JP2016202506A - Eye refractivity measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eye refractivity measurement device capable of measuring eye refractivity accurately regardless of a diopter of a subject eye.SOLUTION: The eye refractivity measurement device includes: a light projecting optical system 3 projecting a measurement light flux in a spot shape to an eyeground from a position separated from a pupil center of a subject eye E by a predetermined distance; a light receiving optical system 5 extracting reflection light from the eyeground by a light block part 52 arranged at a conjugate position with a pupil of the subject eye E and including an opening in a shape of a ring or plural spots and making the reflection light incident on a two-dimensional imaging element 54; calculation means acquiring eye refractivity of the subject eye E based on output of the two-dimensional imaging element 54; and a deflection member 48 for deflecting the measurement light flux to a position separated from the pupil center of the subject eye E by a predetermined distance. The deflection member 48 is arranged at a conjugate position with the pupil of the subject eye E in a shared light path of the light projecting optical system 3 and the light receiving optical system 5. Rotation means is arranged, the rotation means rotating the deflection member 48 with an optical axis of the light projecting optical system 3 and light receiving optical system 5 as a center.SELECTED DRAWING: Figure 1

Description

The present invention relates to an eye refractive power measuring apparatus that can objectively measure the refractive power of an eye to be examined.

Conventionally, using a light source with high coherence (for example, a laser diode (LD), a super luminescent diode (SLD), etc.), a spot light beam is projected from the center of the pupil of the eye to be examined and reflected from the fundus. An eye refractive power measuring device is known that takes out the eye from the periphery of the pupil and receives light with a light receiving element to measure the eye refractive power.

In Patent Document 1, as the correspondence of the small pupil to the eye to be examined, an eye refraction is further provided with means for disposing a prism at a position deviating from the conjugate position with the pupil of the optical path of the measurement optical system and rotating it around the measurement optical axis. A force measuring device is disclosed.

Japanese Patent No. 4492847

However, in the eye refractive power measuring device described in Patent Document 1, since the prism is arranged at a position deviated from the conjugate position with the pupil, the incident position of the light beam on the pupil according to the refractive power (diopter) of the eye to be examined. It was found that the size of the light flux in the lens and the lens changed. Therefore, when the lens is turbid due to a cataract or the like, depending on the refractive power of the eye to be examined, it is likely to be affected by scattering, and there is a concern that the measurement accuracy may deteriorate.

Furthermore, it is considered desirable to measure the refractive power by projecting a light beam on the visual axis of the eye to be examined on the fundus. However, in the eye refractive power measuring device described in Patent Document 1, a negative diopter is particularly used. In the case of a strong eye (high myopic eye), the bright spot position of the luminous flux on the fundus is largely displaced from the visual axis, and there is a concern that the measurement accuracy deteriorates due to the influence of peripheral aberration.

The present invention has been made to solve the above-described problems, and provides an eye refractive power measuring apparatus that can accurately measure the eye refractive power regardless of the refractive power of the eye to be examined.

Hereinafter, embodiments of the present invention made to solve the above-described problems will be described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

According to a first aspect of the present invention, a light projecting optical system that projects a spot-like measurement light beam to a fundus from a position that is a predetermined distance from the center of the pupil of the eye to be examined, and a conjugate position with the pupil of the eye to be examined. A light-receiving optical system that takes out reflected light from the fundus by a light-shielding part having a ring-shaped or a plurality of point-shaped openings and makes the two-dimensional image sensor receive the light, and eye refraction of the eye to be examined based on the output of the two-dimensional image sensor A deflection member for deflecting the measurement light beam at a position away from the center of the pupil of the eye to be examined, and the deflection member includes the light projecting optical system. And rotating means for rotating the deflecting member about the optical axis of the light projecting optical system and the light receiving optical system, which is disposed in a conjugate position with the pupil of the eye to be examined in the shared optical path of the light receiving optical system.

In the ocular refractive power measuring apparatus structured according to this aspect, even when the refractive power of the eye to be examined is different, a light beam having a substantially constant size is incident at a position away from the center of the pupil of the eye to be examined. Therefore, it becomes possible to reduce the influence of scattering due to cataracts and the like, and the measurement accuracy is improved. In addition, since the measurement light is incident while rotating at a position away from the pupil center of the eye to be examined, it is possible to perform measurement while avoiding a turbid site due to cataracts, and the measurement rate is improved. Furthermore, by reducing the deviation of the luminous flux position on the fundus from the visual axis regardless of the refractive power of the eye to be examined, the influence of peripheral aberrations and the like can be reduced, and the measurement accuracy is improved.

According to a second aspect of the present invention, in the eye refractive power measurement apparatus according to the first aspect, the deflection member is a plane parallel plate.

In the eye refractive power measuring apparatus structured according to this aspect, by using a plane parallel plate, a light beam having a substantially constant size is located at a predetermined distance from the pupil center of the subject eye regardless of the refractive power of the subject eye. Can be made incident.

According to a third aspect of the present invention, in the eye refractive power measurement apparatus according to the first or second aspect, the light source used in the light projecting optical system is a coherent laser diode or superluminescent diode. .

According to the present invention, the eye refractive power can be accurately measured regardless of the refractive power of the eye to be examined.

It is a schematic block diagram of the optical system of the eye refractive power measuring apparatus which concerns on a present Example. It is a figure explaining the measurement light beam on a pupil. It is a block diagram of the control system of the eye refractive power measuring apparatus which concerns on a present Example.

First, FIG. 1 shows an apparatus optical system 1 of the eye refractive power measuring apparatus of the present embodiment. The apparatus optical system 1 includes an observation optical system (10, 12, 14, 16, 18, 20) for observing the anterior segment of the eye E, and a target optical system (22) that presents a target for gazing at the eye E. , 24, 26, 28, 30, 32, 16, 14), an XYZ alignment detection optical system (34, 28,...) For positioning the apparatus optical system 1 with respect to the eye E in the vertical, horizontal, and longitudinal directions (XYZ directions). 30, 32, 16, 14, 36, 38), an eye refractive power measuring optical system (40, 42, 44, 46, 48, 32, 16, 14, 50, 52, 54) for measuring the refractive power of the eye. ).

The observation optical system includes, for example, illumination light sources 10 and 12 that irradiate infrared light having a wavelength of 780 nm, a lens 14, a hot mirror 16, a lens 18, and an imaging device 20 for observation. Here, for example, the hot mirror 16 has a characteristic of reflecting a light beam having a wavelength of 400 to 700 nm (visible light region) and a wavelength of 850 nm or more and transmitting a light beam having a wavelength of less than 850 nm. That is, the infrared light from the illumination light sources 10 and 12 is transmitted, and a part of a light beam from an XYZ alignment light source 34 described later, the infrared light from the measurement light source 40, and the visible light from the target light source 22 are reflected. Yes. A light beam emitted from the illumination light sources 10 and 12 and reflected by the anterior eye portion of the eye E to be examined is transmitted through the hot mirror 16 through the lens 14 and guided onto the image sensor 20 for observation through the lens 18.

The target optical system includes, for example, a target light source 22 that emits visible light having a wavelength of 400 to 700 nm, a target 24 that can be moved in the optical axis direction by a first driving device 62 (shown in FIG. 3), a lens 26, and a half. A mirror 28, a reflection mirror 30, a hot mirror 32, a hot mirror 16, and a lens 14 are provided. Here, the half mirror 28 transmits a part of light from the target light source 22 and an XYZ alignment light source 34 described later, and reflects the rest. The hot mirror 32 has a characteristic of reflecting a light beam having a wavelength of 850 nm or more and transmitting a light beam having a wavelength of less than 850 nm, for example. That is, the visible light from the target light source 22 and a part of the light beam from an XYZ alignment light source 34 described later are transmitted, and the infrared light from the measurement light source 40 described later is reflected. The luminous flux emitted from the target light source 22 passes through the lens 26 and the half mirror 28 via the target 24, is reflected by the reflection mirror 30, passes through the hot mirror 32, and is reflected by the hot mirror 16. The eye E is irradiated through the lens 14.

The XYZ alignment detection optical system includes, for example, an XYZ alignment light source 34 that irradiates infrared light having a wavelength of 810 nm, a half mirror 28, a reflection mirror 30, a hot mirror 32, a hot mirror 16, a lens 14, and XYZ alignment detection sensors 36 and 38 ( Profile sensor) is provided. A part of the light beam emitted from the XYZ alignment light source 34 is reflected by the half mirror 28, reflected by the reflection mirror 30, transmitted through the hot mirror 32, reflected by the hot mirror 16, and then passed through the lens 14. The eye E is irradiated. The light beam reflected by the cornea of the eye E is guided to the profile sensors 36 and 38.

The eye refractive power measuring optical system includes a light projecting optical system 3 and a light receiving optical system 5. The light projecting optical system 3 includes a measuring light source 40, a lens 42, a reflecting mirror 44, a perforated mirror 46, a parallel flat surface. The face plate 48, the hot mirror 32, the hot mirror 16, and the lens 14 are provided. The light receiving optical system 5 includes the lens 14 of the light projecting optical system 3, the hot mirror 16, the hot mirror 32, the plane parallel plate 48, and a hole. The mirror 46 is shared, and a lens 50, a ring lens 52, and a measurement imaging device 54 that is movable in the optical axis direction by a third driving device 66 (shown in FIG. 3) are provided. The measurement light source 40 used in the present embodiment is a superluminescent diode (SLD) with high coherence, and for example, an SLD that emits infrared light having a wavelength of 880 nm is used.

Here, the plane parallel plate 48 disposed in the light projecting optical system 3 will be described. The plane parallel plate 48 is disposed at a conjugate position with the pupil of the eye E to be examined in the shared optical path of the light projecting optical system 3 and the light receiving optical system 5. In the present embodiment, the plane parallel plate 48 is tilted so that the measurement light beam is incident at a predetermined distance h from the center of the pupil of the eye E (see FIG. 2). As a result, even when the refractive power of the eye E to be examined is different, a light beam having a substantially constant size is incident at a predetermined distance from the center of the pupil of the eye E, thereby reducing the influence of scattering due to cataracts or the like. It becomes possible to do. Further, since the deviation of the luminous flux position on the fundus from the visual axis can be reduced regardless of the refractive power of the eye E, it is possible to reduce the influence of peripheral aberrations and the like. Further, the plane parallel plate 48 is rotated around the optical axis of the shared optical path of the light projecting optical system 3 and the light receiving optical system 5 by the second driving device 64 (shown in FIG. 3). As a result, the measurement light beam on the pupil is rotated, so that it is possible to perform measurement while avoiding a turbid site due to cataracts and the like, and speckle noise generated by using a highly coherent light source is suppressed. It becomes possible.

The light beam emitted from the measurement light source 40 is reflected by the reflection mirror 44 through the lens 42, passes through the hole in the center of the perforated mirror 46, the parallel plane plate 48, and is reflected by the hot mirror 32 and the hot mirror 32. The fundus of the eye E is irradiated through the lens 14. At this time, the light beam on the pupil is rotated by the plane parallel plate 48 rotating around the optical axis. The light beam reflected by the fundus of the subject E is reflected by the hot mirror 16 and the hot mirror 16 through the lens 14, passes through the plane parallel plate 48, is reflected by the perforated mirror 46 and is reflected by the ring mirror 46, and the lens 50. The light is guided to the measurement image sensor 54 via the ring lens 52.

Next, the configuration of the control system of the eye refractive power measurement apparatus of the present embodiment will be described. As shown in FIG. 3, the eye refractive power measurement device is controlled by a control device 60. The control device 60 is configured by a microcomputer (microprocessor) including a CPU, a ROM, a RAM, and the like. The control device 60 is connected with first to fourth driving devices 62 to 68, a measurement imaging device 54, an observation imaging device 20, profile sensors 36 and 38, a monitor 72, and a memory 74. .

The control device 60 drives the visual target 24, the plane parallel plate 48, the measurement image sensor 54, and the position adjustment mechanism 70 by controlling the first to third drive devices 62 to 66. That is, the control device 60 controls the first driving device 62 to move the visual target 24 in the optical axis direction, and the second driving device 64 controls the parallel plane plate 48 to rotate about the optical axis. The measurement image sensor 54 is moved in the optical axis direction by controlling the third driving device 66, and the position adjusting mechanism 70 is driven by controlling the fourth driving device 68. Further, the anterior segment image captured by the observation imaging element 20 is input to the control device 60 and displayed on the monitor 72. The controller 60 receives the electrical signal of the corneal reflected light detected by the profile sensors 36 and 38, and the controller 60 controls the fourth driving device 68 to drive the position adjusting mechanism 70. The apparatus optical system 1 and the eye E to be examined are aligned. Further, the control device 60 receives the ring image picked up by the measurement image sensor 54, and the control device 60 calculates the refraction value from the ring image, displays the refraction value on the monitor 72, and stores it in the memory 74. input.

Next, the operation in the case of measuring the eye refractive power using the eye refractive power measuring apparatus having the above configuration will be described.

First, the examiner fixes the target 24 with respect to the eye E, and manually operates an operation member such as a joystick (not shown) based on the anterior eye image and the alignment index displayed on the monitor 72. Thus, the optical system 1 is aligned with the eye E. That is, the control device 60 responds to the operation of the operation member of the examiner based on the anterior segment image input from the observation imaging element 20 and the alignment index based on the corneal reflected light input from the profile sensors 36 and 38. The position adjusting mechanism 70 is driven by the fourth driving device 68. Thereby, the position of the apparatus optical system 1 with respect to the eye E to be examined is adjusted in the XY direction (vertical / horizontal direction) and the Z direction (forward / backward direction).

When the alignment is completed, the measurement light source 40 is turned on, and the control device 60 drives the second drive device 64 to rotate the parallel flat plate 48. The infrared light emitted from the measurement light source 40 is spotted on the fundus of the eye E through the lens 42, the reflection mirror 44, the perforated mirror 46, the parallel plane plate 48, the hot mirror 32, the hot mirror 32, and the lens 14. A point light source image is formed. At this time, the measurement light beam is incident at a predetermined distance from the center of the pupil of the eye E, and is rotated on the pupil by the parallel flat plate 48 that is disposed at an inclination and rotates around the optical axis.

The point light source image projected on the fundus is reflected and is measured by the ring lens 52 via the lens 14, the hot mirror 16, the hot mirror 16, the rotating plane parallel plate 48, the perforated mirror 46, and the lens 50. 54 forms an image in a ring shape. At this time, the control device 60 drives the third drive device 66 and moves the measurement image sensor 54 in the optical axis direction to obtain the thinnest and brightest ring image.

The control device 60 obtains the refractive power from the ring image input by the measurement image sensor 54 as a preliminary measurement. Based on the refractive power, the control device 60 drives the first driving device 62 to move the target 24 in the optical axis direction, places the fundus and the target 24 at the conjugate position, and then moves away by an appropriate diopter. The cloud is applied to the eye E to be examined. In this state, the main measurement is performed, and the refractive power is measured based on the ring image acquired by the measurement image sensor 54 as described above.

The control device 60 detects the ring image coordinates in each meridian direction of the ring image input by the measurement image sensor 54. Based on the position of the detected ring image, an ellipse is approximated using the least square method or the like. Then, the refractive values of S (spherical power), C (astigmatic power), and A (astigmatic axis angle) are calculated from the approximate ellipse shape. The refraction value of the eye E thus calculated is displayed on the monitor 72 and stored in the memory 74.

As mentioned above, although the Example of this invention was described in detail, this is only an illustration and does not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

For example, in the above-described embodiment, the position of the apparatus optical system 1 in the up / down / left / right front / rear direction (XYZ direction) with respect to the eye E based on the detection of the profile sensors 36 and 38 using the XYZ alignment light source 34 in the XYZ alignment detection optical system. However, the present invention is not limited to this, and position detection in the XY direction and the Z direction may be configured by independent optical systems. Further, a CCD may be used as the XYZ alignment detection sensors 36 and 38 instead of the profile sensor.

In this embodiment, the plane parallel plate 48 is used as the deflecting member, but a prism may be used. Further, although the super luminescent diode is used as the measurement light source 40, a laser diode may be used.

Further, in this embodiment, the ring image 52 is received by the measurement imaging element 54 by the ring lens 52, but a light shielding member having a plurality of dot-shaped openings may be used instead of the ring lens. In this case, a plurality of point images are received by the measurement image sensor. The control device 60 detects the coordinates of the point image and approximates the ellipse based on the detected position of the point image. Then, the refraction values of S, C, and A are calculated from the approximate ellipse shape.

As described above, the technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

1: device optical system, 3: light projecting optical system, 5: light receiving optical system, 20: imaging device for observation, 36, 38: profile sensor, 24: target, 40: measurement light source, 48: plane parallel plate, 54 : Image sensor for measurement, 60: Control device, 62: First drive device, 64: Second drive device, 66: Third drive device, 68: Fourth drive device, 70: Position adjustment mechanism, 72: Monitor, 74 :memory

Claims (3)

A projection optical system that projects a spot-shaped measurement light beam on the fundus from a position away from the pupil center of the eye to be examined;
A light receiving optical system in which reflected light from the fundus is taken out by a light-shielding portion having a ring-shaped or a plurality of point-shaped openings arranged at a conjugate position with the pupil of the eye to be examined, and received by a two-dimensional imaging device;
Calculating means for obtaining the eye refractive power of the eye based on the output of the two-dimensional imaging device,
A deflection member for deflecting the measurement light beam at a position away from the center of the pupil of the eye to be examined;
The deflecting member is disposed at a conjugate position with the pupil of the eye to be examined in a shared optical path of the light projecting optical system and the light receiving optical system, and the deflecting member is centered on the optical axis of the light projecting optical system and the light receiving optical system. An eye refractive power measuring device comprising a rotating means for rotating. The ocular refractive power measuring apparatus according to claim 1, wherein the deflecting member is a plane-parallel plate. The eye refractive power measuring apparatus according to claim 1, wherein a light source used in the light projecting optical system is a coherent laser diode or a super luminescent diode.