Abstract: Systems and methods are disclosed for measuring fluid pressure in an ophthalmic surgical system. An example system comprises a fluid flow path and a pressure sensor system for measuring pressure in the fluid flow path. The pressure sensor system comprises a conductive, movable diaphragm having a first side and a second side, the first side of the diaphragm facing the fluid flow path, and an eddy current position sensor positioned on the second side of the diaphragm without contacting the diaphragm. The eddy current position sensor comprises a position sensor coil activatable by high frequency alternating current and signal conditioning electronics capable of sensing inductance or impedance or resonant frequency variation in the position sensor coil as a gap between the diaphragm and the position sensor coil changes and of translating that variation into a displacement signal correlated to fluid pressure. A method of measuring fluid pressure may be performed using one or more of the systems described herein.

Abstract: The present disclosure relates in general to an apparatus and method for priming a liquid or surgical cassette. In one embodiment, an infusion system within the liquid cassette is primed using a forward flow of a liquid and a backward flow of the liquid. The forward flow of the liquid creates a first volume of liquid stored within an infusion conduit, which is connected to an infusion chamber via a first valve. The infusion conduit has an infusion port exposed to a non-liquid environment having a first pressure. A second pressure is created in the infusion chamber that is lower than the first pressure. Opening the first valve causes a second volume of liquid within the infusion conduit to flow over the first valve and towards the infusion chamber. The second volume of liquid is less than or equal to the first volume of liquid.

Abstract: Embodiments of this disclosure provide an apparatus and method for gas and debris management. The apparatus comprises a surgical cassette, wherein the surgical cassette is at least partially formed of a cassette material defining a chamber. The surgical cassette has a floor and a plurality of walls. The apparatus also has a drain conduit with a drain entry and a drain exit. The drain entry is connected to the chamber near the floor. The drain conduit has a top portion and a bottom portion. The apparatus also has an aspiration conduit. The aspiration conduit has an aspiration port and an aspiration exit. The aspiration conduit is in liquid communication with the chamber and the drain conduit. At least a portion of the top portion of the drain conduit is positioned above at least a portion of the aspiration exit.

Abstract: In various embodiments, a pneumatic system valve for a surgical console may be controlled by a controller configured to adjust a valve duty cycle (VDC) of the valve to reduce a difference between the valve's differential pressure and a desired differential pressure. In some embodiments, average differential pressures may be detected and relayed from a pressure sensor, coupled to one or more ports of the valve, to the controller. The controller may compare the measured average differential pressure against the desired average differential pressure (e.g., received from the user). The controller may then determine a modified VDC to reduce a difference between the desired average differential pressure and the measured average differential pressure. In some embodiments, the desired average differential pressure may be determined based on input received from a user of the surgical console.

Abstract: Embodiments of this disclosure provide an apparatus and method for gas and debris management. The apparatus comprises a surgical cassette, wherein the surgical cassette is at least partially formed of a cassette material defining a chamber. The surgical cassette has a floor and a plurality of walls. The apparatus also has a drain conduit with a drain entry and a drain exit. The drain entry is connected to the chamber near the floor. The drain conduit has a top portion and a bottom portion. The apparatus also has an aspiration conduit. The aspiration conduit has an aspiration port and an aspiration exit. The aspiration conduit is in liquid communication with the chamber and the drain conduit. At least a portion of the top portion of the drain conduit is positioned above at least a portion of the aspiration exit.

Abstract: The present disclosure relates in general to an apparatus and method for priming a liquid or surgical cassette. In one embodiment, an infusion system within the liquid cassette is primed using a forward flow of a liquid and a backward flow of the liquid. The forward flow of the liquid creates a first volume of liquid stored within an infusion conduit, which is connected to an infusion chamber via a first valve. The infusion conduit has an infusion port exposed to a non-liquid environment having a first pressure. A second pressure is created in the infusion chamber that is lower than the first pressure. Opening the first valve causes a second volume of liquid within the infusion conduit to flow over the first valve and towards the infusion chamber. The second volume of liquid is less than or equal to the first volume of liquid.

Abstract: A dual pump aspiration system having both a vacuum level control loop and a flow rate control loop. The system can be operated either as a vacuum priority system or a flow rate priority system.

Abstract: A surgical cassette have a rigid fluid channel formed into a rigid plastic component or housing. The piezoelectric crystals of an ultrasonic flow meter are positioned on one side of the fluid channel. The side wall of the fluid channel opposite the piezoelectric crystals is exposed to fluid in the flow channel on its interior side and is exposed to ambient air on its exterior side. The interface between the wall and the air acts as an acoustic reflector for the operation of the ultrasonic flow meter.

Abstract: A microsurgical system capable of controlling aspiration and detecting an occlusion via monitoring a change in either suction flow rate or suction impedance.

Abstract: A method for operating a peristaltic pump having a molded flow channel contained on an elastomeric sheet that is bonded or mechanically attached to a rigid substrate. The pump head rollers are mounted radially from the axis of rotation of the pump motor and compress the elastomeric flow channels against the rigid substrate. During reflux, the pump head is positioned so that at least one of the rollers compresses the elastomeric flow channel at the input end of the peristaltic pump. Such an operation minimizes the amount of the elastomeric sheet that is exposed to high transient pressures.

Abstract: A cassette for use with a peristaltic pump. The cassette having a body having an exterior. Additionally, the cassette has a sheet attached to the body forming at least one fluid channel. The fluid channel being generally arcuate and projecting outwardly from the exterior of the body. The fluid channel having at least one outlet port for receiving a liquid. Furthermore, the cassette has a liquid trap in fluid communication with and extending at least in part in an upward direction from the at least one outlet port.

Abstract: An improved method for adaptively cancelling acoustic feedback in hearing aids and other audio amplification devices. Feedback cancellation is limited to a frequency band that encompasses all unstable frequencies. By limiting the bandwidth of the feedback cancellation signal, the distortion due to the adaptive filter is minimized and limited only to the unstable feedback regions. A relatively simple signal processing algorithm is used to produce highly effective results with minimal signal distortion.

Abstract: An improved method for adaptively cancelling acoustic feedback in hearing aids and other audio amplification devices. Feedback cancellation is limited to a frequency band that encompasses all unstable frequencies. By limiting the bandwidth of the feedback cancellation signal, the distortion due to the adaptive filter is minimized and limited only to the unstable feedback regions. A relatively simple signal processing algorithm is used to produce highly effective results with minimal signal distortion.

Abstract: In various embodiments, a pneumatic system valve for a surgical console may be controlled by a controller configured to adjust a valve duty cycle (VDC) of the valve to reduce a difference between the valve's differential pressure and a desired differential pressure. In some embodiments, average differential pressures may be detected and relayed from a pressure sensor, coupled to one or more ports of the valve, to the controller. The controller may compare the measured average differential pressure against the desired average differential pressure (e.g., received from the user). The controller may then determine a modified VDC to reduce a difference between the desired average differential pressure and the measured average differential pressure. In some embodiments, the desired average differential pressure may be determined based on input received from a user of the surgical console.

Abstract: Embodiments of the present invention provide a system and method for detecting the level of a fluid in a surgical cassette by projecting light from a linear light source into a wall of a cassette. Depending on the amount a light reflected or refracted in the cassette (i.e., due to the cassette material/fluid interface or cassette material/air interface (or other interface)) various portions of a linear sensor array will be more or less illuminated. By examining the illumination of the linear sensor array, the level of fluid in the chamber can be determined.

Abstract: An improved surgical cassette for controlling intraocular pressure during ophthalmic surgery.

Abstract: A continuous high resolution fluid level monitoring system is provided by embodiments of the present invention. This continuous high resolution fluid level monitoring system includes a unique fluid level sensor having a point light source, parabolic reflector, sensor array, and detection, processing and control system. The point light source illumines a parabolic reflector wherein the point light source is located at the focus of the parabolic reflector. The parabolic reflector reflects light from the point light source to produce a parallel light curtain. This parallel light curtain is parallel to an axis of symmetry of the parabolic reflector. The parallel light curtain illumines a chamber such as a chamber in an ophthalmic surgical device used to contain surgical fluid. The sensor array coupled to the chamber detects the parallel light curtain illuminating the chamber. The sensor array provides an output to a detection/processing/control system in order to determine the fluid level within the chamber.

Abstract: An improved surgical cassette for controlling intraocular pressure during ophthalmic surgery.

Abstract: Embodiments of the present invention provide a system and method for detecting the level of a fluid in a surgical cassette by projecting light from a linear light source into a wall of a cassette. Depending on the amount a light reflected or refracted in the cassette (i.e., due to the cassette material/fluid interface or cassette material/air interface (or other interface)) various portions of a linear sensor array will be more or less illuminated. By examining the illumination of the linear sensor array, the level of fluid in the chamber can be determined.

Abstract: Embodiments of the present invention provide a system and method for detecting the level of a fluid in a surgical cassette by projecting light from a linear light source into a wall of a cassette. Depending on the amount a light reflected or refracted in the cassette (i.e., due to the cassette material/fluid interface or cassette material/air interface (or other interface)) various portions of a linear sensor array will be more or less illuminated. By examining the illumination of the linear sensor array, the level of fluid in the chamber can be determined.