JP7110681B2 - non-contact ultrasonic tonometer - Google Patents

Description

The present disclosure relates to a non-contact ultrasonic tonometer that measures the intraocular pressure of an eye to be examined using ultrasonic waves.

As a non-contact type tonometer, an air injection type tonometer is still common. The air injection tonometer detects the applanation state of the cornea when air is injected into the cornea and the air pressure injected into the cornea, and converts the air pressure in a predetermined deformed state into the intraocular pressure.

As a non-contact type tonometer, an ultrasonic tonometer that measures intraocular pressure using ultrasonic waves has been proposed (see Patent Document 1). The ultrasonic tonometer of Patent Document 1 detects the applanation state of the cornea when ultrasonic waves are emitted to the cornea and the radiation pressure emitted to the cornea. It is converted into pressure.

Further, as an ultrasonic tonometer, a device for measuring intraocular pressure based on the relationship between the characteristics (amplitude and phase) of reflected waves from the cornea and intraocular pressure has been proposed (see Patent Document 2).

Further, in the ultrasonic tonometer, a device using a broadband air-coupled ultrasonic probe that transmits and receives an ultrasonic beam having a wideband frequency component has been proposed (see Patent Document 3).

Japanese Patent Laid-Open No. 5-253190 JP 2009-268651 JP 2010-068874

However, the conventional apparatus cannot properly irradiate the cornea of the subject's eye with ultrasonic waves. For example, the apparatus of Patent Document 1 cannot properly irradiate the cornea with ultrasonic waves, and cannot actually apply ultrasonic waves to the subject's eye to the extent that the cornea is flattened or depressed. Further, for example, the apparatus disclosed in Patent Document 2 cannot properly irradiate the cornea with ultrasonic waves and cannot sufficiently detect the characteristics of the reflected waves. Further, for example, even when the broadband air-coupled ultrasonic probe disclosed in Patent Document 3 is used, a sufficient ultrasonic output cannot actually be obtained.

In view of the conventional problems, the technical problem of the present disclosure is to provide a non-contact ultrasonic tonometer that can appropriately irradiate an eye to be examined with ultrasonic waves.

In order to solve the above problems, the present disclosure is characterized by having the following configuration.

(1) A non-contact ultrasonic tonometer that measures the intraocular pressure of an eye to be examined using ultrasonic waves,
an ultrasonic wave generating means for generating ultrasonic waves;
a support base for supporting the ultrasonic wave generating means;
Mounting means for mounting the ultrasonic wave generating means on the support base ,
The mounting means is characterized in that it holds the ultrasonic wave generating means via an anti-vibration member .

1 is an external view of a non-contact ultrasonic tonometer of the present embodiment; FIG. It is a schematic diagram showing the optical system of the present embodiment. 1 is a schematic cross-sectional view of an ultrasound unit; FIG. It is a schematic diagram showing the inside of a measuring part. It is a schematic sectional drawing which shows the mounting part of a present Example. It is a block diagram showing a control system of the present embodiment.

<First Embodiment>
A first embodiment according to the present disclosure will be described below. A non-contact ultrasonic tonometer (for example, a non-contact ultrasonic tonometer 1) of the first embodiment measures the intraocular pressure of an eye to be examined using ultrasonic waves. A non-contact ultrasonic tonometer, for example, includes an ultrasonic generator (eg, ultrasonic unit 100). The ultrasonic generator generates, for example, ultrasonic waves. The ultrasonic generator is, for example, a Langevin transducer. A Langevin transducer includes a sonotrode (also called a horn or front mass), a back mass (eg, back mass 132), and an ultrasonic element (eg, ultrasonic element 110). A sonotrode (eg, sonotrode 131) or back mass is a mass member, eg, made of metal or the like. The ultrasonic element is, for example, a piezoelectric element or a magnetostrictive element. An ultrasonic element is sandwiched between the sonotrode and the back mass.

The non-contact ultrasonic tonometer of the first embodiment can measure intraocular pressure by sufficiently deforming the subject's eye with acoustic radiation pressure by using the Langevin transducer.

Note that the ultrasonic generator may include a plurality of ultrasonic elements. In this case, ultrasonic waves may be generated by resonance phenomena of a plurality of ultrasonic elements. A high-power ultrasonic wave can be generated by resonating a plurality of ultrasonic elements.

Note that the Langevin oscillator may be hollow. For example, a Langevin transducer may be cylindrical and include an opening (eg, opening 101). In this case, the optical axis of an optical system such as the measurement optical system or the observation optical system (for example, the optical unit 200) may be arranged at the opening of the Langevin transducer. For example, the optical system projects light onto the eye to be inspected or receives light from the eye to be inspected through the opening of the Langevin transducer. By placing the optical axis of the optical system in the opening of the Langevin transducer in this manner, optical measurement or observation of the subject's eye can be easily performed.

Note that the device may further comprise a clamping member (eg, clamping member 160). A clamping member clamps, for example, the sonotrode and the back mass towards each other. The tightening member may be, for example, a bolt or hollow bolt. In this case, female threads (eg, female threads 133 and 134) may be formed in the sonotrode and back mass. Also, the tightening member may be a vise, a clip, or the like. By using a hollow bolt as the tightening member, the optical axis of the measurement optical system or the observation optical system can be arranged in the opening, so that the sonotrode and the back mass can be tightened, and measurement or observation by the optical system can be easily performed. For example, it is easy to perform measurement or observation using an optical system in the direction of the sound axis of a Langevin oscillator.

Note that the non-contact ultrasonic tonometer may further include a controller (for example, the controller 70). The controller may calculate the intraocular pressure of the subject's eye based on the output information of the ultrasonic wave generator. For example, the output information may be, for example, acoustic radiation pressure of ultrasonic waves, irradiation time (for example, elapsed time after trigger signal is input), frequency, or the like.

Further, for example, a deformation detection unit (for example, deformation detection system 260) that detects deformation of the cornea may be provided. In this case, the controller calculates the intraocular pressure of the subject's eye based on the detection result of the deformation detector. For example, the intraocular pressure may be calculated based on output information of ultrasound when the cornea is deformed into a predetermined shape by ultrasound.

<Second embodiment>
A second embodiment according to the present disclosure will be described below. The non-contact ultrasonic tonometer (for example, the non-contact ultrasonic tonometer 1) of the second embodiment measures the intraocular pressure of the subject's eye using, for example, ultrasonic waves. A non-contact ultrasonic tonometer mainly includes, for example, an ultrasonic generator (eg, ultrasonic unit 100), a support base (eg, support base 6), and a mounting section (eg, mounting section 400). The ultrasonic generator generates, for example, ultrasonic waves and irradiates them to the subject's eye. The support base supports, for example, the ultrasonic generator. For example, the mounting section mounts the ultrasonic wave generating section on the support base so as not to affect the ultrasonic waves irradiated to the eye to be examined. The effects on ultrasonic waves include, for example, a reduction in the sound pressure of ultrasonic waves, disturbance of convergence in ultrasonic beams, and the like. In the non-contact tonometer of the second embodiment, the ultrasonic wave generator is attached to the support base so as not to adversely affect the ultrasonic waves irradiated to the eye to be examined, so that ultrasonic waves with a sufficient output are emitted to the eye to be examined. Can be irradiated.

Note that the mounting section may hold the ultrasonic wave generating section via a vibration isolation member (eg, the first vibration isolation member 421 and the second vibration isolation member 422). As a result, it is possible to prevent ultrasonic vibrations from propagating around the ultrasonic generator. The anti-vibration member may be, for example, anti-vibration rubber such as ethylene propylene rubber, or other resin such as anti-vibration gel. Note that anti-vibration grease may be applied to the mounting portion as the anti-vibration member.

Note that the ultrasonic wave generator may be a Langevin transducer. For example, a Langevin transducer includes a sonotrode (eg, sonotrode 131), a back mass (eg, back mass 132), and an ultrasonic element (eg, ultrasonic element 110) positioned between the sonotrode and the back mass. and may be provided. In this case, the mounting portion may hold the back mass. By holding the back mass, it is possible to suppress the influence on the ultrasonic waves compared to holding the sonotrode. Therefore, the mounting section can hold the ultrasonic wave generator without contacting the sonotrode. As a result, for example, in the non-contact tonometer of the second embodiment, the ultrasonic wave generator is supported so that the output of the ultrasonic wave does not decrease due to contact with the sonotrode that propagates the ultrasonic wave in the air. Can be attached to the base.

Note that the back mass may include a flange portion (eg, flange portion 135). In this case, the mounting portion may hold the flange portion. The flange portion may be, for example, disk-shaped, rectangular, or of any shape. The flange portion may have any shape as long as it can be easily held by the mounting portion. In addition, the flange portion may be configured integrally with the back mass, or may be configured by a separate member. For example, the mounting portion may hold a flange portion attached to the back mass. It should be noted that the back mass or the flange portion may grip the mounting portion, resulting in the mounting portion holding the back mass or the flange portion. The mounting portion, for example, substantially retains the back mass.

Note that the Langevin transducer may include a tightening member (for example, the tightening member 160). The tightening member tightens the sonotrode and the back mass in mutually attracting directions. The tightening member is, for example, a bolt or hollow bolt. In this case, the mounting portion may hold the tightening member. By holding the tightening member, it is possible to suppress the influence on the ultrasonic waves compared to holding the sonotrode.

For example, it should be noted that the support base may comprise an opening (eg opening 6a) that is larger than the diameter of the sonotrode. In this case, for example, even if the sonotrode is inserted into the opening, the supporting base can be prevented from coming into contact with the sonotrode.

<Example>
Examples according to the present disclosure will be described below. The non-contact ultrasonic tonometer of the present embodiment uses, for example, ultrasonic waves to measure the intraocular pressure of the subject's eye in a non-contact manner.

FIG. 1 shows the appearance of the device. The ultrasonic tonometer 1 includes, for example, a base 2, a measuring section 3, a face supporting section 4, a driving section 5, and the like. The measurement unit 3 will be described later. The face support section 4 supports the face of the subject's eye. The face support part 4 is installed on the base 2, for example. The drive unit 5 moves the measurement unit 3 with respect to the base 2 for alignment, for example.

FIG. 2 is a schematic diagram of the main configuration of the measuring section 3. As shown in FIG. The measuring unit 3 performs, for example, measurement and observation of the subject's eye. The measurement unit 3 includes, for example, an ultrasonic unit 100, an optical unit 200, and the like. The ultrasonic unit 100 and the optical unit 200 will be described in order with reference to FIG.

The ultrasonic unit 100 irradiates the eye E to be examined with ultrasonic waves, for example. For example, the ultrasound unit 100 applies ultrasound to the cornea to generate acoustic radiation pressure on the cornea. Acoustic radiation pressure is, for example, the force acting in the direction in which sound waves travel. The ultrasonic tonometer 1 of the present embodiment deforms the cornea using, for example, this acoustic radiation pressure. The ultrasonic unit of this embodiment has a cylindrical shape, and an optical axis O1 of an optical unit 200, which will be described later, is arranged in the central opening 101. As shown in FIG.

3(a) is a cross-sectional view showing a schematic configuration of the ultrasonic unit 100, and FIG. 3(b) is an enlarged view of the range A1 shown in FIG. 3(a). The ultrasonic unit 100 of this embodiment is a so-called Langevin transducer. The ultrasonic unit 100 includes, for example, an ultrasonic element 110, an electrode 120, a mass member 130, a clamping member 160, and the like. The ultrasonic element 110 generates ultrasonic waves. The ultrasonic element 110 may be a voltage element (eg, piezoelectric ceramics), a magnetostrictive element, or the like. The ultrasonic element 110 of this embodiment is ring-shaped. For example, the ultrasonic element 110 may be a stack of piezoelectric elements. In this embodiment, the ultrasonic element 110 uses two laminated piezoelectric elements (for example, the piezoelectric element 111 and the piezoelectric element 112). For example, electrodes 120 (electrodes 121 and 122) are connected to the two piezoelectric elements, respectively. The electrodes 121 and 122 of this embodiment are ring-shaped, for example.

The mass members 130 sandwich the ultrasonic element 110, for example. By sandwiching the ultrasonic element 110 between the mass members 130, for example, the tensile strength of the ultrasonic element 110 is strengthened so that it can withstand strong vibrations. This makes it possible to generate high-power ultrasonic waves. Mass member 130 may be, for example, a metal block. For example, the mass member 130 includes a sonotrode (also called horn or front mass) 131, a back mass 132, and the like.

The sonotrode 131 is a mass member arranged in front of the ultrasonic element 110 (on the subject's eye side). The sonotrode 131 propagates the ultrasonic waves generated by the ultrasonic element 110 into the air. The sonotrode 131 of this embodiment is cylindrical. A female screw portion 133 is formed in a part of the inner circular portion of the sonotrode 131 . The female threaded portion 133 is screwed with a male threaded portion 161 formed on a tightening member 160 which will be described later. Note that the sonotrode 131 may have a shape that converges ultrasonic waves. For example, the end surface of the sonotrode 131 on the side of the subject's eye may be inclined toward the opening 101 to form a tapered shape. Also, the sonotrode 131 may be a cylinder with a non-uniform thickness. For example, the sonotrode 131 may have a shape in which the outer diameter and the inner diameter change in the longitudinal direction of the cylinder.

The back mass 132 is a mass member arranged behind the ultrasonic element 110 . The back mass 132 sandwiches the ultrasonic element 110 together with the sonotrode 131 . The back mass 132 is, for example, cylindrical. An inner circular portion of the back mass 132 is partially formed with a female screw portion 134 . The female threaded portion 134 is screwed with a male threaded portion 161 of a tightening member 160 which will be described later. The back mass 132 also has a flange portion 135 . The flange portion 135 is held by a mounting portion 400 which will be described later.

The tightening member 160 tightens, for example, the mass member 130 and the ultrasonic element 110 sandwiched between the mass members 130 . The tightening member 160 is, for example, a hollow bolt. The tightening member 160 is, for example, cylindrical and has a male threaded portion 161 on its outer circular portion. A male threaded portion 161 of the tightening member 160 is screwed with female threaded portions 133 and 134 formed inside the sonotrode 131 and the back mass 132 . The sonotrode 131 and the back mass 132 are tightened by a tightening member 160 in a direction to attract each other. As a result, the ultrasonic element 101 sandwiched between the sonotrode 131 and the back mass 132 is clamped and pressure is applied.

In addition, the ultrasonic unit 100 may include an insulating member 170 . The insulating member 170 prevents, for example, the electrode 120 or the ultrasonic element 110 from contacting the clamping member 160 . Insulating member 170 is disposed, for example, between electrode 120 and clamping member 160 . The insulating member 170 is, for example, sleeve-shaped.

<Optical unit>
The optical unit 200 performs, for example, observation or measurement of the subject's eye (see FIG. 2). The optical unit 200 includes, for example, an objective system 210, an observation system 220, a fixation target projection system 230, an index projection system 250, an applanation detection system 260, a dichroic mirror 201, a beam splitter 202, a beam splitter 203, a beam splitter 204, and the like. Prepare.

The objective system 210 is, for example, an optical system for introducing light from outside the measurement section 3 into the optical unit 200 or for irradiating the light from the optical unit 200 to the outside of the measurement section 3 . Objective 210 comprises, for example, an optical element. The objective system 210 may comprise optical elements (objective lens, relay lens, etc.).

The illumination optical system 240 illuminates the subject's eye. The illumination optical system 240 illuminates the subject's eye with infrared light, for example. The illumination optical system 240 includes, for example, an illumination light source 241 . The illumination light source 241 is arranged, for example, obliquely in front of the subject's eye. The illumination light source 241 emits infrared light, for example. Illumination source 240 may comprise a plurality of illumination sources 241 .

The observation system 220 captures, for example, an observation image of the subject's eye. The observation system 220 captures, for example, an anterior segment image of the subject's eye. The observation system 220 includes, for example, a light receiving lens 221, a light receiving element 222, and the like. The observation system 220 receives, for example, light from the illumination light source 241 reflected by the subject's eye. The observation system receives, for example, a reflected light flux from the subject's eye centered on the optical axis O1. For example, reflected light from the subject's eye passes through the opening 110 of the ultrasound unit 100 and is received by the light receiving element 222 via the objective system 210 and the light receiving lens 221 .

The fixation target projection system 230 projects a fixation target onto the subject's eye, for example. The fixation target projection system 230 includes, for example, a target light source 231, a diaphragm 232, a projection lens 233, a diaphragm 234, and the like. Light from the target light source 231 passes through the diaphragm 232 , the projection lens 233 , the diaphragm 232 , etc. along the optical axis O 2 and is reflected by the dichroic mirror 201 . The dichroic mirror 201, for example, makes the optical axis O2 of the fixation target projection system 230 coaxial with the optical axis O1. The light from the target light source 231 reflected by the beam splitter 2 passes through the objective system 210 along the optical axis O1 and is applied to the subject's eye. The visual target of the fixation target projection system 230 is fixed by the subject, thereby stabilizing the line of sight of the subject.

The index projection system 250 projects an index onto the subject's eye, for example. The index projection system 250 projects an index for XY alignment onto the eye to be examined. The index projection system 250 includes, for example, an index light source (eg, an infrared light source) 251, an aperture 252, a projection lens 253, and the like. Light from the index light source 251 passes through the diaphragm 252 and the projection lens 253 along the optical axis O3 and is reflected by the beam splitter 202 . The beam splitter 202, for example, makes the optical axis O3 of the target projection system 250 coaxial with the optical axis O1. The light from the index light source 251 reflected by the beam splitter 202 passes through the objective system 210 along the optical axis O1 and is irradiated onto the eye to be examined. The light from the index light source 251 irradiated to the eye to be inspected is reflected by the eye to be inspected, passes through the objective system 210 and the light receiving lens 221 and the like along the optical axis O1 again, and is received by the light receiving element 222 . The indices received by the light receiving elements are used for XY alignment, for example. In this case, for example, index projection system 250 and observation system 220 function as XY alignment detection means.

The deformation detection system 260 detects, for example, the corneal shape of the subject's eye. The deformation detection system 260 detects, for example, deformation of the cornea of the subject's eye. The deformation detection system 260 includes, for example, a light receiving lens 261, an aperture 262, a light receiving element 263, and the like. The deformation detection system 260 may detect deformation of the cornea, for example, based on corneal reflected light received by the light receiving element 263 . For example, the deformation detection system 260 may detect the deformation of the cornea by receiving the light from the index light source 251 reflected by the cornea of the subject's eye with the light receiving element 263 . For example, corneal reflected light passes through objective 210 along optical axis O1 and is reflected by beam splitter 202 and beam splitter 203 . The corneal reflected light passes through the light receiving lens 261 and the diaphragm 262 along the optical axis O4 and is received by the light receiving element 263 .

The deformation detection system 260 may detect the deformed state of the cornea based on the magnitude of the light receiving signal of the light receiving element 236, for example. For example, the deformation detection system 260 may detect that the cornea has become applanated when the amount of light received by the light receiving element 236 reaches its maximum. In this case, for example, the deformation detection system 260 is set so that the amount of light received becomes maximum when the cornea of the subject's eye is in an applanation state.

The deformation detection system 260 may be an anterior segment cross-sectional imaging unit such as an OCT or Scheimpflug camera. For example, the deformation detection system 260 may detect the amount or speed of deformation of the cornea.

The corneal thickness measurement system 270 measures, for example, the corneal thickness of the subject's eye. The corneal thickness measurement system 270 may include, for example, a measurement light source 271, a projection lens 272, an aperture 273, a light receiving lens 274, a light receiving element 275, and the like. Light from the light source 271 passes through, for example, the projection lens 272 and the diaphragm 273 along the optical axis O5, and is irradiated to the subject's eye. Reflected light reflected by the subject's eye is condensed by the light receiving lens 274 along the optical axis O6 and received by the light receiving element 275 .

The Z alignment detection system 280 detects, for example, the alignment state in the Z direction. The Z alignment detection system 280 has a light receiving element 281, for example. The Z alignment detection system 280 may detect the alignment state in the Z direction, for example, by detecting reflected light from the cornea. For example, the Z alignment detection system may receive light reflected by the cornea of the subject's eye from the light source 271 . In this case, the Z alignment detection system 280 may receive, for example, a bright spot formed by the light from the light source 271 being reflected by the cornea of the subject's eye. Thus, the light source 271 may also be used as a light source for Z alignment detection. For example, light from light source 271 reflected by the cornea is reflected by beam splitter 204 along optical axis O6 and received by light receiving element 281 .

<Wearing part>
The mounting section 400 mounts the ultrasonic unit 100 on a supporting base 6 described below so as not to affect the ultrasonic waves emitted by the ultrasonic unit 100 . As shown in FIGS. 3A and 3B, the mounting portion 400 includes, for example, a first flange 411, a second flange 412, a first vibration isolation member 421, a second vibration isolation member 422, bolts 440. The mounting portion 400 holds, for example, the flange portion 135 of the back mass 132 . For example, the mounting portion 400 sandwiches the flange portion 135 of the back mass 132 between the first flange 411 and the second flange 412 . At this time, the mounting portion 400 sandwiches the flange portion 135 via the first vibration isolation member 421 and the second vibration isolation member 422 . That is, the first vibration isolation member 421 is arranged between the first flange 411 and the flange portion 135 , and the second vibration isolation member 422 is arranged between the second flange 412 and the flange portion 135 . This prevents the first flange 411 and the second flange 412 from directly contacting the back mass 132 . The first vibration isolation member 421 and the second vibration isolation member 422 may be, for example, elastic bodies such as rubber. Alternatively, anti-vibration grease may be applied to the first flange 411, the second flange 412, the first anti-vibration member 421, the second anti-vibration member 422, and the like. The bolt 440 passes through a through hole 431 formed in the first flange 411 and is screwed into a female threaded portion 432 formed in the second flange 412 . As a result, the first flange 411 and the second flange 412 are tightened in a direction in which they pull each other. This force allows the mounting portion 400 to clamp the flange portion 135 of the back mass 132 .

When mounting the ultrasonic unit 100 on the support base 6 , the mounting part 400 holding the ultrasonic unit 100 is attached to the support base 6 . As shown in FIG. 4, the support base 6 is provided on a moving table 7 that is moved by the drive unit 5, for example. The support base 6 is provided with an opening 6a for passing the sonotrode 131, for example. In the example of FIG. 4, the support base 6 is box-shaped, but may be of any shape as long as it can support the ultrasonic unit 100 . Of course, the support base 6 may be integrated with the cover of the measuring section 3, integrated with the optical unit 200, or integrated with other components.

FIG. 5(a) is a cross-sectional view of the ultrasonic unit 100 attached to the support base 6, and FIG. 5(b) is an enlarged view of the range A2 shown in FIG. 5(a). As shown in FIG. 5 , the ultrasonic unit 100 is supported by the support base 6 by fixing the first flange 411 and the second flange 412 to the support base 6 . The first flange 411 and the second flange 412 are provided with through holes 451 and 452 through which the bolts 460 pass. Further, the support base 6 is formed with a female screw portion 6b. For example, the mounting part 400 is fixed to the support base 6 by passing the bolts 460 through the through holes 451 and 452 of the first flange 411 and the second flange 412 and screwing the bolts 460 with the female threaded portion 6 b of the support base 6 . Thereby, the ultrasonic unit 100 is attached to the support base 6 .

The method of holding the flange portion 135 by the mounting portion 400 and the method of fixing the mounting portion 400 to the support base 6 may not be a method using bolts. For example, a method using screws, magnets, hook-and-loop fasteners, vices, clips, welding, or the like may be used.

The mounting section 400 may be capable of adjusting the position of the ultrasound unit 100 with respect to the optical unit 200, for example. For example, the mounting position with respect to the support base 6 may be shifted three-dimensionally. In this case, the mounting section 400 functions as an adjustment section that adjusts the relative positions of the optical unit 200 and the ultrasound unit 100 . For example, the mounting section 400 may fix the ultrasonic unit 100 to the support base 6 so that the sound axis of the ultrasonic unit 100 is coaxial with the optical axis O1 of the optical unit 200 .

<Control section>
Next, the configuration of the control system will be described with reference to FIG. The control unit 70 performs, for example, control of the entire apparatus, arithmetic processing of measured values, and the like. The control unit 70 is implemented by, for example, a general CPU (Central Processing Unit) 71, ROM 72, RAM 73, and the like. The ROM 72 stores various programs for controlling the operation of the ultrasonic tonometer 1, initial values, and the like. The RAM 73 temporarily stores various information. Note that the controller 70 may be configured by one controller or a plurality of controllers (that is, a plurality of processors). The control section 70 may be connected to, for example, the drive section 5, the storage section 74, the display section 75, the operation section 76, the ultrasonic unit 100, the optical unit 200, and the like.

The storage unit 74 is a non-transitory storage medium that can retain stored content even when the supply of power is interrupted. For example, a hard disk drive, a flash ROM, a removable USB memory, or the like can be used as the storage unit 74 .

The display unit 75 displays, for example, the measurement result of the subject's eye. The display unit 75 may have a touch panel function.

The operation unit 76 receives various operation instructions from the examiner. The operation unit 76 outputs an operation signal to the control unit 70 according to the input operation instruction. At least one of user interfaces such as a touch panel, a mouse, a joystick, and a keyboard may be used for the operation unit 76, for example. In addition, when the display unit 75 is a touch panel, the display unit 75 may function as the operation unit 76 .

<Control action>
A control operation of the device having the above configuration will be described. First, the control unit 70 aligns the measuring unit 3 with respect to the subject's eye, whose face is supported by the face supporting unit 4 . For example, the control unit 70 detects a bright spot by the index projection unit 250 from the front image of the anterior segment acquired by the light receiving element 222, and drives the driving unit 5 so that the position of the bright spot is at a predetermined position. Of course, the examiner may manually align the subject's eye using the operation unit 76 or the like while looking at the display unit 75 . When the driving unit 5 is driven, the control unit 70 determines whether or not the alignment is appropriate depending on whether the position of the bright spot in the anterior segment image is at a predetermined position.

After completing the alignment for the subject's eye E, the control unit 70 measures the corneal thickness using the corneal thickness measurement system 270 . For example, the control unit 70 calculates the corneal thickness based on the light receiving signal received by the light receiving element 275 . For example, the control unit 70 may obtain the corneal thickness from the positional relationship between the peak value of reflected light from the corneal surface and the peak value of reflected light from the back surface of the cornea, based on the received light signal. The control unit 70 stores, for example, the obtained corneal thickness in the storage unit 74 or the like.

Subsequently, the control unit 70 uses the ultrasound unit 100 to measure the intraocular pressure of the subject's eye. For example, the control unit 70 applies a voltage to the ultrasonic element to irradiate the subject's eye E with ultrasonic waves. The control unit 70 deforms the cornea by, for example, generating acoustic radiation pressure using ultrasonic waves. Then, the control unit 70 detects the deformation state of the cornea using the deformation detection system 260 . For example, the control unit 70 detects that the cornea has deformed into a predetermined shape (applanation state or flattened state) based on the light receiving signal of the light receiving element 263 .

The control unit 70 calculates the intraocular pressure of the subject's eye, for example, based on the acoustic radiation pressure when the cornea of the subject's eye deforms into a predetermined shape. The acoustic radiation pressure applied to the eye to be examined has a correlation with the irradiation time of ultrasonic waves, and increases as the irradiation time of ultrasonic waves increases. Therefore, the control unit 70 obtains the acoustic radiation pressure when the cornea is deformed into a predetermined shape based on the irradiation time of the ultrasonic waves. The relationship between the acoustic radiation pressure when the cornea is deformed into a predetermined shape and the intraocular pressure of the subject's eye is obtained in advance by experiments or the like, and is stored in the storage unit 74 or the like. The control unit 70 determines the intraocular pressure of the subject's eye based on the relationship stored in the storage unit 74 and the acoustic radiation pressure when the cornea is deformed into a predetermined shape.

Of course, the intraocular pressure calculation method is not limited to the above, and various methods may be used. For example, the control unit 70 may obtain the deformation amount of the cornea using the deformation detection system 260 and obtain the intraocular pressure by multiplying the deformation amount by a conversion factor. Note that the control unit 70 may correct the intraocular pressure value calculated according to the corneal thickness stored in the storage unit 74, for example.

Note that the control unit 70 may measure intraocular pressure based on ultrasonic waves reflected by the subject's eye. For example, the intraocular pressure may be measured based on changes in the characteristics of the ultrasonic waves reflected by the eye to be examined, or the amount of deformation of the cornea may be obtained from the ultrasonic waves reflected by the eye to be examined, and the intraocular pressure may be calculated based on the amount of deformation. may be measured.

When ultrasonic waves were generated using a Langevin transducer as the ultrasonic wave unit 100 as in this embodiment, an output of about 165 dB to 172 dB was obtained within a range of 3.6 mm in diameter.

The ultrasonic tonometer 1 of the present embodiment can deform the cornea of the subject's eye into a predetermined shape by providing the Langevin transducer, thereby enabling intraocular pressure measurement. Further, as in the above embodiment, the ultrasound unit 100 is provided with the opening 101, and the observation system 220 observes the subject's eye through the opening 101, thereby observing the subject's eye from the front direction. It is possible to irradiate ultrasonic waves with a sufficient output to Also, the subject's eye can be observed from the direction of the ultrasonic sound axis.

Moreover, by mounting the ultrasonic unit 100 on the support base 6 by means of the mounting portion 400 as in the above embodiment, it is possible to reduce adverse effects such as a reduction in the output of ultrasonic waves. Furthermore, it is possible to prevent the vibration of the ultrasonic unit 100 from being transmitted to other precision parts such as the optical unit 200 .

REFERENCE SIGNS LIST 1 non-contact ultrasonic tonometer 2 base 3 measurement section 4 face support section 6 support base 100 ultrasonic unit 200 optical unit 400 mounting section

Claims (5)

A non-contact ultrasonic tonometer that measures the intraocular pressure of an eye to be examined using ultrasonic waves,
an ultrasonic wave generating means for generating ultrasonic waves;
a support base for supporting the ultrasonic wave generating means;
Mounting means for mounting the ultrasonic wave generating means on the support base ,
The non-contact ultrasonic tonometer , wherein the mounting means holds the ultrasonic wave generating means via a vibration isolating member . the ultrasonic wave generating means is a Langevin transducer comprising a sonotrode, a back mass, and an ultrasonic element disposed between the sonotrode and the back mass;
2. A non-contact ultrasonic tonometer according to claim 1 , wherein said mounting means holds said back mass. The back mass has a flange,
3. The non-contact ultrasonic tonometer according to claim 2 , wherein said mounting means holds said flange portion. 4. The non-contact ultrasonic tonometer according to claim 2 , wherein said mounting means holds said Langevin transducer without contacting said sonotrode. The non-contact ultrasonic tonometer according to any one of claims 2 to 4, wherein said supporting base has an opening larger than the outer diameter of the sonotrode.

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