ophthalmic devices

Abstract

To furthermore simplify and reduce cost, in an ophthalmologic apparatus having a mechanism for blowing gas into an eye.SOLUTION: An ophthalmologic apparatus 300 includes a piston 103 for pushing out gas to be blown into a subject eye, a cylinder 101 for storing the piston 103 inside, a coil spring 104 for showing force for pushing the piston 103 towards the back of the cylinder 101, a spring fixed wall 106 in contact with the opposite side to the piston 103 of the coil spring 104, and a movement mechanism using a trapezoidal thread 107 capable of moving the spring fixed wall 106 in the axial direction of the piston 103.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ophthalmic apparatus. [Background technology]

[0002] There is known an ophthalmic device that blows gas onto an eye to deform the eyeball of the eye, optically measures the degree of deformation, and measures intraocular pressure (see, for example, Patent Document 1). This ophthalmic device requires a mechanism for blowing gas onto the eye (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6797048 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-237516 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for simplification and cost reduction in the mechanism for blowing gas onto the subject's eye. In this context, an object of the present invention is to provide a technology that achieves further simplification and cost reduction in an ophthalmic apparatus having a mechanism for blowing gas onto the eye. [Means for solving the problem]

[0005] The present invention is an ophthalmic device comprising a piston that pushes out gas to be sprayed onto the subject's eye, a cylinder that houses the piston inside, a spring that exerts a force that pushes the piston toward the back of the cylinder, a spring fixing member in contact with the side of the spring opposite the piston, and a moving mechanism that can move the spring fixing member in the axial direction of the piston.

[0006] In the present invention, the piston is fixed to a piston shaft, a first stopper is fixed to the piston shaft, and a second stopper is fixed to the cylinder, and the movement of the piston relative to the cylinder is restricted by the first stopper coming into contact with the second stopper.

[0007] In one embodiment of the present invention, the top dead center of the piston is determined by the positional relationship between the first stopper and the second stopper. In another embodiment of the present invention, the piston is fixed to a piston shaft and includes a linear motion mechanism that linearly moves the piston shaft in the axial direction.

[0008] In the present invention, an example of an embodiment is where the piston shaft is moved away from the cylinder by the linear motion mechanism, thereby storing a repulsive force in the spring, and the piston is released from the constraint of the linear motion mechanism, causing the piston to be pushed into the cylinder by the repulsive force of the spring.

[0009] In the present invention, the linear motion mechanism includes a rack provided on the piston shaft and a piston engaged with the rack. D On and D and a driving means for rotating the pin. D On has a part where no teeth are provided, and D In the process of rotating the on, the pin D The engagement between the ON and the rack is released, and the repulsive force of the spring is released, causing the piston to be pushed into the cylinder by the spring.

[0010] In the present invention, the motor may further include a motor that drives the moving mechanism and the linear motion mechanism, a first one-way clutch that transmits rotation of the motor in a first rotational direction, and a second one-way clutch that transmits rotation of the motor in a second rotational direction opposite to the first rotational direction, wherein the moving mechanism is driven by the rotation in the first rotational direction transmitted from the first one-way clutch, and the linear motion mechanism is driven by the rotation in the second rotational direction transmitted from the second one-way clutch.

[0011] In the present invention, when the piston cannot be pushed any further into the cylinder, the spring force acts on the piston, and this force is adjusted by varying the position of the spring fixing member in the axial direction of the piston, and this adjustment sets the momentum of the gas blown onto the test eye.

[0012] In the present invention, the moving mechanism may be a ball screw mechanism, a feed screw mechanism, a rack pin mechanism, or the like. D An example of the present invention is an embodiment in which the device further includes a means for detecting reflected light irradiated onto the subject's eye, and the spring fixing member is moved in the axial direction of the piston based on the detection of the reflected light.An example of the present invention is an embodiment in which the device further includes a hand for detecting reflected light irradiated onto the subject's eye, and the movement of the piston is stopped based on the detection of the reflected light. [Effects of the Invention]

[0013] According to the present invention, it is possible to realize a simpler and more cost-effective ophthalmic apparatus having a mechanism for blowing gas onto the eye. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a conceptual diagram of an embodiment. [Figure 2] FIG. 1 is a conceptual diagram of an embodiment. [Figure 3] FIG. 1 is a conceptual diagram of an embodiment. [Figure 4] 10 is a graph showing characteristics of the embodiment. [Figure 5] FIG. 1 is a conceptual diagram of an embodiment. [Figure 6] FIG. 1 is a conceptual diagram of an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. First embodiment (composition) 1 shows an ophthalmic apparatus 300. The ophthalmic apparatus 300 measures the intraocular pressure of a subject's eye. The ophthalmic apparatus 300 includes a driving unit 100 that generates high-pressure air and a measuring unit 200 that performs optical measurements necessary to measure the intraocular pressure of the subject's eye. Based on the measurements by the measuring unit 200, a measuring unit 207 performs processing related to measuring the intraocular pressure of the subject's eye.

[0016] The drive unit 100 includes a cylinder 101. The cylinder 101 is fixed to a housing of the ophthalmologic device 300 (not shown). The cylinder 101 has a cylindrical shape, and an air outlet 102 is provided at one end (the left end in FIG. 1) thereof, and the other end (the right end in FIG. 1) is open. A piston 103 is inserted into the cylinder 101 from the open end thereof in a slidable manner.

[0017] One end of a coil spring 104 contacts the piston 103, and a piston shaft 105 is fixed to the piston 103. The piston shaft 105 is disposed so as to be housed inside the coil spring 104. The piston shaft 105 is movable together with the piston 103 in the axial direction of the cylinder 101.

[0018] The other end of the coil spring 104 is in contact with a spring fixing wall 106. The spring fixing wall 106 is movable in the axial direction (movement direction) of the piston 103, and has a semi-fixed structure that can fix its position.

[0019] That is, the spring fixing wall 106 has a female screw portion, and a trapezoidal screw (screw rod) 107 engages with this female screw portion to form a ball screw mechanism or a feed screw mechanism. The trapezoidal screw 107 is driven to rotate by a drive motor 108. The drive motor 108 is fixed to the housing of the ophthalmic device 300 (not shown). When the drive motor 108 is rotated, the trapezoidal screw 107 rotates, and the spring fixing wall 106 moves in the axial direction of the piston shaft 105. Furthermore, when the rotation of the drive motor 108 is stopped, the position of the spring fixing wall 106 is fixed due to the principle of the feed screw mechanism.

[0020] Reference numeral 115 denotes a sensor that measures the initial position of the spring fixing wall 106. In this example, the drive motor 108 is a stepping motor, and the amount of displacement of the spring fixing wall 106 from its initial position is measured from the amount of rotation thereof, thereby measuring the position of the spring fixing wall 106. The method for measuring the position of the spring fixing wall 106 is not limited to the above example, and other methods include measurement using a linear displacement sensor or the like.

[0021] 1, that is, when the piston 103 is pushed all the way into the cylinder 101, the coil spring 104 is compressed to a certain extent, and urges the piston 103 toward the back of the cylinder 101 (toward the air exhaust port 102). The degree of compression can be controlled by adjusting the position of the spring fixing wall 106.

[0022] A stopper 109 is fixed to the piston shaft 105, and a stopper 110 is fixed to the housing of the device (not shown). The contact between the stopper 109 and the stopper 110 reduces the impact when the cylinder 101 contacts the deep part of the piston 103. For example, the occurrence of the above impact can be suppressed by adjusting the positional relationship between the stoppers 109 and 110 so that the stoppers 109 and 110 contact each other at the very edge of the position where the cylinder 101 contacts the deep part of the inside of the piston 103 (the left end in FIG. 1). In addition, the occurrence of the above impact can be prevented by adjusting the positional relationship between the stoppers 109 and 110 so that the cylinder 101 cannot contact the deep part of the inside of the piston 103 (the left end in FIG. 1).

[0023] The contact between stopper 109 and stopper 110 may be made via an elastic body such as rubber, which can reduce the impact when stopper 109 and stopper 110 come into contact with each other, and can suppress the generation of vibrations and noise when the impact occurs.

[0024] Stoppers 109 and 110 limit the relative position of piston 103 when it is pushed into cylinder 101. Stoppers 109 and 110 also determine the top dead center of piston 103 (the position at which piston 103 cannot be pushed any further into cylinder 101).

[0025] A rack (tooth rod) 111 is arranged on the piston shaft 105. D On (gear) 112 is engaged. D The pin 112 does not have teeth formed all around, and there are some areas where there are no teeth. D The pin 112 is driven and rotated by a drive motor 113. D The rotation angle of the ON 112 is detected by a Hall IC 116 .

[0026] By setting the range of this toothless portion, it is possible to determine how far the rack 111 is driven, that is, how far the piston 103 is pulled in the right direction in the drawing.

[0027] For example, D When the rack 111 moves with the rotation of the pin 112, the rack 111 and the pin D The engagement of the on-112 is maintained over a relatively long distance. D Setting the range of the teeth of ON 112 results in a setting that allows the piston 103 (piston shaft 105) to be pulled out from the cylinder 101 for a longer period.

[0028] Conversely, D When the rack 111 moves with the rotation of the pin 112, the rack 111 and the pin D The engagement of the on-112 continues over a relatively short distance. DBy setting the range of the teeth of ON 112, the distance that the piston 103 (piston shaft 105) is pulled out from the cylinder 101 becomes shorter.

[0029] In other words, D By adjusting the range in which the teeth of the on 112 are formed, it is possible to adjust the setting of how far the piston 103 is pulled out, in other words, how far the coil spring 104 is compressed.

[0030] The measurement unit 200 includes a chamber 201, a pressure sensor 202, a nozzle 203, a light-transmitting window 204, an optical unit 205, and an optical filter 206. Compressed air pushed out by the piston 103 is sent into the chamber 201. The pressure inside the chamber 201 is measured by the pressure sensor 202. The compressed air sent into the chamber 201 from the drive unit 100 is sprayed from the nozzle 203 onto the subject's eye.

[0031] The optical unit 205 has a light-emitting element and its optical system for irradiating the measurement light onto the subject's eye, and a light-receiving element and its optical system for receiving the measurement light reflected from the subject's eye. The measurement light emitted from the optical unit 205 passes through an optical filter 206 and an optical window 204 and is irradiated onto the subject's eye. The reflected light from the subject's eye travels the reverse path of the measurement light, enters the optical unit 205, and is detected by the light-receiving element.

[0032] The pressure of the air sprayed from the nozzle 203 deforms the eyeball of the subject's eye, causing the amount of reflected light to change. Specifically, the eyeball changes from convex to flat to concave, and the amount of reflected light increases, reaches a maximum value, and decreases. This change in light amount is detected by a light-receiving element.

[0033] The relationship between the detected light intensity and intraocular pressure is acquired in advance as basic data using a standard eye model. In measuring intraocular pressure, the intraocular pressure of the subject's eye is calculated based on the detected light intensity and the basic data. This process is performed by the measurement unit 207. There are various methods for measuring intraocular pressure, but the method is not limited to a specific method.

[0034] (Basic operation) The drive motor 113 D When the spring 112 is rotated clockwise in FIG. 1, the rack 111 is driven in a direction away from the cylinder 101 (to the right in FIG. 1), and the piston 103 moves in the direction of the spring fixing wall 106. As the piston 103 moves in the direction of the spring fixing wall 106, the compression of the coil spring 104 progresses, and the repulsive force of the coil spring 104 increases. This state is shown in FIG. 2. Furthermore, as the piston 102 is pulled out of the cylinder 101, a space 120 is formed.

[0035] Pi D When the pin 112 rotates to a certain extent and reaches a part without teeth, D The engagement between the on 112 and the rack 111 is released, D The constraint of the rack 111 (piston 103) by the on 112 is released. As a result, the piston 102 is pushed toward the back of the cylinder 101 by the repulsive force of the coil spring 104, and the air in the space 120 in FIG. 2 is pushed toward the back of the cylinder 101 by the piston 102, and the air is ejected from the air outlet 102. The air ejected from this cylinder 101 is sent into the chamber 201, and is finally ejected from the nozzle 203 toward the eye to be examined.

[0036] To inject more powerful air, the position of the spring fixing wall 106 is moved closer to the cylinder 101 (see FIG. 3). This causes the coil spring 104 to be compressed more when the piston 103 is pushed into the cylinder to its maximum extent. When the piston shaft 105 is then pulled out of the cylinder 101, an even stronger repulsive force than in the case of FIG. 2 is stored in the coil spring 104. This allows for a stronger injection of air. The pressure of the injected air needs to be adjusted according to the intraocular pressure of the subject's eye, and the above configuration makes it easy to accommodate this by changing the position of the spring fixing wall 106.

[0037] (characteristic) Fig. 4 shows the characteristics of the present embodiment 1, the present embodiment 2, the conventional example 1, and the conventional example 2. In the present embodiment 1, the biasing force of the coil spring is set to be small (see Fig. 1), and in the present embodiment 2, the biasing force of the coil spring is set to be large (see Fig. 3). The characteristics of the present embodiment 1 and the present embodiment 2 are theoretical values. The conventional examples 1 and 2 are characteristics when the piston is driven by a rotary solenoid.

[0038] When driving using the repulsive force of a coil spring, the piston position u is expressed as u = uma x cos(ωt), where k is the spring constant, m is the mass of the piston and piston shaft, and ω = (k / m). The piston velocity v is v = -uma x ω cos(ωt), and the piston angular velocity a = -uma x ω2 cos(ωt).

[0039] As shown in Figure 4, when the piston is driven using the present invention, the piston movement starts up faster and has better responsiveness than when driven using a conventional rotary solenoid. This is because, in principle, the piston movement starts up faster when driven by the repulsive force of the coil spring, as shown in the above formula, than when driven by electromagnetic force.

[0040] Intraocular pressure is measured by aligning the measuring device with the subject's eye, then blowing air onto the eye and optically measuring the deformation of the eyeball that occurs. However, the eyeball moves slightly, and the position and direction of the face are not strictly constant (for example, it can move due to breathing or palpitations). Therefore, it is desirable to move quickly from alignment to measuring intraocular pressure without delay.

[0041] When driving using electromagnetic force such as a rotary solenoid, it takes time to start up, as shown in Figure 4, which can lead to misalignment and affect measurement accuracy. The present invention has good responsiveness, so this problem can be alleviated.

[0042] (superiority) This embodiment has a simple structure. In addition, the spray air pressure can be varied with a simple structure. In addition, the pin with the tooth formation position adjusted can be used. D The mechanism that pulls the piston shaft when turned on does not require complex drive control, as the piston is driven by a spring when the teeth disengage.

[0043] 2. Second embodiment In FIG. 5, the spring fixing wall 106 is D In this example, a longitudinal driving member 117 is fixed to the spring fixing wall 106, and a rack 118 is provided on the driving member 117. D On gear 119 engages and D The on gear 119 is driven by a motor 121. D The rotation angle of the on gear 119 is detected by a Hall IC 120 using a Hall element.

[0044] Motor 121 drives D When you rotate the on gear 119, D The on gear 119 drives the rack 118, causing the drive member 117 to move in the axial direction of the piston 103, thereby adjusting the position of the spring fixing wall 106.

[0045] 3. Third embodiment (composition) 6 shows a configuration in which one motor drives the piston and adjusts the position of the spring fixing wall. In this example, a longitudinal driving member 131 is fixed to the spring fixing wall 106, and a rack 132 is provided on the driving member 131. The rack 132 has a piston D On gear 133 engages and D The shaft of the on gear 133 extends in the depth direction of the drawing, and a wheel gear 134 is fixed to the shaft. The wheel gear 134 meshes with a worm 135 having a helical thread structure, and the shaft of the worm 135 is connected to a pulley 137 via a one-way clutch 136.

[0046] The pulley 137 is driven by a drive belt 138. The drive belt 138 is driven by a drive pulley 139 driven by the motor 130. The drive belt 138 also drives a pulley 141. The shaft of the pulley 141 is connected to a worm 143 via a one-way clutch 142. The worm 143 is engaged with a wheel gear 144, and the wheel gear 144 and the D The gear 145 is coaxial, and when the wheel gear 144 rotates, D On gear 145 also rotates. D The on gear 145 meshes with a rack 146 disposed on the piston shaft 105 .

[0047] (Adjusting the position of the spring fixing wall) The operation will be explained below. Here, the rotation of the motor 130 will be considered as viewed from the right side of the drawing. Also, it is assumed that the one-way clutch 136 transmits only clockwise rotation, and the one-way clutch 142 transmits only counterclockwise rotation. The right and left rotation directions will be considered as viewed from the right side of the drawing.

[0048] When the motor 130 is rotated clockwise, the clockwise rotation is transmitted from the one-way clutch 136 to the worm 135, causing the worm 135 to rotate clockwise. Then, the wheel gear 133 meshed with the worm 135 rotates clockwise, and at the same time, the pin D The on gear 133 also rotates clockwise. Note that the one-way clutch 142 does not transmit clockwise rotation, so in this case, the pulley 141 rotates clockwise but no driving force is transmitted to the worm 143.

[0049] As a result, the rack 132 is driven to the left, and the driving member 131 moves toward the cylinder 101. This causes the spring fixing wall 106 to move toward the cylinder 101, and the coil spring 104 is compressed. D On gear 133 has some parts where the teeth are not formed, D When the on gear 133 rotates to the right to some extent, D The on gear 133 and the rack 132 are disengaged, and the spring fixing wall 106 returns to the stopper 110 due to the repulsive force of the coil spring 104 .

[0050] Pi D Even if the rotation of the on gear 133 is stopped midway, the position of the spring fixing wall 106 is fixed by the meshing of the worm 135 and the wheel gear 134. In this way, the position of the spring fixing wall 106 can be adjusted by rotating the motor 130 clockwise.

[0051] (piston drive) When the motor 130 is rotated counterclockwise, the pulley 141 rotates counterclockwise. At this time, the one-way clutch 136 does not transmit the counterclockwise rotation, so the pulley 137 also rotates counterclockwise, but no driving force is transmitted to the worm 135.

[0052] When the pulley 141 rotates counterclockwise, a rotational force is transmitted to the worm 143 via the one-way clutch 142, causing the worm 143 to rotate counterclockwise. When the worm 143 rotates counterclockwise, the wheel gear 144 rotates clockwise, and at the same time, the pin D On gear 145 rotates to the right.

[0053] Pi D When the on gear 145 rotates to the right, the rack 146 moves to the right (away from the cylinder 101), the piston shaft 105 moves away from the cylinder 101, and the piston 103 moves in a direction to be pulled out of the cylinder 101. This causes the coil spring 104 to be compressed.

[0054] Pi D On Gear 145 has some parts where the teeth are not formed, D When the on gear 145 rotates to the right to some extent, D The on gear 145 and the rack 146 are disengaged, and the repulsive force of the compressed coil spring 104 pushes the piston 103 toward the back of the cylinder 101. This causes air to be ejected from the air outlet 102. In this way, the air is ejected by the counterclockwise rotation of the motor 130.

[0055] (superiority) A single driving means (motor 130) can adjust the force of the gas being ejected by adjusting the position of the spring fixing wall, and drive the piston for the ejection operation. Because the number of motors is reduced, the driving mechanism can be simplified, the overall structure can be made smaller, and power consumption can be reduced.

[0056] 4. Fourth Embodiment When the spring constant of the coil spring 104 changes, the pressure of the air blown onto the subject's eye also changes. For example, if the spring force weakens, the pressure of the air blown onto the subject's eye decreases. In this case, the reduced air pressure can be restored by moving the spring fixing wall 106 toward the cylinder 101 and compressing the coil spring 101 further.

[0057] For example, calibration is performed periodically using a standard eye model. At this time, control is performed to adjust the position of the spring fixing wall 106 so that the obtained measurement value becomes the standard value. For example, in the case of FIG. 1, the position of the spring fixing wall 106 is adjusted by the motor 108 so that the measurement value becomes the standard value. This makes it possible to maintain the accuracy and reliability of the intraocular pressure measurement value.

[0058] 5. Fifth Embodiment It is desirable to stop blowing the high-pressure air when the reflection of the measurement light from the subject's eye reaches a predetermined intensity in order to avoid unnecessary strain on the subject's eye.

[0059] A method for achieving this object will be described below. For example, a control valve is provided in the cylinder 102, and the control valve is opened and closed based on a detection signal of reflected light. In this case, the control valve is opened when a predetermined detection level of reflected light is obtained. This reduces the pressure in the chamber 201, and unnecessary injection of high-pressure air toward the subject's eye can be stopped.

[0060] It is also possible to stop the injection of air into the subject's eye by stopping the movement of the piston 103 midway. For example, the movement of the piston shaft 105 is stopped by braking when a predetermined detection level of reflected light is obtained. Specifically, there are a method of stopping the moving piston shaft 105 by using a friction brake means, a method of stopping the moving piston shaft 105 by meshing with a gear, a method of inserting an obstacle in the movement path of the stopper 109 to limit or stop its movement, and the like.

[0061] 6. Other embodiments The gas may be a gas other than air, or may be gas stored in a cylinder. A check valve may be provided on the piston so that air is supplied into the cylinder when the piston is pulled out of the cylinder.

[0062] The mechanism for moving the piston shaft 105 is not limited to the illustrated one, and an electromagnetic solenoid or various linear actuators can be used. It is also possible to manually pull the piston shaft 105. For example, it is possible to manually pull the piston shaft 105 out of the cylinder 101, fix it in that state with a hook or the like, and then release the hook to allow the repulsive force of the coil spring 104 to cause the piston shaft 105 to plunge into the cylinder 101.

[0063] It is also possible to have a structure in which the position of the spring fixing wall 106 can be manually adjusted. For example, in the structure of Fig. 1, it is possible to have a structure in which the trapezoidal screw 107 can be manually rotated.

Claims

1. a piston that pushes out gas to be blown onto the subject's eye; a cylinder containing the piston; a spring that exerts a force that pushes the piston toward the back of the cylinder; a spring fixing member in contact with the side of the spring opposite to the piston; a movement mechanism capable of moving the spring fixing member in the axial direction of the piston; An ophthalmic device comprising:

2. The piston is fixed to a piston shaft, a first stopper fixed to the piston shaft; a second stopper fixed to the cylinder; The ophthalmic apparatus according to claim 1 , wherein the first stopper comes into contact with the second stopper, thereby restricting movement of the piston relative to the cylinder.

3. 3. The ophthalmic apparatus according to claim 2, wherein the top dead center of the piston is determined by the positional relationship between the first stopper and the second stopper.

4. The piston is fixed to a piston shaft, 4. The ophthalmic apparatus according to claim 1, further comprising a linear motion mechanism that moves the piston shaft linearly in the axial direction.

5. The linear motion mechanism moves the piston shaft in a direction away from the cylinder, thereby storing a repulsive force in the spring, The ophthalmic apparatus according to claim 4 , wherein the piston is pushed into the cylinder by the repulsive force of the spring when the restriction of the piston by the linear motion mechanism is released.

6. The linear motion mechanism includes: a rack provided on the piston shaft; a pinion meshed with the rack; a driving means for rotating the pinion; and The pinion has a portion where no teeth are provided, 6. The ophthalmic device according to claim 5, wherein, during the process of rotating the pinion, the pinion and the rack disengage at a portion where the teeth are not provided, and this disengagement releases the repulsive force of the spring, causing the spring to push the piston into the cylinder.

7. a motor that drives the moving mechanism and the linear motion mechanism; a first one-way clutch that transmits rotation of the motor in a first rotation direction; a second one-way clutch that transmits rotation of the motor in a second rotation direction opposite to the first rotation direction; Further provided with the movement mechanism is driven by the rotation in the first rotational direction transmitted from the first one-way clutch, 7. The ophthalmic apparatus according to claim 5, wherein the linear motion mechanism is driven by the rotation in the second rotation direction transmitted from the second one-way clutch.

8. When the piston cannot be further pushed into the cylinder, the biasing force of the spring acts on the piston, the biasing force is adjusted by varying the position of the spring fixing member in the axial direction of the piston, 8. The ophthalmologic apparatus according to claim 1, wherein the adjustment sets the force of the gas blown onto the subject's eye.

9. 9. The ophthalmologic apparatus according to claim 1, wherein the movement mechanism utilizes a ball screw mechanism, a feed screw mechanism, a rack and pinion mechanism, or a worm wheel mechanism.

10. a means for detecting reflected light irradiated onto the subject's eye, 10. The ophthalmologic apparatus according to claim 1, wherein the spring fixing member is moved in the axial direction of the piston based on detection of the reflected light.

11. a means for detecting reflected light irradiated onto the subject's eye, The ophthalmologic apparatus according to any one of claims 1 to 10, wherein the movement of the piston is stopped based on detection of the reflected light.

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