Tonometer having acoustic coupling detection
First Claim
1. A tonometer for measuring the intraocular pressure of an eye, comprising,a contacting member having an eye-engaging surface, said eye-engaging surface having at least one raised portion and a recessed portion, said recessed portion being open along said raised portion yet defining a generally enclosed volume when said eye-engaging surface is in contact with an eye under test,means for generating an acoustic test signal and channeling said test signal to a first sector of said recessed area,means for receiving said acoustic test signal at a second sector of said recessed area spaced apart from said first sector,means for monitoring characteristics of said acoustic test signal received at said second sector and for detecting a variance when said characteristics satisfy at least one preselected condition, thereby indicating eye contact, andmeans for sensing the pressure exerted by said eye on said contacting member when said eye-engaging surface is indicated to be in contact with said eye.
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Accused Products
Abstract
A tonometer for measuring the intraocular pressure of an eye featuring an acoustic signaling system for determining the beginning of a pressure measurement. The acoustic system includes a consumable cap having a pair of annular raised surface portions spaced by a recessed area. The raised surface portions provide an eye-engaging surface at the face of the tonometer. A pressure transmitting plunger concentrically suspended between the raised surface portions by a plurality of spider arms combines with the eye-engaging surface to provide a contour which complements a shape of an eye. The recessed area is open along the eye-engaging surface, yet defines a generally enclosed volume when full tonometer-to-eye contact is made. Spaced apart inlet and outlet apertures within the recessed area permit channeling of an acoustic signal to and from the recessed area. Prior to proper coupling of the tonometer to an eye, a substantial amount of the energy of the acoustic signal is lost to free air. However, upon achieving full tonometer-to-eye contact the energy is captured within the recessed ara and channeled to an acoustic receiver when the plunger contacts the eye, constricting the inlet-to-outlet acoustic wave path. Characteristic change of the received signal is marked by a hold signal triggered to initiate an intraocular pressure measurement. Proper coupling may be detected by either monitoring the phase or the change in amplitude at the acoustic wave receiver. Intraocular pressure is measured by means of the plunger which is operatively coupled to a force transducer.
21 Citations
20 Claims
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1. A tonometer for measuring the intraocular pressure of an eye, comprising,
a contacting member having an eye-engaging surface, said eye-engaging surface having at least one raised portion and a recessed portion, said recessed portion being open along said raised portion yet defining a generally enclosed volume when said eye-engaging surface is in contact with an eye under test, means for generating an acoustic test signal and channeling said test signal to a first sector of said recessed area, means for receiving said acoustic test signal at a second sector of said recessed area spaced apart from said first sector, means for monitoring characteristics of said acoustic test signal received at said second sector and for detecting a variance when said characteristics satisfy at least one preselected condition, thereby indicating eye contact, and means for sensing the pressure exerted by said eye on said contacting member when said eye-engaging surface is indicated to be in contact with said eye.
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9. A tonometer of the type having a suspended force-transmitting member having a first end adapted for engagement with an eye to be tested and having a second end operatively attached to a pressure-sensing device, the improvement comprising,
a cap having an eye-engaging surface, said eye-engaging surface having a first portion of a shape to seat an eye to be tested and having a second portion that is recessed relative to said first portion and said eye, said recessed second portion combining with said eye to form a generally enclosed volume, said cap having at least one transmitting channel and at least one receiving channel having apertures at spaced apart areas of said recessed second portion, means for generating an acoustic test signal in said transmitting channel, means for detecting said acoustic test signal in said receiving channel, and means for comparing the characteristics of said acoustic test signal within said receiving channel relative to the characteristics of said test signal within said transmitting channel.
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15. A tonometer comprising,
a tonometer housing having a nose portion, a cap having a shape to slidably receive said nose portion, said cap having a face having first and second eye-seating raised surface segments spaced apart by an annular recessed surface segment, said cap having a signal-transmitting channel having an outlet within said recessed surface segment and said cap having a signal-receiving channel having an inlet within said recessed surface segment spaced apart from said outlet, a plunger suspended at said face of the cap, said plunger mounted for movement relative to said cap and having a first end adapted to contact an eye and having a second end operatively coupled to a pressure-sensing device, a means for conducting an acoustic test signal to said transmitting channel of the cap, and means for monitoring the characteristics of said test signal in said receiving channel.
Specification