Non-contact tonometer and tonometer control program

Abstract

To provide a non-contact tonometer capable of suppressing inhalation of foreign substances such as aerosols scattered by fluid discharge, and a tonometer control program.SOLUTION: A non-contact tonometer for measuring intraocular pressure of an eye to be examined in a non-contact manner comprises fluid discharge means for discharging a fluid to the cornea of the eye to be examined, drive means for driving the fluid discharge means, and control means for controlling the drive means. The control means performs first discharge for deforming the cornea in the intraocular pressure measurement, and after the first discharge and before the next measurement, performs second discharge for removing foreign substances in the vicinity of a discharge port of the fluid discharge means.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a non-contact tonometer that measures intraocular pressure of a subject's eye in a non-contact manner, and a tonometer control program. [Background technology]

[0002] Non-contact tonometers are known that eject a fluid such as air from a nozzle toward a subject's eye and measure intraocular pressure by detecting a predetermined deformation of the cornea (e.g., applanation) caused by the ejected fluid. In such devices, a driving current is supplied to a driving unit such as a solenoid, and the resulting driving force pushes a piston in a cylinder forward, spraying the fluid onto the cornea of ​​the subject's eye and deforming it. After ejecting the fluid into the subject's eye, the piston is returned to its initial position and the fluid is sucked into the cylinder in preparation for the next intraocular pressure measurement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 03-118034 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-89455 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional devices, foreign matter such as aerosols scattered by the fluid discharge may be sucked into the device.

[0005] In view of the problems of the related art, the present disclosure has as its technical object to provide a non-contact tonometer and a tonometer control program that can suppress the inhalation of foreign matter such as aerosols dispersed by fluid ejection. [Means for solving the problem]

[0006] In order to solve the above problems, the present disclosure is characterized by having the following configuration.

[0007] (1) A non-contact tonometer for measuring intraocular pressure of a subject's eye without contact, comprising: a fluid discharge means for discharging a fluid onto the cornea of ​​the subject's eye by means of a cylinder and a piston that moves inside the cylinder; a drive means for driving the fluid discharge means; and a control means for controlling the drive means, wherein the control means deforms the cornea into an applanation state during intraocular pressure measurement. The a first discharge, the piston moving in the forward direction in the first discharge is urged in the backward direction to slow down or stop the piston, and then a second discharge is performed by urging the piston in the forward direction again to perform a discharge to remove foreign matter near the discharge port of the fluid discharge unit before the fluid suction operation is completed. (2) A tonometer control program executed in a non-contact tonometer for non-contactly measuring the intraocular pressure of a subject's eye, the program being executed by a control means of the non-contact tonometer, and including a driving step of driving a fluid ejection means for ejecting a fluid onto the cornea of ​​the subject's eye; and a deforming step of the cornea into an applanation state during intraocular pressure measurement. The a first discharge step of performing one discharge, and a second discharge step of decelerating or stopping the piston by urging the piston in a backward direction while the piston is moving in a forward direction in the first discharge, and then urging the piston in the forward direction again in a second discharge to remove foreign matter near the discharge port of the fluid discharge unit before completing the fluid suction operation. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to prevent inhalation of foreign matter such as aerosols scattered by fluid ejection. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing the external configuration of the present embodiment. FIG. [Figure 2] FIG. 2 is a diagram illustrating the internal configuration of the present embodiment. [Figure 3] FIG. 1 is a diagram illustrating an optical system according to the present embodiment. [Figure 4] 4 is a flowchart showing a control operation of the present embodiment. [Figure 5] 10 is a flowchart showing a control operation of the fluid ejection unit. [Figure 6] FIG. 10 is a diagram showing a standby time setting screen displayed on the display unit. [Figure 7] FIG. 10 is a diagram showing a mode setting screen displayed on a display unit. [Figure 8] 10 is a flowchart showing a control operation of a fluid discharge unit in the second embodiment. [Figure 9] FIG. 10 is a diagram showing a measurement screen displayed on a display unit. [Figure 10] FIG. 10 is a diagram showing a setting screen displayed on a display unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment A first embodiment according to the present disclosure will be described below. The non-contact tonometer of the first embodiment measures the intraocular pressure of a subject's eye in a non-contact manner. The non-contact tonometer includes, for example, a fluid discharge unit (e.g., fluid discharge unit 200), a drive unit (e.g., solenoid 203), and a control unit (e.g., control unit 80). The fluid discharge unit discharges fluid onto the cornea of ​​the subject's eye. The drive unit drives the fluid discharge unit. The control unit controls the drive unit. The control unit changes the timing for starting a fluid suction operation after fluid discharge. For example, the control unit switches between a first timing preset for starting the fluid suction operation and a second timing longer than the first timing. The non-contact tonometer of the first embodiment, having the above-described configuration, can suction fluid into the fluid discharge unit at an appropriate timing. This can prevent the subject's tears, dust, airborne bacteria, and the like from being suctioned into the fluid discharge unit.

[0011] The control unit may change the timing for starting the fluid suction operation by changing the setting of the waiting time after fluid ejection. For example, the control unit may arbitrarily change the second timing. For example, the control unit may change the setting of the waiting time after fluid ejection in seconds. The control unit may start the fluid suction operation when the changed waiting time has elapsed. In this way, by waiting at least several seconds after fluid ejection, the suction operation is performed in a reliably ventilated state, reducing the possibility of inhaling foreign matter. According to experiments by the present inventors, a waiting time of 2 seconds or more is preferable. Furthermore, by changing the timing for starting the fluid suction operation by setting the waiting time, the fluid can be inhaled at a stable timing regardless of the conditions of each measurement.

[0012] The non-contact tonometer may further include an operation receiving unit (e.g., a control unit 80). The operation receiving unit receives, for example, an operation from the examiner. In this case, the control unit may change the timing to start the fluid suction operation based on the operation from the examiner received by the operation receiving unit during standby after fluid ejection. This allows the examiner to perform the fluid suction operation at a timing appropriate for each measurement.

[0013] The non-contact tonometer may further include a detection unit (e.g., a chin rest sensor 3c, a face image capturing unit 90, a CCD camera 35, a position sensor, a distance measuring sensor, etc.). The detection unit may, for example, indirectly detect the possibility of inhaling a foreign object. In this case, the control unit may start the fluid suction operation based on the detection result of the detection unit. The detection unit may, for example, detect the presence or absence of a subject, the subject's blinking, the position of the measurement unit, etc.

[0014] The control unit may switch between a first mode (e.g., a manual change mode) that changes the timing to start the fluid suction operation, and a second mode (e.g., a time setting mode) that changes the timing to start the fluid suction operation based on conditions different from those in the first mode, thereby enabling measurement to be performed in a change mode that suits the examiner's preference.

[0015] The control unit may also be configured to switch whether or not to change the timing for starting the fluid suction operation. For example, the control unit may be configured to allow the examiner to turn off the function for changing the timing for the liquid suction operation by operating the operation unit. This allows measurements to be performed appropriately for each measurement site.

[0016] The control unit may wait until the possibility of inhaling foreign matter after discharging the fluid decreases before starting the fluid suction operation, thereby preventing the subject's tears, dust, airborne bacteria, etc. from being inhaled into the fluid discharging unit.

[0017] The processor of the non-contact tonometer may execute a tonometer control program stored in a memory unit or the like. The tonometer control program includes, for example, a driving step and a changing step. The driving step is a step of driving the fluid ejection unit. The changing step is a step of changing the timing of starting the fluid suction operation after fluid ejection.

[0018] Second Embodiment A second embodiment according to the present disclosure will be described below. The non-contact tonometer of the second embodiment measures the intraocular pressure of a subject's eye in a non-contact manner. The non-contact tonometer of the second embodiment includes, for example, a fluid discharge unit (e.g., fluid discharge unit 200), a drive unit (e.g., solenoid 203), and a control unit (e.g., control unit 80). The fluid discharge unit discharges fluid onto the cornea of ​​the subject's eye. The drive unit drives the fluid discharge unit. The control unit controls the drive unit. For example, the control unit performs a first discharge (first discharge control) to deform the cornea during intraocular pressure measurement, and then performs a second discharge (second discharge control) to remove foreign matter near the discharge port of the fluid discharge unit after the first discharge and before the next measurement. In this way, by performing the second discharge after the first discharge, the non-contact tonometer of the second embodiment can prevent foreign matter, such as aerosols, scattered by the first discharge from being inhaled into the fluid discharge unit.

[0019] The control unit may perform the second ejection before the suction operation of the fluid is completed. For example, the control unit may perform the second ejection even after the suction operation of the fluid has started, as long as the suction operation is not completed.

[0020] The fluid discharge unit may include a cylinder (for example, cylinder 201) and a piston (for example, piston 202) that moves inside the cylinder. In this case, the control unit may perform a second discharge by urging the piston, which is moving forward in the first discharge, in a backward direction to slow down or stop the piston, and then urging the piston further forward from that position (the position after the piston has slowed down or stopped) (to increase the momentum of the piston in the forward direction).

[0021] The pressure of the fluid discharged in the second discharge may be lower than that of the first discharge, thereby making it possible to blow away aerosols and the like around the discharge port without generating new aerosols and the like.

[0022] The control unit may cause a display unit (for example, the display unit 85) to display that the second ejection is being performed. This allows the examiner to confirm that the second ejection is being performed. Also, the examiner can explain to the subject or the like that the second ejection is being performed.

[0023] The control unit may change the amount, pressure, and timing of the fluid discharged during the second discharge. The control unit may also be able to switch between the presence and absence of the second discharge. This allows the second discharge to be performed with settings appropriate for each examiner or facility.

[0024] The control unit may change the timing at which the fluid suction operation starts after the fluid is ejected, thereby shifting the timing at which foreign matter such as aerosols scatters after the fluid is ejected from the timing at which the fluid is suctioned, thereby reducing the possibility of inhaling foreign matter such as aerosols.

[0025] The control unit may execute a tonometer control program stored in a storage unit or the like. The tonometer control program may include, for example, a driving step, a first discharging step, and a second discharging step. The driving step is, for example, a step of driving a fluid discharging unit that discharges fluid onto the cornea of ​​the subject's eye. The first discharging step is, for example, a step of performing a first discharge to deform the cornea in intraocular pressure measurement. The second discharging step is, for example, a step of performing a second discharge to remove foreign matter near the discharge port of the fluid discharging unit after the first discharge and before the next measurement.

[0026] <First Example> A non-contact tonometer according to a first embodiment will be described below with reference to the drawings. The non-contact tonometer according to the first embodiment measures the intraocular pressure of the subject's eye in a non-contact manner. The non-contact tonometer, for example, ejects a fluid onto the cornea of ​​the subject's eye, and measures the intraocular pressure of the subject's eye from the relationship between the deformation of the cornea and the pressure of the fluid at that time. The non-contact tonometer includes, for example, a fluid ejection unit, a drive unit, a control unit, etc. In addition, the X direction in FIGS. 1 to 3 represents the left-right direction, the Y direction represents the up-down direction, and the Z direction represents the front-back direction.

[0027] As shown in FIG. 1 , the non-contact tonometer 1 may include a base 2, a face support unit 3, a drive unit 4, a display unit 85, a face imaging unit 90, and the like. The base 2 movably supports the measurement unit 100. The face support unit 3 supports the subject's face. The face support unit 3 includes a forehead rest 3a, a chin rest 3b, a chin rest sensor 3c, and a chin rest drive unit 3d. The chin rest sensor 3c detects whether the chin is resting on the chin rest 3b. The chin rest drive unit 3d moves the chin rest 3b up and down to adjust its height. The drive unit 4 moves the measurement unit 100 in the X, Y, and Z directions (three-dimensional directions) relative to the base 2. The display unit 85 displays, for example, an observed image of the subject's eye and measurement results. The display unit 85 may be provided integrally with the non-contact tonometer 1 or separately from the device. The display unit 85 may be arranged so that the display screen faces not only the subject but also the subject side. Various operation instructions are input to the display unit 85 by the examiner or the subject. The display unit 85 may also be used as the operation unit 86. In this case, the display unit 85 is used for various settings of the non-contact tonometer 1, starting measurement, operations during air inhalation, etc. Various human interfaces such as a joystick, mouse, keyboard, trackball, button, etc. may also be used as the operation unit 86. The face photographing unit 90 photographs, for example, the face of the subject's eye. The face photographing unit 90 photographs, for example, the face including at least one of the left and right eyes of the subject.

[0028] <Fluid discharge part> The fluid discharge unit 200 discharges fluid onto, for example, the cornea of ​​the subject's eye E. The fluid discharge unit 200 includes, for example, a cylinder 201, a piston 202, a solenoid actuator (hereinafter also referred to as a solenoid) 203, and a nozzle 206. The cylinder 201 and the piston 202 are used as an air compression mechanism that compresses air to be discharged onto the subject's eye. The cylinder 201 is, for example, cylindrical. The piston 202 slides along the axial direction of the cylinder 201. The piston 202 compresses air in an air compression chamber 234 inside the cylinder 201. The solenoid 203 of this embodiment is a so-called direct-acting solenoid, and operates linearly. The solenoid 203 includes a movable body 204 and a coil 205. The movable body 204 is made of, for example, a magnetic material such as a permanent magnet. When a current flows through the coil 205, a magnetic field is generated inside the coil 205. The movable body 204 is moved in the direction A in FIG. 2 by the electromagnetic force received from the magnetic field. The movable body 204 is fixed to the piston 202 by screws, bolts, nuts, etc. (not shown). Therefore, the piston 202 moves together with the movable body 204. The movement of the movable body 204 moves the piston 202 in the compression direction (or forward direction, direction A in FIG. 1). The nozzle 206 discharges the compressed air to the outside of the device. The nozzle 206 has a discharge port 206a.

[0029] The fluid compressed in the air compression chamber 234 in the cylinder 201 by the movement of the piston 202 is discharged from the nozzle 206 toward the cornea of ​​the subject's eye E through a tube (which may be a pipe) 220 connected to the tip of the cylinder 201 and an airtight chamber 221 that stores the compressed air. For example, the cylinder 201 may be arranged parallel to the horizontal plane (XZ plane), and the piston 202 may be moved horizontally within the cylinder 201 by driving the solenoid 203, thereby compressing the fluid. For example, the longitudinal direction of the cylinder 201 may be arranged parallel to the horizontal direction, and the inner surface of the cylinder 201 guides the piston 202. Therefore, the movement direction (compression direction) of the piston 202 is horizontal. Each of the above-mentioned components is arranged on a stage provided within the housing of the device main body.

[0030] Furthermore, the solenoid 203 of this embodiment can change the direction of movement of the movable body 204 by changing the direction of current flowing through the coil 205. For example, when a current flows in the forward direction through the coil 205, the movable body 204 moves in the compression direction (forward direction, direction A in FIG. 2), and when a current flows in the reverse direction, the movable body 204 moves in the opposite direction (rearward direction, direction B in FIG. 2). Therefore, by switching the direction of current flowing through the coil 205, the direction of movement of the piston 202, which moves together with the movable body 204, can be changed. For example, after a current flows in the forward direction through the coil 205, the piston 202 moves in the direction A to compress the fluid in the air compression chamber 234, and then a current flows in the reverse direction through the coil 205, the piston 202 moves in the direction B to return to its initial position.

[0031] The fluid ejection unit 200 may include, for example, a glass plate 208 and a glass plate 209. The glass plate 208 is transparent, holds the nozzle 206, and transmits observation light and alignment light. The glass plate 209 forms the rear wall of the airtight chamber 221 and transmits observation light and alignment light.

[0032] The fluid discharge part 200 may include, for example, a pressure sensor 212 and an air vent hole 213. The pressure sensor 212 detects, for example, the pressure in the airtight chamber 221. The air vent hole 213 reduces resistance until the piston 202 gains initial velocity, for example, and can obtain a time-proportional rise in pressure change.

[0033] <Measurement optical system> 3 is a schematic diagram of the measurement optical system 10 of the non-contact tonometer 1. An image of the subject's eye illuminated by an infrared illumination light source 30 is formed on a CCD camera 35 via a beam splitter 31, an objective lens 32, a dichroic mirror 33, an imaging lens 37, and a filter 34. That is, the optical system from the beam splitter 31 to the CCD camera 35 has an imaging element and is used as an observation optical system for observing the anterior segment of the subject's eye. In this case, the optical axis L1 is used as the observation optical axis.

[0034] The filter 34 transmits light from the light source 30 and the infrared light source 40 for alignment, but is opaque to light from a light source 50 for corneal deformation detection (described later) and visible light. The image formed on the CCD camera 35 is displayed on a display unit 85.

[0035] Infrared light projected from the light source 40 through the projection lens 41 is reflected by the beam splitter 31 and projected from the front onto the subject's eye. A corneal bright spot formed at the corneal vertex by the light source 40 is imaged on the CCD camera 35 via the beam splitter 31 to the filter 34 and is used to detect alignment in the vertical and horizontal directions. In other words, the optical system from the beam splitter 31 to the CCD camera 35 has an image sensor and is used as a detection optical system for detecting the alignment state in the vertical and horizontal directions with respect to the subject's eye. In this case, the optical axis L1 is used as the alignment optical axis. In this embodiment, the detection optical system also serves as an observation optical system for observing the anterior segment of the eye.

[0036] The fixation optical system 48 has an optical axis L1 and presents a fixation target to the eye E from the front direction. In this case, the optical axis L1 is used as the fixation optical axis. The fixation optical system 48 has, for example, a visible light source (fixation lamp) 45, a projection lens 46, and a dichroic mirror 33, and projects light onto the eye E to cause the eye E to fixate in the front direction. The visible light source 45 may be a light source such as an LED or a laser. The visible light source 45 may also be, for example, a pattern light source such as a point light source, a slit light source, or a ring light source, or a two-dimensional display such as a liquid crystal display.

[0037] Visible light emitted from the light source 45 passes through the projection lens 46, is reflected by the dichroic mirror 33, passes through the objective lens 32, and is then projected onto the fundus of the eye E. This causes the eye E to fixate on the fixation point in the front direction, and the line of sight is fixed. Note that the visible light emitted from the light source 45 is converted into a parallel beam of light by passing through the projection lens 46 and the objective lens 32.

[0038] The corneal deformation detection optical system includes a light projecting optical system 500a and a light receiving optical system 500b, and is used to detect the deformation state of the cornea Ec. Each of the optical systems 500a and 500b is disposed in the measurement unit 100 and is moved three-dimensionally by the drive unit 4.

[0039] The light projecting optical system 500a has an optical axis L3 as a light projecting optical axis, and irradiates illumination light obliquely toward the cornea Ec of the eye E. The light projecting optical system 500a includes, for example, an infrared light source 50, a collimator lens 51, and a beam splitter 52. The light receiving optical system 500b includes a photodetector 57, and receives the illumination light reflected by the cornea Ec of the eye E. The light receiving optical system 500b is disposed approximately symmetrically to the light projecting optical system 500a with respect to the optical axis L1. The light receiving optical system 500b includes, for example, a lens 53, a beam splitter 55, a pinhole plate 56, and a photodetector 57, and forms an optical axis L2 as a light receiving optical axis.

[0040] Light emitted from the light source 50 is converted into a substantially parallel beam by a collimator lens 51, reflected by a beam splitter 52, and then becomes coaxial with (coincides with) an optical axis L3 of a light-receiving optical system 70b (described later), and is projected onto the cornea Ec of the subject's eye. The light reflected by the cornea Ec becomes coaxial with (coincides with) an optical axis L2 of a light-projecting optical system 70a (described later), passes through a lens 53, is reflected by a beam splitter 55, passes through a pinhole plate 56, and is received by a photodetector 57. The lens 53 is coated with a coating that is opaque to the light from the light source 30 and the light source 40. The optical system for detecting corneal deformation is positioned so that the amount of light received by the photodetector 57 is maximized when the subject's eye is in a predetermined deformation state (flat state).

[0041] This corneal deformation detecting optical system also serves as part of the first working distance detecting optical system, and the light projecting optical system of the first working distance detecting optical system also serves as the light projecting optical system 500a of the corneal deformation detecting optical system. The light receiving optical system 600b that receives light reflected by the cornea Ec from the light source 50 has, for example, the lens 53, beam splitter 58, condenser lens 59, and position sensitive element 60 of the light projecting optical system 500a, and forms an optical axis L2 as a light receiving optical axis.

[0042] Illumination light projected from the light source 50 and reflected by the cornea Ec forms a target image, which is a virtual image of the light source 50. The light from this target image passes through a lens 53 and a beam splitter 55, is reflected by a beam splitter 58, and then passes through a condenser lens 59 to enter a one-dimensional or two-dimensional position-sensing element 60, such as a PSD or a line sensor. When the subject's eye E (cornea Ec) moves in the working distance direction (Z direction), the target image generated by the light source 50 also moves on the position-sensing element 60. Therefore, the control circuit 20 obtains working distance information based on the output signal from the position-sensing element 60. Note that the output signal from the position-sensing element 60 in this embodiment is used for alignment (coarse adjustment) in the working distance direction (Z direction). The light-receiving optical system 600b of the first working distance detection optical system does not have as high a magnification as the light-receiving optical system 70b (described later). Therefore, the distance detection range of the position-sensing element 60 in the Z direction is wider than that of the light-receiving element 77.

[0043] The corneal thickness measuring optical system includes a light projecting optical system 70a, a light receiving optical system 70b, and a fixation optical system 48, and is used to measure the corneal thickness of the subject's eye E. The light projecting optical system 70a also serves as a part of the corneal deformation detecting optical system and the first working distance detecting optical system.

[0044] The light projection optical system 70a has an optical axis L2 as a light projection optical axis, and irradiates illumination light (measurement light) obliquely toward the cornea Ec of the eye E. The light projection optical system 70a includes, for example, an illumination light source 71, a condenser lens 72, a light-limiting member 73, a concave lens 74, and a lens 53 that also serves as the corneal deformation detection optical system. The illumination light source 71 is a visible light source or an infrared light source (including near-infrared), such as an LED or laser. The condenser lens 72 condenses the light emitted from the light source 71. Note that the light source 50 and the light source 71 each use the same wavelength band.

[0045] The light limiting member 73 is disposed in the optical path of the light projecting optical system 70a and limits the light emitted from the light source 71. The light limiting member 73 is disposed at a position approximately conjugate with the cornea Ec. For example, a pinhole plate, a slit plate, or the like is used as the light limiting member 73. The light limiting member 73 is used as an aperture that passes a portion of the light emitted from the light source 71 and blocks the other light. The light projecting optical system 70a then forms a predetermined pattern light beam (for example, a spot light beam or a slit light beam) on the cornea of ​​the eye E.

[0046] The light-receiving optical system 70b has a light-receiving element 77 and receives reflected light of the illumination light from the front and back surfaces of the cornea of ​​the eye E. The light-receiving optical system 70b is disposed approximately symmetrically with the light-projecting optical system 70a with respect to the optical axis L1. The light-receiving optical system 70b has, for example, a light-receiving lens 75, a concave lens 76, and a light-receiving element 77, and forms an optical axis L3 as a light-receiving optical axis. The light-receiving optical system 70b in FIG. 3 also serves as a second working distance detection optical system that detects the alignment state in the Z direction with respect to the eye E.

[0047] The light-receiving element 77 has multiple photoelectric conversion elements and receives light reflected from the front and back surfaces of the cornea. The light-receiving element 77 may be a light-detecting device such as a one-dimensional line sensor or a two-dimensional area sensor. The light-receiving optical system 70b of the corneal thickness measurement optical system and the second working distance detection optical system performs observation at a high magnification. Therefore, the distance detection range of the light-receiving element 77 in the Z direction is narrower than that of the position detection element 60.

[0048] When the subject's eye E (cornea Ec) moves in the working distance direction (Z direction), the reflected light of the light source 71 on the cornea Ec also moves on the light receiving element 77, and the control unit 80 obtains working distance information based on the output signal from the light receiving element 77 of the second working distance detection optical system. Furthermore, the control unit 80 determines the state of corneal deformation and blinking of the subject's eye E from the output signal from this light receiving element 77, and controls the drive of the solenoid 203.

[0049] Light emitted from the illumination light source 71 is condensed by the condenser lens 72 and illuminates the light-limiting member 73 from behind. After being limited by the light-limiting member 73, the light from the light source 71 is focused (condensed) near the cornea Ec by the lens 53. Near the cornea Ec, for example, a pinhole image (when a pinhole plate is used) or a slit image (when a slit plate is used) is formed. At this time, the light from the light source 71 is focused near the intersection with the visual axis on the cornea Ec.

[0050] When illumination light is projected onto the cornea Ec by the light projection optical system 70a, the reflected light of the illumination light from the cornea Ec travels in a direction symmetrical to the projected light beam with respect to the optical axis L1. The reflected light is then focused onto the light receiving surface of the light receiving element 77 by the light receiving lens 75.

[0051] The lens 53, which is used by both the light receiving optical system 500b, 600b and the light projecting optical system 70a, is positioned so as to focus the light reflected by the cornea Ec from the light source 50 at the center of the hole in the pinhole plate 56, and to focus the illumination light from the light source 71 on the front and back surfaces of the cornea Ec.

[0052] The face photographing unit 90 is, for example, an optical system for photographing a face including at least one of the left and right eyes to be examined. For example, as shown in FIG. 3, the face photographing unit 90 of this embodiment mainly includes, for example, an image sensor 91 and an image pickup lens 92.

[0053] The face image capturing unit 90 is provided at a position where it can capture images of both eyes of the subject when the measurement unit 100 is in its initial position. In this embodiment, the initial position of the measurement unit 100 is set to a position shifted to the right with respect to the optical axis L1 of the measurement unit 100 to facilitate testing of the right eye. Therefore, the face image capturing unit 90 is provided at a position where it can capture images of both eyes of the subject when the measurement unit 100 is in its initial position shifted to the right. For example, the face image capturing unit 90 is located at the mechanical center when the measurement unit 100 is in its initial position. If the initial position is set based on, for example, half the interpupillary distance, i.e., the interpupillary distance of one eye, the face image capturing unit 90 may be located at a position shifted to the left or right by the interpupillary distance of one eye from the mechanical center of the device body.

[0054] The face photographing unit 90 of this embodiment is moved together with the measuring unit 100 by the driving unit 4. Of course, the face photographing unit 90 may be configured to be fixed to the base 2 and not move, for example.

[0055] The imaging lens 92 may be, for example, a wide-angle lens. Examples of wide-angle lenses include a fisheye lens and a conical lens. By providing a wide-angle lens, the face imaging unit 90 can capture an image of the subject's face at a wide angle of view.

[0056] <Control system> As shown in FIG. 2 , the non-contact tonometer 1 includes a control unit 80. The control unit 80 controls various aspects of the non-contact tonometer 1. The control unit 80 includes, for example, a general CPU (Central Processing Unit) 81, a ROM 82, a RAM 83, and the like. For example, the ROM 82 stores a non-contact tonometer control program for controlling the non-contact tonometer 1, initial values, and the like. For example, the RAM 83 temporarily stores various pieces of information. The control unit 80 is connected to the measurement unit 100, the face photographing unit 90, the drive unit 4, the display unit 85, the operation unit 86, the chin rest drive unit 3d, a memory unit (e.g., non-volatile memory) 84, and the like. The memory unit 84 is, for example, a non-transitory storage medium that can retain its contents even when the power supply is interrupted. For example, a hard disk drive, a removable USB flash memory, or the like can be used as the memory unit 84.

[0057] <Control action> The control operation of the non-contact tonometer having the above configuration will be described with reference to FIG.

[0058] (Step S101: Alignment) First, the examiner supports the face of the subject on the face support unit 3 and positions the subject's eye E at a predetermined position. Then, the examiner adjusts the alignment by operating the operation unit 86, etc. Once the alignment is complete, the examiner starts the measurement by operating the operation unit 86 (or the control unit 80 automatically issues a measurement start signal based on a signal from the alignment optical system).

[0059] (Step S102: Corneal thickness measurement) When the alignment is complete, the control unit 80 measures the corneal thickness of the subject's eye using the corneal thickness measurement optical system. The control unit 80 calculates the distance (peak-to-peak distance) between the reflected signal from the anterior surface of the cornea detected by the light receiving element 77 and the reflected signal from the posterior surface of the cornea.

[0060] (Step S103: Intraocular pressure measurement) Once the measurement of the corneal thickness is complete, the control unit 80 measures the intraocular pressure. For example, when the control unit 80 drives the solenoid 203 to move the piston 202, the air in the cylinder 201 is compressed, and the compressed air is blown from the nozzle 206 toward the cornea Ec. The cornea Ec gradually deforms as the compressed air is blown against it, and when it reaches a flat (or applanated) state, the maximum amount of light is incident on the photodetector 57. The control unit 80 calculates the intraocular pressure value based on the output signal from the pressure sensor 212 and the output signal from the photodetector 57. The control unit 80 then displays the measurement result on the display unit 85. Here, when a predetermined measurement completion condition is met, the intraocular pressure measurement of the subject's eye is completed.

[0061] (Step S104: Output result) When the measurement is completed, the control unit 80 outputs the measurement result data. For example, the control unit 80 displays the measurement result on the display unit 85, prints it out, or outputs it to the outside of the device wirelessly or via a wired connection. When the data output is completed, the control unit 80 ends the process.

[0062] <Control operation of fluid discharge unit> Next, the control operation of the fluid discharge part 200 during intraocular pressure measurement will be described with reference to FIG.

[0063] (Step S201: Air discharge) First, the control unit 80 ejects air onto the cornea of ​​the subject's eye. For example, the control unit 80 applies an electric current as driving energy to the solenoid 203. This activates the solenoid 203, and the driving force is transmitted to the piston 202. The piston 202 moves forward in the compression direction (direction A), and the air compressed in the cylinder 201 compresses the air in the airtight chamber 221 via the tube 220. Then, the compressed air is blown onto the cornea of ​​the subject's eye through the nozzle 206, gradually deforming the cornea of ​​the subject's eye.

[0064] (Step S202: Piston stops) When the control unit 80 detects that the cornea has reached an applanation state based on the light reception signal of the photodetector 57, it applies a current in the reverse direction to the coil 205, and applies a driving force (returning force) in direction B to the piston 202. The piston 202, which is moving in direction A, gradually slows down due to the returning force and stops.

[0065] (Step S203: Wait) The control unit 80 waits until a trigger signal to start the intake of air is generated while stopping the piston 202. For example, the control unit 80 stops the supply of current to the solenoid 203 to maintain the stopped state of the piston.

[0066] (Step S204: Trigger signal reception) The control unit 80 receives a trigger signal. The trigger signal is output, for example, by the examiner operating the operation unit 86. For example, after air is ejected into the subject's eye, the examiner operates the operation unit 86 to output a trigger signal for sucking air into the cylinder 201 when a certain amount of time has passed and the area around the nozzle 206 has been ventilated. When the control unit 80 receives the trigger signal output from the operation unit 86, the process proceeds to step S205.

[0067] (Step S205: Air intake) The control unit 80 again applies a returning force to the piston 202. The returning force causes the piston 202 to move in the direction B and return to the initial position. This causes air to be drawn into the cylinder 201. The control unit 80 repeats the processes from step S201 to step S205 until the intraocular pressure value can be measured.

[0068] As described above, in this embodiment, the timing until fluid inhalation can be changed based on the examiner's operation. This allows fluid inhalation to be performed at a timing appropriate for each measurement, and makes it possible to prevent tears, dust, airborne bacteria, etc. from being sucked into the cylinder. For example, even if aerosols or the like remain in the air for a certain period of time, fluid inhalation can be performed at an appropriate timing depending on the ventilation status of the measurement location.

[0069] <Example of transformation> The control unit 80 may start the inhalation of the fluid based on a preset waiting time. For example, after discharging the fluid, the control unit 80 may receive a trigger signal indicating that a preset waiting time has elapsed, and start the inhalation of the fluid. This eliminates the need for the examiner to operate the operation unit 86 or the like to output a trigger signal each time the fluid is discharged. The control unit 80 may also change the waiting time. For example, the control unit 80 may change the waiting time based on an operation signal output from the operation unit 86 by the examiner's operation. For example, as shown in FIG. 6, the control unit 80 displays a waiting time setting screen 300 on the display unit 85. In the example shown in FIG. 6, the current waiting time is displayed on the setting screen 300. For example, the examiner selects the number of seconds for the current waiting time, enters a new value, and presses the OK button. In this manner, the examiner can change the waiting time and set a new waiting time.

[0070] The control unit 80 may be configured to switch between multiple operating modes with different timing change conditions. For example, the control unit 80 may switch between a manual change mode (first mode) in which the inhalation timing is manually changed and a time setting mode (second mode) in which inhalation begins when a preset waiting time has elapsed. As described in the above embodiment, the manual change mode is a mode in which the examiner operates the operation unit 86 or the like to generate a trigger signal each time ejection is performed, thereby starting the inhalation operation. In the manual change mode, the inhalation operation can be started according to the circumstances of each measurement. In the time setting mode, for example, the time from ejection to the start of the inhalation operation is preset, and the inhalation operation automatically begins when the set time has elapsed after ejection. In the time setting mode, if the time is set in advance, there is no need to operate the operation unit 86 for each ejection.

[0071] For example, as shown in Fig. 7, a mode setting screen 400 may be displayed on the display unit 85, and the examiner may select an operation mode. In this case, the control unit 80 switches to the operation mode selected by the examiner. In this way, by being able to switch between a plurality of operation modes with different timing change conditions, the examiner can perform measurement in an operation mode that is easiest for the examiner to use.

[0072] The control unit 80 may be configured to be able to turn off the change function. In this case, the control unit 80 waits a predetermined time after stopping the piston 202 and then starts suctioning the fluid. In this way, the control unit 80 may switch between a mode in which the timing of suctioning the fluid is changed and a mode in which the timing of suctioning the fluid is not changed and the fluid is suctioned at a predetermined timing. Since changing the timing of suctioning may increase the examination time, each facility can set the appropriate settings by switching between enabling and disabling the change function.

[0073] The control unit 80 may detect the presence or absence of the subject using a detection unit such as the chin rest sensor 3c or the face image capturing unit 90, and change the timing of fluid suction depending on the detection result. For example, the control unit 80 may perform fluid suction when it is determined that the subject's face has moved away from the face support unit 3 based on the detection results of the chin rest sensor 3c, the face image capturing unit 90, etc. By detecting the presence or absence of the subject using the face image capturing unit 90, it is possible to indirectly detect the possibility of a foreign object being inhaled into the cylinder 201.

[0074] The control unit 80 may also change the timing of fluid suction based on the position of the measurement unit 100. For example, the non-contact tonometer 1 may be equipped with a position sensor that detects the position of the measurement unit 100. For example, the position sensor may detect that the measurement unit 100 is at the home position (initial position). The control unit 80 may start fluid suction when the position sensor detects that the measurement unit 100 is at the home position. For example, the control unit 80 may start fluid suction after detecting with the position sensor that the examiner has moved the measurement unit 100 back to the home position after discharging the fluid. By detecting the position of the measurement unit 100 with the position sensor, it is possible to indirectly detect the possibility of foreign matter being suctioned into the cylinder 201.

[0075] A distance measuring sensor may be provided instead of the position sensor. For example, a distance measuring sensor may be provided on the subject side of the measurement unit 100, and the timing of fluid suction may be changed based on the distance to the subject (or face support unit 3) measured by the distance measuring sensor. By detecting the distance to the subject using the distance measuring sensor, it is possible to indirectly detect the possibility of inhaling a foreign object into the cylinder 201.

[0076] The non-contact tonometer 1 may also include a nozzle retraction mechanism. The nozzle retraction mechanism moves the nozzle tip away from the subject's eye. The nozzle retraction mechanism may, for example, retract (store) the nozzle inside the measurement unit 100. In this case, for example, the control unit 80 may start fluid suction after the nozzle 206 has been retracted. The nozzle retraction mechanism may retract the nozzle 206 by moving it in the Z direction, X direction, or Y direction, or by rotating it around a horizontal axis or a vertical axis. The non-contact tonometer 1 may also include a nozzle position sensor that detects the position of the nozzle 206. In this case, the control unit 80 may start fluid suction after the nozzle position sensor detects that the nozzle 206 has been retracted.

[0077] The control unit 80 may detect the subject's blinking based on the pupil or bright spot in the anterior eye image captured by the observation optical system (CCD camera 35), and may start inhaling the fluid when the subject's blinking has settled down. For example, the fluid may be inhaled several seconds after the last blink is detected. This prevents the inhalation of tears scattered by blinking. Detecting the subject's blinking using the observation optical system may indirectly detect the possibility of inhaling foreign matter into the cylinder 201.

[0078] The control unit 80 may control the fluid discharge unit 200 when the subject is switched and discharge the fluid several times when the subject is not present. This allows the air inside the cylinder to be replaced even if tears, dust, or debris gets inside the cylinder.

[0079] <Second Example> The second embodiment will be described below. The non-contact tonometer of the second embodiment differs from the first embodiment in the control operation of the fluid discharge unit. The device configuration is the same as that of the first embodiment, so a description thereof will be omitted. <Control operation of fluid discharge unit> The control operation of the fluid discharge unit 200 during intraocular pressure measurement in the second embodiment will be described with reference to Fig. 8. The non-contact tonometer 1 discharges air (second discharge) to blow away and remove foreign matter such as aerosols floating around the nozzle 206, in addition to the discharge (first discharge) to deform the cornea. The aerosols include, for example, tears on the cornea of ​​the subject's eye, deposits on the surrounding tissue, viruses, bacteria, etc., dispersed by the first discharge.

[0080] {Step S301: Piston Drive (First Discharge)} First, the control unit 80 ejects air onto the cornea of ​​the subject's eye. For example, the control unit 80 supplies an electric current as driving energy to the solenoid 203. This activates the solenoid 203, and the driving force is transmitted to the piston 202. The piston 202 moves forward in the direction A, and the air compressed in the cylinder 201 compresses the air in the airtight chamber 221 via the tube 220. Then, the compressed air is blown onto the cornea of ​​the subject's eye through the nozzle 206, thereby deforming the cornea of ​​the subject's eye.

[0081] {Step S302: Stop piston} When the control unit 80 detects that the cornea has reached an applanation state based on the light reception signal of the photodetector 57, it supplies a current in the reverse direction to the coil 205, and applies a driving force (returning force) in direction B to the piston 202. The piston 202, which is moving in direction A, gradually slows down due to the returning force and stops.

[0082] {Step S303: Piston drive (second discharge)} After stopping the piston 202, the control unit 80 supplies a current to the coil 205 again, and moves the piston 202 in the direction A while a force is applied (biased) to the piston 202. This causes air to be discharged again into the subject's eye. Note that the control unit 80 may move (bias) the piston 202 in the direction A up to the movement limit position (the position where the front surface of the piston 202 abuts against the cylinder).

[0083] (Step S304: Wait) The control unit 80 waits until it receives a trigger signal to start drawing air while stopping the piston 202. For example, the control unit 80 stops the supply of current to the solenoid 203 to maintain the stopped state of the piston 202.

[0084] {Step S305: Piston drive (air intake)} The control unit 80 again applies a return force to the piston 202. The return force causes the piston 202 to move in the direction B. As a result, air is sucked into the cylinder 201.

[0085] {Step S306: Stop the piston (home position)} The control unit 80 stops the supply of current when the piston 202 stops at the origin position. The control unit 80 repeats the processes from step S301 to step S306 until the intraocular pressure value can be measured.

[0086] In the non-contact tonometer 1 described above, it is necessary to return the piston 202 to the origin position and draw air into the cylinder for the next measurement. However, there is a possibility that foreign matter such as aerosols may be floating around the nozzle immediately after the measurement. For this reason, the non-contact tonometer 1 of this embodiment ejects air again after ejecting air during the measurement. In this way, by performing a second ejection after the first ejection, it is possible to prevent foreign matter such as aerosols from being sucked into the nozzle 206 due to the inhalation action.

[0087] As in the above embodiment, the second discharge is performed before the air intake operation is completed, thereby allowing foreign matter such as aerosols to be blown away and removed before the air intake is completed, thereby reducing the possibility of foreign matter being sucked into cylinder 201.

[0088] The first and second ejections do not need to be performed in a sequence, but may be performed independently at any timing. For example, the control unit 80 may end the measurement operation after performing the first ejection, and then perform the second ejection at any timing, regardless of the first ejection.

[0089] It is preferable that the pressure of the fluid in the second ejection is lower than that in the first ejection. For example, the first ejection is ejected at a high pressure so as to be able to deform the cornea, whereas the second ejection is ejected at a low pressure so as not to generate new aerosols, etc., as long as it is able to blow away aerosols, etc., near the nozzle 206.

[0090] The control unit 80 may cause the display unit 85 to display that the second discharge is being performed. For example, as shown in Fig. 9, the control unit 80 may cause the display unit 85 to display a second discharge (re-discharge) mark 503 on a measurement screen 500 displayed on the display unit 85. This allows the examiner to confirm that the second discharge is being performed. Furthermore, the examiner can explain to the subject or the like that the second discharge is being performed.

[0091] The control unit 80 may change the discharge amount, discharge pressure, discharge timing, etc. in the second discharge. For example, as shown in Fig. 10, the examiner may be able to arbitrarily set the discharge amount, discharge pressure, and discharge timing using a setting screen 600 displayed on the display unit 85. The control unit 80 may change, for example, the magnitude or supply time of the current supplied to the solenoid based on the set discharge amount, discharge pressure, or discharge timing.

[0092] In the above embodiment, the control unit 80 temporarily stops the piston 202 after the first discharge, but this is not limited to this. For example, the control unit 80 may continue the second discharge slowly, following on from the first discharge. For example, the control unit 80 may perform the second discharge without stopping the piston 202. In this case, for example, the control unit 80 may apply a restoring force in direction B to the piston 202 moving in direction A during the first discharge to slow it down, release the restoring force before it stops, and apply a force in direction A again to urge it, thereby performing a re-discharge without stopping the piston 202.

[0093] In the above embodiment, the control unit 80 performs the second ejection by driving the solenoid 203, but this is not limiting. For example, the piston 202 may be urged by utilizing the magnetic attraction between the metal plate 210 (see FIG. 2) supporting the cylinder 201 and the movable body 204. For example, after the first ejection, the control unit 80 removes the restoring force of the solenoid 203 before the restoring force of the solenoid 203 completely stops the piston 202. The piston 202 continues to move due to inertia, and when the movable body 204 moves to a position where the metal plate 210 and the movable body 204 are attracted to each other by magnetic force, the piston 202 is urged in the direction A by the magnetic force, and the second ejection is performed. In this way, the second ejection may be performed by urging the piston 202 not only by driving the solenoid 203 but also by other urging means.

[0094] The control unit 80 may be configured to switch between the presence and absence of second discharge. When the second discharge function is turned off, for example, the control unit 80 proceeds to the standby operation of step S304 without performing the second discharge operation of step S303. In this way, by being able to switch between the presence and absence of second discharge, measurement can be performed with settings appropriate for each examiner or each facility.

[0095] In the above embodiment, a direct acting solenoid is used as the solenoid 203, but a rotary solenoid or other drive source may also be used. [Explanation of symbols]

[0096] 1. Non-contact tonometer 80 Control Unit 201 Cylinder 202 Piston 203 Solenoid

Claims

1. A non-contact tonometer for measuring intraocular pressure of a subject's eye without contact, a fluid ejection means for ejecting a fluid onto the cornea of ​​the subject's eye by means of a cylinder and a piston that moves inside the cylinder; a driving means for driving the fluid discharge means; a control means for controlling the driving means, the control means performs a first discharge to deform the cornea into an applanated state during intraocular pressure measurement, urges the piston in a backward direction relative to the piston moving in a forward direction during the first discharge to slow down or stop the piston, and then urges the piston in the forward direction again during a second discharge to perform a discharge to remove foreign matter near the discharge port of the fluid discharge unit before the fluid suction operation is completed.

2. 2. The non-contact tonometer according to claim 1, wherein the control means replaces the air inside the fluid discharge means by performing the second discharge.

3. 2. The non-contact tonometer according to claim 1, wherein the control means performs the second ejection when the subject is not present.

4. A tonometer control program executed in a non-contact tonometer that measures intraocular pressure of a subject's eye in a non-contact manner, the program being executed by a control unit of the non-contact tonometer, a driving step of driving a fluid discharge means that discharges a fluid onto the cornea of ​​the subject's eye by means of a cylinder and a piston that moves inside the cylinder; a first ejection step of performing a first ejection for deforming the cornea into an applanation state in intraocular pressure measurement; a second discharge step in which the piston moving in the forward direction in the first discharge is urged in a backward direction to slow down or stop the piston, and then the piston is urged in the forward direction again in the second discharge to remove foreign matter near the discharge port of the fluid discharge part before the fluid suction operation is completed; a control program for controlling the non-contact tonometer, the control program causing the non-contact tonometer to execute the above steps;

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