Feasibility test of an electromagnetically driven valve actuator for glaucoma treatment

Although conventional glaucoma implants have a capability of pressure regulation, they cannot maintain the intraocular pressure (IOP) desired for different patients. In this paper, we present an analysis of the operation of a conventional implant using a bond graph and show its defects and the limitations of a conventional valve analytically. On the basis of the analysis, the design and fabrication of an active valve actuator is performed considering actuation principles, resistance elements, and control methods. An electromagnetic actuator is used for realizing the active resistance element. A passive resistance element is also included in in order to reduce power consumption. A pulsewidth modulation (PWM) control method is used for enhancing the power consumption saving. Finally, we describe experiments and simulations with the fabricated valve actuator in an in vitro environment, and estimate the in vivo performance from the in vitro experimental results.