Tonometer and tonometry program

Abstract

To provide a tonometer and a tonometry program capable of appropriately improving efficiency of medical care using a measurement result of an intraocular pressure.SOLUTION: A control part of a tonometer performs a past intraocular pressure acquisition step, a current intraocular pressure measurement step, and a difference information display step. In the past intraocular acquisition step, the control part acquires a measurement result of a past intraocular pressure measured for a subject eye. In the current intraocular measurement step, the control part measures a current intraocular pressure of the subject eye. In the difference information display step, the control part causes a display part to display difference information being information on a difference between the current intraocular pressure measured in the current intraocular measurement step and the past intraocular pressure acquired in the past intraocular pressure acquisition step.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an intraocular pressure measurement device that measures the intraocular pressure of a subject's eye, and an intraocular pressure measurement program executed by the intraocular pressure measurement device. [Background technology]

[0002] Intraocular pressure measurement devices for measuring the intraocular pressure of a subject's eye are known. In medical treatment, it may be useful for medical professionals to be presented with multiple intraocular pressure measurement results obtained on different days for the same subject's eye. For example, a medical information processing system described in Patent Document 1 displays multiple intraocular pressure measurement results obtained on different days for the same subject's eye in the form of a progress graph, thereby allowing the progress of glaucoma to be monitored. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-301816 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, in the past, after the intraocular pressure measurement of the subject's eye was completed, multiple intraocular pressure measurement results were only presented to the medical professional via an electronic medical record or the like when the medical professional examined the subject's eye. Therefore, if the medical professional determined that the intraocular pressure measurement results were not satisfactory after reviewing them during the examination, they often had to repeat the intraocular pressure measurement even though the subject had already left the intraocular pressure measurement device. Furthermore, no technology had been proposed to improve the efficiency of the procedure for measuring intraocular pressure using an intraocular pressure measurement device by utilizing previous intraocular pressure measurement results. Because conventional technology failed to solve at least some of the above-mentioned problems, it was difficult to appropriately improve the efficiency of medical treatment (examination, diagnosis, etc.) using intraocular pressure measurement results.

[0005] A typical object of the present disclosure is to provide an intraocular pressure measurement device and an intraocular pressure measurement program that can appropriately improve the efficiency of medical treatment using intraocular pressure measurement results. [Means for solving the problem]

[0006] An intraocular pressure measurement device provided by a typical embodiment of the present disclosure is an intraocular pressure measurement device that measures the intraocular pressure of a test eye, and a control unit of the intraocular pressure measurement device executes a past intraocular pressure acquisition step of acquiring measurement results of past intraocular pressures measured for the target test eye, a current intraocular pressure measurement step of measuring the current intraocular pressure of the target test eye, and a difference information display step of displaying, on a display unit, difference information that is information regarding the difference between the current intraocular pressure measured in the current intraocular pressure measurement step and the past intraocular pressure acquired in the past intraocular pressure acquisition step.

[0007] An intraocular pressure measurement program provided by a typical embodiment of the present disclosure is an intraocular pressure measurement program executed by an intraocular pressure measurement device that measures the intraocular pressure of a test eye, and the intraocular pressure measurement program is executed by a control unit of the intraocular pressure measurement device to cause the intraocular pressure measurement device to execute a past intraocular pressure acquisition step of acquiring measurement results of past intraocular pressures measured for the target test eye, a current intraocular pressure measurement step of measuring the current intraocular pressure of the target test eye, and a difference information display step of displaying, on a display unit, difference information that is information regarding the difference between the current intraocular pressure measured in the current intraocular pressure measurement step and the past intraocular pressure acquired in the past intraocular pressure acquisition step.

[0008] The intraocular pressure measurement device and intraocular pressure measurement program according to the present disclosure facilitate appropriate improvement of the efficiency of medical treatment using intraocular pressure measurement results. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a left side view showing the external configuration of an intraocular pressure measurement device 1. FIG. [Figure 2] 1 is a diagram showing the internal configuration of an intraocular pressure measurement device 1. FIG. [Figure 3] 1 is a diagram showing an optical system of an intraocular pressure measurement device 1. FIG. [Figure 4] 4 is a flowchart of a measurement process executed by the intraocular pressure measurement device 1 of the present embodiment. [Figure 5] FIG. 2 is a diagram showing an example of a measurement screen 90 that the intraocular pressure measurement device 1 of the present embodiment displays on the display unit 7. [Figure 6] FIG. 6 is a diagram showing an example of a measurement screen 90 when the measurement of intraocular pressure is completed from the state shown in FIG. 5. [Figure 7] 10 is a graph showing an example of the change over time in the magnitude of the light reception signal from the photodetector 57 when intraocular pressure is detected normally. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Summary> The control unit of the intraocular pressure measurement device exemplified in the present disclosure executes a past intraocular pressure acquisition step, a current intraocular pressure measurement step, and a difference information display step. In the past intraocular pressure acquisition step, the control unit acquires the measurement results of past intraocular pressures measured for the subject's eye. In the current intraocular pressure measurement step, the control unit measures the current intraocular pressure of the subject's eye. In the difference information display step, the control unit displays difference information, which is information regarding the difference between the current intraocular pressure measured in the current intraocular pressure measurement step and the past intraocular pressure acquired in the past intraocular pressure acquisition step, on the display unit.

[0011] According to the technology exemplified in the present disclosure, information (difference information) regarding the difference between the current intraocular pressure and the previous intraocular pressure of the subject's eye is displayed by the intraocular pressure measurement device. Therefore, a user (e.g., a doctor, nurse, or technician) can quickly understand the state of changes in the intraocular pressure of the subject's eye from the difference information displayed by the intraocular pressure measurement device and then provide appropriate medical care (e.g., at least one of examination, examination, treatment, and prescription). For example, if the user learns from the difference information that the intraocular pressure of the subject's eye is rapidly increasing, the user can quickly formulate a treatment plan or examination plan to prevent the onset or worsening of glaucoma. Furthermore, if the difference between the current intraocular pressure and the previous intraocular pressure of the subject's eye appears unnatural, the user can consider the possibility of a flaw in the current intraocular pressure measurement and quickly decide to remeasure the intraocular pressure. This facilitates appropriate improvement in the efficiency of medical care using intraocular pressure measurement results.

[0012] The specific method for the past intraocular pressure acquisition step can be selected as appropriate. For example, multiple intraocular pressure measurement results previously measured for each of multiple test eyes may be stored in a storage device. The control unit may acquire measurement result data for the target test eye from the multiple past measurement results stored in the storage device. The control unit may acquire measurement result data for the target test eye from the multiple past measurement results stored in the storage device based on information for identifying the target test eye (target patient) (e.g., at least one of ID, name, date of birth, etc.). The user may also input past measurement results for the target test eye into the intraocular pressure measurement device by operating the operation unit or by voice input. Note that the model and measurement method of the intraocular pressure measurement device that executes the technology disclosed herein and the intraocular pressure measurement device that previously measured the intraocular pressure of the target test eye may be the same or different. Note that the "previous intraocular pressure measured for the target test eye" refers to the intraocular pressure measured for the target test eye before the start of one or more series of intraocular pressure measurement operations currently being measured. For example, the past intraocular pressure may be the intraocular pressure measured on a day prior to the day on which the current intraocular pressure measurement is taken.

[0013] The configuration of the intraocular pressure measurement unit used by the intraocular pressure measurement device to measure the intraocular pressure of the subject's eye can also be selected appropriately. For example, the intraocular pressure measurement unit may include a measurement optical system and a fluid ejection unit. The fluid ejection unit ejects a fluid (e.g., compressed air) onto the cornea of ​​the subject's eye. The intraocular pressure measurement unit may measure the intraocular pressure of the subject's eye by detecting, using the measurement optical system, the deformation state (e.g., applanation state) of the cornea of ​​the subject's eye when the fluid is ejected. The intraocular pressure measurement unit may also include a measurement optical system and an ultrasonic actuator. The ultrasonic actuator irradiates the cornea of ​​the subject's eye with ultrasonic waves generated by an ultrasonic element. The intraocular pressure measurement unit may measure the intraocular pressure of the subject's eye by detecting, using the measurement optical system, the deformation state of the cornea of ​​the subject's eye when the ultrasonic waves are irradiated. The intraocular pressure measurement unit may measure the intraocular pressure of the subject's eye while in contact with the subject's eye.

[0014] The control unit may cause the display unit to display difference information for the target eye during at least a portion of the time period after the current intraocular pressure of the target eye is measured in the current intraocular pressure measurement step and before the target eye is switched to the eye of another subject. In this case, the difference information is displayed immediately after the current intraocular pressure of the target eye is measured. In other words, the difference information is displayed on the display unit before the subject leaves the intraocular pressure measurement device. This makes it easier to perform various medical procedures, such as remeasurement of the current intraocular pressure or omission of additional measurements, more smoothly.

[0015] The intraocular pressure measurement device may further include an imaging optical system that captures an observation image of the target subject's eye. The control unit may cause the display unit to display difference information of the target subject's eye together with the observation image captured by the imaging optical system. In this case, the difference information is displayed immediately after the current intraocular pressure of the target subject's eye is measured. In other words, the difference information is displayed on the display unit before the subject leaves the intraocular pressure measurement device. This makes it easier to perform various medical treatments, such as remeasurement of the current intraocular pressure of the target subject's eye, more smoothly. For example, the control unit may smoothly remeasure the intraocular pressure based on the observation image displayed together with the difference information.

[0016] The control unit may automatically execute the difference information display step when the measurement of the current intraocular pressure of the subject eye is completed in the current intraocular pressure measurement step. In this case, the user can quickly formulate a treatment plan, etc., by checking the difference information that is automatically displayed after the measurement of the current intraocular pressure of the subject eye is completed. This further facilitates improving the efficiency of treatment using intraocular pressure measurement results.

[0017] However, the control unit may switch whether to automatically display the difference information in accordance with an instruction input by the user. Also, the control unit may switch whether to automatically display the difference information in accordance with whether the difference information satisfies a certain condition (for example, whether the difference is equal to or greater than a threshold).

[0018] In the past intraocular pressure acquisition step, the control unit may acquire the most recent intraocular pressure measurement result from one or more previous intraocular pressure measurement results of the target eye. The control unit may execute the difference information display step based on the most recent acquired past intraocular pressure. In this case, the user can grasp the most recent change in intraocular pressure of the target eye. Therefore, the user can provide appropriate medical treatment according to the most recent change in intraocular pressure.

[0019] However, the control unit may also execute the differential information display step based on a non-latest intraocular pressure measurement result among multiple past intraocular pressure measurements of the subject's eye, allowing the user to appropriately grasp the state of change in the intraocular pressure of the subject's eye.

[0020] In the difference information display step, if the difference between the current intraocular pressure measured in the current intraocular pressure measurement step and the previous intraocular pressure acquired in the previous intraocular pressure acquisition step is equal to or greater than a threshold, the control unit may include alert information indicating that the difference is equal to or greater than the threshold in the difference information to be displayed on the display unit. In this case, the user can more accurately and intuitively understand that the difference between the current and previous intraocular pressures is equal to or greater than the threshold, compared to when a graph showing changes in intraocular pressure is displayed. Therefore, the user can, for example, quickly and appropriately recognize that the intraocular pressure of the subject's eye has significantly increased, and then take necessary measures (e.g., prescribing antihypertensive drugs, performing a visual field test, etc.). Furthermore, a decrease in intraocular pressure measurement accuracy may increase the difference between the current intraocular pressure and the previous intraocular pressure. Therefore, when the alert information is displayed, the user can easily consider the possibility that the accuracy of the current intraocular pressure measurement was low and consider whether a re-examination is necessary. This further facilitates improving the efficiency of medical treatment using intraocular pressure measurement results.

[0021] The threshold for determining whether to display the alert information may be set in advance or may be set by the user. The control unit may also display different alert information depending on the level (degree) of the calculated difference. In this case, the user can more easily and appropriately grasp the degree of the difference in intraocular pressure.

[0022] The control unit may also cause the display unit to display the alert information only when the value obtained by subtracting the previous intraocular pressure from the current intraocular pressure is a positive value and is equal to or greater than the threshold value. In this case, the user can quickly and appropriately recognize that the intraocular pressure of the subject's eye has significantly increased. The control unit may also cause the display unit to display the alert information when the absolute value of the value obtained by subtracting the previous intraocular pressure from the current intraocular pressure exceeds the threshold value, regardless of whether the value obtained by subtracting the previous intraocular pressure from the current intraocular pressure is a positive value. In this case, the user can quickly and appropriately recognize that the difference (absolute value) between the current intraocular pressure and the previous intraocular pressure is large based on the alert information. The control unit may also change the display mode of the alert information when the absolute value exceeds the threshold value depending on whether the value obtained by subtracting the previous intraocular pressure from the current intraocular pressure is a positive value or a negative value. In this case, the user can quickly and appropriately recognize that the intraocular pressure of the subject's eye has significantly increased or decreased based on the display mode of the alert information.

[0023] However, the difference information displayed on the display unit is not limited to alert information. For example, the control unit may display, together with or instead of the alert information, a difference value or level between the current intraocular pressure measured in the current intraocular pressure measurement step and the previous intraocular pressure acquired in the previous intraocular pressure acquisition step on the display unit. Even in this case, the user can appropriately grasp the state of change in the intraocular pressure of the subject's eye by checking the difference value or level of the intraocular pressure displayed on the display unit. When displaying the difference value or level, the control unit may display the value obtained by subtracting the previous intraocular pressure from the current intraocular pressure, or the level of the calculated value. In this case, the user can appropriately grasp whether the intraocular pressure of the subject's eye has increased since the previous measurement. Furthermore, the control unit may display both the current intraocular pressure value measured in the current intraocular pressure measurement step and the previous intraocular pressure value acquired in the previous intraocular pressure acquisition step as difference information on the display unit. Even in this case, the user can appropriately grasp the state of change in the intraocular pressure of the subject's eye by manually calculating the difference between the displayed values.

[0024] The tonometry device may further include an ocular pressure measurement unit that applies a deformation force to the cornea of ​​the subject's eye to deform the cornea and measures the intraocular pressure of the subject's eye by detecting the state of corneal deformation. The control unit may further execute a deformation force setting step that sets the deformation force to be applied to the cornea of ​​the subject's eye by the ocular pressure measurement unit based on the past intraocular pressure acquired in the past intraocular pressure acquisition step. When measuring the intraocular pressure of the subject's eye by applying a deformation force to the cornea, the appropriate deformation force to be applied to the cornea varies depending on the intraocular pressure of the subject's eye. In conventional tonometry devices, if the deformation force applied to the cornea during the initial measurement was inappropriate, the user had to remeasure the intraocular pressure with a different deformation force. Furthermore, to reduce the frequency of remeasurements, the user had to somehow acquire or predict the approximate intraocular pressure of the subject's eye and manually set the deformation force to be applied to the cornea based on the acquired or predicted intraocular pressure value. In contrast, setting the deformation force based on the past intraocular pressure makes it easier to automatically set an appropriate deformation force for the subject's eye. This makes it easier to further improve the efficiency of medical treatment.

[0025] The control unit may further execute a past reliability display step of acquiring the measurement reliability of the previous intraocular pressure measurements acquired in the past intraocular pressure acquisition step and displaying information about the acquired measurement reliability on the display unit. The measurement reliability of intraocular pressure varies depending on the subject's fixation state, eyelid state, blinking status, and the like at the time of measurement, so the measurement reliability is likely to vary depending on the subject. When measuring the intraocular pressure of a target eye, the measurement reliability of previous intraocular pressure measurements of the same eye (hereinafter referred to as "past reliability") is displayed, allowing the user to measure the intraocular pressure of the target eye after understanding that the subject is likely to engage in behaviors that reduce the measurement reliability. In other words, the user can prevent a reduction in measurement reliability by urging the subject to maintain fixation or refrain from blinking. This further improves the efficiency of medical treatment. It goes without saying that the control unit may acquire the current measurement reliability and display information about the current measurement reliability on the display unit upon completing measurement of the current intraocular pressure of the target eye.

[0026] Any method for obtaining the reliability of intraocular pressure measurement can be selected. For example, a method involves applying a deforming force (e.g., a blow of compressed air) to the cornea of ​​the subject's eye and measuring the intraocular pressure of the subject's eye based on the applanation state of the cornea (the timing at which the cornea becomes flat) when the deforming force is applied. The optical system for applanation deformation is positioned so that the amount of light reflected from the cornea by the photodetector is maximized when the cornea of ​​the subject's eye reaches a predetermined deformed state (flattened state). As an example, light is reflected obliquely from the cornea of ​​the subject's eye, and the photodetector is positioned in a reflection direction where the angle of incidence of the light on the cornea is the same as the angle of reflection of the light from the cornea. The timing at which the cornea becomes flat is obtained based on the detection result by the photodetector. In this case, if the intensity of the detected light detected by the photodetector increases rapidly as the cornea approaches flattening, reaches a maximum when the cornea is flattened, and then decreases rapidly as the cornea returns to its original state, the reliability of the intraocular pressure measurement is high. On the other hand, when at least one of the increase and decrease in the detected light is gradual, the reliability of the intraocular pressure measurement is low. Therefore, the reliability of the intraocular pressure measurement may be obtained by analyzing the rate of at least one of the increase and decrease in the detected light detected by the photodetector. Furthermore, the more accurate the alignment of the intraocular pressure measurement unit with respect to the subject's eye, the higher the reliability of the intraocular pressure measurement. Therefore, the reliability of the intraocular pressure measurement may be obtained based on the state of alignment of the subject's eye and the intraocular pressure measurement unit during intraocular pressure measurement.

[0027] A specific method for acquiring the past reliability can also be selected as appropriate. For example, when the intraocular pressure was measured in the past, the measurement reliability may already have been acquired and stored in a storage device together with the measurement results. The control unit may acquire the past intraocular pressure measurement results and measurement reliability for the target eye from the storage device. Furthermore, data for acquiring the measurement reliability when the intraocular pressure was measured in the past (e.g., data indicating the increase and decrease in the detected light detected by the photodetector, or data indicating the alignment state of the intraocular pressure measurement unit with respect to the test eye) may be stored in the storage device together with the measurement results. The control unit may acquire data for acquiring the measurement reliability together with the past intraocular pressure measurement results for the target eye, and acquire the past reliability based on the acquired data.

[0028] A specific method for displaying information regarding measurement reliability on the display unit can also be selected as appropriate. For example, the control unit may cause the display unit to display a numerical value or an icon indicating the level (degree) of measurement reliability. The level (degree) of measurement reliability may be indicated by color. The control unit may also include a message according to the measurement reliability (e.g., a message such as "Please note that the reliability of the previous measurement was low") in the information regarding measurement reliability. Furthermore, if the past reliability is low, the control unit may perform processing to increase the number of measurements of the current intraocular pressure from the usual number of measurements, thereby improving the reliability of the current intraocular pressure measurement.

[0029] The technology of the present disclosure can also be expressed as follows: An ocular pressure measurement device for measuring the intraocular pressure of a subject's eye, comprising: an ocular pressure measurement unit that applies a deformation force to the cornea of ​​the subject's eye to deform the cornea and measures the intraocular pressure of the subject's eye by detecting the state of deformation of the cornea; and a control unit, wherein the control unit executes a past intraocular pressure acquisition step that acquires results of past intraocular pressure measurements of a target subject's eye, and a deformation force setting step that sets a deformation force to be applied next to the cornea of ​​the target subject's eye by the ocular pressure measurement unit, based on the past intraocular pressure acquired in the past intraocular pressure acquisition step.

[0030] An intraocular pressure measurement device for measuring the intraocular pressure of a subject's eye, wherein a control unit of the intraocular pressure measurement device executes a past intraocular pressure acquisition step of acquiring past intraocular pressure measurement results measured for the subject's eye, and a past reliability display step of acquiring measurement reliability at the time when the past intraocular pressure acquired in the past intraocular pressure acquisition step was measured, and displaying information about the acquired measurement reliability on the display unit the next time the intraocular pressure of the subject's eye is measured.

[0031] <Embodiment> A typical embodiment of the present disclosure will be described below with reference to the drawings. An ocular pressure measurement device 1 measures the intraocular pressure of a subject's eye (examined eye) E with an examination axis IO aligned with the subject's eye (examined eye) E. The ocular pressure measurement device 1 illustrated in this embodiment includes an examination protrusion (a nozzle in this embodiment) 9 that protrudes toward the examinee's eye along the examination axis IO. The examination protrusion 9 sprays a fluid onto the cornea of ​​the examinee's eye E, thereby measuring the intraocular pressure of the examinee's eye E from the deformed shape of the cornea. In other words, the ocular pressure measurement device 1 illustrated in this embodiment is a non-contact tonometer that uses a fluid. However, the ocular pressure measurement device to which the technology illustrated in this disclosure can be applied is not limited to a non-contact tonometer that uses a fluid. For example, the technology illustrated in this disclosure can also be applied to a non-contact tonometer that irradiates ultrasound onto the cornea of ​​the examinee's eye E and measures the intraocular pressure of the examinee's eye E from the deformed shape of the cornea. Furthermore, the technology exemplified in this disclosure can also be applied to a contact tonometer that measures the intraocular pressure of the subject's eye E while a member is in contact with the subject's eye E.

[0032] The schematic configuration of an intraocular pressure measurement device 1 of this embodiment will be described with reference to Figure 1. In the following description, the left-right direction on the paper in Figure 1 is referred to as the Z direction (front-back direction), the up-down direction on the paper is referred to as the Y direction (up-down direction), and the depth direction on the paper is referred to as the X direction (left-right direction). In detail, the left side of the paper in Figure 1 (the subject side) is referred to as the front side of the intraocular pressure measurement device 1, and the right side of the paper is referred to as the rear side of the intraocular pressure measurement device 1. The upper side of the paper in Figure 1 is referred to as the upper side of the intraocular pressure measurement device 1, and the lower side of the paper is referred to as the lower side of the intraocular pressure measurement device 1. The front side of the paper in Figure 1 is referred to as the left side of the intraocular pressure measurement device 1, and the depth side of the paper is referred to as the right side of the intraocular pressure measurement device 1.

[0033] As shown in FIG. 1, the intraocular pressure measurement device 1 of this embodiment comprises a base 2, a housing 3, a drive unit 4, and a face support unit 5. The base 2 is placed at an installation location and supports the entire intraocular pressure measurement device 1. The housing 3 comprises various components for performing an examination of the subject's eye E (details will be described later). The housing 3 is supported on the base 2 via the drive unit 4. The face support unit 5 supports and positions the subject's face. In this embodiment, a chin rest and a forehead rest are used as the face support unit 5. The subject places their chin on the chin rest and their forehead on the forehead rest, thereby positioning the face. The drive unit 4 moves the position of the housing 3 relative to the subject's face, which has been positioned by the face support unit 5.

[0034] As an example, the drive unit 4 of this embodiment moves the housing 3 relative to the subject's face (or the subject's eye) by using an actuator such as a motor to move the housing 3 in the front-back, up-down, and left-right directions (three-dimensional directions) relative to the base 2. However, the configuration of the drive unit can be changed. For example, the drive unit may move the face support unit 5 to move the relative position of the housing 3 relative to the subject's face. Alternatively, the drive unit may move both the housing 3 and the face support unit 5. For example, the drive unit may move the housing 3 in the front-back and left-right directions and also move the face support unit 5 in the up-down direction to move the relative position of the housing 3 relative to the subject's face.

[0035] The housing 3 includes an examination protrusion (nozzle) 9, a face photographing unit 12, a display unit 7, and an operation unit 8. The examination protrusion 9 protrudes toward the eye to be examined along an examination axis IO from a surface 3A of the housing 3 facing the eye to be examined, which is the side on which the face of the subject is positioned (in this embodiment, the front side facing the eye to be examined). The examination axis IO is aligned with the eye to be examined E when the examination is performed. As an example, the examination protrusion 9 in this embodiment is a nozzle that sprays a fluid (e.g., compressed air) onto the cornea of ​​the eye to be examined E.

[0036] The face photographing unit 12 photographs the face of the subject. The display unit 7 displays various images. In this embodiment, the display unit 7 is disposed on the rear side of the housing 3 facing the examiner. Various operation instructions are input to the operation unit 8 by the user. As an example, in this embodiment, a touch panel installed on the display surface of the display unit 7 is used as the operation unit 8. However, at least one of a joystick, a mouse, a keyboard, a drag ball, a button, a remote controller, etc. may also be used as the operation unit 8.

[0037] The internal configuration of the intraocular pressure measurement device 1 will be described with reference to FIG. 2. The intraocular pressure measurement device 1 includes a measurement optical system 10, a fluid discharge unit 20, and a control unit 80. The measurement optical system 10 and the fluid discharge unit 20 are an example of an intraocular pressure measurement unit that performs an examination of the subject's eye. As described above, the intraocular pressure measurement unit of this embodiment measures the intraocular pressure of the subject's eye in a non-contact manner. Details of the measurement optical system will be described later with reference to FIG. 3.

[0038] The fluid discharge unit 20 discharges fluid onto the cornea of ​​the subject's eye E. The fluid discharge unit 20 includes, for example, a cylinder 201, a piston 202, a solenoid actuator (hereinafter also referred to as a solenoid) 203, and an examination protrusion 9. The cylinder 201 and the piston 202 are used as an air compression mechanism that compresses air to be discharged into 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 includes a movable body 204 and a coil 205. A magnetic body such as a permanent magnet is used for the movable body 204. 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 an electromagnetic force received from the magnetic field. The movable body 204 is fixed to the piston 202 with 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 inspection protrusion 9 discharges the compressed air to the outside of the device.

[0039] The fluid compressed in the air compression chamber 234 in the cylinder 201 by the movement of the piston 202 is discharged from the testing protrusion 9 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 compressed air. As a result, a deformation force that deforms the cornea of ​​the subject's eye E is applied to the cornea.

[0040] 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). The intraocular pressure measurement device 1 can move the piston 202 in direction A to compress the fluid in the air compression chamber 234, and then move the piston 202 in direction B to return it to its initial position.

[0041] The fluid discharge unit 20 includes a glass plate 208 and a glass plate 209. The glass plate 208 is transparent, holds the inspection protrusion 9, and transmits observation light and index light. The glass plate 209 forms the rear wall of the airtight chamber 221, and transmits observation light and index light.

[0042] The control unit 80 includes a CPU (controller) 81, a ROM 82, and a RAM 83. The CPU 81 controls various aspects of the intraocular pressure measurement device 1. The ROM 82 stores various programs, initial values, and the like. The RAM 83 temporarily stores various pieces of information. The control unit 80 is connected to the display unit 7, the operation unit 8, and a storage unit 84. The storage unit (e.g., a non-volatile memory) 84 is a non-transitory storage medium that can retain its contents even when the power supply is cut off. For example, a hard disk drive, a flash ROM, or a removable USB memory may be used as the storage unit 84. In this embodiment, an intraocular pressure measurement program and the like for executing the measurement process (see FIG. 4 ), which will be described later, are stored in the storage unit 84. Furthermore, the control unit 80 is connected to the drive unit 4, the measurement optical system 10, the face photographing unit 12, and the like.

[0043] The optical system of the intraocular pressure measurement device 1 will be described with reference to FIG. 3. The intraocular pressure measurement device 1 includes an infrared illumination light source 30 that illuminates the subject's eye. The infrared illumination light source 30 may also serve as at least a part of an index projection unit that projects an index onto the subject's eye E. An image of the anterior segment of the subject's eye illuminated by the infrared illumination light source 30 is formed on an anterior segment imaging unit (e.g., 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 (the above configuration is referred to as an anterior segment imaging optical system). The imaging optical axis L1 of the anterior segment imaging unit 35 coincides with the examination axis IO (see FIG. 1). The filter 34 transmits light from the light source 30 and an infrared light source 40 used for alignment, but is opaque to light from a light source 50 for corneal deformation detection (described later) and visible light. A frontal observation image of the anterior segment of the subject's eye E captured by the anterior segment imaging unit 35 is displayed on a display unit 7.

[0044] The light source 40 is part of an on-axis target projection optical system 39 that projects a target onto a position on the subject's eye E through which the examination axis IO passes (i.e., on the examination axis IO). The on-axis target projection optical system 39 emits target light along an optical axis L1 that coincides with the examination axis IO, thereby projecting a target, which is a bright spot, onto the cornea of ​​the subject's eye E (the apex of the cornea when alignment is complete). The on-axis target projection optical system 39 includes a projection lens 41 and a beam splitter 31. Infrared light projected from the light source 40 via the projection lens 41 is reflected by the beam splitter 31 and projected onto the subject's eye E from the front. The target (corneal bright spot) formed on the cornea by the light source 40 is imaged onto the anterior eye imaging unit 35 via the beam splitter 31 to the filter 34 and is used to detect alignment in the up, down, left, and right directions and to evaluate the focus state of the anterior eye image.

[0045] The fixation optical system 48 has an optical axis L1 and presents a fixation target to the subject's eye E from a front direction. The fixation optical system 48 has a visible light source (fixation lamp) 45, a projection lens 46, and a dichroic mirror 33, and projects light onto the subject's eye E to make the subject's eye fixate in a front direction. A light source such as an LED or laser is used as the visible light source 45. The visible light emitted from the visible 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 subject's eye E. As a result, the subject's eye E is brought into a state of fixating the fixation target in a front direction, and its line of sight is fixed.

[0046] 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 optical system 10 in the examination unit, and is moved three-dimensionally by the drive unit 4.

[0047] 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 subject's 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 subject's 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.

[0048] The light emitted from the light source 50 is converted into a substantially parallel beam by the collimator lens 51, reflected by the beam splitter 52, and then becomes coaxial with (coincides with) the optical axis L3 of the light-receiving optical system 70b (described later), and is projected onto the cornea Ec of the subject's eye E. The light reflected by the cornea Ec becomes coaxial with (coincides with) the optical axis L2 of the light-projecting optical system 70a (described later), passes through the lens 53, is reflected by the beam splitter 55, passes through a pinhole plate 56, and is received by the 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).

[0049] The corneal deformation detection optical system also serves as part of a working distance detection optical system for detecting the working distance (distance in the Z direction in this embodiment) of the examination unit (including the measurement optical system 10 and the examination protrusion 9, etc.) relative to the subject's eye E. In detail, the light projecting optical system of the working distance detection optical system in this embodiment also serves as the light projecting optical system 500a of the corneal deformation detection optical system. The light receiving optical system 600b of the working distance detection optical system has a lens 53, a beam splitter 58, a condenser lens 59, and a position detection element 60.

[0050] Illumination light projected from the light source 50 and reflected by the cornea Ec forms an index image, which is a virtual image of the light source 50. The light of the index image passes through the lens 53 and the beam splitter 55, is reflected by the beam splitter 58, passes through the condenser lens 59, and is incident on a one-dimensional or two-dimensional position detection 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 index image formed by the light source 50 also moves on the position detection element 60. Therefore, the CPU 81 can detect the working distance based on the output signal from the position detection element 60.

[0051] The corneal thickness measurement optical system includes a light projection 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. In this embodiment, part of the light projection optical system 70a is used in combination with parts of the corneal deformation detection optical system and the working distance detection optical system. The light projection optical system 70a irradiates illumination light (measurement light) obliquely toward the cornea Ec of the subject's eye E. The light projection optical system 70a includes 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.

[0052] 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.

[0053] 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 a light-receiving lens 75, a concave lens 76, and the light-receiving element 77, and forms an optical axis L3 as a light-receiving optical axis.

[0054] 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. For example, a pinhole image (when a pinhole plate is used) or a slit image (when a slit plate is used) is formed near the cornea Ec. At this time, the light from the light source 71 is focused near the intersection with the visual axis on the cornea Ec. The illumination light reflected 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 by the light-receiving lens 75 on the light-receiving surface of the light-receiving element 77.

[0055] (Measurement processing) 4 to 7, the measurement process executed by the intraocular pressure measurement device 1 of this embodiment will be described. In the measurement process of this embodiment, information regarding the difference between the current intraocular pressure measured for the target eye and the previous intraocular pressure measured for the same target eye (hereinafter referred to as "difference information") is displayed on a measurement screen 90 (see FIGS. 5 and 6) that is displayed when measuring the intraocular pressure of the target eye. The measurement process illustrated in FIG. 4 is executed by the CPU 81 of the intraocular pressure measurement device 1 in accordance with an intraocular pressure measurement program stored in the storage unit 84.

[0056] As shown in FIG. 4, the CPU 81 determines whether or not an instruction to start measuring intraocular pressure has been input (S1). In this embodiment, the instruction to start measurement is input by inputting information for identifying the subject whose intraocular pressure is to be measured into the intraocular pressure measurement device 1. For example, the user may input an instruction to start measurement by operating the operation unit 8 and inputting information for identifying the subject (for example, at least one of the subject's ID, name, etc.). Alternatively, the user may input an instruction to start measurement by having an identification reading unit (not shown) read an identifier associated with information for identifying the patient. If an instruction to start measurement has not been input (S1: NO), the process of S1 is repeated and the device enters a standby state.

[0057] When an instruction to start measurement is input (S1: YES), the CPU 81 displays a measurement screen 90 (see FIG. 5) before starting intraocular pressure measurement of the subject to be measured on the display unit 7, and identifies the subject's eye (i.e., at least one of the left eye and the right eye of the subject whose intraocular pressure is to be measured) (S2). For example, the CPU 81 may identify the subject's eye based on the information input in S1.

[0058] An example of a measurement screen 90 displayed on the display unit 7 when measuring intraocular pressure will be described with reference to FIGS. 5 and 6. FIG. 5 shows an example of the measurement screen 90 before the start of intraocular pressure measurement. FIG. 6 shows an example of the measurement screen 90 when intraocular pressure measurement is completed. The measurement screen shown in FIGS. 5 and 6 includes a subject information display unit 91, a deformation force display unit 92, past reliability display units 93R and 93L, current intraocular pressure display units 94R and 94L, difference information display units 95R and 95L, and an anterior eye front observation image display unit 97. The CPU 81 displays information about the subject identified in S2 on the subject information display unit 91. The CPU 81 displays an anterior eye front observation image of the target subject's eye, captured by the anterior eye imaging optical system including the anterior eye imaging unit 35 (see FIG. 3), on the anterior eye front observation image display unit 97. The other display units will be described later.

[0059] The CPU 81 acquires information about past intraocular pressure measurement results of the target eye identified in S2 (S3). In this embodiment, as an example, multiple intraocular pressure measurement results previously measured for each of multiple test eyes are stored in a storage device (e.g., the storage unit 84) in association with information about the measurement reliability (described in detail below) at the time of measurement and the date and time of measurement. In S3 of this embodiment, the CPU 81 acquires the past intraocular pressure measurement results (measured intraocular pressure values) for the target eye identified in S2 from the multiple stored intraocular pressure measurement results, information about the measurement reliability when the intraocular pressure was previously measured, and the measurement date and time. Note that in this embodiment, the measurement reliability was already acquired when the intraocular pressure was previously measured and stored in the storage device together with the measurement results. Therefore, in S3, the measurement reliability itself at the time of measurement is acquired from the storage device together with the intraocular pressure measurement results. However, in S3, data for acquiring the measurement reliability when the intraocular pressure was previously measured may also be acquired from the storage device together with the measurement results as measurement reliability information. In this case, the CPU 81 may acquire the measurement reliability when the intraocular pressure was measured in the past based on the acquired data.

[0060] An example of the reliability of intraocular pressure measurement will now be described with reference to FIG. 7 . The reliability of intraocular pressure measurement varies depending on the fixation state of the subject's eye, the state of the eyelids, whether the subject blinks, and other factors during measurement. As described above, in this embodiment, a deformation force (a blow of compressed air) is applied to the cornea of ​​the subject's eye, and the intraocular pressure of the subject's eye is measured based on the corneal applanation state (the timing at which the cornea becomes flat) when the deformation force is applied. The corneal deformation detection optical system (the light projecting optical system 500a and the light receiving optical system 500b, etc.) is arranged so that the amount of light reflected from the cornea and received by the photodetector 57 is maximized when the cornea of ​​the subject's eye reaches a predetermined deformation state (flat state). In this case, as shown in FIG. 7 , the intensity of the detected light (the magnitude of the received light signal) detected by the photodetector 57 increases rapidly as the cornea approaches flattening, reaches a maximum when the cornea is flattened, and then decreases rapidly as the cornea returns to its original state. This indicates high reliability of intraocular pressure measurement. On the other hand, if at least one of the increase and decrease in the detected light is slow, the reliability of the intraocular pressure measurement is low. Therefore, in this embodiment, the reliability of the intraocular pressure measurement is obtained by analyzing the rate of at least one of the increase and decrease in the detected light detected by the photodetector 57. As shown in Fig. 7, the intraocular pressure of the subject's eye is measured based on the time T required for the cornea to become flattened after the application of a deforming force to the cornea (in this embodiment, the application of compressed air) is initiated.

[0061] If there are multiple past intraocular pressure measurement results for the target eye identified in S2, the CPU 81 acquires the most recent measurement result among the multiple measurement results. As a result, by performing S9 to S11 described below, the user can easily and appropriately grasp at least one of the most recent change in intraocular pressure of the target eye and the quality of the current intraocular pressure measurement result. However, the process of S3 can be changed. For example, past information about the target eye may be input via the user's operation of the operation unit 8, etc.

[0062] Returning to the description of FIG. 4 , the CPU 81 displays information about the measurement reliability of past intraocular pressure measurements (hereinafter referred to as “past reliability”) acquired in S3 in the past reliability display areas 93R and 93L of the measurement screen 90 (S4). In this embodiment, the past reliability for the right target eye is displayed in the past reliability display area 93R, and the past reliability for the left target eye is displayed in the past reliability display area 93L. The measurement reliability of intraocular pressure changes depending on the subject's visual fixation state, eyelid state, blinking status, etc. at the time of measurement, so the measurement reliability is likely to change depending on the subject. When the intraocular pressure of the target eye is measured, information about the past reliability for the same eye is displayed on the display unit 7, so the user can measure the intraocular pressure of the target eye after understanding that the subject is likely to perform actions that reduce measurement reliability. That is, the user can prevent the measurement reliability from decreasing by urging the subject not to break their gaze or refrain from blinking, which makes it easier to improve the efficiency of medical treatment.

[0063] In the examples shown in FIGS. 5 and 6, at least one of letters, numbers, icons, etc. indicating the level of past reliability (in this embodiment, three levels of past reliability are displayed, "OK," "2," and "1," in descending order of past reliability) is displayed on the past reliability display units 93R and 93L. Furthermore, the level of past reliability is also indicated by color. However, it is also possible to change the manner in which information about past reliability is displayed on the display unit 7. For example, the CPU 81 may include a message according to the past reliability (e.g., a message such as "Caution: The reliability of the previous measurement was low") in the information about past reliability to be displayed on the display unit 7. Furthermore, when the past reliability is low, the CPU 81 may perform processing to increase the number of measurements of the current intraocular pressure from the normal number of measurements, thereby improving the reliability of the current intraocular pressure measurement.

[0064] The CPU 81 sets a deformation force (in this embodiment, the pressure of compressed air blown onto the cornea) to be applied to the cornea of ​​the target eye to be examined based on the previous intraocular pressure measurement results acquired in S3 (i.e., intraocular pressure values ​​previously measured for the same target eye to be examined) (S5). When measuring the intraocular pressure of the test eye by applying a deformation force to the cornea, the appropriate deformation force to be applied to the cornea varies depending on the intraocular pressure of the test eye. For example, if the intraocular pressure of the test eye is high but the deformation force applied to the cornea is small, the cornea may not deform appropriately, and the intraocular pressure may not be measured appropriately. On the other hand, if the intraocular pressure of the test eye is low but a deformation force greater than the appropriate deformation force is applied to the cornea, the intraocular pressure may be measured, but the test subject is likely to experience discomfort due to the application of such a large deformation force. In conventional intraocular pressure measurement devices, if the deformation force applied to the cornea during the initial measurement was inappropriate (for example, if the deformation force applied to the cornea was too small and the intraocular pressure was not measured appropriately), the user had to repeat the intraocular pressure measurement using a different deformation force. Furthermore, to reduce the frequency of re-measurements, the user had to somehow obtain or predict the approximate intraocular pressure of the subject's eye and manually set the deformation force to be applied to the cornea based on the obtained or predicted intraocular pressure value. By contrast, setting the deformation force based on past intraocular pressure makes it easier to automatically set an appropriate deformation force for the subject's eye. This further improves the efficiency of medical treatment.

[0065] The relationship between the time elapsed from the start of application of a deforming force to the cornea until the cornea reaches a deformed state (a flattened state in this embodiment) and the intraocular pressure of the subject's eye varies depending on the magnitude of the deforming force applied to the cornea. Therefore, in S5 of this embodiment, the algorithm (parameters, etc.) for calculating the intraocular pressure value based on the elapsed time as well as the deforming force applied to the cornea are set based on past intraocular pressure measurement results.

[0066] Next, the CPU 81 determines whether a trigger to execute measurement has been input (S6). If not (S6: NO), it determines whether an instruction to end the intraocular pressure measurement process for the target eye has been input (S7). If not (S7: NO), the process returns to S6, and the processes of S6 and S7 are repeated. If an instruction to end the measurement process has been input (S7: YES), the intraocular pressure measurement process for the target eye is ended (for example, a process to end the display of the measurement screen 90 for the target eye is executed), and the process returns to S1.

[0067] When a trigger to execute measurement is input (S6: YES), the CPU 81 measures the current intraocular pressure of the subject eye (S9). The CPU 81 displays the current intraocular pressure of the subject eye measured in S9 on the current intraocular pressure display sections 94R and 94L of the measurement screen 90 (see FIGS. 5 and 6). In this embodiment, the current intraocular pressure measured for the right subject eye is displayed on the current intraocular pressure display section 94R, and the current intraocular pressure measured for the left subject eye is displayed on the current intraocular pressure display section 94L.

[0068] The CPU 81 calculates the difference between the past intraocular pressure of the subject's eye acquired in S3 and the current intraocular pressure of the subject measured in S9 (in this embodiment, the value obtained by subtracting the past intraocular pressure from the current intraocular pressure), and displays the difference on the display unit 7 (more specifically, the difference information display units 95R and 95L on the measurement screen 90) (S10). Therefore, the user can quickly grasp the state of change in the intraocular pressure of the subject's eye based on the difference between the past intraocular pressure and the current intraocular pressure displayed by the intraocular pressure measurement device 1, and then perform appropriate medical treatment (e.g., at least one of examination, testing, treatment, and prescription). For example, if the user determines from the difference information that the intraocular pressure of the subject's eye is rapidly increasing, the user can quickly formulate a treatment plan or testing plan to prevent the onset or worsening of glaucoma. Furthermore, if the difference between the current intraocular pressure of the subject's eye and the past intraocular pressure is unnatural, the user can consider the possibility that there was a flaw in the current intraocular pressure measurement and quickly decide to remeasure the intraocular pressure. Therefore, the efficiency of medical treatment using the results of intraocular pressure measurements can be appropriately improved.

[0069] In particular, in this embodiment, if there are multiple past intraocular pressure measurement results for the target eye identified in S2, information regarding the difference between the most recent measurement result among the multiple measurement results and the current measurement result is displayed. Therefore, the user can understand the most recent change in the intraocular pressure of the target eye by checking the difference information displayed on the difference information display units 95R and 95L. Note that in S10, the difference value between the past intraocular pressure and the current intraocular pressure may itself be displayed, or a value indicating the level (degree) of the difference value may be displayed.

[0070] If the difference between the current intraocular pressure and the previous intraocular pressure of the subject's eye calculated in S10 is equal to or greater than a threshold, the CPU 81 includes alert information indicating that the difference is equal to or greater than the threshold in the difference information displayed on the display unit 7 (more specifically, the difference information display units 95R and 95L on the measurement screen 90). As a result, the user can more accurately and intuitively understand that the difference between the current and previous intraocular pressures has exceeded the threshold, compared to when a graph showing changes in intraocular pressure is displayed. This allows the user to quickly and appropriately recognize that the intraocular pressure of the subject's eye has significantly increased, and then take necessary measures (e.g., prescribing antihypertensive drugs, conducting a visual field test, etc.). Furthermore, a decrease in intraocular pressure measurement accuracy may increase the difference between the current intraocular pressure and the previous intraocular pressure. Therefore, when the alert information is displayed, the user can easily consider the possibility that the current intraocular pressure measurement accuracy was low and consider whether a re-examination is necessary. This further improves the efficiency of medical treatment using intraocular pressure measurement results. The threshold value for determining whether or not to display the alert information may be set in advance or may be set by the user.

[0071] 6, in this embodiment, when the difference between the current intraocular pressure and the past intraocular pressure is equal to or greater than a threshold, a symbol "!" indicating that the difference is equal to or greater than the threshold is displayed as alert information in the difference information display section 95L. The CPU 81 also notifies the user of the level of the difference by changing the color of the frame or the like of the difference information display section 95L in accordance with the level (degree) of the difference calculated in S10 (for example, by changing the color from yellow to orange to red in order of decreasing difference level).

[0072] Furthermore, in this embodiment, when the value obtained by subtracting the past intraocular pressure from the current intraocular pressure is a positive value and is equal to or greater than the threshold value, the CPU 81 displays alert information on the display unit 7. As a result, the user can quickly and appropriately recognize that the intraocular pressure of the subject's eye has significantly increased.

[0073] Next, the CPU 81 acquires the measurement reliability of the intraocular pressure of the target eye measured in S9 and stores it in a storage device (for example, the storage unit 84) (S12). The measurement reliability stored in S12 will be used when measuring the intraocular pressure of the same target eye in the future. The CPU 81 determines whether an instruction to measure the intraocular pressure of the same target eye again has been input (S15). If not input (S15: NO), the CPU 81 determines whether an instruction to end the measurement process of the intraocular pressure of the target eye has been input (S16). If not input (S16: NO), the process returns to S15, and the processes of S15 and S16 are repeated. If an instruction to measure the intraocular pressure of the same target eye again has been input (S15: YES), the CPU 81 measures the intraocular pressure of the same target eye again (S9 to S12). When an instruction to end the measurement process is input (S16: YES), the measurement process of the intraocular pressure of the target eye to be examined is ended, and the process returns to S1.

[0074] As described above, the CPU 81 displays the difference information of the target eye on the display unit 7 (in this embodiment, at least one of the difference calculated in S10 and the alert information) during at least a part of the time period from after the current intraocular pressure is measured in S9 until the target eye is switched to the eye of another subject (S16: YES). As a result, the difference information is displayed by the intraocular pressure measurement device 1 immediately after the current intraocular pressure of the target eye is measured. In other words, the difference information is displayed on the display unit 7 before the subject leaves the intraocular pressure measurement device 1. This makes it easier to perform various medical treatments more smoothly, such as remeasurement of the current intraocular pressure or omission of additional measurements.

[0075] As shown in Fig. 6, the CPU 81 displays, on the display unit 7, a frontal observation image of the anterior eye of the subject's eye (an example of an observation image) captured by the anterior eye imaging optical system including the anterior eye imaging unit 35 (see Fig. 3). As a result, the difference information is displayed by the tonometry device 1 immediately after the current intraocular pressure of the subject's eye is measured. In other words, the difference information is displayed on the display unit 7 before the subject leaves the tonometry device 1. This makes it easier to perform various medical treatments more smoothly, such as remeasurement of the current intraocular pressure or omission of additional measurements.

[0076] In this embodiment, the CPU 81 automatically displays the difference information on the display unit 7 upon completion of measurement of the current intraocular pressure of the subject eye in S9. As a result, the user can quickly formulate a treatment plan, etc., by checking the difference information that is automatically displayed after completion of measurement of the current intraocular pressure of the subject eye. This further facilitates improving the efficiency of treatment using intraocular pressure measurement results.

[0077] The techniques disclosed in the above embodiments are merely examples. Therefore, the techniques exemplified in the above embodiments can be modified. For example, it is possible to cause the intraocular pressure measurement device 1 to execute only some of the processes exemplified in the above embodiments. For example, the intraocular pressure measurement device 1 can execute at least one of the following processes: a process (S4) for displaying the measurement reliability at the time of past intraocular pressure measurement, and a process (S5) for setting the deformation force based on the results of past intraocular pressure measurements, without executing the process (S10) for displaying the difference information between past and current intraocular pressures.

[0078] The process of acquiring past intraocular pressure measurement results in S3 of FIG. 4 is an example of a "past intraocular pressure acquisition step." The process of measuring current intraocular pressure in S9 is an example of a "current intraocular pressure measurement step." The processes of displaying difference information on the display unit 7 in S10 and S11 are an example of a "difference information display step." The process of setting the deformation force in S5 is an example of a "deformation force setting step." The process of displaying past reliability in S4 is an example of a "past reliability display step." [Explanation of symbols]

[0079] 1. Intraocular pressure measuring device 7 Display section 8 Control section 35 Anterior segment imaging department 57 Photodetector 81 CPU 84 Memory section 90 Measurement screen 92 Deformation force display unit 93R, 93L past reliability display 94R, 94L current intraocular pressure display 95R,95L Difference information display section 97 Frontal observation image display unit for anterior segment

Claims

1. An intraocular pressure measuring device for measuring intraocular pressure of a subject's eye, The control unit of the intraocular pressure measuring device a past intraocular pressure acquisition step of acquiring past intraocular pressure measurement results of the target eye; a current intraocular pressure measuring step of measuring a current intraocular pressure of the subject's eye; a difference information display step of displaying, on a display unit, difference information that is information regarding the difference between the current intraocular pressure measured in the current intraocular pressure measuring step and the past intraocular pressure acquired in the past intraocular pressure acquiring step; An intraocular pressure measuring device characterized by performing the above.

2. The intraocular pressure measuring device according to claim 1, The control unit displays the difference information of the target eye on the display unit during at least a portion of the time period after the current intraocular pressure is measured in the current intraocular pressure measurement step and before the target eye is switched to the eye of another subject.

3. 3. The intraocular pressure measuring device according to claim 1, further comprising an imaging optical system for capturing an observation image of the target eye to be examined; The control unit causes the display unit to display the difference information of the target eye together with the observation image captured by the imaging optical system.

4. 4. The intraocular pressure measuring device according to claim 1, The control unit automatically executes the difference information display step when the measurement of the current intraocular pressure of the subject eye is completed in the current intraocular pressure measurement step.

5. 5. The intraocular pressure measuring device according to claim 1, The control unit In the past intraocular pressure acquisition step, a latest intraocular pressure measurement result is acquired from one or more intraocular pressure measurement results previously measured for the target eye; An intraocular pressure measuring device, characterized in that the step of displaying the difference information is performed based on the most recent intraocular pressure obtained in the past.

6. 6. The intraocular pressure measuring device according to claim 1, In the difference information display step, the control unit an intraocular pressure measuring device characterized in that, when the difference between the current intraocular pressure measured in the current intraocular pressure measuring step and the past intraocular pressure acquired in the past intraocular pressure acquiring step is equal to or greater than a threshold, the difference information to be displayed on the display unit includes alert information indicating that the difference is equal to or greater than a threshold.

7. 7. The intraocular pressure measuring device according to claim 1, an intraocular pressure measuring unit that applies a deformation force to the cornea of ​​the subject's eye to deform the cornea and measures the intraocular pressure of the subject's eye by detecting the deformation state of the cornea; The control unit an intraocular pressure measuring unit for measuring a deformation force to be applied to the cornea of ​​the subject eye based on the past intraocular pressure acquired in the past intraocular pressure acquiring step;

8. 8. The intraocular pressure measuring device according to claim 1, The control unit The intraocular pressure measurement device further executes a past reliability display step of acquiring the measurement reliability when the past intraocular pressure was measured in the past intraocular pressure acquisition step, and displaying information about the acquired measurement reliability on the display unit.

9. An intraocular pressure measurement program executed by an intraocular pressure measurement device for measuring intraocular pressure of a subject's eye, The intraocular pressure measurement program is executed by a control unit of the intraocular pressure measurement device, a past intraocular pressure acquisition step of acquiring past intraocular pressure measurement results of the target eye; a current intraocular pressure measuring step of measuring a current intraocular pressure of the subject's eye; a difference information display step of displaying, on a display unit, difference information that is information regarding the difference between the current intraocular pressure measured in the current intraocular pressure measuring step and the past intraocular pressure acquired in the past intraocular pressure acquiring step; an intraocular pressure measuring program that causes the intraocular pressure measuring device to execute the above steps.

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