 mL/min ADPJ stream was stable at a pulse frequency of 10 Hz and that at this flow rate/frequency the ADPJ pressure was closely correlated with the applied voltage (P < 0.001, r² = 0.9991). The minimum voltage and distance to achieve intravenous DBC without causing retinal tearing or hemorrhage were 40 V and 0.5 mm, respectively.

With an appropriate flow rate and surgical time, ADPJ successfully induced massage of the retinal vessels and intravenous DBC while maintaining safe IOP and not causing retinal complications.

The ADPJ system has promise as a safe and minimally invasive instrument for the intraocular surgical treatment of human retinal vascular diseases.