JP2002253511A - Tonometer and ophthalmoscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact tonometer of easy alignment capable of measuring at high precision. SOLUTION: As a measuring button, correctly positioned and not illustrated, is pushed, a current is sent to a drive part 10, and a rod member 3 is pushed out through a core member 7, so that an applanation piece 4 gets in contact with an eyelid L. As the applanation piece 4 pushes a subject eye E, the eyelid L is deformed to be thinner first. When the eyelid L becomes thinner to a certain degree, then the cornea C is deformed. This deformation is detected by measuring the position of the rod member 3 by a position sensor 9 in order. An intraocular pressure value is computed based on pressure measured by a pressure sensor 8 when specified deformation is reached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tonometer and an optometry apparatus used for optometry in an ophthalmic hospital.

[0002]

2. Description of the Related Art In a conventional tonometer, the cornea is deformed by applying a force to the cornea while the eye is open, and measurement is performed. For this reason, it is difficult to measure by the subject himself, and it is used in hospitals and the like.

[0003] However, treatment of glaucoma requires measurement of fluctuations in intraocular pressure, and there is a demand for a tonometer that measures the intraocular pressure at home. As a self-measurement tonometer, a press-fit tonometer that measures by pressing from above the eyelid has been proposed.

In this press-fit tonometer typified by the Shetz tonometer, a contact member is applied to the periphery of the cornea, and the central portion of the cornea is deformed by using a rod-shaped press-fit member protruding from the central portion thereof. Measure intraocular pressure.

[0005] An air-blowing self-measurement tonometer has also been developed which measures air by blowing air onto the cornea to deform the cornea.

[0006]

However, in the above-described conventional example, alignment is a problem when an attempt is made to measure from above the eyelid by a conventional self-measuring tonometer. It is difficult to make the press-fit member abut on the central part of the cornea, and it has not been put to practical use. Further, it is difficult to reduce the size of the air-blowing tonometer.

It is an object of the present invention to solve the above-mentioned problems and to provide a tonometer which can be easily aligned, miniaturized, and capable of accurate measurement.

Another object of the present invention is to provide an optometric apparatus which can automatically determine the left and right of the eye to be inspected.

[0009]

According to the present invention, there is provided a tonometer for measuring an intraocular pressure by pressing an examinee's eye from above an eyelid. And a sighting mirror or a visual target is disposed on the target.

Further, the tonometer according to the present invention is characterized in that in the tonometer for measuring the intraocular pressure by pressing the eye to be examined from above the eyelid, a contact member for contacting a face near the eye to be examined is provided. .

A tonometer according to the present invention is a tonometer for measuring an intraocular pressure by pressing an examinee's eye from above an eyelid, and an input unit for inputting a value measured by another reference tonometer; Calculating means for calculating a calibration value so as to be able to measure the same value as the reference tonometer from the measurement value obtained by the calibration.

The tonometer according to the present invention is characterized in that the optotype can be moved left and right, and the movement is detected to determine the left and right eyes of the eye to be examined.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiment. FIG. 1 is a cross-sectional view of the tonometer according to the first embodiment as viewed from the side, and shows an internal configuration. A contact member 2 for pressing against the face under the closed eye E is attached to the eye E side of the housing 1. A flat applanator 4 attached to a rod member 3 is disposed at the tip of the housing 1, and the rod member 3 is a cylindrical guide member 5.
It is configured to slide inside through a bearing 6. The rod member 3 is connected to the core member 7 at the rear part, a pressure sensor 8 is provided near the joint, and the position of the rod member 3 is detected by a position sensor 9 such as a potentiometer.

The core member 7 is inserted into a driving unit 10 composed of a coil for generating a magnetic field, and the current flowing through the driving unit 10 pushes the core member 7 toward the eye E to be examined. The outputs of the pressure sensor 8 and the position sensor 9 are connected to a calculation control unit 11 that calculates the position of the intraocular pressure.

FIG. 2 is a plan view. At the end of the housing 1, an arm 13 for attaching the aiming mirror 12 to the tip is provided with a shaft 14.
Is mounted so as to be rotatable 180 degrees. The length of the arm 13 can be adjusted by the adjusting member 15 in accordance with the interpupillary distance between the eye E and the other eye e. A display member 1 for displaying a measurement result is provided on an upper part of the housing 1.
6 and a reference intraocular pressure value input unit 17 are provided.
7 consists of four buttons.

FIG. 3 is a front view of the aiming mirror 12 as viewed from the subject. Crosshairs 12a on the aiming mirror 12
Are drawn, and the other eye e of the subject is aligned with the center of the crosshair 12a. Note that the crosshair 12a is
Is not always necessary when the image is small and it is easy to center the image of the other eye e. The subject closes the subject's eye E and opens the other eye e, and performs alignment by viewing the image of the other eye e reflected on the aiming mirror 12. At the time of measurement, the contact member 2 is pressed against the face H under the eye E while holding the housing 1. In this state, the applanator 4 is not in contact with the eyelid L as shown in FIG.

When the subject adjusts himself so that the center of the pupil of the other eye e reflected on the aiming mirror 12 is aligned with the center of the crosshair 12a, the applanator 4 substantially matches the eye E to be examined. Since the applanator 4 is flat on the cornea C side, slight lateral displacement has no effect. When the other eye e is aligned with the center of the aiming mirror 12, the direction of the line of sight of the eye E to be examined and the direction in which the applanator 4 moves, that is, the movable direction of the rod member 3, substantially match. Then, the applanator 4 always applies a force to the vertex of the cornea C via the eyelid L.

When the measuring button (not shown) is pressed after the position is adjusted, an electric current flows to the driving unit 10 and the rod member 3 is inserted through the core member 7.
Is pushed out, and the applanator 4 comes into contact with the eyelid L as shown in FIG. Further, when the applanator 4 presses the eye E, the eyelid L is first deformed and thinned. If the eyelids L become thin to some extent, then the cornea C is deformed. This deformation is detected by sequentially measuring the position of the bar member 3 with the position sensor 9. An intraocular pressure value is calculated from the pressing force measured by the pressure sensor 8 when the predetermined deformation occurs.

FIG. 4 shows the pressure of the pressure sensor 8 and the position sensor 9.
FIG. 4 is a graph showing a relationship between the displacement of the bar member 3 and the displacement measured in FIG.
At the beginning near the displacement 0, the frictional force of the rod 3 is
Is detected by At the displacement A, the applanator 4 contacts the eyelid L,
The repulsive force is detected. Deformation of the cornea C starts to occur near the displacement B, and the displacement C is the position where the predetermined deformation has occurred,
The intraocular pressure value is calculated from the pressures D to F at that time. The solid line pressure F is the first measurement, and the dotted line is the case where the intraocular pressure subsequently decreases, and the same deformation occurs in the cornea C at a low pressure D.

Since the thickness of the eyelid L does not change even if the intraocular pressure fluctuates, almost the same change curve is obtained for displacements 0 to B. Since the contact member 2 is lightly pressed against the face H, the initial position of the applanator 4 does not change. For example, even if the housing 1 slightly moves back and forth in the direction of the eye E due to the way in which the contact member 2 is pressed, a predetermined deformation can be detected by shifting the change curve up to about the displacement B sideways.

Since the thickness of the eyelid L varies among individuals, the eye E to be examined is measured in advance with another reference tonometer, and the value is input using the input unit 17 in advance. The input value is displayed on the display member 16.

Next, measurement is performed by the present apparatus, and the apparatus is calibrated based on the difference between the two measured values. If the value is 12 mmHg using the Goldman tonometer as a reference, the numerical value is input. Immediately, measure the same eye with this device, for example, 13 mm
When Hg is obtained and the calibration button (not shown) is pressed, the difference is 1m
mHg is calculated and stored as a correction value. In subsequent measurements,
The measured value obtained by subtracting 1 mmHg from the measured value is displayed on the display member 16.

When measuring the other eye e of the subject, the arm 13 is rotated by 180 degrees around the axis 14 and the aiming mirror 12 is brought to the opposite side of the housing 1. By detecting the rotational position of the arm 13 with a microswitch or the like, the calculating means 11 identifies the left and right eyes of the eye E to be inspected, and this identification is displayed on the display member 16 and stored together with the intraocular pressure measurement value, date and time, etc. Is done.

The position of the contact member 2 may be adjusted with respect to the housing 1 in the direction of the eye E. With the contact member 2 pressed against the face H regardless of the eye E,
The distance from the eyelid L to the applanator 4 can be constant.

FIG. 5 shows another example of the aiming target viewed by the other eye e. The aiming target is composed of a round target 18 having a small circle at the center and a cross target 19. These targets 18 and 19 are fixed at predetermined intervals by a support member 20, and the support member 20 is attached to the arm 13. When the line of sight O1 of the other eye e is aligned so as to pass through the center of the cross target 19 and the small circle of the round target 18, the line of sight of the eye E to be examined is also directed substantially in the pressing direction. It will be deformed by pressure.

FIG. 6 shows a tonometer according to a second embodiment.
Members having the same functions as those in the first embodiment are denoted by the same reference numerals. The applanator 4 is fixed to the eye E side of the core member 21, and the displacement of the core member 21 is detected by the optical position sensor 22. The optical position sensor 22 includes an LED 23, a grid 24 fixed to the core member 21, a grid 25 slightly different from the grid 24 and fixed to the housing 1, and a photoelectric sensor 26. The abutment member 2 can be adjusted in the front-rear position by an adjusting section 27, and a pressure sensor 28 is attached to the abutment member 2.

When the core member 21 moves during measurement, the grid 2
Moiré fringes due to the movements 4 and 25 move, and the movement detects a strong or weak signal in the photoelectric sensor 26, so that the displacement of the core member 21 can be detected. When the contact member 2 comes into contact with the face H, it is adjusted in advance before the measurement so that a gap is slightly formed between the applanator and the eyelid L as shown in FIG.

When a predetermined press on the eyelid L by the applanator 4 is detected and the measurement is started, the current applied to the solenoid of the drive unit 10 is increased, and the core member 21 is driven in the direction of the eye E to be examined. Then, an intraocular pressure value is calculated from a current value when a predetermined displacement occurs.

FIG. 7 is a graph showing the relationship. The horizontal axis indicates the displacement of the core member 21 and the vertical axis indicates the current flowing through the solenoid. After starting the measurement at a displacement of 0, the subject holds the housing 1 and aligns the contact member 2 against the face H,
Press hard little by little. When the predetermined pressure is detected, the displacement is 0, and the applanator 4 starts to move and contacts the cornea C with the displacement A.

The movement when there is no repulsive force from the eye E is shown by a line L1. A solid line L2 indicates a high intraocular pressure, and a dotted line L3.
Indicates a curve of low intraocular pressure. Current values reaching the predetermined displacement B are C and D, respectively. When the intraocular pressure is high, the repulsive force is strong, and the current up to the same displacement is large. An intraocular pressure value is obtained based on the current values C and D.

In the above description, the intraocular pressure is measured based on the pressure at which a predetermined displacement occurs. However, the intraocular pressure may be measured based on the relationship between the pressure and the displacement until the predetermined pressure is reached. That is,
The higher the intraocular pressure, the smaller the change in displacement when the pressure is raised.

[0032]

As described above, in the tonometer according to the present invention, when measuring the intraocular pressure with the eyes closed, alignment can be performed without contact, and the intraocular pressure can be accurately measured by deforming the corneal apex.

The tonometer according to the present invention can accurately detect the amount of corneal deformation when measuring intraocular pressure with the eyes closed, so that accurate tonometry can be performed.

The tonometer according to the present invention enables accurate measurement regardless of individual eyelid differences when measuring intraocular pressure with the eyes closed.

The optometry apparatus according to the present invention can automatically distinguish between the left and right eyes.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tonometer according to a first embodiment as viewed from a side.

FIG. 2 is a plan view.

FIG. 3 is a front view of the aiming mirror as viewed from a subject.

FIG. 4 is a graph showing the relationship between the pressure of the pressure sensor and the displacement of the applanator.

FIG. 5 is a side view of another aiming target.

FIG. 6 is a cross-sectional view of a tonometer according to a second embodiment as viewed from a side.

FIG. 7 is a graph showing the relationship between current and displacement.

[Explanation of symbols]

 Reference Signs List 1 housing 2 contact member 3 rod member 4 applanator 5 cylindrical guide member 7, 21 core member 8, 28 pressure sensor 9 position sensor 10 drive unit 11 control unit 12 aiming mirror 16 display member 17 input unit 18, 19 optotype 22 Light Position Sensor 23 LED 27 Adjustment Unit

Claims (7)

[Claims] 1. A tonometer for measuring an intraocular pressure by pressing an examinee's eye from above an eyelid, wherein a sighting mirror or an optotype is arranged in front of the other eye of the examinee. 2. The tonometer according to claim 1, wherein the interpupillary distance of the aiming mirror or the target is adjustable. 3. A tonometer for measuring an intraocular pressure by pressing an eye to be examined from above an eyelid, wherein a tonometer is provided which is in contact with a face near the eye to be inspected. 4. The tonometer according to claim 3, wherein a pressure sensor is provided on the contact member, and measurement is automatically started when a predetermined pressure is detected. 5. The tonometer according to claim 1, wherein the subject's eye is pressed via the applanator. 6. An tonometer for measuring an intraocular pressure by pressing an eye to be examined from above an eyelid, wherein an input unit for inputting a value measured by another reference tonometer, and an input unit for inputting a value measured by another reference tonometer Calculating means for calculating a calibration value so as to be able to measure to the same value as the reference tonometer. 7. A target is configured to be movable left and right,
An optometric apparatus characterized in that the movement is detected to determine the left and right eyes of the eye to be examined.