JPH0566125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ophthalmological measuring device that is capable of continuously measuring the refractive power and corneal shape of an eye to be examined using the same device.

[Prior Art] Generally, when testing the refractive power of the eye, it is necessary to measure the corneal shape to test for astigmatism in parallel with the eye refractive power measurement. It is becoming increasingly important to carry out measurements in parallel.

Conventionally, eye refractive power has been measured separately using an automatic refractive power measuring device called an autoref, and corneal shape measurement has been performed using an automatic corneal shape measuring device called an autokerato. When measuring eye refractive power with an auto-reflex, the eye under test has an accommodative effect, so each eye is measured approximately 3 to 5 times, and the results are averaged to select a stable value. I'm looking for. Also,
In the case of corneal topography measurement, the corneal topography is relatively stable, but the measurement accuracy is more sensitive to alignment accuracy and eye movement than in the case of ocular refractive power measurement, so autoreflex and Similarly, a method is adopted in which measurements are taken about 3 to 5 times and the average value is determined.

In this way, in the conventional case, eye refractive power measurement and corneal topography measurement are performed using separate devices, and each measurement is repeated about 3 to 5 times, and the average is used to select stable data from among them. Because the process requires a lot of time to measure each patient and organize the obtained measurement values, it is a considerable burden on both the patient and the examiner. It's summery.

[Object of the Invention] An object of the present invention is to improve the above-mentioned conventional drawbacks by selecting and storing the order and/or measurement of eye refractive power and corneal shape using the same device. Make measurements based on stored information,
An object of the present invention is to provide an ophthalmologic measuring device that can continuously perform a necessary number of measurements in one measurement operation and that reduces the time and labor required for examination.

[Summary of the invention] The gist of the present invention for achieving the above object is as follows:
An ophthalmological measuring device having an optical system for measuring eye refractive power and an optical system for measuring corneal shape that partially share an optical system, wherein the measurement order and/or the number of measurements for eye refractive power measurement and corneal shape measurement are A selection means to select,
An ophthalmological measuring device characterized by comprising a storage means for storing information selected by the selection means, and a control means for performing each measurement according to the information stored in the storage means.

[Embodiments of the Invention] The present invention will be described in detail below based on illustrated embodiments.

FIG. 1 shows an optical system showing one embodiment of the present invention. When measuring the corneal shape, visible light emitted from the ring-shaped strobe 1 illuminates a circular slit 3 provided on the opposite side of the collimator ring lens 2 to the eye E to be examined. This slit 3
is the ring lens 2 when viewed in one cross section including the optical axis.
The slit 3 is optically located at the eyeless far point, and the light projected from the eyeless far point illuminates the cornea Ec of the eye E. Since the surface of the cornea Ec is shaped like a convex mirror, it forms a corneal reflection image Sa of the slit 3, and this corneal reflection image Sa is transmitted through the objective lens 4 as a dichroic mirror that transmits visible light and reflects infrared light. 5, passes through a half mirror 6, passes through a multi-hole aperture 7, is further deflected by a prism 8,
The image is re-imaged onto the one-dimensional position detection element 9.

The multi-hole diaphragm 7 has, for example, five openings 7a to 7e, as shown in FIG. It has five elements 8a to 8e,
Each of the elements 8a to 8e has a cross-sectional shape as shown in b. The five corneal reflection images separated by the multi-hole aperture 7 and the prism 8 are
They are coupled at the position of the detection element 9 in the relationship shown in FIG. In this figure 3, Sb is the corneal reflection image.
Sa represents the corneal reflection image formed and separated by the objective lens 4, and 9a to 9e are detection elements, respectively, and the apertures 7a to 7ee and the prism element 8.
It corresponds to each of a to 8e. As a result, the coordinates of five points in the corneal reflection image Sb are detected, and by substituting the coordinates of these five points into the general formula of the quadratic curve, AX ² + BXY + CY ² + DX + EY + F = 0, the simultaneous The coefficient A by solving the equation
Find ~E and use the general formula for an ellipse, (x-xo) ² /a ² + (y-yo) ² /b ² = 1, where x = X cosθ - Y sinθ y = X sinθ + Y cosθ Transform the ellipse The radius of curvature of both principal meridians of the cornea Ec can be derived from the major axis a and the minor axis b, and the astigmatic axis can be calculated from the angle θ.

On the other hand, in the case of refractive power measurement, as shown in FIG. 1, light from a light emitting diode 10 that emits infrared light passes through a condenser lens 11 and illuminates a fundus projection chart 12. As shown in FIG. 4, this chart 12 is provided with three slits 12a to 12c in three meridian directions that form an angle of 120 degrees with each other. The light from the light emitting diode 10 further passes through a relay lens 13 and forms an image on a fundus illumination diaphragm 14, and then passes through a perforated mirror 15,
It passes through the relay lens 16, is reflected by the dichroic mirror 5 because it is infrared light, and is imaged on the pupil of the eye E through the objective lens 4.
It is designed to illuminate Ef.

In addition, the slits 12a to 12c of the chart 12
is once imaged through relay lenses 13 and 16,
It is projected by the objective lens 4 so as to be conjugate with the fundus of the emmetropic eye. The reflected image from the fundus Ef passes through the objective lens 4 again, is reflected by the dichroic mirror 5 to form an image, and further passes through the relay lens 16 and is reflected by the perforated mirror 15. A diaphragm plate 17 is arranged on the reflection side of the perforated mirror 15, and this diaphragm plate 17 has six apertures 17 as shown in FIG.
a to 17f. And opening 17a
and 17d, 17b and 17e, 17c and 17f are
Each corresponds to form one channel. The fundus illumination diaphragm 14 and the diaphragm plate 17 form images on the pupil of the eye E to be examined, as shown at 14A and 17A in FIG. 6, and separate the projection system and measurement system of the chart 12. .

The light beam divided by the aperture plate 17 passes through the imaging lens 18 and is separated by the prism 19, and is focused by the cylindrical lens 20 in the transverse direction of the one-dimensional position detection element 21. The image is formed on the detection elements 21a to 21c. The prism 19 is 6 as shown in FIG. 7a.
The prism 19 has six elements 19a to 19f and is designed to separate images corresponding to the six apertures 17a to 17f of the aperture plate 17. FIG. 7b shows the cross-sectional shape of the prism 19. It is something that

The thus separated images are focused in the longitudinal direction of the images by three cylindrical lenses 20a to 20c, and are imaged onto detection elements 21a to 21c. FIG. 8 shows the state of formation of this fundus image, and 22a to 22f represent fundus images formed corresponding to the openings 17a to 17f.

If the eye E to be examined is an ametropic eye, the light ray that exits the fundus Ef and passes through a certain point on the pupil will exit at an angle that corresponds to the refractive power, so an optical system such as the one in this example is used. Then, two fundus images 2 are formed on each of the detection elements 21a to 21c according to the refractive power of the eye E to be examined.
2 distance will change. Therefore, 2 in advance
By determining the relationship between the distance between the two fundus images 22 and the refractive power, the refractive power in the three radial directions can be measured. Substituting each refractive power into the following equation, D = A sin (2ω + θ) + B, the spherical surface can be calculated. Can calculate power, astigmatism power, and astigmatism axis. The variables D and ω represent the refractive power and the radial angle, respectively, and the constants A, B, and θ correspond to the degree of astigmatism, the average refractive power, and the astigmatic axis, respectively.

The alignment between the eye E and the instrument is achieved by focusing the light rays from the anterior segment of the eye that have passed through the dichroic mirror 5 and reflected off the half mirror 6 using the objective lens 4 onto the TV image pickup tube 24 using the TV relay lens 23. The images can be imaged and adjusted using a television monitor connected to the television image tube 24.

Furthermore, once the eye refractive power and the corneal shape are determined, the astigmatic power can be determined by subtracting the corneal astigmatic power from the total astigmatic power. In other words, the total astigmatic power of the eye refractive power is
Ct, astigmatism axis is AXt, corneal astigmatism power is Cc, astigmatism axis is AXc, astigmatism power other than cornea is Cr, astigmatism axis is
If Axr is Cr sin2AXr=Ct sin2Axt− Cc Sin2AXc Cr cos2Axr=Ct cos2AXt −Cc cos2Axc, AXr=(1/2) tan ^-1 {(Ct sin2AXt Cc sin2AXc) /(Ct cos2AXt−Cc cos2AXc)} Cr= (Ct sin2AXt−Cc sin2AXc) /sin2AXr.

FIG. 9 is a block diagram of the electric control circuit, and the same reference numerals as in FIG. 1 represent the same members. The signal from the one-dimensional position detecting element 9 described above is sent to the corneal shape signal processing circuit 25 and to the one-dimensional position detecting element 21.
The signals from the eye refractive power signal processing circuit 26 are inputted to the eye refractive power signal processing circuit 26, processed, and outputted to the internal bus 27. The internal bus 27 includes a CPU 28 that controls and calculates the entire system, a ROM 29 that stores a control program, and a first RAM 30.
A second RAM 32 that can retain memory contents even when the power is turned off by the battery VB and power switching circuit 31, a video memory 33 for displaying characters such as measurement results on images, and other external An interface 34 and the like for inputting and outputting signals to and from an input device is connected.

A mixer circuit 35 is connected to the video memory 33, and a television image pickup tube 22 is connected to the mixer circuit 35.
4 is also input and further output to the television monitor 36. The interface 34 includes a measurement switch 37, a light emitting diode 10 for measuring eye refractive power, a strobe drive circuit 38 for driving the ring-shaped strobe 1, a printer 39 for printing measurement results, and a corneal shape measurement and A priority switch 40 is connected to determine which of the eye refractive power measurements should be prioritized. Furthermore, a digital switch 41 is provided for setting the number of corneal topography measurements.
and preset counters 43 and 44 that respectively preset the values set in the digital switch 42 for setting the number of measurements of eye refractive power.
is connected to the interface 34, and the preset signal S1 from the interface 34 to the preset counters 43, 44, the preset counter 43
A countdown signal S2 to the preset counter 44 and a countdown signal S3 to the preset counter 44 are respectively connected.

When performing measurements, first the number of measurements of eye refractive power measurement and corneal shape measurement and which one to perform first are determined. For example, if you want to prioritize corneal topography measurement, turn on the priority switch 40, and if the number of corneal topography measurements is 3, turn on the digital switch 41.
If the number of eye refractive power measurements is 5, the digital switch 42 is set to 6.

Next, after adjusting the alignment of the extraocular image of the eye E displayed on the TV monitor 36 via the TV tube 24, when the measurement switch 37 is pressed, the preset signal S1 is sent from the interface 34. output and digital switch 41,4
The value set to 2 is preset counter 4.
They are set to 3 and 44, respectively. Next, the countdown signal S2 is sent to the preset counter 3 to decrease the number of stored sets by 1, and the strobe drive circuit 3
8 to cause the ring-shaped strobe 1 to emit light, a reflected image Sb from the cornea Ec of the eye E to be examined is focused on the one-dimensional position detection element 9. The output signal from the one-dimensional position detection element 9 is waveform-shaped, amplified, and A/D converted by the corneal shape signal processing circuit 25, and then stored in the RAM 30. And RAM3
The peak address of the waveform is determined from the signal stored at 0 and stored at another address in the RAM 30.

This measurement is repeated until the value of the preset counter 43 becomes zero, and the peak address of the waveform is stored in the RAM 30 for each measurement. When the value of the preset count 43 becomes zero, the process immediately shifts to eye refractive power measurement. In that case, first, a countdown signal S3 is output to decrease the number of stored sets in the preset counter 44 by 1, and the light emitting diode 10 is caused to emit light to project the fundus projection chart 12 onto the fundus Ef.
A reflected image 22 from the fundus Ef is formed on the one-dimensional position detection element 21. The output signal from the one-dimensional position detection element 21 is input to the eye refractive power signal processing circuit 26, subjected to waveform shaping, amplification, and A/D conversion processing, and then stored in the RAM 30. Then, as in the case of corneal topography measurement, find the peak address of the waveform.
It is stored in yet another address in the RAM 30. After that, repeat the measurement until the value of the preset counter 44 becomes zero, and check the peak of the waveform for each measurement.
Store it in RAM30.

After both measurements have been completed, that is, after the values of the preset counters 43 and 44 have reached zero,
The measurement result for each measurement is calculated from the peak address of the corneal shape measurement signal and the peak address of the eye refractive power measurement signal stored in the RAM 30, and the total astigmatism is further calculated from both results obtained by averaging processing. The astigmatic power obtained by subtracting the corneal astigmatism power from the dioptric power and its axial degree are determined and displayed on the television monitor 36, and, if necessary, are output to the printer 39 and printed.

Next, at the time of measurement, the number of measurements has already been set in the digital switch, so there is no need to reset it, and the measurement can proceed directly. If it is desired to reverse the measurement order, the priority switch 40 can be turned off. Further, if only corneal topography measurement is required, the value of digital switch 42 may be set to zero, and no eye refractive power measurement will be performed.

If the waveform captured during measurement is lower than the predetermined value due to movement or blinking of the eye E to be examined, the measurement may be performed again without subtracting the values of the preset counters 43 and 44. good.

In the above-mentioned embodiment, a case was shown in which the number of measurements was set and the counter was performed using hardware.
It is also possible to set the number of measurements using a keyboard or switch (not shown) and count down on the program.

[Effects of the Invention] As explained above, the ophthalmological measuring device according to the present invention can perform eye refractive power measurement and corneal shape measurement with the same device, and can change the order of each measurement and/or the number of measurements. By selecting, memorizing, and performing measurements based on the stored information, the required number of measurements can be performed continuously in one measurement operation, reducing the time and effort required for inspection compared to conventional methods. The effect is that it can be significantly reduced.

[Brief explanation of the drawing]

The drawings show an embodiment of the ophthalmological measurement device according to the present invention, and FIG. 1 is an optical layout diagram, FIG. 2a is a relationship diagram with a multi-hole aperture prism, FIG. Figure 3 is a diagram of the relationship between the detection element and the corneal reflection image, Figure 4 is a diagram of the arrangement of the slits in the fundus projection chart, Figure 5 is a front view of the aperture of the aperture plate, and Figure 6 is a diagram of the relationship between the detection element and the corneal reflection image.
The figure is an explanatory diagram of the image of the fundus illumination diaphragm and the aperture plate on the pupil of the subject's eye, Figure 7a is a front view of the prism element, b is its cross-sectional view, and Figure 8 is the relationship between the detection element and the fundus image. FIG. 9 is a block circuit diagram of the control circuit. 1 is a ring-shaped strobe, 2 is a ring lens, 3 is a slit, 4 is an objective lens, 5 is a dichroic mirror, 6 is a half mirror, 7 is a multi-hole diaphragm, 8 is a prism, 9 is a detection element, 10 is a light emitting device Diode, 12 is a fundus projection chart, 14 is a fundus illumination diaphragm, 15 is a perforated mirror, 17 is an aperture plate, 19 is a prism, 20 is a cylindrical lens, 21 is a detection element, 24 is a television imaging tube, 25
26 is a corneal shape signal processing circuit, 26 is an eye refractive power signal processing circuit, 27 is an internal bus, 28 is a microprocessor, 29 is a ROM, 30 and 32 are RAMs, and 33
is a video memory, 34 is an interface, 35 is a mixer circuit, 36 is a television monitor, 37 is a measurement switch, 38 is a strobe drive circuit, 39 is a printer, 40 is a priority switch, 41 and 42 are digital switches, 43 and 44 are This is a preset counter.

Claims (1)

[Scope of Claims] 1. An ophthalmological measuring device having an eye refractive power measuring optical system and a corneal shape measuring optical system that partially share an optical system, the measurement order of eye refractive power measurement and corneal shape measurement and/or comprising a selection means for selecting each number of measurements, a storage means for storing information selected by the selection means, and a control means for performing each measurement according to the information stored in the storage means. An ophthalmological measuring device characterized by: 2. The ophthalmologic measuring device according to claim 1, further comprising means for calculating and obtaining measurement results after each measurement is completed. 3. Obtain the average value for each measurement of corneal shape and eye refractive power from the measurement results of each of the above measurements, and remove the corneal astigmatism power from the total astigmatism power of the eye to be examined from the corneal shape average value and eye refractive power average value. The ophthalmologic measuring device according to claim 1, further comprising means for calculating an astigmatic power and an axial angle thereof. 4. The ophthalmologic measuring device according to claim 1, further comprising means for subtracting 1 from the number of measurements in the storage means for each measurement prior to each measurement, and repeating the measurement until the number becomes zero. 5. Claim 4, further comprising means for comparing the measurement signal obtained in each of the measurements with a predetermined value, and performing re-measurement without subtracting the number of measurements in the storage means if the signal is smaller than the predetermined value. The ophthalmological measuring device described in . 6. The ophthalmological measuring device according to claim 1, wherein the selection means is capable of setting the number of measurements of either eye refractive power measurement or corneal shape measurement to zero.