Applanation tonometer
First Claim
1. An applanation tonometer for measuring an intraocular pressure of an eye, comprising:
- an applanator for applanating a portion of an eye, wherein the applanator comprises a fiber optics array for transferring an image of a contact surface of an eye from a first end to a second end of the array within the tonometer;
a force transducer operatively coupled to the applanator, wherein the force transducer is adapted to measure a force applied to the eye by the applanator as transferred by the array;
an image sensor adapted to receive from the second end of the array an image of the applanated portion of the eye from the first end of the array and measure therefrom a geometrical property of the applanated portion of the eye; and
a processing circuit communicatively coupled to the force transducer and the image sensor for acquiring data at a rate of approximately 20 Hz to 60 Hz, wherein the processing circuit is adapted to calculate an intraocular pressure of the eye using a measured force from the force transducer and a corresponding measured geometrical property from the image sensor.
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Accused Products
Abstract
For calculating the intraocular pressure (IOP) of an eye, an applanation tonometer comprises an applanator formed of an optics array, a force transducer, an image sensor, and a processing circuit configured to calculate an intraocular pressure of the eye using one or more pairs of measured force and applanated area. The tonometer is provided with a disposable tip that covers the applanator, thereby providing a replaceable, sterile and transmissive interface between the tonometer'"'"'s applanator and a patient'"'"'s eye. Preferably, the applanating surface has a matte finish. The tonometer calculates the intraocular pressure using a predetermined relationship between interocular pressure and the slope of the line defined by data relating to the forces required to applanate the eye and the geometry of applanated portions of the eye. In a preferred embodiment, the data acquisition is synchronous. The tonometer may be of the type of a portable, hand-held device or a device affixed to and used in conjunction with a slit-lamp design. Also disclosed is a method and device for applying a disposable tip to the applanator.
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Citations
33 Claims
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1. An applanation tonometer for measuring an intraocular pressure of an eye, comprising:
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an applanator for applanating a portion of an eye, wherein the applanator comprises a fiber optics array for transferring an image of a contact surface of an eye from a first end to a second end of the array within the tonometer;
a force transducer operatively coupled to the applanator, wherein the force transducer is adapted to measure a force applied to the eye by the applanator as transferred by the array;
an image sensor adapted to receive from the second end of the array an image of the applanated portion of the eye from the first end of the array and measure therefrom a geometrical property of the applanated portion of the eye; and
a processing circuit communicatively coupled to the force transducer and the image sensor for acquiring data at a rate of approximately 20 Hz to 60 Hz, wherein the processing circuit is adapted to calculate an intraocular pressure of the eye using a measured force from the force transducer and a corresponding measured geometrical property from the image sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An applanation tonometer comprising:
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a fiber optics array adapted to applanate a portion of an eye at a distal end of the fiber optics array, whereby an image of the applanated portion of the eye is transmitted to a proximal end of the fiber optics array;
a first sensor optically coupled to the proximal end of the fiber optics array, the first sensor adapted to produce a first signal relating to the image of the applanated portion of the eye;
a second sensor adapted to produce a second signal relating to a force applied to the eye by the tonometer; and
a processor communicatively coupled to the first and second sensors for receiving first and second signals, respectively, therefrom, a rate of approximately 20 Hz to 60 Hz, wherein the processor is adapted to calculate therefrom an intraocular pressure of the eye using the first and second signals. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of determining an intraocular pressure of an eye comprising:
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applanating a portion of an eye, varying the applanation of the eye over a period of time;
acquiring a plurality of data points at distinct times, each data point comprising a first datum and a second datum, wherein the first datum relates to a force required to applanate the eye, and the second datum relates to a geometrical property of the applanated portion of the eye;
determining a slope of a line defined by the plurality of data points; and
calculating the intraocular pressure using the slope and a predetermined relationship between said slope and intraocular pressure. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A method of forming a disposable tip on a distal end of an applanator of a tonometer comprising the steps of
disposing an elastic ring in an intermediate cavity of an assembly tool, disposing an optically light-diffusing film in an upper cavity of the assembly tool, and moving a distal end of the applanator of the tonometer axially into the assembly tool and down into a lower cavity to cause the film to wrap around the distal tip of the applanator and the elastic member to secure the ring thereto.
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31. An applanation tonometer for measuring an intraocular pressure of an eye, comprising:
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an applanator for applanating a portion of an eye, the applanator comprising a fiber optics array for transferring an image of a contact surface of an eye from a first end to a second end of the array within the tonometer;
a force transducer operatively coupled to the applanator, wherein the force transducer is adapted to measure a force applied to the eye by the applanator as transferred by the array;
an image sensor adapted to receive an image of the applanated portion of the eye from the first end of the array and measure therefrom a geometrical property of the applanated portion of the eye;
a processing circuit communicatively coupled to the force sensor and the image sensor for acquiring data at a rate of approximately 20 Hz to 60 Hz, wherein the processing circuit is adapted to calculate an intraocular pressure of the eye using a measured force from the force transducer and a corresponding measured geometrical property from the image sensor; and
a disposable tip for the distal end of the applanator comprising a small sheet of thin light-transmitting but optically light-diffusing film secured onto a distal end of the fiber optics array. - View Dependent Claims (32, 33)
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Specification