Non-contact tonometer

Abstract

To provide a non-contact type tonometer capable of detecting approach of a nozzle to the eye to be examined and the face.SOLUTION: A non-contact type tonometer 14A includes a nozzle 20 for spraying fluid onto the cornea of an eye to be examined, and one or a plurality of non-contact type sensors (electrostatic capacity type sensors 26) for detecting approach of the nozzle 20 to the face of a subject including the eye to be examined. According to this non-contact type tonometer 14A, approach of the nozzle 20 to the face and the eye to be examined of the subject can be detected in a non-contact manner.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a non-contact tonometer that measures the intraocular pressure of a subject's eye in a non-contact manner. [Background technology]

[0002] Conventionally, there is known a non-contact tonometer that measures the intraocular pressure of a subject's eye without contacting the cornea by blowing air (fluid) from a nozzle toward the cornea of ​​the subject's eye to deform the cornea and detect the state of deformation (see Patent Document 1). This non-contact tonometer irradiates the cornea with index light in synchronization with the blowing of air from the nozzle onto the cornea, detects the amount of reflected light of the index light reflected by the cornea, and calculates the intraocular pressure of the subject's eye based on the amount of reflected light and the air pressure when the deformed state of the cornea becomes flat (applanation state).

[0003] In order to accurately measure the intraocular pressure of the subject's eye using such a non-contact tonometer, the position of the subject's face (head) relative to the non-contact tonometer must be appropriate. Therefore, Patent Documents 2 and 3 disclose an ophthalmic device that includes contact sensors in a chin rest and a forehead rest that support the subject's face, and determines whether the position of the subject's face relative to the non-contact tonometer is appropriate based on the detection results of the contact sensors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-47036 A [Patent Document 2] JP 2019-165991 A [Patent Document 3] JP 2017-217121 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, before starting to measure the intraocular pressure value of the subject's eye with a non-contact tonometer, it is necessary to align the measurement head (nozzle) of the non-contact tonometer with the subject's eye, and at this time, it is necessary to prevent the nozzle from coming into contact with the subject's eye and the subject's face. For this reason, it is necessary to detect the approach of the nozzle to the subject's eye, etc., but the non-contact tonometers described in the above patent documents cannot detect the approach of the nozzle to the subject's eye. In particular, in recent years, there are cases where the examiner remotely operates the non-contact tonometer from a remote location (see Patent Document 2 above), and there is a demand for reliable detection of the approach of the nozzle to the subject's eye and face.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-contact tonometer capable of detecting the approach of a nozzle to a subject's eye and face. [Means for solving the problem]

[0007] To achieve the objectives of the present invention, a non-contact tonometer includes a nozzle that sprays fluid onto the cornea of ​​the test eye, and one or more non-contact sensors that detect the approach of the nozzle to the test subject's face, including the test eye.

[0008] This non-contact tonometer makes it possible to detect the approach of the nozzle to the subject's face (subject's eye) in a non-contact manner.

[0009] In a non-contact tonometer according to another aspect of the present invention, a non-contact sensor is provided around at least a portion of the nozzle, thereby making it possible to detect the approach of the nozzle to the subject's face in a non-contact manner.

[0010] In a non-contact tonometer according to another aspect of the present invention, the non-contact sensor is formed in a ring shape surrounding the nozzle when viewed from the tip side of the nozzle, and has directivity toward the front side of the nozzle, thereby improving the directivity of the non-contact sensor toward the front side of the nozzle and increasing the detection sensitivity of the non-contact sensor to the test eye located in front of the nozzle.

[0011] In a non-contact tonometer according to another aspect of the present invention, when a direction parallel to the central axis of the nozzle is defined as a working distance direction and a direction perpendicular to both the working distance direction and the up-down direction is defined as a left-right direction, the non-contact sensor has directivity toward the front side of the nozzle, and when the nozzle is viewed from the left-right direction, the directivity is weaker toward the upper side of the central axis than toward the lower side. This prevents the nozzle from being mistakenly determined to be close to the subject's eye or the subject's face, even when there is no risk of the nozzle coming into contact with the subject's eye or the subject's face.

[0012] In the non-contact tonometer according to another aspect of the present invention, when a straight line perpendicular to the central axis and parallel to the left-right direction is taken as a parallel line, the non-contact sensor is formed in a region below the parallel line in the annular region surrounding the nozzle when viewed from the tip side of the nozzle, thereby weakening the above-mentioned upward directionality of the non-contact sensor.

[0013] A non-contact tonometer according to another aspect of the present invention includes a window glass having a nozzle provided therein, and a glass holding portion that holds the window glass, and a non-contact sensor is provided in the glass holding portion in a shape that surrounds at least a portion of the window glass.

[0014] A non-contact tonometer according to another aspect of the present invention includes a measurement head in which a detection value of a non-contact sensor increases as the nozzle approaches a face, a drive mechanism for moving the measurement head relative to the subject's eye, a detection value acquisition unit for repeatedly acquiring detection values ​​from the non-contact sensor while the measurement head is being moved relative to the subject's eye by the drive mechanism, and a drive control unit for controlling the drive mechanism to stop the relative movement of the measurement head or to move the measurement head away from the subject's eye when the detection value newly acquired by the detection value acquisition unit becomes greater than a predetermined threshold value, thereby preventing the nozzle from coming into contact with the subject's face and the subject's eye.

[0015] A non-contact tonometer according to another aspect of the present invention includes a measurement head having a nozzle, the detection value of which increases as the nozzle approaches the face, a drive mechanism for moving the measurement head relative to the subject's eye, an initial value acquisition unit for acquiring an initial value of the detection value from the non-contact sensor, a detection value acquisition unit for repeatedly acquiring the detection value from the non-contact sensor after the initial value acquisition unit acquires the initial value and while the drive mechanism is moving the measurement head relative to the subject's eye, and a drive control unit for calculating a difference between the detection value and the initial value acquired by the initial value acquisition unit each time the detection value acquisition unit acquires a detection value, and controlling the drive mechanism to stop the relative movement of the measurement head or to move the measurement head away from the subject's eye when the difference becomes greater than a predetermined difference threshold value. This makes it possible to accurately determine whether the nozzle is close to the subject's eye or the like without being affected by the surrounding environment.

[0016] In the non-contact tonometer according to another aspect of the present invention, the non-contact sensor is a capacitance sensor, which makes it possible to detect the subject's eye located in front of the nozzle.

[0017] A non-contact tonometer according to another aspect of the present invention includes a remote operation receiving unit that receives remote operation from outside, and an operation control unit that controls the operation of the non-contact tonometer in accordance with the remote operation received by the remote operation receiving unit. Effect of the Invention

[0018] The present invention is capable of detecting the proximity of the nozzle to the subject's eye and face. [Brief description of the drawings]

[0019] [Figure 1] 1 is a perspective view of an ophthalmic apparatus according to a first embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a front view of the nozzle, window glass, and glass holding part of the non-contact tonometer as viewed from the subject side. [Figure 4]10 is an explanatory diagram for explaining an example of an approach pattern of a nozzle to a subject's eye (face). FIG. [Diagram 5] 11 is a graph showing a change in capacitance detected by a capacitance type sensor for each approach pattern of the nozzle to the subject's eye (face). [Figure 6] 2 is a functional block diagram of a control device of the ophthalmologic apparatus of the first embodiment. FIG. [Figure 7] 5 is a flowchart showing the flow of intraocular pressure measurement processing of a subject's eye by a non-contact tonometer in the ophthalmic apparatus of the first embodiment. [Figure 8] 5A to 5C are explanatory diagrams for explaining problems with the capacitance type sensor according to the first embodiment. [Figure 9] 5A to 5C are explanatory diagrams for explaining problems with the capacitance type sensor according to the first embodiment. [Figure 10] FIG. 13 is a perspective view of a nozzle and a capacitance sensor (electrode) of an ophthalmic apparatus according to a second embodiment. [Figure 11] FIG. 11 is a front view of a nozzle and a capacitance sensor (electrode) of an ophthalmic apparatus according to a second embodiment. [Figure 12] FIG. 11 is an explanatory diagram for explaining the directivity of a capacitive sensor according to a second embodiment. [Figure 13] 11 is a graph showing the correspondence relationship between the face distance under different ambient environments (temperature and humidity) and the detection value (pF) detected by the capacitance sensor. [Figure 14] 13 is a flowchart showing the flow of intraocular pressure measurement processing of an eye to be examined by a non-contact tonometer in an ophthalmic apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] [First embodiment] Fig. 1 is a perspective view of an ophthalmic apparatus 10 according to a first embodiment. As shown in Fig. 1, the ophthalmic apparatus 10 is a multifunction machine (multifunction examination device) capable of measuring (examining) various ophthalmic characteristics of a subject's eye, such as an intraocular pressure value, an ocular refractive power, and a corneal curvature, all by itself. The ophthalmic apparatus 10 according to this embodiment is capable of measuring various ophthalmic characteristics by remote operation in addition to direct operation input by an examiner.

[0021] The ophthalmologic apparatus 10 includes a base 11, a face support unit 12, a drive mechanism 13, a measurement head 14 (also called an apparatus main body), a display unit 15, and a control device 16 (see FIG. 6).

[0022] A face support section 12 and a drive mechanism 13 are provided on the base 11 from the subject side toward the examiner side.

[0023] The face support portion 12 includes a chin rest portion 12a for supporting the subject's chin and a forehead rest portion 12b against which the subject's forehead rests, and supports the subject's face when the ophthalmic device 10 measures eye characteristics such as the intraocular pressure, eye refractive power, and corneal curvature of the subject's eye.

[0024] The driving mechanism 13 is composed of actuators (not shown) such as motors, and moves the measurement head 14 in three axial directions (left-right, up-down, front-back directions: XYZ directions) relative to the base 11. This allows the measurement head 14 to move in the three axial directions relative to the subject's eye. Then, by driving the driving mechanism 13 under the control of a control device 16 (see FIG. 6), which will be described later, it becomes possible to adjust the alignment of the measurement head 14 in the three axial directions relative to the subject's eye.

[0025] Fig. 2 is an enlarged view of the measurement head 14. As shown in Fig. 2 and the above-described Fig. 1, the measurement head 14 is provided with a variety of ophthalmic measurement devices including a non-contact tonometer 14A and an autorefractometer 14B.

[0026] The non-contact tonometer 14A measures the intraocular pressure of the subject's eye in a non-contact manner by blowing air (fluid) from a nozzle 20 toward the cornea of ​​the subject's eye to deform the cornea and detecting the state of the deformation.

[0027] The non-contact tonometer 14A includes a nozzle 20, a window glass 22 in which the nozzle 20 is provided, and a convex glass holding portion 24 that holds the window glass 22. The non-contact tonometer 14A emits alignment index light, fixation target light, and the like toward the subject's eye through the inside of the nozzle 20 or the window glass 22, and receives reflected light of the alignment index light, fixation target light, and the like reflected by the subject's eye.

[0028] Except for the fact that an electrode 26a (see FIG. 3) of a capacitance-type sensor 26 described below is formed in the glass holding portion 24, the detailed configuration of the non-contact tonometer 14A is a publicly known technology (see, for example, Patent Document 1 mentioned above), and therefore will not be described here.

[0029] The autorefkeratometer 14B measures the ocular refractive power and corneal curvature of the subject's eye using various optical systems 25. Note that the specific configuration of the autorefkeratometer 14B is also a publicly known technique (see, for example, JP 2016-7774 A), and therefore description thereof will be omitted here.

[0030] The display unit 15 is attached to the back side of the measuring head 14 facing the examiner. For example, a touch panel monitor is used as the display unit 15. The display unit 15 displays an observed image of the anterior segment of the subject's eye under the control of a control device 16 (see FIG. 6) described below. The display unit 15 also displays measurement results such as the intraocular pressure value of the subject's eye. Furthermore, the display unit 15 displays an operation menu screen for performing various operations, and a position adjustment screen for adjusting the position of the measuring head 14 in three axial directions (manual alignment).

[0031] Fig. 3 is a front view of the nozzle 20, window glass 22, and glass holder 24 of the non-contact tonometer 14A as viewed from the subject side. As shown in Fig. 3, the non-contact tonometer 14A is provided with a capacitance sensor 26, which corresponds to the non-contact sensor of the present invention. This capacitance sensor 26 detects the approach of the nozzle 20 to the subject's face and eye while alignment (relative movement) of the non-contact tonometer 14A with respect to the eye is being performed. For example, a self-capacitance type is used for this capacitance sensor 26, and it is composed of an electrode 26a and a detection circuit 26b.

[0032] The electrode 26a is formed so as to surround the window glass 22, and is provided on the glass holding portion 24. That is, the electrode 26a is formed in a ring shape surrounding the nozzle 20 when viewed from the tip side of the nozzle 20. The electrode 26a forms a pseudo capacitor between itself and the face (eye to be examined) of the subject.

[0033] The detection circuit 26b is provided, for example, inside (or outside) the measurement head 14, and is connected to the electrode 26a via the wiring 26c. The detection circuit 26b detects the capacitance generated by the pseudo capacitor and outputs the detection value to the control device 16 (see FIG. 6) described later. The capacitance of the pseudo capacitor increases as the distance between the electrode 26a and the face of the subject decreases, and conversely, the capacitance of the pseudo capacitor decreases as the distance between the electrode 26a and the face of the subject increases. Therefore, the distance between the electrode 26a (nozzle 20) and the face of the subject (eye to be examined) can be detected based on the capacitance detection value by the detection circuit 26b. As a result, the approach of the nozzle 20 to the face of the subject and the eye to be examined can be detected by the capacitance sensor 26.

[0034] 4 is an explanatory diagram for explaining an example of an approach pattern of the nozzle 20 with respect to the subject's eye (face). As shown in Fig. 4, the first pattern is a pattern in which the nozzle 20 moves forward in the Z direction (the direction from the measurement head 14 toward the subject) from a state in which the subject's eye is located in front of the nozzle 20, as indicated by the symbol C, to approach the subject's eye.

[0035] In the second pattern, as indicated by the symbol L, the nozzle 20 moves forward in the Z direction to approach the subject's eye from a state in which the subject's eye is shifted to the left from a position in front of the nozzle 20. In the third pattern, as indicated by the symbol R, the nozzle 20 moves forward in the Z direction to approach the subject's eye from a state in which the subject's eye is shifted to the right from a position in front of the nozzle 20.

[0036] In the fourth pattern, as indicated by the symbol U, the nozzle 20 moves forward in the Z direction to approach the subject's eye from a state in which the subject's eye is shifted upward from a position in front of the nozzle 20. In the fifth pattern, as indicated by the symbol D, the nozzle 20 moves forward in the Z direction to approach the subject's eye from a state in which the subject's eye is shifted downward from a position in front of the nozzle 20.

[0037] Fig. 5 is a graph showing the change in the capacitance detection value by the capacitance sensor 26 for each approach pattern of the nozzle 20 with respect to the subject's eye (face). The horizontal axis in Fig. 5 indicates the Z-direction distance between the nozzle 20 (electrode 26a) and the subject's eye (face). The appropriate Z-direction distance between the nozzle 20 and the subject's eye when measuring intraocular pressure is approximately 11 mm. The vertical axis in Fig. 5 indicates the capacitance detection value detected by the capacitance sensor 26.

[0038] As shown in FIG. 5, the capacitance sensor 26 of this embodiment has a detection value that increases as the nozzle 20 (electrode 26a) approaches the subject's eye (face). In addition, the capacitance sensor 26 of this embodiment has a characteristic (gain) that the detection value of the capacitance increases when the Z direction distance becomes 5 mm or less, that is, when the nozzle 20 is at a distance or less at which the nozzle 20 contacts the eyelashes of the face, in all approach patterns. As a result, the capacitance sensor 26 can detect the approach of the nozzle 20 to the subject's face and the subject's eye even if the subject's eye is shifted up, down, left, or right from the position in front of the nozzle 20. In this way, the capacitance sensor 26 is formed in a ring shape surrounding the nozzle 20, so that the capacitance sensor 26 has directivity toward the front side of the nozzle 20. As a result, the directivity of the capacitance sensor 26 toward the front side of the nozzle 20 can be increased, and the detection sensitivity of the capacitance sensor 26 to the subject's eye located in front of the nozzle 20 can be increased.

[0039] In this embodiment, the capacitance sensor 26 is described as being of the self-capacitance type, but a mutual capacitance type capacitance sensor 26 may be used. In this case, the electrode 26a is composed of a transmitting electrode and a receiving electrode. The detection circuit 26b detects a change in capacitance according to a change in the electric field generated between the transmitting electrode and the receiving electrode. In this case, it is also possible to detect the approach of the nozzle 20 to the subject's face and eye.

[0040] Fig. 6 is a functional block diagram of the control device 16 of the ophthalmic apparatus 10 of the first embodiment. As shown in Fig. 6, the control device 16 is provided, for example, inside the base 11 or the measurement head 14, and controls the operations of the ophthalmic apparatus 10 (intraocular pressure measurement, eye refractive power measurement, corneal curvature measurement, etc.). In addition to the drive mechanism 13, the measurement head 14 (non-contact tonometer 14A and auto refraction meter 14B), and the display unit 15, a storage unit 30, an operation unit 32, a communication interface 34, and a remote operation reception unit 36 ​​are connected to the control device 16.

[0041] The storage unit 30 stores a control program for the ophthalmic apparatus 10, measurement results of intraocular pressure values ​​obtained by the non-contact tonometer 14A, and measurement results of eye refractive power and the like obtained by the autorefractive tonometer 14B.

[0042] The operation unit 32 accepts operations such as turning on and off the power of the ophthalmic device 10, selecting between intraocular pressure measurement and measurement of ocular refractive power and corneal curvature, starting measurement of intraocular pressure values, starting measurement of ocular refractive power, etc., and setting operations for the ophthalmic device 10. Examples of the measurement start operation include reading a barcode attached to a subject (patient) and inputting patient information.

[0043] The communication interface 34 is connected, via various networks, to an external remote control device 38 (such as a computer) that remotely controls the ophthalmic apparatus 10. The communication interface 34 outputs remote operation information input from the remote control device 38 to a remote operation reception unit 36 ​​described later. The communication interface 34 also outputs to the remote control device 38 an anterior eye image captured by the non-contact tonometer 14A and the auto refraction keratometer 14B, the measurement results of the intraocular pressure value by the non-contact tonometer 14A, and the measurement results of the eye refractive power, etc., by the auto refraction meter 14B, which are input from the control device 16.

[0044] The remote operation reception unit 36 ​​receives remote operations input from the remote operation device 38 via the communication interface 34 and inputs the remote operations to the control device 16. As a result, the control device 16 controls the operation of the ophthalmic apparatus 10 based on the remote operations input from the remote operation reception unit 36. In this case, the control device 16 functions as an operation control unit of the present invention.

[0045] The control device 16 includes an arithmetic circuit including various processors and memories. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., simple programmable logic devices (SPLD), complex programmable logic devices (CPLD), and field programmable gate arrays (FPGA)). The various functions of the control device 16 may be realized by one processor, or may be realized by multiple processors of the same or different types.

[0046] The control device 16 reads out and executes the control program in the storage unit 30, thereby functioning as a tonometer control unit 16A that controls the intraocular pressure measurement of the subject's eye by the non-contact tonometer 14A, and an auto refraction meter control unit 16B that controls the measurement of the ocular refractive power, etc. of the subject's eye by the auto refraction meter 14B. Note that the function of the auto refraction meter control unit 16B, i.e., the measurement of the ocular refractive power, etc. by the auto refraction meter 14B, is a known technique, and therefore a detailed description thereof will be omitted here.

[0047] The tonometer control unit 16A functions as an observation control unit 40, a fixation control unit 42, an alignment control unit 44, a detection value acquisition unit 46, a drive control unit 48, a spray control unit 50, a measurement control unit 52, and an intraocular pressure value calculation unit 54.

[0048] In response to a measurement start operation of the non-contact tonometer 14A, the observation control unit 40 controls the observation optical system (see Patent Document 1) of the non-contact tonometer 14A to capture an image of the anterior segment of the subject's eye, and sequentially outputs the observed image (moving image) of the anterior segment to the remote control device 38 via the display unit 15 or the communication interface 34. As a result, the observed image is displayed as a moving image on the display unit 15 or the remote control device 38.

[0049] The fixation control unit 42 controls the fixation target projection optical system (see Patent Document 1) of the non-contact tonometer 14A in response to a measurement start operation of the non-contact tonometer 14A to project a fixation target light onto the subject's eye. This allows the subject's line of sight to be fixed. The timing of projecting the fixation target light onto the subject's eye is not particularly limited as long as it is before air is blown onto the cornea from the nozzle 20.

[0050] The alignment control unit 44 controls the alignment index projection optical system and alignment detection optical system (see Patent Document 1) of the non-contact tonometer 14A in response to a measurement start operation of the non-contact tonometer 14A to irradiate the XY alignment index light and the Z alignment index light to the subject's eye and capture (receive) the reflected light of each alignment index light. Next, the alignment control unit 44 performs alignment detection to calculate the positional relationship in the three-axis direction between the subject's eye and the non-contact tonometer 14A based on the image signal (received light signal) of each alignment index light. Note that a stereo camera (not shown) may be provided in the measurement head 14, and alignment detection may be performed based on a pair of anterior eye images of the subject's eye captured by the stereo camera (for example, JP 2013-248376 A).

[0051] Then, the alignment control unit 44 drives the drive mechanism 13 based on the result of this alignment detection to perform auto-alignment of the non-contact tonometer 14A with respect to the subject's eye.

[0052] The detection value acquisition unit 46 functions as an interface that acquires the detection value of the capacitance from the detection circuit 26b of the capacitance sensor 26. The detection value acquisition unit 46 repeatedly acquires the detection value of the capacitance from the detection circuit 26b while auto-alignment (relative movement) of the non-contact tonometer 14A with respect to the subject's eye is being performed. The detection value is an index indicating the face distance (hereinafter abbreviated as face distance), which is the distance from the nozzle 20 to the subject's face (subject's eye) as shown in FIG. 5, and increases as the face distance becomes shorter.

[0053] Each time the detection value acquisition unit 46 acquires a new capacitance detection value from the detection circuit 26b, the drive control unit 48 judges whether the detection value is greater than a predetermined threshold value. This threshold value is determined based on the capacitance detection value when the face distance is 5 mm, that is, the capacitance detection value corresponding to the face distance at which the nozzle 20 contacts the eyelashes of the face. When the capacitance detection value is greater than the threshold value, the drive control unit 48 drives the drive mechanism 13 to stop the auto-alignment, or retracts the measurement head 14 (nozzle 20) away from the subject's eye.

[0054] In addition, instead of the drive control unit 48 determining whether or not to stop auto-alignment based on the detection value of the detection circuit 26b, the drive control unit 48 may detect the face distance from the detection value of the detection circuit 26b and determine whether or not to stop auto-alignment based on whether this face distance is less than a predetermined distance threshold (e.g., 5 mm).

[0055] When auto-alignment of the non-contact tonometer 14A with the test eye is completed, i.e., when the non-contact tonometer 14A moves to within the measurable range (measurable position) of the intraocular pressure value of the test eye, the spray control unit 50 drives the spray mechanism (see Patent Document 1) of the non-contact tonometer 14A to blow air from the nozzle 20 onto the cornea of ​​the test eye.

[0056] While air is being blown onto the cornea of ​​the test eye from the nozzle 20, the measurement control unit 52 irradiates the cornea with visual target light from the XY alignment target projection optical system (see Patent Document 1) of the non-contact tonometer 14A, and detects the reflected light of the visual target light reflected by the cornea using the applanation detection optical system (see Patent Document 1).

[0057] The intraocular pressure value calculation unit 54 calculates the intraocular pressure value of the subject's eye based on the amount of reflected light detected by the above-mentioned applanation detection optical system (see Patent Document 1). Note that a specific method for calculating the intraocular pressure value is a publicly known technique (see Patent Document 1), so a detailed description thereof will be omitted here.

[0058] [Ophthalmic device function] Fig. 7 is a flow chart showing a flow of intraocular pressure measurement processing of the subject's eye by the non-contact tonometer 14A of the ophthalmic apparatus 10 of the first embodiment having the above-mentioned configuration. As shown in Fig. 7, when the examiner inputs an operation to start measurement of the intraocular pressure value of the subject's eye to the operation unit 32, or when the remote operation reception unit 36 ​​receives a measurement start operation from the remote operation device 38, the tonometer control unit 16A starts intraocular pressure measurement of the subject's eye (step S1). As a result, under the control of the observation control unit 40, the anterior segment of the subject's eye is photographed, and the observation image is displayed on the display unit 15 or the remote operation device 38. Also, under the control of the fixation control unit 42, a fixation target light is projected onto the subject's eye.

[0059] Furthermore, under the control of the alignment control unit 44, the alignment index light is irradiated onto the subject's eye, and the reflected light of each alignment index light is captured (received), and then, based on the image signal (received light signal) of each alignment index light, alignment detection is performed in three axial directions between the subject's eye and the non-contact tonometer 14A. As described above, alignment detection may be performed using a stereo camera (not shown). Next, based on the result of this alignment detection, the alignment control unit 44 drives the drive mechanism 13 to start auto-alignment of the non-contact tonometer 14A with respect to the subject's eye (step S2).

[0060] When the auto-alignment is started, the detection value acquisition unit 46 acquires the detection value of the capacitance from the detection circuit 26b of the capacitance sensor 26 (step S3). Next, the drive control unit 48 judges whether the detection value of the capacitance detected by the detection value acquisition unit 46 is greater than the above-mentioned threshold value or not, and goes into a standby state if it is equal to or less than the threshold value (NO in step S4). This makes it possible to detect the approach of the nozzle 20 to the subject's face and subject's eye in a non-contact manner.

[0061] Thereafter, while the auto-alignment is being performed, the detection value acquiring unit 46 repeatedly acquires the capacitance detection value, and the drive control unit 48 repeatedly performs a determination (NO in step S5).

[0062] Then, when the capacitance detection value detected by the detection value acquisition unit 46 during the execution of the auto-alignment becomes larger than the above-mentioned threshold value (YES in step S4), the drive control unit 48 drives the drive mechanism 13 to stop the auto-alignment, or moves the measurement head 14 (nozzle 20) away from the subject's eye (step S6). In this case, warning information may be output to the display unit 15 of the ophthalmic apparatus 10 (or the remote control device 38) or a speaker (not shown).

[0063] On the other hand, when the auto-alignment is completed with the capacitance detection value remaining below the threshold value (YES in step S5), the intraocular pressure of the subject's eye is measured (step S7). As a result, air is blown onto the cornea of ​​the subject's eye from the nozzle 20 under the control of the blowing control unit 50. At the same time, under the control of the measurement control unit 52, the cornea is irradiated with visual target light and the reflected light of the visual target light reflected by the cornea is detected, and then the intraocular pressure value of the subject's eye is calculated by the intraocular pressure value calculation unit 54. This intraocular pressure value is stored in the memory unit 30 and is displayed on the display unit 15 or the remote control device 38.

[0064] As described above, in the first embodiment, the approach of the nozzle 20 to the subject's face and the subject's eye can be detected in a non-contact manner by the capacitance sensor 26 during the execution of auto-alignment. This makes it possible to prevent the nozzle 20 from coming into contact with the subject's face and the subject's eye. Even if the nozzle 20 does come into contact with the subject's eye, damage to the subject's eye is minimized. Furthermore, even when the examiner remotely operates the ophthalmic apparatus 10 from a remote location, it is possible to reliably prevent the nozzle 20 from coming into contact with the subject's face and the subject's eye.

[0065] Furthermore, in the first embodiment, by using the capacitance sensor 26, the detection sensitivity of the eye to be examined located in front of the nozzle 20 can be improved.

[0066] Furthermore, in the first embodiment, since the electrode 26a is formed in a ring shape surrounding the nozzle 20, the directivity of the capacitance sensor 26 toward the front side of the nozzle 20 can be increased, and the detection sensitivity of the capacitance sensor 26 to the test eye located in front of the nozzle 20 can be improved.

[0067] [Second embodiment] 8 and 9 are explanatory diagrams for explaining the problem of the capacitance sensor 26 of the first embodiment. In the first embodiment, the electrode 26a of the capacitance sensor 26 is formed in a ring shape so as to surround the nozzle 20, thereby increasing the directivity of the capacitance sensor 26 toward the front side of the nozzle 20, and making it possible to detect the approach of the subject's eye E or the face of the subject (hereinafter, abbreviated as the subject's eye E, etc.) from any direction in front of the nozzle 20.

[0068] 8, even if the nozzle 20 is brought close to the subject's eye E by a predetermined distance, the distance LA between the electrodes 26a (not shown in FIG. 8) around the nozzle 20 and the subject's forehead is sufficiently secured. Therefore, the detection value of the capacitance sensor 26 is unlikely to be greater than the threshold value, i.e., the possibility of the nozzle 20 being erroneously recognized as approaching the subject's eye E is low.

[0069] 8, depending on the shape of the subject's face, such as a protruding forehead (deep facial features), the distance LA may become shorter when the nozzle 20 is brought within a predetermined distance from the subject's eye E, and the detection value of the capacitance sensor 26 may become larger than the threshold value. In this case, even if the face distance is sufficiently secured and there is no risk of the nozzle 20 coming into contact with the subject's eye E, it may be erroneously determined that the subject's eye E has come close to the nozzle 20.

[0070] 9, when the examiner opens the eyelids of the subject, the distance LB between the electrode 26a (not shown in FIG. 9) around the nozzle 20 and the examiner's finger becomes shorter, so that the detection value of the capacitance sensor 26 may become larger than the above-mentioned threshold value. In this case, too, even though there is no risk of the nozzle 20 coming into contact with the subject's eye E, it may be erroneously determined that the subject's eye E is approaching the nozzle 20.

[0071] Therefore, in the ophthalmic device 10 of the second embodiment, the shape of the electrode 26a of the capacitance sensor 26 is adjusted to prevent the nozzle 20 from being mistakenly recognized as approaching the subject's eye E, even though there is no risk of the nozzle 20 coming into contact with the subject's eye E. The ophthalmic device 10 of the second embodiment has a basically the same configuration as the above-mentioned first embodiment except for the shape of the electrode 26a, and therefore the same reference numerals are used for components that are the same in function or configuration as the above-mentioned first embodiment, and their description will be omitted.

[0072] Fig. 10 is a perspective view of the nozzle 20 and the capacitance sensor 26 (electrode 26a) of the ophthalmic device 10 of the second embodiment. Fig. 11 is a front view of the nozzle 20 and the capacitance sensor 26 (electrode 26a) of the ophthalmic device 10 of the second embodiment. In the figure, the symbol AX indicates the central axis of the nozzle 20 parallel to the working distance direction of the ophthalmic device 10, the symbol UL indicates the up-down direction, and the symbol LR indicates the left-right direction that is perpendicular to both the central axis AX and the up-down direction UL (the subject's eye width direction). In addition, the symbol HL in the figure is a parallel line that is perpendicular to the central axis AX and parallel to the left-right direction LR.

[0073] 10 and 11, the electrode 26a in the second embodiment is formed in a region below the parallel line HL in an annular region (the region where the electrode 26a in the first embodiment is formed) surrounding the nozzle 20, that is, formed in a substantially semi-annular shape, when viewed from the tip side of the nozzle 20. Here, "formed in a region below the parallel line HL" includes both the case where the electrode 26a is formed in the entire region below the parallel line HL as shown in FIGS. 10 and 11, and the case where the electrode 26a is formed in a part of the region below the parallel line HL.

[0074] Fig. 12 is an explanatory diagram for explaining the directivity of the capacitance sensor 26 of the second embodiment. In addition, the symbol RD in the figure indicates the detection range of the capacitance sensor 26. Moreover, the detection range RD shown in Fig. 12 is an example, and the range can be changed as appropriate.

[0075] 12, by forming the electrode 26a in a substantially semi-annular shape, the detection range RD of the capacitance type sensor 26 is more limited above the central axis AX than in the first embodiment when the nozzle 20 is viewed from any one side in the left-right direction LR. As a result, the capacitance type sensor 26 of the second embodiment has directivity toward the front side of the nozzle 20 as in the first embodiment, but the directivity is weaker above the central axis AX than below it when the nozzle 20 is viewed from any one side in the left-right direction LR.

[0076] By thus weakening the directivity of the capacitance sensor 26 toward the upper side of the central axis AX, the above-mentioned distance LA (see FIG. 8) or distance LB (see FIG. 9) is sufficiently ensured when the nozzle 20 is brought within a predetermined distance from the subject's eye E. As a result, it is possible to prevent the nozzle 20 from being mistakenly recognized as being close to the subject's eye E, even though there is no risk of the nozzle 20 coming into contact with the subject's eye E.

[0077] [Third embodiment] FIG. 13 is a graph showing the correspondence relationship (hereinafter, simply referred to as the correspondence relationship) between the face distance (mm) described above under different ambient environments (temperature and humidity) and the detection value (pF) detected by the capacitance sensor 26. Here, the correspondence relationship is measured and graphed for each of a plurality of temperature conditions in a low humidity environment (humidity 40%) shown by reference symbol XIIIA and a high humidity environment (humidity 90%) shown by reference symbol XIIIB. Note that since a temperature of 0° is the freezing point, it is not possible to set the humidity accurately, but since the amount of moisture in the air is small at a humidity of 40%, the correspondence relationship is measured and graphed only under a low humidity environment at a temperature of 0°. Also, the detection object in FIG. 13 indicates the subject's eye E, etc.

[0078] As shown in Fig. 13, the correspondence relationship differs depending on the surrounding environment (temperature and humidity). For this reason, when a determination is made as to whether or not the nozzle 20 is close to the subject's eye E, etc., based on whether or not the detection value of the capacitance sensor 26 is greater than a threshold value (fixed value), as in the above-described first embodiment, there is a risk of a false determination that the nozzle 20 is close to the subject's eye E, etc., when it is not. Conversely, there is a risk of a false determination that the nozzle 20 is not close to the subject's eye E, etc., when it is.

[0079] Therefore, in the third embodiment, it is possible to determine whether or not the nozzle 20 is close to the subject's eye E, etc., regardless of the surrounding environment. Specifically, in the third embodiment, an initial value of the detection value of the capacitance sensor 26 is acquired in advance before the start of auto-alignment, and whether or not the nozzle 20 is close to the subject's eye E, etc. is determined based on whether or not the difference between this initial value and a detection value newly detected by the capacitance sensor 26 during auto-alignment is greater than a predetermined difference threshold.

[0080] The ophthalmic device 10 of the third embodiment has basically the same configuration as the above-mentioned embodiments, except for some differences in the functions of the detection value acquisition unit 46 and the drive control unit 48 of the control device 16 (see FIG. 6). Therefore, the same reference numerals are used for components that are the same in function or configuration as the above-mentioned embodiments, and their description is omitted.

[0081] The detection value acquiring unit 46 of the third embodiment functions as an initial value acquiring unit of the present invention at a predetermined timing before the start of auto-alignment, and acquires a detection value from the capacitance sensor 26 as an initial value in a state in which the nozzle 20 is not approaching the subject's eye E, etc. Examples of this predetermined timing include when the power of the ophthalmic apparatus 10 is turned on, when a measurement start operation is performed, or when the subject is switched. Note that the detection value acquiring unit 46 repeatedly acquires detection values ​​from the capacitance sensor 26 during auto-alignment, similarly to the first embodiment.

[0082] The drive control unit 48 of the third embodiment calculates the difference between the new detection value and the initial value previously acquired by the detection value acquisition unit 46 every time the detection value acquisition unit 46 acquires a new detection value from the capacitance sensor 26 during auto-alignment, and judges whether or not this difference is greater than a predetermined difference threshold. This difference threshold is determined based on, for example, the difference when the face distance is 5 mm, that is, the difference corresponding to the face distance at which the nozzle 20 comes into contact with the eyelashes, as with the detection value threshold of the first embodiment. Then, when the calculated difference is greater than the above-mentioned difference threshold, the drive control unit 48 drives the drive mechanism 13 to stop the auto-alignment, or retracts the measurement head 14 (nozzle 20) away from the subject's eye E.

[0083] The drive control unit 48 may detect the face distance from the calculated difference and determine whether or not to stop the auto-alignment based on whether or not the face distance is less than a predetermined distance threshold (for example, 5 mm).

[0084] Fig. 14 is a flowchart showing the flow of intraocular pressure measurement processing of the subject's eye E by the non-contact tonometer 14A of the ophthalmic apparatus 10 of the third embodiment. As shown in Fig. 14, when a measurement start operation is performed (step S1) as in the first embodiment (see Fig. 7), the detection value acquisition unit 46 acquires an initial detection value from the capacitance sensor 26 (step S1A). The timing of acquiring this initial value is not particularly limited as long as it is before the start of auto-alignment, that is, when the nozzle 20 is at a position away from the subject's eye E, etc.

[0085] Then, as described in the first embodiment, after alignment detection is executed under the control of the alignment control unit 44, auto-alignment of the non-contact tonometer 14A with respect to the subject's eye E is started (step S2).

[0086] When auto-alignment is started, the detection value acquisition unit 46 acquires a detection value from the capacitance sensor 26 (step S3). Next, the drive control unit 48 calculates the difference between the detection value newly acquired by the detection value acquisition unit 46 and the initial value previously acquired by the detection value acquisition unit 46 (step S3A) and determines whether this difference is greater than a difference threshold (step S4A). Then, the drive control unit 48 goes into a standby state if the difference is equal to or less than the difference threshold (NO in step S4A).

[0087] Thereafter, unless the difference becomes larger than the difference threshold value until the auto-alignment is completed, the acquisition of the detection value by the detection value acquisition unit 46 and the difference calculation and judgment by the drive control unit 48 are repeatedly executed (NO in step S4A, NO in step S5).

[0088] On the other hand, when the difference is greater than the difference threshold value (YES in step S4A), the drive control unit 48 drives the drive mechanism 13 to stop the auto-alignment as in the first embodiment, or moves the measurement head 14 away from the subject's eye E (step S6). Note that, as in the first embodiment, a notice of warning information (display, audio output) may be executed.

[0089] When the auto-alignment is completed (YES in step S5), the intraocular pressure of the subject's eye E is measured in the same manner as in the first embodiment (step S7).

[0090] As described above, in the third embodiment, the initial value of the capacitance sensor 26 is acquired in advance, and it is determined whether the difference between this initial value and the detection value newly acquired by the capacitance sensor 26 is greater than the difference threshold, making it possible to accurately determine whether the nozzle 20 is close to the test eye E, etc., without being affected by the surrounding environment.

[0091] [others] In each of the above-described embodiments, air is blown from the nozzle 20 toward the cornea of ​​the subject's eye, but various fluids other than air may also be blown.

[0092] In each of the above embodiments, the approach of the nozzle 20 to the subject's face and eye to be examined during auto-alignment is detected in a non-contact manner by the capacitance sensor 26, but similar detection may also be performed by the capacitance sensor 26 during manual alignment. Also, in the above embodiments, alignment is performed by moving the measuring head 14 in three axial directions by the drive mechanism 13, but alignment may also be performed by, for example, driving the motorized face support unit 12 to move the subject's face in three axial directions.

[0093] In each of the above embodiments, the electrode 26a of the capacitance sensor 26 is formed in a ring or semi-ring shape surrounding the nozzle 20, but may be divided into a plurality of parts along the axial direction centered on the nozzle 20. The electrode 26a may be provided on at least one side of the nozzle 20, above, below, left, or right. That is, the electrode 26a may be provided on at least a part of the periphery of the nozzle 20. Furthermore, the electrode 26a may be embedded in the glass holding portion 24. Furthermore, the position and shape of the electrode 26a may be appropriately changed as long as it is possible to detect the approach of the subject's face (examined eye) to the nozzle 20.

[0094] In each of the above embodiments, one capacitance sensor 26 is provided around the nozzle 20, but multiple capacitance sensors 26 may be provided around the nozzle 20. In this case, the drive control unit 48 stops the auto alignment when any of the face distances detected for each capacitance sensor 26 falls below the above-mentioned threshold value.

[0095] In each of the above embodiments, a capacitance sensor 26 is used to detect the approach of the nozzle 20 to the subject's face and eye, but various known non-contact sensors (proximity sensors), such as an ultrasonic sensor and an infrared proximity sensor, may also be used.

[0096] In each of the above embodiments, the ophthalmic apparatus 10 which is a combination device of the non-contact tonometer 14A and the autorefractometer 14B has been described as an example, but the present invention is also applicable to the non-contact tonometer 14A alone. [Explanation of symbols]

[0097] 10 Ophthalmological equipment 11. Base 12 Face support 12a Chin rest 12b Forehead rest 13 Drive mechanism 14 Measuring Head 14A Non-contact tonometer 14B Auto Ref Keratometer 15 Display 16 Control device 16A Tonometer control unit 16B Auto-refractometer control unit 20 Nozzles 22 Window Glass 24 Glass holder 25 Optical system 26 Capacitive Sensor 26a electrode 26b Detection circuit 26c Wiring 30 Storage section 32 Operation section 34 Communication Interface 36 Remote Control Reception 38 Remote Control Device 40 Observation control section 42 Fixation control unit 44 Alignment control unit 46 Detection value acquisition section 48 Drive control unit 50 Spray control section 52 Measurement control section 54 Intraocular pressure value calculation unit AX center axis E. Examined eye HL parallel lines LA,LB distance LR left / right direction RD Detection Range UL Vertical direction

Claims

1. A nozzle for spraying a fluid onto the cornea of ​​the subject's eye; one or more non-contact sensors that detect the proximity of the nozzle to a face of a subject including the eye; Equipped with the non-contact sensor is a capacitance sensor, A non-contact tonometer in which the direction parallel to the central axis of the nozzle is defined as the working distance direction, the direction perpendicular to both the working distance direction and the up-down direction is defined as the left-right direction, and straight lines perpendicular to the central axis and parallel to the left-right direction are defined as parallel lines, wherein the electrodes of the capacitance type sensor are formed in an annular region surrounding the nozzle in a region below the parallel lines when viewed from the tip side of the nozzle.

2. The non-contact tonometer according to claim 1 , wherein the non-contact sensor is provided around at least a portion of the circumference of the nozzle.

3. A non-contact tonometer as described in claim 1 or 2, wherein the non-contact sensor has directionality toward the front side of the nozzle, and when the nozzle is viewed from the left-right side, the directionality is weaker toward the upper side of the central axis than toward the lower side.

4. A window glass provided with the nozzle; and A glass holding portion that holds the window glass; Equipped with 4. The non-contact tonometer according to claim 1, wherein the non-contact sensor is provided on the glass holding portion in a shape surrounding at least a portion of the window glass.

5. As the nozzle approaches the face, the detection value of the non-contact sensor increases, a measuring head provided with the nozzle; a drive mechanism that moves the measurement head relative to the subject's eye; a detection value acquiring unit that repeatedly acquires the detection value from the non-contact sensor while the driving mechanism is moving the measuring head relatively; a drive control unit that controls the drive mechanism to stop the relative movement of the measurement head or to move the measurement head away from the subject's eye when the detection value newly acquired by the detection value acquisition unit becomes larger than a predetermined threshold value; The non-contact tonometer according to claim 1 , further comprising:

6. As the nozzle approaches the face, the detection value of the non-contact sensor increases, a measuring head provided with the nozzle; a drive mechanism that moves the measurement head relative to the subject's eye; an initial value acquisition unit that acquires an initial value of the detection value from the non-contact sensor; a detection value acquiring unit that repeatedly acquires the detection value from the non-contact sensor after the initial value acquiring unit acquires the initial value and while the driving mechanism is moving the measuring head relatively; a drive control unit that calculates a difference between the detection value and the initial value acquired by the initial value acquisition unit every time the detection value acquisition unit acquires the detection value, and when the difference becomes larger than a predetermined difference threshold, controls the drive mechanism to stop the relative movement of the measurement head or to retract the measurement head from the subject's eye; The non-contact tonometer according to claim 1 , further comprising:

7. a remote control reception unit that receives remote control from an external device; an operation control unit that controls an operation of the non-contact tonometer in accordance with the remote operation accepted by the remote operation acceptance unit; The non-contact tonometer according to claim 1 , further comprising:

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