Non-contact type tonometer

Abstract

To provide a non-contact type tonometer capable of achieving cost reduction while reducing loss of fluid.SOLUTION: A non-contact type tonometer for measuring intraocular pressure of an eye to be examined in a non-contact manner having: a storage part for storing a cylinder and a piston for compressing fluid; an airtight chamber for storing the fluid compressed by the cylinder and the piston; and a nozzle connected to the airtight chamber includes fluid discharge means for discharging fluid to the cornea of the eye to be examined through the nozzle. A tube member that constitutes a flow passage through which the fluid is discharged from the storage part to the airtight chamber is composed by the connection of a linear part and a bent part, the linear part having first material quality and the bent part having second material quality whose rigidity is stronger than that of the first material quality.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There is known a non-contact tonometer that measures the intraocular pressure of a subject's eye by ejecting a fluid such as air from a nozzle toward the subject's eye. For example, in a non-contact tonometer, a fluid in a cylinder compressed by the movement of a piston is sent to an airtight chamber, and the fluid is ejected from a nozzle connected to the airtight chamber onto the cornea to detect the deformation state of the cornea caused by the fluid (for example, the applanation state) (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-89454 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, the fluid flow path from the cylinder through the airtight chamber and nozzle has a uniform material.

[0005] For example, the fluid flow path may be formed by a metal tube. In this case, the space required for the device can be saved by bending a portion of the metal tube. Even if the metal tube is partially bent, the loss of the fluid sprayed onto the subject's eye is small. However, since the tube is made of metal, the cost tends to be high.

[0006] Also, for example, the fluid flow path may be formed by a resin tube. Resin tubes are less expensive than metal tubes, and it is easy to bend a part of them by applying force. However, when a resin tube is bent, its diameter is crushed, and the loss of fluid is likely to be large. For this reason, if the resin tube is provided in a straight line, the device may become large. In order to solve this problem, a resin tube with a bellows shape has been considered, but since the fluid is sent while hitting the bellows shape, the loss of fluid remains.

[0007] In view of the above problems, the present disclosure has as its technical object to provide a non-contact tonometer that can reduce fluid loss while achieving low costs. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention is characterized by having the following configuration.

[0009] A non-contact tonometer according to a first aspect of the present disclosure is a non-contact tonometer for measuring the intraocular pressure of a test eye in a non-contact manner, the non-contact tonometer having a storage section that contains a cylinder and a piston for compressing a fluid, an airtight chamber that contains the fluid compressed by the cylinder and the piston, and a nozzle connected to the airtight chamber, and is equipped with a fluid ejection means that ejects the fluid through the nozzle onto the cornea of ​​the test eye, the non-contact tonometer being characterized in that a tubular member that forms a flow path through which the fluid is ejected from the storage section to the airtight chamber is formed by connecting a straight section and a bent section, the straight section having a first material, and the bent section having a second material having greater rigidity than the first material. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the external configuration of a non-contact tonometer. [Diagram 2] FIG. 2 is a diagram showing the internal configuration of a non-contact tonometer. [Diagram 3] FIG. 2 is a schematic diagram of a tubular member. [Figure 4] FIG. 2 is a schematic diagram of a measurement optical system of a non-contact tonometer. [Diagram 5] 13 is a diagram showing an example in which a nozzle portion and a measurement optical system move integrally. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Summary> An overview of a non-contact tonometer according to an embodiment of the present disclosure will be described. The items classified in <> below can be used independently or in conjunction with each other.

[0012] The non-contact tonometer of this embodiment (for example, the non-contact tonometer 1) is a device that measures the intraocular pressure of a subject's eye in a non-contact manner.

[0013] The non-contact tonometer of this embodiment may include a fluid ejection means (e.g., fluid ejection unit 200). The fluid ejection means ejects a fluid (e.g., air, etc.) through a nozzle onto the cornea of ​​the subject's eye. The fluid ejection means also includes a storage unit (e.g., storage unit 260), an airtight chamber (e.g., airtight chamber 221), and a nozzle (e.g., nozzle 206). For example, the storage unit accommodates a cylinder and a piston for compressing the fluid. For example, the airtight chamber accommodates the fluid compressed by the cylinder and the piston. For example, the nozzle is connected to the airtight chamber. Furthermore, the fluid ejection means may include a tube member (e.g., tube member 270). The tube member constitutes a flow path through which the fluid is ejected from the storage unit to the airtight chamber.

[0014] <Pipe members> In this embodiment, the pipe member may be configured by connecting a straight portion (e.g., straight portion 271) and a bent portion (e.g., bent portion 272). For example, the straight portion may be formed as a straight shape with zero or small curvature in the fluid flow path. For example, the bent portion may be formed as a curved shape with large curvature in the fluid flow path. In other words, the bent portion may be formed as a shape in which the fluid flow path is bent (in other words, angled). Note that it is sufficient for the pipe member to allow fluid to pass through and to have a cavity inside.

[0015] For example, the straight portion may be configured to have a first material. For example, the first material may be a material having a lower rigidity than a second material described later. For example, the bent portion may be configured to have a second material. For example, the second material may be a material having a higher rigidity than the first material. For example, in contrast to a case where the pipe member is uniformly formed of a material having a higher rigidity, the straight portion constituting the pipe member may be formed of a material having a lower rigidity, thereby reducing costs. In addition, by making the bent portion constituting the pipe member of a material having a higher rigidity, the loss of fluid can be reduced even if the flow path is bent in any direction. Furthermore, since the flow path can be bent in any direction, the device can be made more space-saving.

[0016] For example, the straight portion may have a rigidity such that the diameter of the flow path may be deformed when a force is applied to the pipe member. For example, even if the straight portion constituting the pipe member is made of a material having a rigidity such that the diameter of the flow path may be deformed, the straight portion is arranged linearly, so that the fluid can flow smoothly and loss can be suppressed. In addition, for example, the bent portion may have a rigidity such that the diameter of the flow path does not deform even when a force is applied to the pipe member. For example, by forming the bent portion constituting the pipe member from a material having a rigidity such that the diameter of the flow path does not deform, the fluid can flow smoothly and loss can be suppressed. Note that, as an example, the force applied to the pipe member may be the pressure of the fluid passing through the inside of the pipe member (wind pressure), external pressure acting on the pipe member, etc.

[0017] For example, the straight portion and the bent portion may be formed of different materials. That is, for example, the straight portion and the bent portion may be formed of different materials, so that the bent portion has a stronger rigidity than the straight portion. For example, different materials may be appropriately selected for the straight portion and the bent portion depending on the shape of the flow path of the pipe member, and the like, and the materials may be combined to have different rigidities, which can lead to lower costs, reduced fluid loss, and the like.

[0018] For example, the straight portion and the bent portion may be formed of the same material. That is, for example, the straight portion and the bent portion may be formed of the same material, but due to differences in strength, hardness, etc., the bent portion may be formed to have a stronger rigidity than the straight portion. As an example, the stiffness of the bent portion may be made stronger by increasing the plate thickness (wall thickness) of the bent portion relative to the straight portion, or by adjusting the type and amount of additives or plasticizers in the material to increase the hardness of the bent portion. For example, forming and combining the straight portion and the bent portion of the pipe member to be made of the same material but with different stiffness can lead to lower costs, reduced fluid loss, and the like.

[0019] For example, the straight section may be made of metal or resin, which has a lower rigidity than the bent section. For example, when the straight section is made of metal, at least one of aluminum alloy, alloy steel such as stainless steel, etc. may be used. Also, for example, when the straight section is made of resin, at least one of plastic resin, silicon resin, fluororesin, etc. may be used. For example, as the plastic resin, at least one of vinyl chloride, AS (Acrylonitrile Styrene), ABS (Acrylonitrile Butadiene Styrene), polycarbonate, etc. may be used. For example, as the silicon resin, silicone, etc. may be used. For example, as the fluororesin, PFA (Perfluoroalkoxy alkane) etc. may be used.

[0020] As an example, the straight section may be made of silicone, which is a type of silicone resin. For example, the straight section is less susceptible to wind pressure of the fluid or external pressure, and the diameter of the flow path is less likely to deform than the bent section. In addition, for example, silicone is often less rigid and less expensive than metals, etc. For this reason, by forming the straight section from silicone, it is possible to reduce fluid loss and costs.

[0021] For example, the bent portion may be formed of a metal or resin that has a higher rigidity than the straight portion. For example, when the bent portion is formed of a metal, at least one of an aluminum alloy, an alloy steel such as stainless steel, and the like may be used. Also, for example, when the bent portion is formed of a resin, at least one of a plastic resin, a silicon resin, a fluororesin, and the like may be used. For example, as the plastic resin, at least one of vinyl chloride, AS, ABS, polycarbonate, and the like may be used. For example, as the silicon resin, silicone, etc. may be used. For example, as the fluororesin, PFA, etc. may be used.

[0022] <Example> An example of the non-contact tonometer according to the present embodiment will be described. The non-contact tonometer of the present embodiment measures the intraocular pressure of the subject's eye in a non-contact manner. The non-contact tonometer, for example, ejects a fluid onto the cornea of ​​the subject's eye, and measures the intraocular pressure of the subject's eye from the relationship between the deformation state of the cornea at that time and the pressure of the fluid. Note that the X direction in Figs. 1 to 5 represents the left-right direction, the Y direction represents the up-down direction, and the Z direction represents the front-back direction.

[0023] <Device configuration> FIG. 1 is a diagram showing the external configuration of a non-contact tonometer 1. The non-contact tonometer 1 includes a base 2, a face support unit 3, a drive unit 4, a measurement unit 100, and the like. The base 2 supports the measurement unit 100 so that it can move. The face support unit 3 supports the face of the subject. The face support unit 3 includes a forehead rest 3a, a chin rest 3b, a chin rest sensor 3c, a chin rest drive unit 3d, and the like. The chin rest sensor 3c detects whether the chin is placed on the chin rest 3b. The chin rest drive unit 3d moves the chin rest 3b up and down to adjust the height. The drive unit 4 moves the measurement unit 100 in the XYZ directions (three-dimensional directions) relative to the base 2. The measurement unit 100 includes a fluid discharge unit 200 and a measurement optical system 10, which will be described later, and the like.

[0024] The non-contact tonometer 1 may include a display unit 85, a face photographing unit 90, and the like. The display unit 85 displays, for example, an observation image of the subject's eye and a measurement result. The display unit 85 may be provided, for example, integrally with the non-contact tonometer 1, or may be provided separately from the device. The display unit 85 may be arranged so that the display screen faces not only the subject but also the subject side. The display unit 85 may be used as an operation unit 86. In this case, the display unit 85 is used for various settings of the non-contact tonometer 1, an operation to start measurement, and the like. The operation unit 86 may be various human interfaces such as a joystick, a mouse, a keyboard, a trackball, and a button. The face photographing unit 90 photographs, for example, the face of the subject's eye. The face photographing unit 90 photographs, for example, a face including at least one of the left and right subjects' eyes.

[0025] 2 is a diagram showing the internal configuration of the non-contact tonometer 1. For example, in this embodiment, the measurement optical system 10 is provided below the fluid discharge unit 200, and a part of the tubular member 270 (in other words, the fluid flow path) in the fluid discharge unit 200 is curved downward to make the center of the nozzle 206 coincide with the optical axis of the measurement optical system 10. This allows the measurement unit 100 to be configured in a space-saving manner, as compared to, for example, a case in which the tubular member 270 is provided linearly.

[0026] <Fluid discharge section> The fluid ejection part 200 ejects a fluid onto the cornea of ​​the subject's eye E. The fluid ejection part 200 includes, for example, a cylinder 201, a piston 202, a solenoid actuator (hereinafter also referred to as a solenoid) 203, a nozzle 206, a glass plate 208, a glass plate 209, a pressure sensor 212, an airtight chamber 221, a storage part 260, and a tube member 270.

[0027] The accommodation section 260 accommodates at least a cylinder 201 and a piston 202 for compressing a fluid such as air to be discharged to the subject's eye. The cylinder 201 and the piston 202 are used as a fluid compression mechanism for compressing the fluid. The cylinder 201 is, for example, cylindrical, and the inside is divided into a compression chamber 234 and an intake chamber 235. An intake port 213 is provided on the side of the intake chamber 235. The piston 202 slides along the axial direction (longitudinal direction) of the cylinder 201. The piston 202 compresses the air in the compression chamber 234 in the cylinder 201.

[0028] The solenoid 203 is, for example, a direct acting solenoid, and operates linearly. The solenoid 203 includes a movable body 204 and a coil 205. The movable body 204 is made of, for example, a magnetic material such as a permanent magnet. When a current flows through the coil 205, a magnetic field is generated inside the coil 205. The movable body 204 is moved in the axial direction by the electromagnetic force received from the magnetic field. The piston 202 is fixed to the movable body 204, and therefore moves in the axial direction together with the movable body 204.

[0029] In addition, the moving direction of the movable body 204 can be changed by changing the direction of the current flowing through the coil 205. For example, when a current flows through the coil 205 in the forward direction, the movable body 204 moves in the compression direction (forward direction, direction A in FIG. 2), and when a current flows through the coil 205 in the reverse direction, the movable body 204 moves in the opposite direction (rearward direction, direction B in FIG. 2). Therefore, by switching the direction of the current flowing through the coil 205, the moving direction of the piston 202 moving together with the movable body 204 can be changed. For example, after a current flows through the coil 205 in the forward direction to move the piston 202 in the direction A to compress the air in the compression chamber 234, the piston 202 can be moved in the direction B to return to the initial position by flowing a current through the coil 205 in the reverse direction. The solenoid 203 is not limited to a linear solenoid, but may be a rotary solenoid or another driving source.

[0030] The piston 202 is provided with an inlet 250 penetrating in the axial direction. The piston 202 is also provided with a check valve 251. For example, the check valve 251 is fixed to the compression chamber 234 side of the piston 202 by a fastening part 252. The check valve 251 is made of a flexible resin film or the like, and when the piston 202 moves in the A direction in FIG. 2, it blocks the inlet 250 and acts to prevent the pressure of the compression chamber 234 from leaking to the intake chamber 235. When the piston 202 moves in the B direction in FIG. 2, the check valve 251 is deformed and turned over due to the pressure difference between the compression chamber 234 and the intake chamber 235, and air moves from the inlet 250 to the compression chamber 234.

[0031] The pipe member 270 constitutes a flow path through which air is discharged from the storage section 260 to the airtight chamber 221. For example, as described above, a portion of the pipe member 270 is curved downward, which divides the pipe member 270 into a straight portion and a curved portion (details will be described later). The airtight chamber 221 contains air compressed by the cylinder 201 and the piston 202. The nozzle 206 discharges the compressed air to the outside of the device. The glass plate 208 is transparent, holds the nozzle 206, and transmits observation light and alignment light. The glass plate 209 constitutes the rear wall of the airtight chamber 221 and transmits observation light and alignment light. The pressure sensor 212 detects, for example, the pressure of the airtight chamber 221.

[0032] The air compressed in the compression chamber 234 in the cylinder 201 by the movement of the piston 202 is discharged from the nozzle 206 toward the cornea of ​​the test eye E through a tube member 270 connected to the outlet of the storage section 260 (in other words, the tip of the cylinder 201) and an airtight chamber 221 connected to the tube member 270.

[0033] <Pipe members> 3 is a schematic diagram of a pipe member 270. The pipe member 270 is formed by connecting a straight portion 271 and a bent portion 272. For example, the pipe member 270 includes a straight portion 271, a bent portion 272, a connecting portion 273, a connecting portion 274, a connecting portion 275, and the like.

[0034] Straight portion 271 has a first material that is less rigid than bent portion 272. For example, straight portion 271 may have a rigidity that allows the diameter of the air flow path to be deformed when force is applied to straight portion 271. However, since straight portion 271 is arranged linearly, the possibility that the diameter of the air flow path will be deformed is low. One end of straight portion 271 is connected to the discharge port of storage portion 260 via connecting portion 273. The other end of straight portion 271 is connected to bent portion 271 via connecting portion 274.

[0035] Bent portion 272 has a second material that is more rigid than straight portion 271. For example, bent portion 272 may have a rigidity that prevents the diameter of the air flow path from being deformed even when a force is applied. For example, in this case, even if the air flow path is bent at bent portion 272, the diameter of the flow path does not collapse, so air is less likely to stagnate and loss is small. One end of bent portion 272 is connected to straight portion 271 via connecting portion 274. The other end of bent portion 272 is connected to airtight chamber 221 via connecting portion 275.

[0036] The connecting portions 273-275 connect the straight portion 271, the bent portion 272, the storage portion 260, and the airtight chamber 221, respectively. For example, the connecting portions 273-275 may be configured to connect the respective portions by using fasteners (for example, screws, bands, etc.). Also, for example, the connecting portions 273-275 may be configured to connect the respective portions by performing a retaining process using a shape such as forming a plurality of wedges on each portion.

[0037] In this embodiment, the straight portion 271 and the bent portion 272 are made of different materials and have different rigidities. For example, the straight portion 271 is a tube made of silicone, and the bent portion 272 is a resin molded product made of plastic.

[0038] For example, air compressed in the compression chamber 234 in the cylinder 201 first passes through the straight section 271 when being sent from the storage section 260 to the tube member 270. For example, even if an inexpensive and flexible silicone tube is used for the straight section 271, the tube is not bent by applying a force from the outside, and the diameter of the flow path is not easily deformed. In addition, since the air flows smoothly inside the tube, the diameter of the flow path is not easily deformed by the wind pressure of the air. Therefore, the air heads toward the bent section 272 without loss. Next, the air passes through the bent section 272. For example, by molding an inexpensive and hard resin molded product into a curved shape in advance for the bent section 272, the bent section 272 is not further bent even when a force is applied from the outside, and the diameter of the flow path is not easily deformed. In addition, even in a place where the curvature is large and air is likely to concentrate, the diameter of the flow path is not easily deformed by the wind pressure of the air. Therefore, the air heads toward the airtight chamber 221 without loss.

[0039] <Measurement optical system> 4 is a schematic diagram of the measurement optical system 10 of the non-contact tonometer 1. An image of the subject's eye illuminated by an infrared illumination light source 30 is formed on a CCD camera 35 via a beam splitter 31, an objective lens 32, a dichroic mirror 33, an imaging lens 37, and a filter 34. That is, the optical system from the beam splitter 31 to the CCD camera 35 has an imaging element and is used as an observation optical system for observing the anterior segment of the subject's eye. In this case, the optical axis L1 is used as the observation optical axis.

[0040] The filter 34 transmits light from the light source 30 and the infrared light source 40 for alignment, but is opaque to light from a light source 50 for corneal deformation detection (described later) and visible light. The image formed on the CCD camera 35 is displayed on a display unit 85.

[0041] The infrared light projected from the light source 40 through the projection lens 41 is reflected by the beam splitter 31 and projected from the front onto the subject's eye. The corneal bright spot formed at the corneal apex by the light source 40 is imaged on the CCD camera 35 through the beam splitter 31 to the filter 34, and is used for detecting alignment in the up, down, left and right directions. That is, the optical system from the beam splitter 31 to the CCD camera 35 has an image sensor and is used as a detection optical system for detecting the alignment state in the up, down, left and right directions with respect to the subject's eye. In this case, the optical axis L1 is used as the alignment optical axis. In this embodiment, the detection optical system also serves as an observation optical system for observing the anterior segment.

[0042] The fixation optical system 48 has an optical axis L1 and presents a fixation target to the eye E from the front direction. In this case, the optical axis L1 is used as a fixation optical axis. The fixation optical system 48 has, for example, a visible light source (fixation lamp) 45, a projection lens 46, and a dichroic mirror 33, and projects light onto the eye E to fixate the eye E in the front direction. The visible light source 45 may be a light source such as an LED or a laser. The visible light source 45 may also be, for example, a pattern light source such as a point light source, a slit light source, or a ring light source, or a two-dimensional display such as a liquid crystal display.

[0043] Visible light emitted from the light source 45 passes through the projection lens 46, is reflected by the dichroic mirror 33, passes through the objective lens 32, and is then projected onto the fundus of the eye E. As a result, the eye E is fixated on the fixation point in the front direction, and the line of sight is fixed. The visible light emitted from the light source 45 passes through the projection lens 46 and the objective lens 32, and is converted into a parallel beam.

[0044] The corneal deformation detection optical system includes a light projecting optical system 500a and a light receiving optical system 500b, and is used to detect the deformation state of the cornea Ec. Each of the optical systems 500a and 500b is disposed in the measurement unit 100 and moved three-dimensionally by the driving unit 4.

[0045] The light projecting optical system 500a has an optical axis L3 as a light projecting optical axis, and irradiates illumination light from an oblique direction toward the cornea Ec of the eye E. The light projecting optical system 500a has, for example, an infrared light source 50, a collimator lens 51, and a beam splitter 52. The light receiving optical system 500b has a photodetector 57, and receives the illumination light reflected by the cornea Ec of the eye E. The light receiving optical system 500b is disposed approximately symmetrically to the light projecting optical system 500a with respect to the optical axis L1. The light receiving optical system 500b has, 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.

[0046] The light emitted from the light source 50 is made into a substantially parallel beam by the collimator lens 51, and after being reflected by the beam splitter 52, becomes coaxial (coincident) 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. The light reflected by the cornea Ec becomes coaxial (coincident) 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 the pinhole plate 56, and is received by the photodetector 57. The lens 53 is coated with a coating that is opaque to the light of the light source 30 and the light source 40. The optical system for detecting corneal deformation is disposed so that the amount of light received by the photodetector 57 is maximized when the subject's eye is in a predetermined deformation state (for example, applanation state).

[0047] This corneal deformation detection optical system also serves as a part of the first working distance detection optical system, and the light projecting optical system of the first working distance detection optical system also serves as the light projecting optical system 500a of the corneal deformation detection optical system. The light receiving optical system 600b that receives the light reflected by the cornea Ec from the light source 50 has, for example, the lens 53, beam splitter 58, condenser lens 59, and position detection element 60 of the light projecting optical system 500a, and forms an optical axis L2 as a light receiving optical axis.

[0048] 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 enters 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, so that the control circuit 20 obtains working distance information based on the output signal from the position detection element 60. Note that the output signal from the position detection element 60 in this embodiment is used for alignment (coarse adjustment) in the working distance direction (Z direction). The light receiving optical system 600b of the first working distance detection optical system does not have a magnification as large as the light receiving optical system 70b described later. Therefore, the distance detection range of the position detection element 60 in the Z direction is wider than that of the light receiving element 77.

[0049] The corneal thickness measuring optical system includes a light projecting optical system 70a, a light receiving optical system 70b, and a fixation optical system 48, and is used to measure the corneal thickness of the subject's eye E. The light projecting optical system 70a also serves as a part of the corneal deformation detecting optical system and the first working distance detecting optical system.

[0050] The light projection optical system 70a has an optical axis L2 as a light projection optical axis, and irradiates illumination light (measurement light) from an oblique direction toward the cornea Ec of the eye E. The light projection optical system 70a has, for example, an illumination light source 71, a condenser lens 72, a light limiting member 73, a concave lens 74, and a lens 53 that also serves as the corneal deformation detection optical system. A visible light source or an infrared light source (including near-infrared) is used as the illumination light source 71, and light sources such as an LED or a laser are used. The condenser lens 72 condenses the light emitted from the light source 71. Note that the light source 50 and the light source 71 each use a wavelength band.

[0051] 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 that is 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 forms a predetermined pattern light beam (for example, a spot light beam, a slit light beam) on the cornea of ​​the eye E.

[0052] The light receiving optical system 70b has a light receiving element 77, and receives the illumination light reflected by the front and back surfaces of the cornea of ​​the eye E. The light receiving optical system 70b is disposed approximately symmetrically with the light projecting optical system 70a with respect to the optical axis L1. The light receiving optical system 70b has, for example, a light receiving lens 75, a concave lens 76, and a light receiving element 77, and forms an optical axis L3 as a light receiving optical axis. The light receiving optical system 70b in Fig. 6 also serves as a second working distance detection optical system that detects the alignment state in the Z direction with respect to the eye E.

[0053] The light receiving element 77 has a plurality of photoelectric conversion elements and receives reflected light from the front and back surfaces of the cornea. For example, a light detection device such as a one-dimensional line sensor or a two-dimensional area sensor is used for the light receiving element 77. The light receiving optical system 70b of the corneal thickness measurement optical system and the second working distance detection optical system performs observation with a large magnification. Therefore, the distance detection range in the Z direction of the light receiving element 77 is narrower than that of the position detection element 60.

[0054] When the subject's eye E (cornea Ec) moves in the working distance direction (Z direction), the reflected light of the light source 71 on the cornea Ec also moves on the light receiving element 77, so that the control unit 80 obtains working distance information based on the output signal from the light receiving element 77 of the second working distance detection optical system. In addition, the control unit 80 knows the state of corneal deformation and blinking of the subject's eye E from the output signal from this light receiving element 77, and controls the drive of the solenoid 203.

[0055] Light emitted from an illumination light source 71 is collected by a collecting lens 72 and illuminates a light limiting member 73 from behind. Then, the light from the light source 71 is limited by the light limiting member 73, and then focused (collected) 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 imaged near the intersection with the visual axis on the cornea Ec.

[0056] When illumination light is projected onto the cornea Ec by the light projection optical system 70a, the illumination light reflected by 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 imaged on the light receiving surface of the light receiving element 77 by the light receiving lens 75.

[0057] In addition, the lens 53, which is used both in the receiving optical system 500b, 600b and the projecting optical system 70a, is positioned so as to focus the light reflected from the cornea Ec by the light source 50 at the center of the hole in the pinhole plate 56, and to focus the illumination light from the light source 71 on the front and back surfaces of the cornea Ec.

[0058] The face photographing unit 90 is, for example, an optical system for photographing a face including at least one of the left and right eyes to be examined. For example, as shown in FIG. 4, the face photographing unit 90 of this embodiment mainly includes, for example, an image sensor 91 and an image pickup lens 92.

[0059] The face photographing unit 90 is provided at a position where both eyes of the subject can be photographed when the measurement unit 100 is at the initial position, for example. In this embodiment, the initial position of the measurement unit 100 is set at a position shifted to the right with respect to the optical axis L1 of the measurement unit 100 so as to make it easier to examine the right eye. Therefore, the face photographing unit 90 is provided at a position where both eyes of the subject can be photographed when the measurement unit 100 is at the initial position shifted to the right. For example, the face photographing unit 90 is disposed at the machine center when the measurement unit 100 is at the initial position. When the initial position is set based on, for example, half the interpupillary distance, that is, the interpupillary distance of one eye, the face photographing unit 90 may be disposed at a position shifted to the left or right by the interpupillary distance of one eye with respect to the machine center of the device body.

[0060] The face photographing unit 90 of this embodiment is moved together with the measurement unit 100 by the driving unit 4. Of course, the face photographing unit 90 may be configured to be fixed to the base 2 and not move, for example.

[0061] The imaging lens 92 may be, for example, a wide-angle lens. The wide-angle lens is, for example, a fisheye lens, a conical lens, etc. By providing a wide-angle lens, the face imaging unit 90 can capture an image of the subject's face with a wide angle of view.

[0062] <Control system> As shown in FIG. 2, the non-contact tonometer 1 includes a control unit 80. The control unit 80 controls various aspects of the non-contact tonometer 1. The control unit 80 is, for example, a processor. The control unit 80 includes, for example, a general CPU (Central Processing Unit) 81, a ROM 82, a RAM 83, and the like. For example, the ROM 82 stores a non-contact tonometer control program for controlling the non-contact tonometer 1, initial values, and the like. For example, the RAM 83 temporarily stores various information. The control unit 80 is connected to the measurement unit 100, the face photographing unit 90, the driving unit 4, the display unit 85, the operation unit 86, the chin rest driving unit 3d, a storage unit (for example, a non-volatile memory) 84, and the like. The storage unit 84 is, for example, a non-transient storage medium that can retain the stored contents even if the power supply is cut off. For example, a hard disk drive, a removable USB flash memory, and the like can be used as the storage unit 84.

[0063] <Control action> The control operation of the non-contact tonometer having the above-mentioned configuration will be described.

[0064] <Alignment> First, the measurement unit 100 is aligned with the subject's eye. For example, the examiner supports the subject's face on the face support unit 3. For example, the examiner operates the display unit 81 and selects a switch (not shown) for performing alignment. For example, the control unit 80 executes alignment control based on an input signal from the display unit 81.

[0065] For example, the control unit 80 photographs the subject's face using the face photographing optical system 90 and acquires a face photographed image. For example, the control unit 80 detects the subject's eye from the acquired face photographed image. The control unit 80 moves the measurement unit 100 based on position information of the subject's eye detected from the face photographed image. For example, the control unit 80 determines a straight line on which the subject's eye exists based on the coordinates of the subject's eye on the face photographed image, and moves the measurement unit 100 along the straight line (for example, see JP 2017-064058 A).

[0066] When the position of the measurement unit 100 relative to the subject's eye is adjusted to a certain extent and the anterior segment of the subject's eye can be photographed by the observation optical system 130, the control unit 80 moves the measurement unit 100 as a unit based on the anterior segment image. For example, the control unit 80 obtains alignment information (information on the positional deviation between the measurement unit 100 and the subject's eye, etc.) by pupil detection or bright spot detection in the anterior segment image, and aligns the measurement unit 100 with the subject's eye. When the alignment is completed, the examiner operates the operation unit 86 (or the control unit 80 automatically issues a measurement start signal based on a signal from the alignment optical system) to start the measurement.

[0067] <Corneal thickness measurement> The control unit 80 measures the corneal thickness of the subject's eye using the corneal thickness measurement optical system based on the measurement start signal. The control unit 80 calculates the distance (peak-to-peak distance) between the reflected signal from the anterior surface of the cornea and the reflected signal from the posterior surface of the cornea detected by the light receiving element 77.

[0068] <Intraocular pressure measurement> When the measurement of the corneal thickness is completed, the control unit 80 measures the intraocular pressure. For example, when the control unit 80 drives the solenoid 203 to move the piston 202, the air in the cylinder 201 is compressed, and the compressed air is blown from the nozzle 206 toward the cornea Ec. The cornea Ec gradually deforms as the compressed air is blown, and when it reaches a flat (or applanated) state, the maximum amount of light is incident on the photodetector 57. The control unit 80 determines the intraocular pressure value based on the output signal from the pressure sensor 212 and the output signal from the photodetector 57. Then, the measurement result is displayed on the display unit 85. Here, when a predetermined measurement end condition is satisfied, the intraocular pressure measurement of the subject eye is completed.

[0069] <Result output> When the measurement is completed, the control unit 80 outputs the data of the measurement result. For example, the control unit 80 displays the measurement result on the display unit 85, prints it out, or outputs it to the outside of the device wirelessly or via wire. When the data output is completed, the control unit 80 ends the process.

[0070] As described above, for example, in the non-contact tonometer of this embodiment, in the fluid ejection means for ejecting fluid through a nozzle onto the cornea of ​​the subject's eye, the tube member constituting the flow path through which the fluid is ejected from the container to the airtight chamber is formed by connecting a straight section and a bent section, the straight section having a first material, and the bent section having a second material having a higher rigidity than the first material. For example, in contrast to a conventional tube member (e.g., a metal tube member, etc.) that is uniformly formed from a material with a high rigidity, the straight section can be formed from a material with a low rigidity, thereby reducing costs. In addition, by making the bent section from a material with a high rigidity, the loss of the fluid can be reduced even if the flow path is bent in any direction, and the device can be made space-saving. Therefore, the device configuration of this embodiment can appropriately spray a predetermined amount of fluid onto the subject's eye. Furthermore, since the flow path can be bent in any direction, the device can be made space-saving.

[0071] Also, for example, in the non-contact tonometer of this embodiment, the bent portion of the tubular member has a rigidity that prevents the diameter of the flow path from being deformed even when a force is applied to the tubular member. For example, when the diameter of the flow path is deformed by wind pressure when the fluid passes from the storage portion through the airtight chamber, or when the diameter of the flow path is deformed by external pressure, loss of fluid is likely to occur. However, for example, by configuring the bent portion with a rigidity that can withstand wind pressure or external pressure, it is possible to send the fluid to the nozzle while suppressing loss of the fluid.

[0072] In addition, for example, in the non-contact tonometer of this embodiment, the straight section and the bent section of the tubular member are made of different materials. For example, different materials can be appropriately selected for the straight section and the bent section depending on the shape of the flow path of the tubular member, and the materials can be combined to have different rigidities, which can lead to lower costs, reduced fluid loss, and the like.

[0073] Also, for example, in a non-contact tonometer, the straight section of the tubular member is made of silicone. For example, wind pressure of the fluid or external pressure is less likely to be applied to the straight section, and the diameter of the flow path is less likely to deform than in the bent section. Also, for example, silicone is often less rigid and less expensive than metals, etc. Therefore, by forming the straight section from silicone, it is possible to reduce fluid loss and costs.

[0074] <Example of transformation> In the non-contact tonometer of this embodiment, the tubular member 270 has been described as having one straight portion 271 and one bent portion 272, but the present invention is not limited thereto. For example, the tubular member 270 may have a plurality of straight portions or a plurality of bent portions. Even in such a case, for example, by appropriately combining silicone or a resin molded product so that the bent portion has a stronger rigidity than the straight portion, it is possible to reduce the cost and space of the device while reducing air loss.

[0075] In the non-contact tonometer of this embodiment, a configuration in which the bent portion 272 of the tubular member 270 and the airtight chamber 221 are provided separately has been described as an example, but the present invention is not limited to this. For example, the bent portion 272 of the tubular member 270 and the airtight chamber 221 may be configured to be integrally formed. As an example, the bent portion 272 and the airtight chamber 221 may be injection molded from the same resin. For example, when there is no straight portion between the bent portion 272 and the airtight chamber 221, or when the straight portion between the bent portion 272 and the airtight chamber 221 is short, the bent portion 272 and the airtight chamber 221 may be integrally formed to reduce costs.

[0076] In the non-contact tonometer of this embodiment, the straight portion 271 and the bent portion 272 of the tubular member 270 are formed from different materials, but the present invention is not limited to this. For example, the straight portion 271 and the bent portion 272 of the tubular member 20 may be formed from the same material. In this case, for example, it is preferable to form the straight portion 271 and the bent portion 272 from the same material while making the rigidity of each portion different.

[0077] This will be described by taking as an example a case where both the straight portion 271 and the bent portion 272 of the tube member 270 are made of silicone. For example, the straight portion 271 and the bent portion 272 may be silicone tubes. However, for example, if a silicone tube is used for the bent portion 272, when the tube is bent so that the bent portion 272 has a predetermined shape, the diameter of the air flow path is crushed and deformed. This problem is particularly likely to occur with soft silicone tubes. For this reason, for example, the rigidity of the bent portion 272 may be made different from that of the straight portion 271 so as to suppress deformation of the diameter of the air flow path due to bending. As an example, the rigidity may be made different by using silicone tubes with different hardness. Also, as another example, the rigidity may be made different by making the plate thickness (wall thickness) of the silicone tube different.

[0078] Also, for example, in the non-contact tonometer of this embodiment, the straight section and the bent section of the tubular member are formed from the same material. For example, by forming and combining the straight section and the bent section of the tubular member from the same material but with different rigidity, it is possible to reduce costs, reduce fluid loss, etc. As an example, when forming the straight section and the bent section of the tubular member from the same resin, at least one of the types of additives or plasticizers, or the mixing ratio of additives or plasticizers, etc., is made different between the straight section and the bent section to change the hardness, which can lead to reduced costs, reduced fluid loss, etc.

[0079] In the non-contact tonometer of this embodiment, when aligning the measurement unit 100 with the subject's eye, the fluid discharge unit 200 and the measurement optical system 10 are moved together as an integral unit, but the present invention is not limited to this. For example, when the straight portion 271 (see FIG. 4) of the tube member 270 is formed of a silicone tube, a part of the fluid discharge unit 200 and the measurement optical system 10 may be moved together as an integral unit. For example, the part of the fluid discharge unit 200 may be the tip of the fluid discharge unit 200 (for example, the nozzle 206, the airtight chamber 221, and the bent portion 272 connected to the airtight chamber 221).

[0080] FIG. 5 is a diagram showing an example in which the tip of the fluid discharge unit 200 and the measurement optical system 10 move together. For example, as shown by the solid line in FIG. 5, when the intraocular pressure measurement of the subject's eye is not performed, the straight part 271 of the tube member 270 may be stored in the measurement unit 100 in a folded state. For example, since the straight part 271 is a silicone tube, the shape of the straight part 271 can be easily deformed. For example, as shown by the dotted line in FIG. 5, when the intraocular pressure measurement of the subject's eye is performed, the tip 280 of the fluid discharge unit 200 and the measurement optical system 10 are moved forward (toward the subject's eye) by a driving unit (not shown). The storage unit 260 is fixed at a predetermined position and does not move. Therefore, the straight part 271 changes from a folded shape to a straight shape, and compressed air can be smoothly sent during intraocular pressure measurement. For example, when the intraocular pressure measurement of the subject's eye is completed, the tip 280 and the measurement optical system 10 are moved backward (toward the storage unit 260) again. For example, this eliminates the need for a large-scale moving mechanism compared to the case where the fluid discharge unit 200 of the measurement unit 100 and the measurement optical system 10 are moved together, simplifying the configuration of the device and thus reducing the space required for the device.

[0081] Of course, by configuring only the tip of the fluid ejection section 200 to move in the forward and backward directions and by fixing the measurement optical system 10, the shape of the straight section 271 can be changed when measuring the intraocular pressure of the test eye, thereby allowing the intraocular pressure to be measured. [Explanation of symbols]

[0082] 1. Non-contact tonometer 80 Control section 100 Measuring part 200 Fluid discharge section 201 Cylinder 202 Piston 203 Solenoid 206 Nozzle 221 Airtight Room 260 Storage unit 270 Pipe members

Claims

1. In a non-contact tonometer that measures the intraocular pressure of the eye being examined without contact, It comprises a housing for housing a cylinder and a piston for compressing a fluid, an airtight chamber for housing the fluid compressed by the cylinder and the piston, and a nozzle connected to the airtight chamber, and is equipped with a fluid discharge means for discharging the fluid through the nozzle to the cornea of ​​the eye under examination, The pipe member constituting the flow path through which the fluid is discharged from the containment to the airtight chamber is formed by connecting a straight section and a bent section. The straight section has a first material, The bent portion has a second material which is more rigid than the first material. A non-contact tonometer characterized by the following features.

2. In the non-contact tonometer of claim 1, The non-contact tonometer is characterized in that the bent portion has rigidity such that the diameter of the flow path does not deform even when force is applied to the tube member.

3. In the non-contact tonometer of claim 1 or 2, A non-contact tonometer characterized in that the straight portion and the bent portion are formed from different materials.

4. In the non-contact tonometer of claim 1 or 2, A non-contact tonometer characterized in that the straight portion and the bent portion are formed from the same material.

5. In the non-contact tonometer of claim 1, A non-contact tonometer characterized in that the linear portion is formed of silicone.

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