JPH08206076A - Ophthalmological device - Google Patents

Abstract

PURPOSE: To receive both of a measurement reflective light and an anterior part image of eye from a tested eye only by one photoelectric detector, by providing an optical system for observing the anterior part of the tested eye and sharing this photoelectric detector with the photoelectric detector for detecting the measurement reflective light. CONSTITUTION: A luminous element 9 in a measurement target projecting system 1 and a tungsten lamp 30 in a chart projecting system 4 are respectively lighted and an invisible light measuring target image and visible light chart image are superimposedly projected on eyegrounds 8 of a tested eye 6 and only the chart image as a fixation target is observed. A movable lens 34 in the chart projecting system 4 and an index board 11 in the measurement target projecting system 1 are respectively initially set up. Furthermore, the index board 11 and movable lens 25 are moved in one body until the measurement target image 46 comes to the position focused on the eyegrounds 8. A refractive degree of each connecting direction is calculated by rotating the image rotator 18 successively while the target board 11 is fixed and by reading the interval difference according to this rotational position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus capable of detecting an image of an anterior segment of an eye to be inspected and measurement reflected light projected on the eye to be inspected by one photoelectric detector. The present invention relates to an ophthalmologic apparatus suitable for use in an automatic eye refractive power measuring apparatus or the like having a fixation target projection system for measuring in a state of farsightedness or cloudy vision with the accommodation power removed.

[0002]

2. Description of the Related Art Conventionally, an automatic system for projecting a measurement target image as measurement light on an eye to be examined and photoelectrically detecting a focus state of the measurement target image to automatically measure the refractive power of the eye to be examined. Various ophthalmic devices such as an eye refractive power measuring device have been proposed.

As one of the devices of this type, the measurement target image is moved so as to obtain the in-focus state based on the detection signal indicating the in-focus state of the measurement target image, and the refractive power of the eye to be inspected is determined from this movement amount. Are known to be configured to measure.

By the way, in this type of apparatus, a fixation target projection system is provided for removing the accommodation force of the eye to be inspected and performing measurement in the state of farsightedness or cloudy vision, and the measurement target at the time of measurement is provided. The fixation target can be adjusted in conjunction with the movement of the. Further, a sighting optical system for observing the eye to be examined and aiming the eye is also provided.

[0005]

However, in an apparatus having such a fixation target projection system, the subject is apt to be psychologically agitated when the fixation target is moved and adjusted, and as a result, the adjustment power is reduced. There was a problem that it had a considerable influence and that accurate measurement results could not be obtained. Therefore, it is possible to perform the measurement while observing the measurement target image, but to provide a dedicated photoelectric detector different from the photoelectric detector included in the aiming optical system for observing and aiming the subject's eye. Then, there arises a problem that the structure of the optical system becomes unnecessarily complicated.

As described above, in the ophthalmologic apparatus, the dedicated photoelectric detector for the optical system for observing the subject's eye and the dedicated photoelectric detector for the optical system for detecting the measurement reflected light are separately provided. , The structure of the optical system becomes unnecessarily complicated.

[0007]

The ophthalmologic apparatus according to the present invention has been made in view of the above circumstances, and includes a projection system for projecting the measurement light on the eye to be inspected and the measurement reflected light of the eye to be inspected. In an ophthalmologic apparatus for inspecting an eye to be inspected by a signal from the photoelectric detector, comprising an optical system for observing the anterior segment of the eye, and photoelectric detection of the optical system. The device is also used as a photoelectric detector for detecting the measurement reflected light.

[0008]

According to the ophthalmologic apparatus of the present invention, the measurement reflected light from the eye to be examined and the anterior segment image are received by one photoelectric detector.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an ophthalmologic apparatus according to the present invention is applied to an automatic eye refractive power measuring apparatus will be described below with reference to the drawings.

FIG. 1 is a view showing an optical system of an automatic eye refractive power measuring device.

In FIG. 1, 1 is a target image projection system, and 2 is a target image projection system.
Is an imaging optical system, 3 is a shared optical system shared by the target image projection system 1 and the imaging optical system 2, 4 is a chart projection system, 5 is an aiming optical system, 6 is an eye to be examined, and 7 is an anterior segment of the eye. Is. The target image projection system 1 has a function of forming a target image on the fundus 8 by projecting measurement target light as measurement light onto the fundus 8 of the eye 6 through the shared optical system 3. Element 9, condenser lens 10, index plate 11, reflection prisms 12 and 13, relay lens 14, reflection prism 15,
It is roughly constituted by a half-moon diaphragm plate 16. Here, the light emitting element 10 emits infrared light which is invisible light, and the infrared light becomes a parallel light flux by the condenser lens 10 and illuminates the index plate 11. As shown in FIG. 2, the index plate 11 is provided with slits 11a to 11d, and
Four deflection prisms 11e to 11h are attached. As a result, the index plate 11 is illuminated with infrared light to form measurement target light, and the deflection prisms 11e to 11h deflect the target light in a direction perpendicular to the longitudinal direction of the slit.

On the other hand, the common optical system 3 includes the slit prism 1
7. Image rotator 18, objective lens 19, and beam splitter 20. Then, the target light from the index plate 11 is reflected by the reflecting prisms 12, 13, 15 and guided to the half moon diaphragm plate 16, passes through the half moon holes 16a, 16b,
It is reflected by the reflecting surface 17a of the slit prism 17, and then,
The image rotator 18, the objective lens 19, and the beam splitter 20 pass through the pupil of the eye 6 to be examined and are projected on the fundus 8. The half-moon diaphragm plate 16 is arranged so as to be conjugate with the pupil position of the eye 6 to be inspected at an appropriate position with respect to the objective lens 19, and blocks reflected light harmful to measurement from the anterior segment 7 of the eye 6 to be inspected, and the target. The light is made to enter the eye 6 to be inspected. Further, the image rotator 18 rotates about the optical axis L of the shared optical system 3 by an angle of θ / 2 so that the measurement target image formed on the fundus 8 is rotated by an angle of θ in the meridian direction of the eye 6 to be inspected. It is to rotate.

The measurement target image, which is the measurement reflected light projected on the fundus 8, is a beam splitter 20 and an objective lens 1.
9, slit hole 19a of slit prism 19, aperture stop plate 2
The light is guided to the image forming optical system 2 through an opening 21a formed in the central portion of 1, a relay lens 22 and a reflecting prism 23. Further, the aperture stop plate 21 is arranged at a conjugate position with the pupil of the eye 6 to be inspected, and guides the reflected light passing through the central part of the pupil to the relay lens 22. Further, the image forming optical system 2 is roughly composed of a reflecting mirror 24, a moving lens 25, a reflecting mirror 26, a half mirror 27 and an image forming lens 28, and reflects the reflected light of the measurement target image formed on the fundus 8. It is configured to lead to the photocathode 29a of the image pickup device 29 and form a measurement target image on the photocathode 29a. here,
As described above, when the image rotator 18 is rotated about the optical axis L by the angle θ / 2, the measurement target image is rotated by the angle θ in the rotation direction.
Since the reflected light of the measurement target image reflected on the fundus 8 passes through the image rotator 18 again, the measurement target image rotates in the direction opposite to the rotation direction of the image rotator 18 by the angle θ, and the imaging device 29 of the image pickup device 29. A measurement target image oriented in a predetermined direction is formed on the photocathode 29a regardless of the rotation of the image rotator 18.

The chart projection system 4 includes a tungsten lamp 30, which is a visible light source, a color correction filter 31, a condenser lens 32, a chart plate 33, a moving lens 34, and reflecting mirrors 36 and 3.
7, a relay lens 38, a reflection mirror 39, and an objective lens 40. Here, the chart plate 33 is adapted to be illuminated by the tungsten lamp 30 via the condenser lens 31 and the color correction filter 32, and the emitted light of the tungsten lamp 30 is wavelength-selected by the color correction filter 32, from 400 nm. Only visible light up to 700 nm is transmitted. Then, a chart 33a as shown in FIG. 3 is formed on the chart plate 33,
The light from the chart 33a is moved by the moving lens 34 and the relay lens 3
It is guided to 8, the optical path is changed by the reflection mirrors 36, 37, 39,
It is guided to the beam splitter 41 through the relay lens 38 and the objective lens 40, and the eye to be inspected via the beam splitter 20.
It is projected toward 6.

Further, the aiming optical system 5 is an anterior segment of the subject's eye 6.
This is for forming the image of 7 on the photocathode 29a of the image pickup device 29, and the light flux reflected by the anterior segment 7 is the beam splitter 2
After being reflected by 0, 41 and the reflection mirror 42, they pass through the imaging lens 43, the half mirror 27, and the imaging lens 28, and an anterior segment image is formed on the photoelectric surface 29a of the imaging device 29. There is.

The image pickup device 29 is connected to the television monitor 44, and 45 is its display surface. An image formed on the photocathode 29a based on a video signal from the image pickup device 29 is displayed on the display surface 45 as a visible image. In FIG. 1, 46 is a measurement target image formed by the imaging optical system 2, and 47 is an anterior segment image formed by the aiming optical system 2.

Here, when the target image 46 displayed on the display surface 45 of the television monitor 44 is in focus at the fundus 8, as shown in FIG.
46a and distance L ₂ distance L ₁ and the lower pair of target image 46b of those that match. For example, the measurement target image is the fundus
If the focus is made in front of 8, the distance L ₁ becomes smaller than the distance L ₂ as shown in FIG. 5, while if the measurement target image is made in focus behind the fundus 8, As shown in, the interval L ₁ is larger than the interval L ₂ .

When objectively measuring the refractive power, the index plate 11 is moved so that the distances L ₁ and L ₂ of the measurement target images match, and the index refraction power is adjusted by the amount of movement of the index plate 11 at this time. Will be required. In this case, the moving lens 25 is driven integrally while maintaining a conjugate relationship with the index plate 11.

Next, the measuring circuit shown in FIG. 7 will be described.

A part of the video signal from the above-mentioned image pickup device 29 is input to the television monitor 44 to display an image of the anterior eye part, and the other part is a video signal based on the command signal of the extraction command circuit 51. The signal extraction circuit 52 extracts the video signal of the measurement target image. Then, the extracted video signal is subjected to waveform processing in the rectangular wave generation circuit 53 so as to be converted into a predetermined rectangular wave, and the obtained rectangular wave is processed by the video signal level determiner 54 to determine its brightness. While the level, that is, the light amount level of the measurement target image 46 is detected,
The target image position detection circuit 55 detects the signal interval, that is, the interval of the measurement target image 46.

Here, the signal processing of the output signals from the video signal level determiner 54 and the target image position detection circuit 55 or each signal described later is performed by the CPU 50 of the microcomputer.

The CPU 50 has a chart plate 33 as a fixation target.
Alternatively, a moving lens 34 and a fixation target drive switch 56 for moving the index plate 11, a drive switch 57 for fixing the position of the chart plate 33, and an automatic measurement start switch 58 for starting automatic measurement are respectively provided. It is designed to be controlled. Further, the CPU 50 is a drive control unit.
61 is controlled, and this control unit 61 is an index plate.
11 and a first drive control unit 62 for moving the moving lens 25 along the optical axis, a second drive control unit 63 for rotationally driving the image rotator 18 around the optical axis, and movement of the chart projection system 4. It comprises a third drive control unit 64 for moving the lens 34 along the optical axis. The CPU 50 is adapted to execute a predetermined automatic measurement program 64 installed in advance, and each measurement result is sequentially recorded by the printer 67.

Next, the operation of the eye refracting power measuring apparatus thus constructed will be described with reference to the flowchart of FIG.

First, it is assumed that both the infrared light emitting element 9 of the measurement target system 1 and the tungsten lamp 30 of the chart projection system 4 are turned on. This allows the eye to be examined
A measurement target image by invisible light and a chart image by visible light are superimposed and projected on the fundus 8 of 6, and the subject can observe only the chart image of the chart 33 as a fixation target. .

Next, when execution of arithmetic processing by the CPU 50 is started by turning on the power source or the like, in step 100, the moving lens 34 of the chart projection system 4 and the index plate 11 of the measurement target system 1 are initially set at positions corresponding to 0 diopters. To be done.

Here, when the eye 6 to be inspected is normal or hyperopic, the chart image can be focused,
The measurement target image 46 observed on the display surface 45 of the television monitor 44 is in a state in which the distances L ₁ and L ₂ are substantially the same as shown in FIG. 4, that is, a focused state. In this case, the examiner turns on the fixation target drive switch 58 to the plus drive side.
(Step 101), moving lens 34 and index plate 1 by a predetermined distance
Move 1 in the plus diopter direction (steps 102, 1
03), thereby changing the in-focus state of the chart image and the measurement target image.

When the moving lens 34 moves, the eye to be inspected
Within the range where the adjusting force of 6 acts, the subject comes to focus on the chart image, so that both the intervals L ₁ and L _{2 of the} measurement target image are kept in the same state, but the subject's eye 6
When the far point position of is exceeded, the chart image cannot be focused, and the measurement target image becomes a split state as shown in FIG.

The examiner observes the measurement target image 46 on the display surface 45 of the television monitor 44, and measures the measurement target image 46.
Until the split state is reached, the fixation target drive switch 57 is turned on to the plus drive side to move the moving lens 34 and the index plate.
Move 11 Set position after the movement (step 104)
Corresponds to the far point position of the eye 6 to be inspected.

On the other hand, in the initial setting of step 100, as shown in FIG.
When the split state as shown in (1) is observed, it means that the subject's eye 6 is myopia. In this case, the examiner turns on the fixation target drive switch 57 to the minus drive side to move the moving lens 34 and the index plate 11 in the minus diopter direction.

While observing the measurement target image 46 on the display surface 45 of the television monitor 44, the examiner moves the moving lens 34 and the index plate 11 to a position where the distances L ₁ and L ₂ match each other. The moving position at this time corresponds to the far point position of the eye 6 to be inspected. Instead of fixing to the far point position, the far point position may be set as a reference and fixed at a far position by a predetermined amount so as to be viewed as a cloud.

In this way, the examiner can set the chart image at the far point position of the subject's eye 6 while observing the in-focus state of the measurement target image 46.

Upon completion of such setting adjustment, the examiner turns on the fixation target position setting switch 56 (step 104), and the movable lens 34 is always placed at the same position during the subsequent measurement period. That is, in the subsequent steps 105 to 105, the chart projection system 4 is fixed.

Next, when the automatic measurement start switch 59 is turned on (step 105), the CPU 50 calls the automatic measurement program 65, and the following measurement is performed according to the automatic measurement program 65.

First, in the initial setting in step 106, the first drive control unit 62 sets the index plate 11 to the 0 diopter position, and the second drive control unit 63 sets the image rotator 18.
Is set to the 0 ⁰ position, respectively.

In the following step 107, the video signal level determiner 54 checks the light amount level of the measurement target image 46 based on the video signal from the image pickup device 29. As a result of this level check, when the light amount level exceeds the predetermined level, the intervals L ₁ and L ₂ between the measurement target images are detected based on the output from the target image position detection circuit 55.

When the intervals L ₁ and L ₂ are detected, the CPU
50 calculates the distance difference L ₁ over L _2, the distance difference L ₁ over L ₂ is 0
Until, that is, to the position where the measurement target image 46 is focused on the fundus 8, the index plate 11 and the moving lens 25 move integrally along the optical axis (steps 108 and 109). Then, when the interval difference L ₁ -L ₂ becomes 0, the position of the moved index plate 11 is read (step 110), and 0 is obtained based on this moved position.
Degree of refraction in the meridian direction is obtained.

Then, while the position of the index plate 11 is fixed,
The image rotator 18 is rotated 15 times in succession every 6 ° (direction of meridian to be measured), and the interval difference L ₁ -L ₂ corresponding to each rotational position is read (step 1
11-113), the refractive power in each meridian direction is calculated
(Step 114). Here, the refractive power Dθ in the θ direction is the diopter value corresponding to the stop position of the index plate 11 and the interval difference L ₁
It is obtained by finding the sum of the L ₂ value and the corresponding diopter value. The refractive power D has a relationship with the spherical power A, the astigmatic power B, and the astigmatic axis α as shown by the following expression (1).

[0038] D? = A + Bcos (theta over alpha) ... (1) Thus, based on the refractive power Dishita～dishita ₁₅ obtained in each meridian direction (15 meridian direction), the spherical power A by the method of least squares, astigmatic power B, And the astigmatic axis α are calculated respectively
(Step 115).

The spherical power A, the astigmatic power B, and the astigmatic axis α thus obtained are displayed on the television monitor 44 and recorded by the printer 67 (steps 116, 11).
7).

In the above embodiments, the case where the present invention is applied to an automatic eye refractive power measuring device has been described, but the present invention is not limited to this, and a corneal shape measuring device, a non-contact tonometer, and a corneal thickness. It is also applicable to ophthalmologic devices such as measuring devices.

[0041]

According to the ophthalmologic apparatus of the present invention, the measurement reflected light from the eye to be examined and the anterior segment image can be received by one photoelectric detector with a simple structure without complicating the optical system. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical system of an automatic eye refractive power measuring device according to the present invention.

FIG. 2 is a perspective view of an index plate that constitutes the optical system.

FIG. 3 is a plan view of a chart plate that constitutes the optical system.

FIG. 4 is a schematic diagram showing a first aspect of an image formation state of a measurement target image formed by the optical system.

FIG. 5 is a schematic diagram showing a second aspect of an image formation state of a measurement target image formed by the optical system.

FIG. 6 is a schematic diagram showing a third aspect of an image formation state of a measurement target image formed by the optical system.

FIG. 7 is a measurement circuit diagram for driving the device.

FIG. 8 is a flowchart for executing a program by the measuring circuit.

[Explanation of symbols]

 1 ... Target image projection system 4 ... Chart projection system 6 ... Eye 33 ... Chart plate 46 ... Measurement target image 29 ... Imaging device 44 ... TV monitor 50 ... CPU 64 ... Auto measurement program

Claims (1)

[Claims] 1. A projection system for projecting measurement light of an eye to be inspected,
In the ophthalmologic apparatus that projects the measurement reflected light of the eye to be examined onto a photoelectric detector, and inspects the eye to be inspected by a signal from the photoelectric detector, an optical system for observing the anterior segment of the eye to be examined is provided. An ophthalmologic apparatus in which a photoelectric detector of the optical system is also used as a photoelectric detector for detecting the measurement reflected light.