JPH08229006A - Ophthalmic device - Google Patents

Abstract

PURPOSE: To provide an efficient measurement while preventing misoperation and reduce burdens to an operator and a subject, by receiving a scattered light of a target forming means which is reflected by eyelids, by detecting the presence of eyelid or not from received light amount, and by stopping initiation of operation when the eyelids are detected. CONSTITUTION: Light bundles ejected from light sources 10 and 20 do not focus into image and are reflected on an eyelid surface when cornea Ec is covered by the eyelid by means of blinking of a test eye. This scattered light is incident into each detecting optic system through the same pathway as the reflected light of the cornea Ec. A measurement stopping signal is outputted to a measurement control system 31 when the output is larger than a standard value by comparing the output signal of a receiving element 16 with the standard value, by means of a stopping signal generating system 33. A trigger signal is stopped to be generated and the operation of a measurement system 32 is stopped regardless of input of alignment completion signal from a position operating system 30, when this stopping signal is received by the measurement control system 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus for measuring an eye to be inspected, and more specifically to an alignment mechanism for aligning the eye to be inspected and the apparatus in a predetermined positional relationship.

[0002]

2. Description of the Related Art In an ophthalmologic apparatus such as a non-contact tonometer and an objective eye refractive power measuring apparatus, position adjustment (alignment) between the eye to be inspected and the apparatus is necessary. Are known. A corneal reflection image is formed by projecting alignment light toward the cornea of the eye to be inspected, and the position of the corneal reflection image is detected by a position detection element such as a divided light receiving element or PSD. Based on this detection position, the alignment between the eye to be inspected and the apparatus is performed manually or automatically. When the position detecting element detects the corneal reflection image at a predetermined position, a start signal is emitted and the measurement is automatically started.

[0003]

However, the conventional alignment mechanism as described above has a drawback in that if the eye to be inspected blinks, it is erroneously determined that the alignment has been completed and the measurement is started. The alignment light is scattered by the eyelids due to the blinking of the eye to be inspected, and the scattered light is received by the position detecting element similarly to the cornea reflected light. The scattered light may be uniformly incident on the position detecting element depending on the situation, and in the case of the type in which the position of the eye to be inspected is detected by detecting the distribution of the amount of light incident on the position detecting element, the output of the position detecting element is It is indistinguishable from the completed alignment. For this reason, the apparatus has a drawback that unnecessary measurement is started and unnecessary time is spent, and an extra burden is imposed on the examiner and the subject.

The present invention has been devised in view of the above drawbacks, and provides an ophthalmologic apparatus which prevents malfunction of the apparatus, enables efficient measurement, and reduces the burden on the examiner and the examinee. To do is a technical issue.

[0005]

In order to solve the above problems, the present invention is characterized by having the following configuration. (1) Index forming means for forming an alignment index on the eye to be inspected, detection means for detecting the alignment index, determination means for determining an alignment state based on the detection result of the detection means, and measurement of the eye to be inspected In an ophthalmologic apparatus having a measuring means for doing so, a light receiving means for receiving the scattered light of the index forming means reflected by the eyelid, a detecting means for detecting the presence or absence of the eyelid based on the amount of light received by the light receiving means, and the detecting means. Stop means for stopping the operation start of the measuring means when the eyelid is detected by the means.

(2) The detecting means of (1) is characterized by having a comparing means for comparing the amount of light received by the light receiving means with a predetermined reference level.

(3) The ophthalmologic apparatus of (1) is characterized by further having control means for issuing a trigger signal for operating the measuring means when the judging means satisfies a predetermined measurement start condition. .

(4) In the ophthalmologic apparatus of (1), fluid ejecting means for ejecting a compressed gas to the cornea of the eye to be deformed, corneal deformation detecting means for detecting the corneal deformation state of the eye to be inspected, and the cornea. It is a non-contact tonometer that measures the intraocular pressure of the eye to be inspected based on the detection result of the deformation detecting means.

(5) The corneal deformation detecting means of (4) is also used as the light receiving means.

[0010]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an alignment optical system and a control system of the apparatus of Example 1, and the optical system is a view seen from above. As the measurement system, various known configurations such as a non-contact tonometer (see FIG. 5) and an eye-refractive-power measuring device can be used, but the description thereof is omitted. An optical system (observation optical system) L indicates the optical axis of the observation optical system, and on the observation optical axis L, Haarmylar-1, objective lens 2, filter 3,
A half mirror-4 and a CCD camera 5 are provided. The filter 3 has the characteristic of transmitting the wavelength of the light flux of the front index projection optical system, which will be described later, and not transmitting the wavelength of the light flux of the distance index projection optical system, and unnecessary noise in the CCD camera 5 and the detection elements of the front index detection optical system. Prevents light from entering.
Reference numeral 6 denotes a television monitor which displays an anterior ocular segment image of the eye E to be inspected.

(Frontal target projection optical system) 10 is a light source for frontal target projection that emits near-infrared light, and 11 is a projection lens. The light from the light source 10 is collimated by the light projecting lens 11 and is then projected from the front to the eye E to be inspected along the optical axis L by the Haarmylar-1. (Front optotype detection optical system) The front optotype detection optical system includes an objective lens 2 and a filter 3, which are also used as an observation optical system, and an optical axis La.
It is composed of a half mirror 12 and a two-dimensional position detecting element 13 such as a PSD arranged above. Two-dimensional position detection element 1
The center of 3 is located on the optical axis La, and the two-dimensional position detecting element 1
Reference numeral 3 detects the vertical and horizontal directions of the eye to be inspected from the deviation of the barycentric position of the light amount distribution of the incident light beam with the origin intersecting with the optical axis La. (Eyelid detection optical system) Lb is an optical axis of the eyelid detection optical system branched from the optical axis La by the Haarmylar-12. The eyelid detection optical system shares the objective lens 2 and the filter 3 of the observation optical system, and has a diaphragm 15 and a light receiving element 16 having an opening at a position displaced from the optical axis Lb.

(Distance index projection optical system) M is an optical axis of the distance index projection optical system, and the optical axis M is provided so as to obliquely intersect the observation optical axis L. On the optical axis M, a light source 20 that emits light having a wavelength different from that of the light source 10 and a light projecting lens 21 are arranged. (Distance index detection optical system) N is an optical axis of the distance index detection optical system, and the optical axis N is arranged symmetrical to the optical axis M with respect to the optical axis L. A light receiving lens 22 and a filter 2 are provided on the optical axis N.
3, a cylindrical lens 24, and a one-dimensional position detecting element 25 are arranged. The filter 23 has a characteristic of transmitting light of the wavelength of the light source 20 and not transmitting light of the wavelength of the light source 10 of the front index projection optical system, and prevents the corneal reflected light flux of the light source 10 from entering the position detection element 25. . The position detection element 25 is a one-dimensional PSD, and its center is located on the optical axis N. The one-dimensional position detecting element 25 detects the position of the eye to be examined in the front-back direction from the position of the center of gravity of the light amount distribution.

The control system 30 is a position calculation system that obtains the position of the eye to be inspected by subjecting the output signals from the two-dimensional position detecting element 13 and the one-dimensional position detecting element 25 to predetermined processing. Reference numeral 31 is a measurement control system for controlling the measurement system 32. Reference numeral 33 denotes a stop signal generation system that generates a measurement stop signal for stopping the operation of the measurement system 32. The stop signal generation system 33 performs a predetermined process on the output signal from the light receiving element 16 and presets the signal. A measurement stop signal is generated by comparing with a stored reference value (described later).

The operation of the apparatus having the above configuration will be described. Light source 10 by frontal target projection optical system
When this light flux is projected onto the cornea Ec of the eye E to be examined, this light flux forms a virtual image index i1 which is a corneal reflection image of the light source 10 on the cornea Ec. The luminous flux of the index i1 forms an image of the index i1 on the image pickup device of the CCD camera 5 by the observation optical system. The examiner observes the index image and the anterior ocular segment image of the subject's eye illuminated by an illumination light source (not shown) on the television monitor 6 and uses them as information for the alignment operation.

The light beam of the front index i1 reflected by the cornea Ec is guided to the front target detection optical system by the Hahmira-4 and is received by the two-dimensional position detection element 13. In addition, a part of the light flux guided to the front target detection optical system is a half mirror.
Although it enters the eyelid detection optical system by 12, the light flux does not enter the light receiving element 16 because the aperture of the diaphragm 15 is displaced from the optical axis Lb when the position adjustment is completed (see (c) of FIG. 2). On the other hand, the light emitted from the light source 20 is made into a substantially parallel light flux by the light projecting lens 21, and is projected obliquely from the front to the cornea Ec along the optical axis M. The light flux specularly reflected by the cornea Ec forms an index i2 that is a virtual image of the light source 20, and the cornea reflected light is incident on the detection element 25 via the filter 23 and the cylindrical lens 24 by the light receiving lens 22. Cylindrical lens 2
4 is arranged so that the generatrix direction thereof coincides with the detection direction of the one-dimensional position detecting element 25, so that the one-dimensional position detecting element 25 can receive the light flux of the index i2 even if the eye to be inspected is vertically swung. .

The inspector performs the alignment of the device, and the index i
When the light flux of 1 enters the two-dimensional position detecting element 13 and the light flux of the index i2 enters the one-dimensional detecting element 25, each position detecting element detects the index image. FIG. 2 is a diagram showing a state of a light beam incident on each element when the eye to be inspected and the device are adjusted in a predetermined positional relationship,
(A) is a view of the two-dimensional position detecting element 13 viewed from the optical axis La direction, (b) is a view of the one-dimensional position detecting element 25 viewed from the optical axis N direction, and (c) is a light receiving element 16 of the optical axis. It is the figure seen from the Lb direction. The dotted line in the figure shows the distribution of the incident light flux. The position calculation system 30 calculates the position of each index image based on the signals from the two position detection elements 13 and 25, and when both index images are determined to be within a predetermined tolerance, the position calculation system 30 aligns them with the measurement control system 31. Output a completion signal. When the eye to be inspected is normally aligned without blinking, the stop signal generation system 33 does not output the stop signal because the light flux of the index i1 of the corneal reflection does not enter the light receiving element 16.
The measurement control system issues a trigger signal to the measurement system 32, and the measurement system 3
2 starts the measurement.

Next, when the eye E blinks and the cornea Ec is covered by the eyelids, the light beams emitted from the light sources 10 and 20 are scattered and reflected on the surfaces of the eyelids without forming an image. This scattered light enters each detection optical system through the same path as the reflected light of the cornea Ec (see FIG. 3). The dotted line in the figure shows the distribution of the incident light flux, and the scattered light from the eyelids spreads widely and enters each element, and the position detecting element 13 and the one-dimensional position detecting element 25 detect the barycentric position of the light amount distribution. If the state of FIG. 2 and the state of FIG. 3 cannot be discriminated, and the position of the center of gravity is within the predetermined tolerance even in the state of FIG. Output to. In the state where the eyelids are closed, the light receiving element 16 of the eyelid detection optical system is shown in FIG.
As shown by, a part of the luminous flux is incident. FIG. 4 shows an output example (a) when alignment is completed without closing the eyelids of the light receiving element 16 and an output example (b) when the eyelids are closed, and the threshold value is a reference value in advance. Two states can be discriminated by setting the value I ₀ . Therefore, the eyelids can be detected from the output of the light receiving element 16.

The stop signal generation system 33 compares the output signal of the light receiving element 16 with the reference value (I ₀ ) and outputs a measurement stop signal to the measurement control system 31 when an output exceeding the reference value is detected. . When receiving the stop signal, the measurement control system 31 stops the generation of the trigger signal regardless of the input of the alignment completion signal from the position calculation system 30, and does not operate the measurement system 32. In this way, even if the eye deviation signal detected by blinking falls within a predetermined tolerance, the device determines that it is due to blinking, and thus it is possible to prevent erroneous measurement start. You can

[0019]

Second Embodiment A second embodiment is a case where the present invention is applied to a non-contact tonometer and is configured to be shared with an optical system for detecting a corneal deformation state of a measurement system. FIG. 5 is a diagram showing a schematic configuration of the fluid ejection mechanism, the optical system, and the control system. In the figure, the elements common to those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The non-contact tonometer deforms the cornea by injecting compressed gas onto the cornea of the eye to be inspected, and receives the light flux reflected by the cornea by the light receiving optical system,
Detecting that the cornea is deformed to a predetermined state by the amount of received light, obtain the gas pressure deformed to a predetermined state, and measure the intraocular pressure based on the gas pressure. Only the elements related to the invention will be described, and the detailed description of the measuring mechanism itself will be made by the present applicant in Japanese Patent Application No. 3-29415.
No. (Invention title “Non-contact tonometer”) is incorporated by reference.

The gas injection mechanism includes a cylinder 40, a piston 42 driven by a solenoid 41 to reciprocate, a nozzle 43 for injecting a compressed gas, a glass member 45 for holding the nozzle 43, and a rear wall constituting a rear wall of the cylinder 40. Window 46,
It is composed of a pressure sensor 47 and the like for detecting the pressure in the cylinder 40. The compressed gas is generated by the measurement system 32 driving the solenoid 41 and pressing it with the piston 42, and is ejected from the nozzle 43 toward the cornea Ec.

Reference numeral 50 denotes a corneal deformation detecting optical system, which is a light source 2
The corneal reflected light of the light flux of 0 (shared with the light source of the distance index detection optical system) is detected to detect the deformed state of the cornea Ec.
The corneal deformation detection optical system 50 shares the light receiving lens 22 and the filter 23 of the distance index detection optical system, and is provided with a half mirror 51, a light receiving element 52, and a light receiving element 52 arranged on the optical axis N.
It is composed of a diaphragm 53 that limits the incident light to the. Aperture 5
Reference numeral 3 is provided at a position that is conjugate with the light source 20 when the position adjustment is completed and the measurement is performed and the cornea Ec is deformed into a predetermined shape. The corneal deformation detection optical system 50 is also used as an eyelid detection optical system, and the light receiving element 52 detects light reflected by the eyelid during alignment. This is because the eyelid is closer to the flat surface between the cornea and the eyelid, and therefore, when the alignment is completed and when the eyelid is closed, the amount of light received by the light-receiving element 52 is smaller when the eyelid is closed. It takes advantage of many things.

Reference numeral 55 denotes a measurement waveform processing system. The measurement waveform processing system 55 analyzes changes in the amount of light received by the light receiving element 52 during measurement, and performs peak detection processing and the like. When the amount of light received by the light receiving element 52 being aligned by the stop signal generation system 33 exceeds a preset reference value, a stop signal is output to the measurement control system 31 to prevent false start of measurement due to blinking. Can be prevented. As described above, in the second embodiment, since the well-known constituent elements of the non-contact tonometer can be used without providing a dedicated optical system for eyelid detection, this function can be added to the apparatus more easily. .

[0023]

As described above, according to the present invention,
It is possible to prevent malfunction of the device, enable efficient measurement, and reduce the burden on the examiner and the subject. Further, when the present invention is applied to the non-contact tonometer, the above-mentioned effects can be easily achieved by utilizing the constituent elements of the non-contact tonometer.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an alignment optical system and a control system of an apparatus according to a first embodiment.

FIG. 2 is a diagram showing a state of a light beam incident on each element when the eye to be inspected and the device are adjusted in a predetermined positional relationship.

FIG. 3 is a diagram showing a state of a light beam incident on each element when the cornea is covered with an eyelid.

FIG. 4 is a diagram showing an output example when alignment is completed without closing the eyelids and an output example when the eyelids are closed.

FIG. 5 is a diagram showing a schematic configuration of a fluid ejection mechanism, an optical system, and a control system of an apparatus according to a second embodiment in which the present invention is applied to a non-contact tonometer.

[Explanation of symbols]

 10 light source 13 two-dimensional position detection element 16 light receiving element 20 light source 25 one-dimensional position detection element 30 position calculation system 31 measurement control system 32 measurement system 33 stop signal generation system

[Procedure amendment]

[Submission date] November 30, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (5)

[Claims] 1. An index forming means for forming an alignment index on an eye to be inspected, a detecting means for detecting the alignment index, a determining means for determining an alignment state based on a detection result of the detecting means, and an eye to be inspected. In an ophthalmologic apparatus having a measuring means for measuring, a light receiving means for receiving scattered light of the index forming means reflected by an eyelid, and a detecting means for detecting the presence or absence of an eyelid from the amount of light received by the light receiving means, An ophthalmologic apparatus comprising: stop means for stopping the operation start of the measuring means when the eyelid is detected by the detecting means. 2. The ophthalmologic apparatus according to claim 1, further comprising a comparing unit that compares the amount of light received by the light receiving unit with a predetermined reference level. 3. The ophthalmologic apparatus according to claim 1, further comprising control means for issuing a trigger signal for activating the measuring means when the judging means satisfies a predetermined measurement start condition. apparatus. 4. The ophthalmologic apparatus according to claim 1, wherein fluid injection means for injecting a compressed gas onto the cornea of the eye to be inspected to deform the cornea, corneal deformation detection means for detecting a corneal deformation state of the eye to be inspected, and the corneal deformation. An ophthalmologic apparatus, which is a non-contact tonometer that measures the intraocular pressure of the eye to be inspected based on the detection result of the detection means. 5. The ophthalmologic apparatus according to claim 4, wherein the corneal deformation detecting means is also used as the light receiving means.