JP3423403B2 - Ophthalmic instruments - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic instrument having a safety device for preventing damage to the cornea when an optometric unit is brought close to an examinee's eye and an optometric unit is approached. It is. [0002] The following safety devices are known for conventional non-contact ophthalmic instruments. (1) Prior to the optometry, the face of the subject is placed on a face cradle, the object of the optometry unit is brought as close as possible to the eye to be examined, and the limit of the safe distance is checked before the optometry of the optometry unit. The restricting means for restricting the movement to the side is operated so that the objective portion of the optometric unit does not approach the eye to be examined more than the safe distance. (2) Further, the distance between the nozzle and the eye to be inspected is measured by utilizing the change in capacitance caused by the distance between the eye and the eye of the fundus measurement unit closest to the eye to be inspected. When approaching the optometry below the safe distance, the stopper is activated to prevent the nozzle from coming into contact with the subject's eye. (3) Further, the cornea of the eye to be inspected is irradiated with a light beam using an extraocular illumination system, a reflected image from the cornea is detected by a photodetector, and a nozzle of a fundus measuring unit is formed based on the detected image. The distance to the cornea is measured, and if the nozzle approaches the cornea too much, a stopper is activated to prevent the nozzle from contacting the eye to be examined. [0006] However, the conventional
In (1), the examiner may forget to set the safety distance, and (2)
In some cases, the distance may be misrecognized due to individual differences or the surrounding air condition. The distance between the nozzle and the cornea may not be measured correctly. For this reason, there is a possibility that the cornea of the eye to be examined may be damaged by contact of the objective portion or the like with the cornea. An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an ophthalmic instrument capable of reliably preventing corneal damage to an eye to be examined due to contact between a cornea of the eye to be examined and an objective part of an optometry unit during optometry. An ophthalmologic instrument according to the present invention for achieving the above object is a non-contact type ophthalmic instrument in which an optometric unit is brought close to an examinee's eye and provided in the optometric unit. A fixed lens barrel, a movable lens barrel slidably protruding toward the subject's eye from the fixed lens barrel with a weak urging force,
Detecting means for detecting contact of the movable lens barrel with or near the eye to be examined by operating the electrical contact by pushing the movable lens barrel back against the urging force; and detecting the optometry by an output of the detecting means. And a drive unit for stopping or moving the unit forward or backward. The ophthalmic instrument according to the present invention having the above-described structure is
When the movable lens barrel comes into contact with the eye to be examined or its vicinity, the impact at the time of contact is reduced, and the detection unit detects or stops the advancement or retreat of the optometry unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a non-contact tonometer of the first embodiment. A tonometer main body 2 is provided on the fixed stage 1, and a face support unit 3 is erected on the fixed stage 1 on the left side of the tonometer main body 2. On the tonometer main body 2, an optometric unit 4 having an objective part 4a protruding toward the face support unit 3 is slidably installed in an operation direction indicated by an arrow. It is driven by the provided auto alignment drive mechanism 5. On the other hand, an operation panel 6 is provided on the fixed stage 1, and a CRT display 7 is provided in the tonometer main body 2. In the tonometer main body 2, as shown in FIG.
A PU 8 is provided, and a detection circuit 9, a drive circuit 10, and an electronic buzzer 11 are connected to the CPU 8, and the drive circuit 10 is connected to a pulse motor 12, which is a drive source in the auto alignment drive mechanism 5. The CPU 8, the drive circuit 10, and the pulse motor 12 constitute a restricting unit or an evacuation unit, and the CPU 8 and the electronic buzzer 11 constitute a warning unit. As shown in FIG. 3, a fixed lens barrel 13 constituting the objective section 4a is attached to the optometry unit 4, and a movable lens barrel 14 is fitted outside the fixed lens barrel 13. The fixed lens barrel 13 and the movable lens barrel 14 have thick portions 13a, respectively.
14a is provided in an annular shape along the peripheral surface, and the inner peripheral surface of the thick portion 14a is in contact with the outer peripheral surface of the fixed lens barrel 13, and the thick portion 13a is provided.
The outer peripheral surface of the movable barrel 1 contacts the inner peripheral surface of the movable barrel 14 and
4 is slidable in its length direction. A substantially cylindrical elastic member 15 made of a coil spring or the like is provided between the movable lens barrel 14 and the optometry unit 4 as a buffer, and presses the movable lens barrel 14 toward the distal end of the fixed lens barrel 13. are doing. The elastic member 15 has a minimum necessary weak elastic force. Also,
An annular electrode 16 is provided on the outer peripheral surface of the fixed lens barrel 13 with a thick portion 13.
a detecting means is formed by mounting an annular electrode 17 on the inner peripheral surface of the movable lens barrel 14 adjacent to the thick portion 14a, and the state of the electrodes 16 and 17 is detected by a detection circuit 9 Is to be detected. An objective lens 18 is mounted in the fixed lens barrel 13, and a cover 19 made of a transparent disk-shaped material is mounted on the tip of the movable lens barrel 14. Each of the cover 19 and the objective lens 18 is A nozzle 20 is provided through the center for spraying fluid onto the cornea.
Project slightly forward from the cover 19. Note that the nozzle 20 is fixed to the cover 19 and is slidable with respect to the objective lens 18. When the eye examination unit 4 is advanced by the auto-alignment drive mechanism 5 and approaches the eye to be examined, when the objective part 4a comes into contact with the eyelid or eyelashes in the cornea of the eye to be examined or in the periphery thereof, the elastic force of the elastic member 15 Is weak, the movable lens barrel 14 easily slides toward the optometry unit 4, and the nozzle 20,
The cover 19 also slides to reduce the impact at the time of contact. When this contact occurs, the electrodes 16 and 17 serving as detecting means are separated from each other to detect the contact, and a signal is sent to the CPU 8 by the detecting circuit 9. And C as a regulation means
The pulse motor 12 in the auto alignment drive mechanism 5 is stopped via the drive circuit 10 in accordance with an instruction from the PU 8, and the advance of the optometry unit 4 is stopped. In addition, the pulse motor 12 can be driven in the reverse direction as a retracting unit, and the optometric unit 4 can be retracted from the subject's eye. And
In any case, the electronic buzzer 11 is controlled by the instruction of the CPU 8 at that time.
Sound to warn the examiner. FIG. 4 shows the objective section 4a in the second embodiment. In this embodiment, a transparent electrode 21 is attached to the tip of the movable lens barrel 14 instead of the cover 19, and a transparent electrode 22 having a disk shape is attached to the tip of the fixed lens barrel 13. The electrodes 21 and 22 are both connected to the detection circuit 9. The nozzle 20 is fixed to the transparent electrode 21 and slidably penetrates the objective lens 18 and the transparent electrode 22. A dielectric 23 is filled between the transparent electrodes 21 and 22, and the transparent electrodes 21 and 22 and the dielectric 2 are filled.
3 constitutes detection means. In this case, air is used as the dielectric 23, but other dielectrics do not cause any problem. In the second embodiment, when the optometry unit 4 approaches the eye to be examined and the objective unit 4a comes into contact with the cornea of the eye to be examined or the periphery thereof, the movable lens barrel 14 slides toward the optometry unit 4a. As a result, the dielectric 23 is compressed, the interval between the transparent electrodes 21 and 22 is shortened, the capacitance between the transparent electrodes 21 and 22 changes, and the contact is detected by the detection circuit 9. Then, a signal is sent to the CPU 8 by the detection circuit 9, and the control means, the retreating means, and the warning means operate as in the previous embodiment. FIGS. 5 and 6 show a third embodiment, in which a transparent electrode 24 is mounted on the front surface of the movable lens barrel 14. This transparent electrode 24 is composed of two interdigitated transparent electrodes 24a and 24b. Are located in Further, a bridge circuit is used as a detection circuit, and a circuit is configured by the A / D converter 25, the power supply 26, and the resistors R1 to R4, and the relationship of R1 / R2 = R3 / R4 is satisfied. Is normally not applied with a voltage. Then, the transparent electrodes 24a, 2
5b is connected in parallel with the resistor R1, and these constitute a detecting means. When the optometry unit 4 approaches the eye to be examined and the objective part 4a comes into contact with the cornea of the eye to be examined or the periphery thereof, conduction between the transparent electrodes 24a and 24b is conducted through the cornea or the like, and the bridge circuit The balance is broken and a voltage is applied to the A / D converter 25. Since the electrical resistivity varies depending on the contact portion of the eye to be examined, A / A varies depending on the contact portion.
The voltage applied to the D converter 25 is different. For example,
Eyelids and the like have a high electrical resistivity of the skin, but have a low electrical resistivity because the cornea is covered with a layer of electrolyte liquid. Therefore, by utilizing this difference in electrical resistivity, it is possible to specify and detect which part of the eye to be examined is in contact with the objective part 4a. Therefore, according to the output of the A / D converter 25, the CPU 8 determines the contact area and determines whether to stop only the optometric unit 4 or to retract the electronic optics unit 4.
Can be changed depending on the contact area. FIG. 7 shows the objective section 4a in the fourth embodiment. The objective section 4a has only a fixed lens barrel 13, and a transparent disk-shaped cover 19 is attached to the distal end of the fixed lens barrel 13. The nozzle 20 has a length slightly protruding from the center of the cover 19. Further, a thin annular electrode 27 having a width corresponding to the thickness of the fixed lens barrel 13 and having the same diameter as the fixed lens barrel 13 is attached to the tip of the fixed lens barrel 13. Also,
A conductive member 28 having the same degree of pressurization as that of the annular electrode 27 and an annular electrode 29 are sequentially mounted on the annular electrode 27 so as to be overlapped with each other to constitute a detecting means. Although not shown, these are covered with a thin insulating material, and are connected to the detection circuit 9 by conducting wires. The tip of the nozzle 20 is at least retracted from the annular electrode 29. When the optometry unit 4 is brought close to the subject's eye,
When the objective part 4a comes into contact with the cornea of the eye to be examined or the eyelid or eyelashes in the periphery thereof, the annular electrode 29 as the detection means comes into contact first. Therefore, the pressurized conductive member 28 is brought into a conductive state to detect contact, and the detection circuit 9
A signal is sent to 8 to stop the optometry unit 4 by the restricting means, or to retreat by the retracting means, and to give a warning by a buzzer by the warning means. FIGS. 8 and 9 show a fifth embodiment, in which three light emitting elements 31 composed of LEDs and the like are arranged at substantially equal intervals on the inner peripheral surface of the front end of the fixed lens barrel 13. A light receiving element group 32 to which light receiving elements are attached is provided along the peripheral surface of. The output of the light receiving element group 32 is connected to the interface 33, and the interface 33 is connected to the drive circuit 10, the electronic buzzer 11, and the storage element 34 via the CPU 8, and the drive circuit 10 is connected to the pulse motor 12. . Prior to bringing the optometric unit 4 close to the eye to be examined, light from the light emitting element 31 is received by the light receiving element group 32,
The intensity distribution of the received light is referred to as interface 33, CP
The data is stored in the storage element 34 via U8. Next, at a certain short time interval, the light intensity distribution of the light receiving element group 32 is taken into the CPU 8 via the interface 33, and compared with the previous light intensity distribution stored in the storage element 34, The current light intensity distribution is stored in the storage element 34. This is repeated in a short cycle. If the objective section 4a comes into contact with the eye to be examined, the first contact is the eyelashes. Eyelashes are light emitting element 3
1 and the light receiving element group 32, the eyelashes do not completely block the light, but the light intensity distribution received by the light receiving element group 32 is different from the previous light intensity distribution. A change in the light intensity distribution is detected in comparison with the distribution.
If this change is greater than a certain level, it is determined that the contact has occurred. When it is determined that the approach or contact is made, the optometry unit 4 is stopped by the restricting unit, or the evacuation unit is evacuated, and the electronic buzzer 11 issues a warning. In the fifth embodiment, the detecting means determines whether the light intensity distribution in the light receiving element group 32 is not based on the presence or absence of light to the light receiving element group 32 by comparing with the previous light intensity distribution. 32 and the light emitting element 3
It is not affected by the leakage of light from 1. In addition, by using the light receiving element group 32 as the light receiving section, even if some of the light receiving elements fail, they are hardly affected. As described above, in the ophthalmic instrument according to the present invention, when the movable lens barrel comes into contact with the eye to be examined or in the vicinity thereof, the impact is alleviated, and the optometric unit is caused to stop moving forward or backward. Damage to the subject's eye can be prevented. [0034]

[Brief description of the drawings] FIG. 1 is a schematic configuration diagram of a first embodiment. FIG. 2 is a block circuit diagram. FIG. 3 is a sectional view of an objective section. FIG. 4 is a sectional view of an objective section according to a second embodiment. FIG. 5 is a circuit diagram of a third embodiment. FIG. 6 is a block circuit diagram. FIG. 7 is a sectional view of an objective section according to a fourth embodiment. FIG. 8 is a circuit diagram of a fifth embodiment. FIG. 9 is a sectional view of an objective section. [Explanation of symbols] 2 Tonometer body 4 Optometry unit 4a Objective part 13 Fixed lens barrel 14 Movable lens barrel 15 Elastic member 16, 17 electrodes 19 Cover 21,22,24 Transparent electrode 23 Dielectric 27, 29 Ring electrode 28 Pressurized conductive member

Claims (1)

(57) [Claims 1] In a non-contact type ophthalmic instrument for optometry by bringing an optometry unit close to an eye to be examined, the optometry unit is provided in the optometry unit.
The fixed barrel that is slid and slides out of the fixed barrel with a weak biasing force.
The movable lens barrel that is currently protruding toward the subject's eye, and the movable lens barrel is
The electrical contact is made by being pushed back against the urging force.
Detection means for detecting a contact with the subject's eye or near the movable lens barrel is actuated, more said analyzing the output of said detection means
An ophthalmologic apparatus comprising: driving means for stopping or moving the eye unit forward or backward .