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.

Abstract: Embodiments of the present invention provide a system and method for determining the location of the bottom of a fluid chamber in a surgical cassette to calibrate the surgical system. According to one embodiment, the surgical cassette is shaped to allow light from a light source to pass unobstructed to a linear sensor array in an area that is a known distance from the bottom of a fluid chamber. Light rays intersected by solid cassette material, on the other hand, will insufficiently illuminate the linear sensor array. Because the slot is a known distance from the bottom of the chamber, the location of the bottom of the chamber can be determined by determining the transition between illuminated and insufficiently illuminated portions of the linear sensor array.

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

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 surgical cassette having an aspiration chamber with a bubble separating structure. The bubble separating structure facilitates accurate, reliable measurement of the fluid level in the chamber.

Abstract: A surgical cassette having an aspiration chamber or infusion chamber with a sensing portion and a storage portion. The sensing portion has a small transverse cross sectional area and facilitates accurate fluid level measurements. The storage portion has a larger transverse cross sectional area to facilitate fluid storage.

Abstract: A microsurgical system capable of improving reflux via programmable, pre-defined reflux profiles and a pressure accumulator.

Abstract: A microsurgical system capable of controlling aspiration via a vacuum control mode, a suction control mode, or a flow control mode.

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: Embodiments of the present invention provide an apparatus and method controlling the flow of aspiration fluid in an aspiration chamber of a surgical cassette. One embodiment of the present invention provides an aspiration chamber having an aspiration port positioned at or close to the bottom of the chamber. When the aspiration fluid enters the aspiration chamber from below the fluid surface (e.g., from a port located at the bottom or on a sidewall close to the bottom), it does not create disturbance at the liquid/air interface and thus does not disturb the continuous level sensing. Also, since the aspiration port is placed at or very close to the bottom of the aspiration chamber, the liquid inside the chamber can be fully used for sustained reflux and push priming.

Abstract: A microsurgical system capable improving reflux via programmable, pre-defined reflux profiles and a pressure accumulator.

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: An improved method 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 determining the location of the bottom of a fluid chamber in a surgical cassette to calibrate the surgical system. According to one embodiment, the surgical cassette is shaped to allow light from a light source to pass unobstructed to a linear sensor array in an area that is a known distance from the bottom of a fluid chamber. Light rays intersected by solid cassette material, on the other hand, will insufficiently illuminate the linear sensor array. Because the slot is a known distance from the bottom of the chamber, the location of the bottom of the chamber can be determined by determining the transition between illuminated and insufficiently illuminated portions of the linear sensor array.

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: A hearing test device is capable of presenting a variety of acoustical or vibratory stimuli and can be easily calibrated. Transfer functions for the device are calculated at two different attenuation levels to derive the characteristic impedance and sensitivity of the acoustic or vibratory transducer. The predicted sound pressure level emitted by the transducer may then be calculated as a function of input signal and attenuation.

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.