JPH0410332B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an eye refraction testing device, more specifically, an optotype projection system that projects an optotype onto the fundus of an examinee's eye using near-infrared light, and an eye refraction tester. The present invention relates to an ocular refraction measurement apparatus that includes a measurement optical system that detects an optotype image, and a gaze target system that projects at least one of a fixation target and a trial visual acuity chart onto the fundus of an eye to be examined using visible light.

[Prior art]

As an example of a conventional subjective/objective eye refraction measuring device, an eye chart is built into the gaze target system to enable confirmation of unaided visual acuity and corrected visual acuity, and the eye chart is used after objective measurement. A device has been proposed that allows a subjective test to check the measured value of the spherical power by an objective test.

However, in the conventional apparatus described above, the subjective measurement is only performed using the gaze target system of the objective refraction measurement apparatus, and therefore, the subjective measurement is extremely difficult in practice. In other words, objective refraction measurement is easy to operate and can be performed relatively easily and accurately even by inexperienced examiners, but subjective refraction measurement has various expressions for how the examinee sees the visual acuity chart. The examiner must proceed with the visual acuity test while estimating the state in which the examinee is viewing the visual acuity chart based on the responses, and accurate measurements are only possible with years of experience. There was a problem.

As another example of a conventional eye refraction measuring device, an apparatus has been proposed in which a subjective measuring device is provided independently of an objective measuring device. This is because the subjective measurement device is designed exclusively for subjective measurement, so by fully operating it, highly accurate measurements can be expected. The problem remains that it cannot be done accurately.

[Purpose of the invention]

The object of the present invention is to provide an optotype projection system that projects an optotype onto the fundus of an examinee's eye using near-infrared light, a measurement optical system that detects the optotype image on the fundus of the examinee's eye, and a measurement optical system that projects an optotype onto the fundus of an examinee's eye using visible light. In an eye refraction measurement device consisting of a gaze target system that selectively projects a fixation target and a trial visual acuity chart, a cylindrical dioptric power is placed at a fixed position approximately conjugate to the eyeglass wearing position of the subject's eye within the gaze target system branched from the measurement optical system. An object of the present invention is to provide an eye refraction testing device configured by arranging a cylinder optical system for converting a cylinder axis.

[Structure of the invention]

In order to achieve the above object, the present invention has the configuration shown below. That is, the present invention includes an optotype projection system that projects an optotype onto the fundus of the examinee's eye using near-infrared light, a measurement optical system that detects the optotype image on the fundus of the examinee's eye, and a visual target image that projects the optotype onto the fundus of the examinee's eye using visible light. In an eye refraction measuring device comprising a gaze target system that projects at least one of a fixation target and a trial visual acuity chart onto It consists of a cylinder optical system.

The present invention further provides that the cylinder optical system comprises:
It is constructed by selectively arranging a plurality of cylindrical lenses on a predetermined optical axis. Alternatively, a pair of the same refracting powers may be arranged adjacently so that the intersection points of their axes coincide with a predetermined optical axis, and can be rotated by the same angle in opposite directions with the initial position being the position where the mutual axes intersect perpendicularly. It consists of a cylindrical lens.

[First embodiment: manual refractometer] As shown in FIG. It consists of an optotype projection system 102 that projects a measurement optotype onto the fundus R, and a measurement optical system 104 that measures the refractive power of the eye to be examined.

The gaze target system 100 is reflected by a mirror M ₃ and an infrared-transmissive visible-reflection mirror HM, and is directed toward the subject's eye E.
A condenser lens L ₈ for illuminating the target T ₃ with the light flux from the light source _{E 2 sequentially} from the light source E ₂ in the direction of the eye E to be examined on the gaze target optical axis O 1 incident on the eye.
target T ₃ , relay lens L ₇ for relaying the target image of target T ₃ , cylindrical lens system C ₂ , mirror M ₃ , target image to be examined fundus R
An objective lens L ₆ for forming an image, and an infrared transmitting and visible reflecting mirror HM are arranged.

The gaze target T ₃ allows the Stabast visual chart for objective testing, Landolt visual chart for each visual acuity value for subjective testing, astigmatism chart, R&G test visual chart, etc. to be selectively inserted onto the gaze target optical axis O ₁ . configured.

The cylindrical lens system _C2 is placed at a position that is optically conjugate with the subject's glasses-wearing position (12 mm in front of the cornea) with respect to the objective lens _L6 , and its cylindricity is adjusted in a stepwise manner, as will be described in detail later. A changing system and a continuous system changing configuration are selectively adopted.

The optotype projection system 102 includes a condenser lens L ₃ , an infrared filter F, and a measurement target T ₁ for sequentially illuminating the measurement target T 1 with the light beam from the light source E in the direction from the light source E ₁ to the eye E to be examined _. , a projection lens L ₂ that projects the target image of the measurement target T ₁ onto a position 120 on the optical axis 102, and a mirror.
M ₂ , a cylindrical lens system C ₁ , an aperture D ₁ having four openings outside the optical axis, a perforated mirror M ₁ , an image rotator IR that rotates the light beam around the optical axis O ₂ , and an aperture D ₁ connected to the subject's eye An objective lens L ₁ that forms an image on the pupil P and a target image formed at a position 120 on the fundus R of the eye to be examined, and an infrared transmitting and visible reflecting mirror HM are arranged. In the optotype projection system 102, the optical paths of the light beams that have passed through the four openings of the aperture _D1 are schematically shown in FIGS. 2A and 2B, and will be explained in detail later.

The measurement target _T1 is as shown in Fig. 3.
It has one set of slits S ₁ and S ₂ parallel to the horizontal axis H, and two sets of slits S ₃ to S ₆ parallel to the vertical axis V, and each of the slits S ₁ to S ₆ is from the optical axis O ₂ . They are set apart. Also, Slit S ₁ or
As shown in _{FIG .}
or P ₁₂ is installed. Cylindrical lens system C ₁
is arranged conjugately with the eyeglass wearing position with respect to the objective lens _L1 , and the cylinder power is changed in conjunction with the change in power of the cylinder lens system _C2 of the gaze target system 100, and the lens is centered on the optical axis _O2 . No rotational movement.

The measuring optical system 104 includes an infrared transmitting visible reflecting mirror _HM , an infrared transmitting visible reflecting mirror HM,
An objective lens L ₁ that images the fundus R of the subject's eye at a position 120 on the optical axis O ₃ , an image rotator IR that rotates the light flux of the optotype projection system 102 and the measurement optical system 104 around the optical axis O ₃ , and a hole. Mirror M ₁ ,
The fundus image formed on position 120 is transferred to reticle T ₂
An imaging lens L ₄ to form an image on the reticle T ₂ , relay lenses L ₅ and L ₆ to form an image of the reticle T ₂ onto an infrared TV camera, an infrared TV camera TV, and an infrared TV camera TV. Captured fundus image R of the subject's eye
as well as displaying the reticle image of Reticle T ₂
Consists of CRT display M.

The reticle T ₂ and the relay lens L ₅ are integrally movable on the measurement optical axis O ₃ , and the gazing target system 100
and target T _{3 of} the optotype projection system 102 . Image rotator IR is
It rotates around the optical axis O ₃ in conjunction with the cylindrical lens system C ₁ of the gaze target system 100 .

By the way, the optical path of the light beam that has passed through the four openings A ₁ to A ₄ of the aperture D ₁ of the optotype projection system 102 is shown in FIGS. 2A and 2B as a measurement target. Only the light beams passing through the two sets of slits S ₁ to S ₄ at T ₁ are shown. Moreover, FIG. 2A shows the case where the cylindricity of the cylindrical lens system C ₁ is 0, and the luminous flux passing through the slits S ₁ , S ₂ and the apertures A ₁ , A ₂ , and the slits S ₃ , S ₄ and the aperture A ₃ , the light flux that passed through _A4 is transmitted to the projection lens _L2
Both positions 120 on the optotype projection optical axis O ₂
The images are formed as I _1,2 and I _3,4 , and the images are further formed as 1' _1,2 and I' _3,4 on the fundus R by the objective lens L ₁ . At this time, I' _{3 and 4} are vertically divided and separated due to the astigmatism of the eye E to be examined.

On the other hand, in Fig. 2B, the cylindrical lens system C ₁ is
I _1,2 is imaged at position 120 as in FIG. 2A, but I _3,4 is imaged at position 120 by the cylindrical lens system C ₁ . 1
20, the image is formed closer to the eye E to be examined. but,
I _1,2 and I _3,4 are imaged as I' _1,2 and I' _3,4 on the fundus R by the objective lens L ₁ and the refractive power of the eye to be examined with astigmatism.

On the other hand, the configuration of the method of changing the cylindricity of the cylindrical lens system _C2 of the gaze target system 100 in a stepwise manner is as follows.
As shown in the figure and FIG. 5, the lens support plate 17,
19 is a slot 17 formed to extend in the radial direction between the respective cylindrical lenses 2a and 2b.
a, 19a. A drive plate 21 for driving the lens support plates 17 and 19 is a drive plate 21 for driving the lens support plates 17 and 19.
7 and 19, and is rotationally driven via gears 23 and 24 by a cylindricity measuring knob 22a on the outer shaft of an operation knob 22 provided on the device housing (not shown). The drive plate 21 has a plurality of pins 25 protruding in the axial direction around the periphery, and the pins 25 sequentially engage the slots 17a of the first lens support plate 17 to drive the support plate 17 in stages. and lens 2
a is placed on the optical axis O ₁ of the gaze target system 100. One of the pins 25, ie, the pin designated 25a, has a longer axial dimension than the other pins, and is attached to the support plate 1.
It can be engaged with both slots 17a and 19a of 7 and 19. Therefore, when the lens support plate 17 is driven step by step by the drive plate 21 and rotates once, the lens support plate 19 is rotated by one step and places one of the lenses 2b on the optical axis _O1. .
For positioning the support plates 17 and 19, the drive plate 21
A recess 26 is provided around the support plate 19, and a recess 27 is provided around the support plate 19, and these recesses 26 and 27 engage with stoppers 28 and 29, respectively.

Note that the above-mentioned cylindrical lens system _C2 may be constructed from a known variable cross cylinder.

Next, various visual acuity measurements using the manual refractometer will be explained.

Measurement of naked eye visual acuity Turn on the light source _E2 of the gaze target system 100, and use the Landolt optotype, astigmatism chart, and R&G as the target _T3.
A test chart or the like is sequentially inserted into the optical path, and the naked eye visual acuity is measured based on the test subject's responses. At this time, it goes without saying that the targets T ₁ and T ₂ and the cylindrical lens systems C ₁ and C ₂ are all reset to their initial positions (zero).

Objective test and subsequent subjective test (1) Objective test Turn on the light source E ₁ of the visual target projection system 102 _;
Only the infrared light is transmitted through an infrared filter F to illuminate the target _T1 . The light passing through the slits S ₁ to _{S 6} of the target T ₁ is transmitted through the projection lens L ₂ ,
The fundus R of the eye E to be examined passes through the mirror M ₂ , the aperture D ₁ , the perforated mirror M ₁ , the image rotator IR, the objective lens L ₁ , and the infrared transmission visible reflection mirror HM.
are projected upward to form images S ₁ to _{S 6} of the slits S ₁ to _{S 6} on the fundus.

The slit images S ₁ to _{S 6} projected onto the fundus R are formed onto a reticle T ₂ through an objective lens L ₁ , an image rotator IR, a perforated mirror M ₁ , and an imaging lens _{L 4} . The upper slit image is received by the TV camera via relay lenses L ₅ and L ₆ , and the slit images S ₁ '~ are displayed on the CRT display M.
S ₆ ′ is displayed.

Figure 6A shows the case where the eye to be examined has astigmatism and neither the first focal line nor the second focal line has been determined.
3 is a schematic diagram showing a slit image display state on a CRT display M. FIG.

First, in the cylinder degree adjustment mechanism shown in FIGS. 4 and 5, rotate the cylinder axis setting knob 22b on the inner axis of the cylinder lens operation knob 22 to adjust the cylinder lens 2a,
Rotate 2b. Since the rotation of the lenses 2a and 2b is linked to the image rotator IR, the image rotator IR is rotated about the optical axis _O3 . Turn the knob 22b to align the slit lines S ₅ ' and S ₆ ' in a straight line, as shown in FIG. 6B. This determines the cylinder axis direction.

Next, the target _T1 is moved along the optical axis _O2 by operating a spherical power measuring knob (not shown).
This target T ₁ is linked to the reticle T ₂ of the measurement optical system, the relay lens L ₅ , and the target T ₃ of the gaze target system, so when the target T ₁ moves, these four also move on their respective optical axes. do. Then, as shown in Figure 6C, the slit line
The target T ₁ is moved until each of S ₁ ′ and S ₂ ′ is focused on a straight line. The spherical power is measured from the amount of movement of the target _T1 .

Next, the cylindrical power measuring knob 22a on the outer axis of the operation knob 22 is rotated, and the cylindrical lens system C ₂ of the gaze target system 100 and the cylindrical lens system C ₁ of the optotype projection system 102 interlocked with the cylindrical lens system The cylindrical lenses 2a and 2b are sequentially inserted into the optical path in the direction of increasing power so that the slit lines S ₃ ′ and S ₄ ′ are aligned in a straight line as shown in FIG. 6D, thereby eliminating astigmatism. Measure frequency. The above-mentioned objective test results are digitally displayed on a CRT display M.

(2) Subjective test after objective test As a result of the above-mentioned objective test, the cylindrical lens system _C2 of the gaze target system has the cylindrical lens power and cylinder axis angle set according to the astigmatism component of the subject's eye, and the target Since T ₃ has been moved to a position that corresponds to the spherical component of the subject's eye, this target T ₃ can be replaced with a Landolt chart for subjective testing, an astigmatism test chart, an R&G test chart, etc., so that it can be used for objective testing. A subjective test can be performed in the corrected state.

If the visual acuity value according to the Landolt chart is not sufficient (for example, if a visual acuity of 1.0 cannot be obtained), operate the spherical measurement knob (not shown) to adjust the target T ₃ .
(Landolt visual acuity chart with visual acuity of 1.0) is moved along the optical axis O ₁ to a position where a visual acuity value of 1.0 can be seen, and a measured value can be obtained from the subjective test from this amount of movement.

Astigmatism power, astigmatic axis objective test value, correction by subjective test is cylindrical lens power of cylindrical lens system _C2 ,
This can be done by correcting the cylindrical lens axis angle. In addition, a known cross cylinder optical system is additionally inserted into the gaze target system for precise measurement of astigmatism.
This allows for precise measurements.

Next, the shaft 18 is rotated via the bevel gears 30 and 31 by the cylindrical shaft measuring knob 22b on the inner shaft of the operation knob 22, and the gear 18a attached to the shaft 18 is rotated.
Rotate. Since the gear 18a meshes with teeth formed on the outer circumferential surfaces of holding pieces 20a and 20b that rotatably hold the lenses 2a and 2b within the lens plates 17 and 19, by rotating the axis setting knob 22b, The axial angles of the cylindrical lenses 2a and 2b can be set.

The measurement results of the above subjective tests are also digitally displayed on the CRT display M.

Subjective test and real-time objective measurement Light source E ₂ of gaze target system 100 and optotype projection system 10
The second light source _E1 is turned on to illuminate the target _T3 . First, insert an astigmatism chart (for example, a sunburst type) into the optical path as the target _T3 , and move the target _T3 along the optical axis until you can see each axis of the astigmatism chart.
Move along O ₁ .

Next, we asked whether each radial line on the astigmatism chart looks uniform, and whether there are radial lines that appear sharper than others.
If there is a line that is clearly visible, have the children answer its direction. The astigmatic axis direction is determined from the answered radial direction, and the cylindrical lens axis of the cylindrical lens system _C2 is set accordingly by rotating the cylindrical axis angle measuring knob 22b. Next, the cylindrical power measuring knob 22b is operated, and the cylindrical lens is inserted into the optical path until each meridian on the astigmatism table becomes uniformly visible.

Next, the target _T3 is switched from the astigmatic chart to the Landolt chart, and the target _T3 is moved along the optical axis _O1 until the desired visual acuity value (for example, 1.0) is obtained on the Landolt chart. At this time, the spherical power in the subjective test can be determined from the moving position of the target _T3 , and the astigmatic power can be determined from the cylindrical lens power of the cylindrical lens system _C2 .
Further, the astigmatism axis direction is determined from the axial direction of the cylindrical lens.

The movement of the target _T3 in the above-mentioned subjective test simultaneously moves the target _T1 of the optotype projection system, the reticle _T2 of the measurement optical system, and the relay lens _L5 . In addition, the rotation of the cylindrical lens axis of the cylindrical lens system _C2 is controlled by the image rotator IR of the measurement optical system.
The rotation of the lens is linked, and the cylindrical lens system
The addition of the cylindrical lens in C ₂ is linked to the addition of the cylindrical lens in the cylindrical lens system C ₁ of the optotype projection system, so the examiner can check the results in real time during the subjective test.
Using the slit images _S1 to _S6 on the CRT display M, the refractive state of the eye to be objectively examined can be checked at any time. In particular, if the slit lines S ₁ '' to S ₄ '' are separated as shown by the broken lines in FIG. 6D, it is immediately obvious through a subjective test that overcorrection has occurred.

Simultaneous subjective/objective testing of appropriateness/inappropriateness of worn eyeglasses The values of the eyeglass lenses currently worn by the examinee (measured by a lens meter) are determined in advance by the movement of the target _T3 of the gaze target system and the cylindrical lens. Set by operating system _C2 .

Next, the light sources E ₁ and E ₂ are turned on, and the subject is subjected to a subjective test, and the state of the slit line on the CRT display M is also checked objectively at the same time.
If all of the slit lines S ₁ ′ to _{S 6} ′ match, it can be determined that the wearing glasses are appropriate.

Testing near visual acuity and accommodative power After determining distance visual acuity using one of the methods described above, move target T ₃ of the gaze target system to the minus side (in the direction of L ₇ ) and measure the visual acuity displayed on CRT display M. The near spherical refractive power D _N is determined from the movement position of the target T ₃ when the slit lines S ₁ ′ and S ₂ ′ begin to separate. Then, the accommodation power D _A is determined from the difference between the distance spherical refractive power D _F and the spherical refractive power D F |D _N −D _F |.

In addition, near visual acuity is measured using the Landolt chart as the target _T3 at the moved position of the near vision target _T3 .

[Example: Autorefractometer]

Next, an example of an autorefractometer will be described. The measurement principle and device configuration of the autorefractometer on which this embodiment is based are roughly based on Japanese Patent Application Laid-open No. 57-200128, and for details, please refer to the above-mentioned application.

As shown in FIG. 7, the autorefractometer in this embodiment includes a target projection optical system 350 that projects a measurement target onto the fundus of the eye to be examined, and a target light receiving optical system that projects an image of the measurement target on the fundus of the eye to be examined onto a measurement optical system 351. 352, measurement optical system 35 that detects refractive power from the measurement target image
1. It is composed of a gaze target system 353 for fixing the line of sight of the subject's eye during an objective test and for observing a visual chart during a subjective test. Each optical system will be explained in detail below.

The target projection optical system 350 includes a pair of infrared light sources 301a and 301 arranged around the optical axis.
b, condensing lenses 302a and 302b that condense the light from the infrared light sources 301a and 301b, respectively;
A collimator lens 303 that creates parallel light, a measurement target 305 with a circular aperture stop 304, an imaging lens 306, a projection imaging lens 307, a half mirror 308 for infrared light, and a mirror that reflects infrared light in the long wavelength region and in the visible region. and a dichroic mirror 309 having a characteristic of transmitting infrared light in the vicinity thereof,
and a cylindrical lens system 320 having the same configuration as the cylindrical lens system _C1 of the manual refractometer placed between the lenses 6 and 7 of the first embodiment.
It consists of The above pair of infrared light sources 301
The light sources 301a and 301b are turned on alternately at high speed, and both light sources 301a and 301b are integrally configured to be rotatable around the optical axis, and the measurement target 5
is configured to be movable in the optical axis direction.

In the above configuration, a pair of infrared light sources 301
The light from a and 301b is transmitted through the condenser lens 3, respectively.
02a and 302b, the collimator lens 303 converts the light into parallel light, and the light enters the circular aperture stop 304 obliquely. circular aperture 30
After the light passing through the lens 307 is formed into an image by the imaging lens 306, the light passes through the cylindrical lens system 320, which is placed at an optically conjugate position with respect to the glasses wearing position (12 mm in front of the eyes) and the lens 307, and the projection imaging lens. 30
7. The light enters the eye E through the half mirror 308 and the dichroic mirror 309. here,
The images of the infrared light sources 301a and 301b are formed on the pupil position of the eye E to be examined, and the image of the circular aperture stop 304 of the measurement target 305 is formed on the fundus R of the eye to be examined.

When the measurement target 305 and the fundus R of the eye E are in a conjugate positional relationship, the image of the circular aperture stop 304 illuminated by the light from the infrared light source 301a and the light from the infrared light source 301b are combined. The image of the illuminated circular aperture stop 304 is formed at the same position on the fundus R. On the other hand, when the measurement target 305 and the fundus R of the eye E to be examined are not in a conjugate positional relationship, the images of the circular aperture diaphragm 304 illuminated by the light from each of the infrared light sources are located at two separate locations on the fundus R. Each forms an image.

In this embodiment, the fundus R of the circular aperture diaphragm 304 of the measurement target 305 fixed on the optical axis is
The images in the infrared light sources 301a and 302b
Distinguish whether they match or separate by lighting up alternately, and if they are separated, measure the separation distance,
The refractive power of the eye to be examined is calculated from the measurement position and the position of the measurement target at that time.

As shown in FIG. 10, the target light receiving optical system 352 is composed of a dichroic mirror 309, a half mirror 308, a light receiving objective lens 310, a mirror 311, an aperture 312, and a relay lens 313. Furthermore, the aperture 312 is arranged at the front focal point of the relay lens 313, and the projection optical system using the relay lens 313 is configured as a telecentric optical system. The relay lens 313 has an aperture 31
2 and is configured to be movable in the optical axis direction in conjunction with the measurement target 305.

In the above configuration, the measurement target image of the fundus R of the eye to be examined is projected into the measurement optical system 351, which will be explained in detail later, by the dichroic mirror 309, the half mirror 308, the light receiving objective lens 310, the mirror 311, and the relay lens 313. be done.

Since the aperture 312 and the relay lens 313 constitute a telecentric optical system, the measurement target image formed on the measurement optical system 351 is composed of a light beam consisting of principal rays parallel to the optical axis, and the image is It has a property that the center position of the circular hole image, which is the measurement target image, does not change even before and after the position.

As shown in FIG. 8, the measurement optical system 351 includes a half mirror 315 and a mirror 316 placed behind the relay lens 313, a relay lens 317 placed on the reflection optical axis of the mirror 316, and the mirror 3.
18. An X-direction detection system 356 consisting of a chopper 319 placed on the reflection optical axis of the mirror 318, a condenser lens 320, and a light receiving element 321, a half mirror 315, and a mirror placed on the reflection optical axis of the half mirror 315. 322, a relay lens 323 arranged on the reflection optical axis of the mirror 322, a chopper 319, a condenser lens 324, and a light receiving element 325
and a Y direction detection system 357 consisting of.
The chopper 319 has a group of continuous slits in the circumferential direction and rotates around the optical axis.

In the above configuration, a measurement target image of the fundus R of the eye to be examined is projected near the upper part 319a of the chopper 319 by the target light receiving optical system 352 and a part of the X direction detection system 356. At the same time, the target light receiving optical system 352 and a part of the Y direction detection system 357 detect the fundus R of the subject's eye.
The measurement target image is the side 3 of the chopper 319.
It is projected near 19b.

Here, the measurement target 305 and the fundus R of the examined eye
If there is no conjugate relationship between
a' and 330b' are projected onto the slit group separated by Δx in the X direction and Δy in the Y direction.

Furthermore, in the above configuration, the infrared light source 30
1a is turned on, and the circular aperture image 330a is created by the light.
The signal from the light receiving element 321 when the chopper 319 scans the signal, and the signal from the light receiving element 3 when the infrared light source 301b is turned on and the circular aperture image 330b generated by the light is scanned by the chopper 319.
Δx is calculated from the phase difference with the signal from 21.
Similarly, when the circular aperture images 330a' and 330b' are scanned by the chopper 319, the light receiving element 3
Δy is calculated from the phase difference of the signals from 25.

Next, the conjugate relationship between the measurement target 305 and the fundus R of the eye to be examined, the degree of astigmatism of the eye E to be examined, and the relationship between the circular aperture images 330a and 330b on the chopper 319 will be explained based on FIGS. 10A to 10C. It is assumed that the light sources 301a and 301b are arranged side by side at positions rotated by θ from the vertical direction. That is, it is assumed that the measurement radial direction is a direction rotated by θ from the vertical direction.

(1) When the measurement target 305 and the fundus R of the eye to be examined are in a conjugate relationship, and the eye E to be examined does not have astigmatism, as shown in FIG.
Circular aperture images 330a, 330b on 19
is projected overlapping the optical axis passing position. That is, Δx=Δy=0.

(2) When the measurement target 305 and the fundus R of the eye to be examined are not in a conjugate relationship and the eye E to be examined does not have astigmatism or has astigmatism, the direction of the measurement radius by the main meridians 301a and 301b of the eye E to be examined is If they match, as shown in FIG. 10B, a circular aperture image 330 is created on the stopper 319.
a and 330b are projected separately onto the measurement meridian.

(3) The measurement target 305 and the fundus R of the eye to be examined are not in a conjugate relationship, the eye E to be examined includes astigmatism, and the main meridian of the eye E to be examined and the light sources 301a, 301b
If the measurement radius directions are different, the first
As shown in FIG. 0C, circular aperture images 330a and 330b are separately projected on the stopper 319 in the measurement radial direction and in a direction perpendicular thereto.

In this embodiment, as shown in FIG. 10, the separation amounts Δx and Δy in the horizontal and vertical directions are detected, and the detection results are converted to the separation amounts in the measurement radius direction.
This is to detect the eye refractive power in the measurement radial direction.

As shown in FIG. 7, the gaze target system 353 includes a visible light source 331, a condenser lens 332, a gaze target 333 movable in the direction of the optical axis, a cylindrical lens system 390, a mirror 334, and a mirror 334 on the reflected optical axis. It is composed of a projection lens 335 and a dichroic mirror 336 that reflects visible light and transmits infrared light.

Here, the targets 333 include a fixation chart for objective testing (for example, starburst chart), a Landolt chart for subjective testing, an astigmatism chart (sunburst chart),
It has a configuration that allows an R&G test viewing table and the like to be selectively inserted into and removed from the optical path, and is configured to be movable on the optical axis in conjunction with the target 305 of the target projection system 350. Further, the cylindrical lens system 390 has a similar configuration to the cylindrical lens system 320 of the target projection system 350, and is configured to be driven in conjunction with the cylindrical lens system 320.

In the above configuration, the light from the visible light source 331 illuminates the gaze target 333 via the condenser lens 332. The light from the gaze target 333 passes through a mirror 334, a projection lens 335, a dichroic mirror 336, and the dichroic mirror 309, and is projected onto the eye E to be examined. The subject uses the gaze target 333 as a fixation table, and fixes the collimation direction during the objective test by gazing at this.

The autorefractometer of this embodiment further includes a calculation control circuit 1000 and a gaze target control circuit 110 for calculation, measurement control, display, etc.
0, cylindrical lens control circuit 1200, display 130
Contains 0.

The arithmetic control circuit 1000 connected to the light receiving elements 321 and 325 of the measurement optical system 351 determines the separation amounts Δx and Δy as shown in FIG. 13, and converts them into the separation amount ΔPθ in the direction of the measurement meridian θ. ΔPθ=Δxcosθ+Δy sinθ... …(21) Convert by. Here, the separation amount ΔPθ is: ΔPθ=mf×(Dθ−D _T )...(22) Here, Dθ : The refractive power of the eye to be examined in the radial direction θ in the pupil of the eye to be examined D _T : The diopter conversion value at the measurement target position f: Focal length of the relay lens 3 m: Since there is a relationship between the imaging magnification of the diaphragm 4 to the subject's eye, Dθ is determined from equation (22).
In this example, Dθ (Dθ ₁ ,
Dθ ₂ , Dθ ₃ ), Dθ ₁ = A + Bcos2 (θ _{1 -} α) Dθ ₂ = A + Bcos2 (θ ₂ - α) (13) Dθ ₃ = A + Bcos2 (θ ₃ - α) From spherical power A, astigmatic power B, Find each astigmatism axis α. A detailed explanation of this arithmetic/control circuit section is described in the earlier application, Japanese Patent Laid-Open No. 57-200128.

The obtained spherical power A, astigmatic power B, and astigmatic axis α
is displayed on the display 1300, and the gaze target control circuit 1100 moves the gaze target 333 onto the optical axis based on the spherical power A.
Prepare for the next subjective measurement.

Further, the cylindrical lens system control circuit 1200 controls the cylindrical lens system 320, 3 based on the astigmatic power B and the astigmatic axis α.
90 is driven to set the cylindrical lens of astigmatic power B in the optical path in the direction of the axis α in preparation for the next subjective measurement.

In the subjective measurement, the gaze target 333 is changed from the starburst visual chart used in the objective test to the Landolt visual chart or the R&G test visual chart, and the subjective test is performed. If the desired visual acuity value (for example, 1.0) is not obtained, move to the position where the desired visual acuity value can be obtained.
The target 33 is moved onto the optical axis, and the spherical power is determined by a subjective test from the moved position.

In addition, in the autorefractometer of this example, measurement of unaided visual acuity, subjective examination, real-time objective measurement, and appropriateness/inappropriateness of wearing glasses are performed in the same way as explained in the example of the manual refractometer described above. Subjective/objective tests and near visual acuity and accommodative tests can be performed.

〔Effect of the invention〕

As explained above, the present invention has a cylinder optical system arranged in the optotype projection system and the gaze target system at a substantially conjugate position with respect to the eyeglass wearing position of the subject's eye and each objective lens. The refractive state of the eye to be examined can be objectively observed during subjective measurement, and even an unskilled person can perform a refraction test with high precision within a short time.

The present invention further provides sphericity, astigmatism, and
By setting the astigmatism axis in advance and measuring the refraction with the naked eye, it is possible to determine the suitability of the glasses worn, and by showing the eye chart, corrected visual acuity can be measured. By performing the measurements simultaneously, it is possible to obtain high measurement accuracy.

The present invention also has the effect of being able to measure the accommodative power and near visual acuity of the subject's eye with high precision by using a combination of subjective and objective measurements.

[Brief explanation of drawings]

Figures 1 to 6 show a manual autorefractometer according to an embodiment of the present invention, in which Figure 1 is an optical diagram of the entire device, Figure 2 is an optical path diagram of the optotype projection system, and Figure 3 is a diagram of the optical path of the optotype projection system. is a perspective view of the measurement target, Figure 4 is a side view including a partial cross section of the cylindrical lens system, Figure 5 is a perspective view of the cylindrical lens system, and Figure 6 is an explanation of the slit line displayed on the CRT display. It is a diagram. 7 to 10 show an autorefractometer according to an embodiment of the present invention, FIG. 7 is an explanatory view of the entire device, FIG. 8 is a perspective view of the measurement optical system, and FIG. 9 and 10 are explanatory diagrams of the measuring method of the measuring optical system. E... Eye to be examined, R... Fundus of the eye to be examined, HM... Infrared transmitting visible reflection mirror, T ₁ ... Target for measurement, L ₆ ... Objective lens, T ₃ ... Gazing target,
C ₁ , C ₂ ... Cylindrical lens system, 100 ... Gaze target system, 102 ... Target projection system, 104 ... Measurement optical system, 301 ... Infrared light source, 305 ... Measurement target, 320 ... Cylindrical lens System, 350... Target optical system, 351... Measurement optical system, 352
...Target light receiving optical system, 353... Gazing target system, 1000... Arithmetic control circuit, 1100... Gazing target control circuit, 1200... Cylindrical lens control circuit, 1300... Display device.

Claims (1)

[Scope of Claims] 1. An optotype projection system that projects an optotype onto the fundus of the eye to be examined using near-infrared light; a measurement optical system that detects the optotype image on the fundus of the eye to be examined; In an eye refraction measuring device comprising a gaze target system that selectively projects a fixation target and a trial visual acuity chart, a fixed position approximately conjugate with the eyeglass wearing position of the eye to be examined within the gaze target system branched from the measurement optical system; An eye refraction measuring device characterized in that a cylinder optical system for converting a cylinder power and a cylinder axis is arranged. 2. The eye refraction testing device according to claim 1, wherein the cylinder optical system is configured to selectively arrange a plurality of cylindrical lenses on a predetermined optical axis. 3 The cylinder optical systems are arranged adjacent to each other so that the intersection points of their axes coincide with a predetermined optical axis, and are rotatable in opposite directions at the same angle, with the initial position being a position where their axes intersect perpendicularly. A refraction testing device according to claim 1, comprising a pair of cylindrical lenses having the same refractive power.