JP3085679B2 - Eye refractometer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an eye refractometer used in, for example, an ophthalmic clinic.

[Prior Art] In a conventional ocular refractometer, when measuring an eye refraction value by changing a diameter line, a light receiving optical system is moved in an optical axis direction so that a photoelectric sensor and a fundus are always conjugate. To measure
Some light receiving optical systems are fixed in the direction of the optical axis and measure based on the position and timing of the light beam projected on the photoelectric sensor, and the latter is a refractometer using the fixed light receiving optical system. However, the structure is simple. However, when measuring with a refractometer using a fixed optical system, for example, when projecting a ring-shaped light beam to the pupil and measuring diopter from the size of the ring on the photoelectric sensor of the reflected light, the pupil Is small, the outside of the projection light beam is not projected onto the pupil, so the projected image of the ring on the optical sensor becomes small due to factors other than the eye refraction value,
There is a problem that the measurement of the eye refraction value includes an error.

An object of the present invention is to provide an eye refractometer capable of accurately measuring an eye refraction value even in an eye to be examined smaller than a predetermined pupil diameter.

[Means for Solving the Problems] An eye refractometer according to a first invention for achieving the above object is a refractometer that projects a light beam on a fundus of an eye to be examined, detects a reflected light beam thereof, and performs eye refraction measurement. In, imaging means for imaging the anterior segment of the eye to be inspected, a monitor for displaying the anterior eye part including the pupil of the eye to be imaged imaged by the imaging means, and a pupil according to the size of the pupil observed on the monitor Diaphragm means for changing the outer diameter of the measurement light beam at a substantially conjugate position.

Further, an eye refractometer according to a second aspect of the present invention includes a projection unit that projects a measurement light beam onto the fundus of the eye to be inspected, and a position detection unit that detects the position of the measurement light beam reflected by the fundus. In an eye refractometer that obtains an eye refraction value based on position information according to the present invention, size detection means for detecting size information of the pupil of the eye to be examined is provided, and the position information detected by the position detection means and the size detection means An eye refraction measurement is performed based on the detected size information.

[Operation] The eye refractometer having the above configuration makes the system of the measurement light flux variable at a position conjugate with the pupil of the eye to be examined, or performs eye refraction measurement based on size information of the pupil of the eye to be examined. Obtain the eye refraction value.

[Example] The present invention will be described in detail based on an illustrated example.

FIG. 1 shows a configuration diagram of an eye refractometer, in which a light source 1 and an eye E are examined.
The lens 2, the aperture stop 3,
A perforated mirror 4, a light splitting mirror 5, and an objective lens 6 are sequentially provided, and a six-hole aperture 7, a lens 8, a prism 9, and a photoelectric sensor 10 are arranged in the direction in which the perforated mirror 4 reflects light from the eye E to be examined. A lens 11 and a television camera 12 composed of a two-dimensional CCD or the like are provided in the direction in which the light splitting mirror 5 reflects the light beam from the eye E, and the output of the television camera 12 is connected to a television monitor 13. An aperture 3a as shown in FIG. 2 is perforated at the center of the aperture stop 3, and a six-hole aperture 7 is provided with six apertures 7a to 7f as shown in FIG. The prism 9 is composed of six wedge prisms 9a to 9f corresponding to the openings 7a to 7f of the 6-hole aperture 7 as shown in FIG. 4, and the apertures 3 and 7 correspond to the pupil Ep of the eye E to be examined. , Light source 1
The photoelectric sensor 10 is conjugate with the fundus Er of the eye E.

A light beam from the light source 1 passes through a lens 2, an aperture stop 3, a perforated mirror 4, a light splitting mirror 5, and an objective lens 6, and the eye E to be examined.
The reflected light flux returns along the same optical path, is reflected by the perforated mirror 4, and is separated from the optical axis by the wedge prisms 9a to 9f of the prism 9 via the 6-hole stop 7 and the lens 8. The fifth direction on the photoelectric sensor 10.
Six light beams A to F are formed as shown in the figure.

From the interval between the light beams A and D on the photoelectric sensor 10, the eye refractive value in the meridian direction connecting the openings 7a and 7d of the 6-hole aperture 7 is measured, and similarly, the other four light beams B, C, E and F are measured. The eye refraction values in the other two meridian directions can be measured from the above, and assuming that the eye refraction value changes sinusoidally in the meridian direction, the spherical refraction value, astigmatism, and astigmatism angle are calculated from the eye refraction values in the three meridian directions. can do.

When the pupil Ep of the subject's eye E is large, the positions and sizes of the light beams A to F on the photoelectric sensor 10 do not change, but when the pupil Ep is smaller than a certain diameter, the openings 7a to 7a of the 6-hole aperture 7 are formed. Since the light beam on the outside of 7f and the light beam AF on the photoelectric sensor 10 are absent, the center of gravity of the light beam AF on the photoelectric sensor 10 changes when the eye E to be examined is a non-emmetropic eye. The refraction value contains an error.

Therefore, in order to prevent this error, at the time of measuring the eye refraction value, the anterior eye portion of the eye E to be inspected taken by the television camera 12 is observed by the television monitor 13, and the alignment mark M having a known pupil diameter is electrically transmitted to the television. The pupil diameter is measured by causing the pupil diameter to be generated on the monitor 13 and making a comparison. If the pupil diameter of the eye E is larger than the alignment mark M, the correction of the eye refraction value does not have to be performed, but if the pupil diameter is smaller than that of the alignment mark M, as shown in FIGS. Gradually reduce the diameter of the alignment mark M
The pupil diameter is measured by a numerical value displayed on the television monitor 13 by adjusting the pupil diameter to the pupil diameter, and based on the measured value, the eye refraction value is corrected using, for example, a correction unit based on a mathematical formula obtained from actual measurement data. If the large pupil diameter is erroneously measured in the small pupil diameter measurement state, an error is included in the eye refraction value. Therefore, it is preferable to automatically return the size of the alignment mark M after the measurement.

FIG. 8 is a configuration diagram of a light receiving optical system of a second embodiment,
The same reference numerals as in the first embodiment denote the same members, and a variable aperture stop 14 is provided at a position conjugate with the pupil Ep of the light receiving optical system. In the first embodiment, the alignment mark M
The diameter of the pupil was measured by changing the size of the alignment mark M. In this embodiment, the diameter of the alignment mark M is kept constant, and the eye E having a smaller pupil diameter than the diameter of the alignment mark M is measured in this embodiment.
In this case, stop the variable aperture stop 14 and
The pupil diameter is measured based on the degree of focusing, and the eye refraction value is similarly corrected.

When the variable aperture stop 14 is stopped down, the amount of light reaching the photoelectric sensor 10 is reduced, so that it is difficult to detect the position of the light beam.However, it is possible to reduce the error when the pupil diameter is small, and to erroneously detect the small pupil diameter. There is no danger as in the previous embodiment in which a large pupil diameter is measured in the measurement state.

FIG. 9 shows six openings 7a used in the first and second embodiments.
FIG. 9 shows a light flux R on the photoelectric sensor 10 when a stop having a ring-shaped opening is used instead of the 6-hole stop 7 provided with .about.7f. In this embodiment, the eye refraction value is measured from the shape of the ring-shaped light beam R on the photoelectric sensor 10, but the intervention of the error is reduced by measuring the pupil diameter and correcting similarly as in the previous embodiment. .

FIG. 10 shows a configuration diagram of the third embodiment. The main body 20 of the conventional refractometer including a projection system / light receiving system, a refraction value calculation means, and a control means, and a correction means for numerical values added thereto.
And dichroic mirrors 5 and 21 are sequentially obliquely provided on the optical axis between the lens and the subject's eye E. Dichroic mirror
A fixation target 22 is provided on the reflection side of 21, and is movable toward the dichroic mirror 21. A lens 11 and a television camera 12 are installed on the reflection side of the dichroic mirror 5 as in the first embodiment. The output of the television camera 12 is connected to a television monitor 13, and the output of the television monitor 13 is a pupil diameter measuring unit 23. And the output of the pupil diameter measuring means 23 is
It is connected to the.

The pupil diameter measuring means 23, based on the output content of the TV camera 12,
The two scanning lines L1 and L2 concerning the pupil Ep of the eye E to be examined are selected, and the intersections Q1 to Q4 of the outer peripheral portion of the pupil Ep and the scanning lines L1 and L2 are selected.
The pupil diameter is measured from the level difference of the video signal, and the pupil diameter is compared with the light flux diameter of the optical system. If the light flux diameter is larger, the measured value is transmitted to the eye refractometer main body 20. The main body 20 instructs the movement of the fixation target 22, and simultaneously emits a light beam toward the pupil Ep of the eye E to be examined. At this time, the mark M projected on the television monitor 13 indicates the position of the light beam, and alignment is performed by superimposing the light beam on the pupil Ep in the image.
The main body 20 detects the reflected light from the eye E and measures the refraction value. At this time, if the measured value of the pupil diameter by the pupil diameter measuring means 23 is smaller than the luminous flux diameter, the main body 20 performs correction by a certain mathematical formula, and The refraction value is displayed by a display means that does not.

In this case, since the measurement of the refraction value, including the correction, is all performed by the apparatus, the measurement is performed only by the examiner performing alignment so that the light flux enters the pupil Ep while watching the television monitor 13. That is, the pupil diameter is measured by the pupil diameter measuring means 23 using the image information from the television camera 12, and the pupil diameter is measured.
Is displayed after the correction based on the pupil diameter is added to the refraction value measured by. Accordingly, the correction is automatically performed even when the pupil diameter is smaller than the light flux diameter, and a refraction value that does not include an error due to the pupil diameter is obtained.

FIG. 11 shows a layout of a main part of the fourth embodiment,
As in the first embodiment, a lens 2, an aperture stop 3, a perforated mirror 4, and an objective lens 6 are sequentially provided from the light source 1 side on the optical axis between the camera and the eye E to be examined. A 6-hole aperture 24 having six fan-shaped openings 24a to 24f provided at equal angles in the reflection direction of the perforated mirror 4 as shown in FIG. 12, a lens 8, a prism 9, and a photoelectric sensor 10 are arranged. solenoid
The rotary aperture 26 which is moved by 25 and overlaps the 6-hole aperture 24 is 6
It is located near the hole drawer 24. An opening 26a as shown in FIG. 13 is bored in the rotary stop 26, and the diameter of the opening 26a is smaller than the outer diameter of the openings 24a to 24f of the six-hole stop 24.

The light beam from the light source 1 irradiates the fundus Er of the eye E through the lens 2, the aperture stop 3, the perforated mirror 4, and the objective lens 6, and the reflected light beam returns along the same optical path and is reflected by the perforated mirror 4, Since the light is deflected in six directions separated from the optical axis by the wedge prisms 9a to 9f of the prism 9 via the six-hole aperture 24 and the lens 8, the six light beams A as shown in FIG. F are formed, and the spherical refraction value, astigmatism degree, and astigmatism angle can be calculated by detecting them. When the pupil Ep of the eye E to be examined becomes smaller than a certain pupil diameter, a 6-hole aperture is determined.
Since the light beams outside the openings 24a to 24f of 24 and the light beams A to F on the photoelectric sensor 10 are absent, the light beams A to F on the photoelectric sensor 10 when the eye E to be inspected is a non-emmetropic eye. The center of gravity changes and the eye refraction value includes an error.

In order to prevent this error, an annular alignment mark indicating the light beam diameter is made visible on a television monitor used for alignment, and when the pupil diameter is smaller than the alignment mark, a rotary diaphragm 26 is provided by a solenoid 25.
Is inserted into the optical path. As a result, the rotary stop 26 overlaps the six-hole stop 24, and only the center side of the openings 24a to 24f is used, so that the center of gravity of the light fluxes A to F does not change depending on the pupil diameter. In this case, the refraction value is corrected using the known diameter of the rotary stop 26 without measuring the pupil diameter.
By using the rotary stop 26, the amount of light reaching the photoelectric sensor 10 is reduced, so that it is difficult to detect the position of the light beam, but it is possible to reduce errors when the pupil diameter is small.

In the embodiment, the rotary stop 26 is arranged in the light receiving optical system, but may be arranged in the projection optical system to regulate the beam diameter.

[Effects of the Invention] As described above, according to the eye refractometer according to the present invention,
By making the diameter of the measurement light flux variable at a position conjugate with the pupil of the eye to be examined or by performing eye refraction measurement based on the size information of the pupil of the eye to be examined, it is appropriate for an eye to be examined having a small pupil diameter. Eye refraction measurement can be performed, and an accurate eye refraction value is always obtained.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an eye refractometer according to the present invention. FIG. 1 is a block diagram of the first embodiment, FIG. 2 is a front view of a projection stop, FIG. The figure is a front view of the prism,
FIG. 5 is an explanatory view of a light beam on a photoelectric sensor, FIGS. 6 and 7 are explanatory views of an alignment mark generated on a television monitor, FIG. 8 is a main part configuration view of the second embodiment, and FIG. FIG. 10 is an explanatory diagram of a ring light beam on a sensor, FIG. 10 is a configuration diagram of a third embodiment, FIG. 11 is a configuration diagram of a fourth embodiment, FIG. The figure is a front view of the rotary stop. 1 is a light source, 3 is an aperture stop, 4 is a perforated mirror, 5 is a light splitting mirror, 6 is an objective lens, 7 and 24 are 6-hole stops, 9
Is a prism, 10 is a photoelectric sensor, 12 is a TV camera, 13 is a TV monitor, 14 is a variable aperture stop, 20 is an eye refractometer body,
23 is a pupil diameter measuring means, 25 is a solenoid, and 26 is a rotary diaphragm.

Claims (3)

(57) [Claims] 1. An eye refractometer for projecting a light beam onto a fundus of an eye to be examined and detecting a reflected light beam to measure an eye refraction, and an image pickup means for picking up an anterior segment of the eye to be examined, and an image picked up by the image pickup means. A monitor for displaying the anterior segment including the pupil of the eye to be examined, and diaphragm means for varying the outer diameter of the measurement light beam at a position substantially conjugate with the pupil according to the size of the pupil observed by the monitor An eye refractometer characterized by the following. A projection means for projecting the measurement light beam onto the fundus of the eye to be inspected; and a position detection means for detecting a position of the measurement light beam reflected on the fundus, and the eye is detected based on the position information by the position detection means. In an eye refractometer for obtaining a refraction value, size detection means for detecting size information of the pupil of the eye to be examined is provided, and the position information detected by the position detection means and the size information detected by the size detection means are provided. An eye refractometer that performs an eye refraction measurement based on the following. 3. The method according to claim 2, wherein the diameter of the measurement light beam in the pupil of the eye to be inspected is changed based on the size information of the pupil of the eye to be inspected.
An eye refractometer according to item 1.