JP2806432B2 - Eye refractive power measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye refractive power measuring device, and more particularly to an eye refractive power measuring device useful for children to infants.

[Prior Art] Conventionally, as an eye refractive power measuring device, there are a so-called subjective ophthalmoscope for measuring eye refractive power based on a response of a subject, a so-called auto-refractometer for objectively measuring an eye to be examined, and the like. Devices are known.

However, when measuring infants with this kind of device, it is not possible to measure with a subjective ophthalmoscope because of the lack of cooperation of infants, and the position of the eye to be examined must be fixed with a general auto-refractometer. However, in the case of infants, it is difficult to fix the position of the eye to be examined, and the measurement is extremely difficult.

In order to eliminate these drawbacks, a so-called photorefraction method is used in which the fundus of the subject's eye is illuminated with strobe light, the state of the luminous flux at the pupil of the subject's eye is photographed with a camera, and the eye refractive power of the subject's eye is measured from the result. Measurement methods have been proposed.

In this photorefraction method measurement, it is possible to measure sufficiently even if the optical axis of the eye to be examined is slightly shifted, and it is useful for measuring the eye refractive power of infants who have difficulty fixing the eye to be examined. It is supposed to be.

[Problems to be Solved by the Invention] However, in such a photorefraction type eye refractive power measuring apparatus, a strobe light source illuminates the optical axis of a camera from an oblique direction, and a pupil image at that time is simply taken. There is a problem that there is a diopter value that cannot be measured depending on the position of the light source, and that the measurable range is narrow.

In view of this, the present applicant has disclosed a light source image on the fundus of the eye to be examined and blocked a light beam from the light source reflected on the fundus with an edge-shaped light-blocking member in the prior application Japanese Patent Application No. 1-24491. An eye-refractive-power measuring apparatus that receives a light beam by a light receiving element and measures the eye refractive power based on the light amount distribution state of the light beam has been proposed, and the above-described problem has been solved.

Further, the present applicant has filed Japanese Patent Application Nos. 1-74187 and 1-160.
In No. 083, from the light amount distribution state of the reflected light flux in a plurality of meridian directions, while measuring the eye refractive power, astigmatism degree, astigmatic axis angle, etc., which were not conventionally measured in this type of device,
The present invention proposes an eye-refractive-power measuring apparatus capable of measuring astigmatism, and an object of the present invention is to provide a light source useful for such an eye-refractive-power measuring apparatus of the earlier application.

Means for Solving the Problems The present invention has a slit-shaped measurement light source, a projection system for projecting a measurement light source image on the fundus of the eye to be examined, and a light receiving element arranged at a substantially conjugate position with a pupil of the eye to be examined. A light receiving system for guiding a reflected light beam from the fundus of the eye to be inspected, and a light shielding member arranged in the light receiving system to shield a part of the reflected light beam; In an eye-refractive-power measuring device that measures the eye refractive power of the subject's eye from the light amount distribution by the reflected light flux,
The slit-shaped measurement light source is constituted by a slit hole and a plurality of light emitters arranged along the slit hole.

[Operation] The light emitted from the plurality of light emitters passes through the slit hole to be converted into a slit-like light flux and projected onto the fundus of the eye to be examined. A part of the slit-shaped light beam reflected by the fundus is shielded by a light-shielding member of a light-receiving system, and is projected to a light-receiving element. The projected reflected light beam has a light amount distribution corresponding to the eye refractive power, and the eye refractive power is obtained from the light amount distribution.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

The following example relates to a case of measuring the eye refractive power in two meridian directions.

1 is a projection system for projecting the measurement light source image onto the fundus 7 of the eye 3 to be inspected, 2 is a light receiving system for receiving the light beam 10 reflected by the fundus 7, and the projection system 1 and the light receiving system 2 It is arranged to face the eye 3 to be examined.

The projection system 1 has four slit-shaped light-emitting surfaces 4a, 4 located on two orthogonal meridians in a plane orthogonal to the optical axis of the projection system.
The projection system 1 includes a measurement light source unit 4 having b, 4c, and 4d, and a half mirror 5 for reflecting a light beam 11 from the slit-shaped light emitting surface toward the subject's eye 3. The projection system 1 includes light emitting surfaces 4a and 4b. , 4c, 4
The luminous flux 11 from the light-emitting surface 4a, 4
Projection is performed to form images of b, 4c, and 4d.

Next, the light source unit 4 will be described with reference to FIGS.

The light source unit 4 has a target plate 14 in which slit holes 13a, 13b, 13c, 13d perpendicular to edge portions 12a, 12b, 12c, 12d to be described later are formed, and a diffusion surface on the slit hole side. A diffusion plate 15 covering the slit holes 13a, 13b, 13c, 13d;
And the same number of small lenses 16a, 16b, 16c, 16d, 16e as the number of illuminants to be described later, and each of the slit holes 13a, 13b, 13e.
For each c, 13d, a lens 17 arranged along the slit hole,
A light-emitting body 18a, 18b, 18c, 18d, 18 that emits infrared light with an LED or the like provided corresponding to each of the small lenses 16a, 16b, 16c, 16d, 16e
e, a luminous body group composed of the luminous bodies 18a, 18b, 18c, 18d, 18e
Aperture 2 disposed between 19a, 19b, 19c, 19d and lens 17
And aperture plates 21 having 0a, 20b, 20c, 20d, and 20e.

Also, as shown in FIG. 5, the image of the luminous bodies 18a, 18b, 18c, 18d, 18e is formed on the anterior segment of the subject's eye by the small lenses 16a, 16b, 16c, 16d, 16e. At the same time, each image is superimposed, that is, each illuminant and the anterior segment are conjugate with respect to the small lens. Therefore, each small lens 16a, 16b, 16c, 16
d, 16e, the apertures 20a, 20b, 20c, 20d, 20e and the luminous body
The positions of 18a, 18b, 18c, 18d, and 18e are eccentric toward the periphery.

Light from the luminous bodies 18a, 18b, 18c, 18d, 18e
b, 20c, 20d, and 20e are respectively stopped so that they do not enter the incompatible small lenses, and the small lenses 16a, 16b, 16c, 16d, 16e, and the diffusion plate 1
5 is transmitted through, uniformized, slit holes 13a, 13b, 13c, 13d
The light is projected onto the fundus 7 of the subject's eye from the light-emitting surfaces 4a, 4b, 4c, 4d of the diffusion plate 15 surrounded by.

Next, in the target plate 14, the slit holes 13a,
A luminous body such as an LED that emits visible light at a required pitch on a meridian different from the meridian on which 13b, 13c, and 13d are arranged (another meridian that forms 45 'with respect to the meridian of the slit hole in this embodiment). Provide the required number of 22.

The symbol formed by the luminous body 22 is a fixation target, and the luminous body 22 is designed to be able to blink sequentially from the periphery toward the center.

The light receiving system 2 includes an objective lens 8 and a light receiving element 9, and a light beam 10 from the fundus 7 passes through the half mirror 5 and is guided onto the light receiving element 9.

The light receiving element 9 is an area CCD, an image pickup tube, or an aggregate of two or more light receiving elements. The light receiving surface 9a of the light receiving element 9 is disposed at a position conjugate with the pupil 6 of the eye 3 with respect to the objective lens 8.

In the optical path of the light receiving system 2, when the eye refractive power of the eye 3 to be inspected is a reference diopter value, the light flux 10 with the optical axis O of the objective lens 8 as a boundary is formed at the position where the luminescent image is formed. A light-shielding member 12 having edge portions 12a, 12b, 12c, and 12d for shielding one side of the light-shielding member is arranged in a plane perpendicular to the optical axis.

A square hole 23 is formed in the light shielding member 12, and four edges of the hole 23 are perpendicular to the images of the light emitting surfaces 4a, 4b, 4c, and 4d.
2a, 12b, 12c, and 12d.

An arithmetic unit 13 is connected to the light receiving element 9, and the arithmetic unit 3 stores the data of the light receiving state of the light receiving element 9 at each radial line, further calculates, and outputs the result to the display 14. It is like.

 Hereinafter, the operation will be described.

First, when the measurement is started, the apparatus and the subject, particularly the eye to be examined, are aligned. Regarding the alignment, the following method is appropriately selected and performed.

With respect to the apparatus, a chair on which the subject sits is arranged at a predetermined distance, and the subject is seated on the chair to perform measurement.

In order to determine the measurement area, for example, a square frame is placed at a predetermined position, and the measurement is performed by instructing the subject so that the face of the subject enters the frame.

The measurement is performed by instructing the device to place a spotlight on a predetermined position and instructing the subject to be located at the spotlight position.

As a method of setting the position where these chairs, frames, or spotlights are applied to a predetermined reference position with respect to the apparatus, prepare a graduated pole, observe the pole on a monitor of the apparatus, and monitor the monitor. Adjust the positional relationship between the measuring instrument and the pole so that the image of the pole is in focus on the center position above, and place the chair or frame at the position determined by this method, or place it on the spotlight Adjust settings. The vertical position of the frame can be set to the reference position by reading the scale of the pole.

The monitor television is observed to determine whether or not the eye 3 is within a measurable range.
All the luminous bodies 18a, 18b, 18c, 18d and 18e of a, 19b, 19c and 19d are turned on. Each illuminator illuminates the anterior eye, but each small lens
Since the focal lengths of 16a, 16b, 16c, 16d, and 16e are small and the imaging magnification is large, a light source image having a size of, for example, about 150 mm is formed near the anterior eye part. Therefore, the anterior eye part can be illuminated without using a special light source, and even if the eye to be examined is shifted, the light beam enters the pupil of the eye to be examined, and the measurement light beam is projected on the fundus 7 of the eye to be examined. be able to.

In addition, the target plate 14 is a fixation target, and blinks sequentially toward the luminous body 22,
The subject naturally collimates the center by this movement, and can fix the line of sight of the subject's eye to the optical axis of the measuring device. Further, it is more effective to make a sound in accordance with the blinking of the light emitting body 22.

One of the illuminant groups 19a, 19b, 19c, 19d is selected and lit, and the light amount distribution for the meridian to which the selected illuminant group belongs,
Find the eye refractive power.

FIG. 1 shows a state in which the subject's eye 3 has a reference diopter value.
10 is condensed by a light shielding member 12. In this state, when the light shielding member 12 blocks a part of the light beam 10, the light amount distribution of the light beam projected on the light receiving surface 9a becomes uniform.

Next, in the subject's eye having a diopter value that is larger or smaller than the reference diopter value, the condensing position of the light flux 10 is higher than the light shielding member 12 due to the magnitude of the diopter value.
It is deviated toward the eye 3 or the objective lens 8. Due to this deviation, the light blocking state of the light beam 10 by the light blocking member 12 changes, and the light amount distribution of the light beam projected on the light receiving surface 9a becomes non-uniform and has a slope. This tilt corresponds to the eye refractive power.

The arithmetic unit 13 takes in the light receiving signal for one screen of the light receiving element 9 and calculates the light quantity distribution state and the eye refractive power.

The measurement of the eye refractive power is also performed for the other light emitter groups, and the eye refractive power is obtained for a plurality of meridians. Further, the astigmatic axis angle and the astigmatic degree can be obtained by calculation from the eye refractive powers of a plurality of meridians. These calculation results are displayed on the display 14 as measurement results.

In the above embodiment, the lens is a set of small lenses, but may be a Fresnel lens.

In addition, the light source section may have a set of slit-shaped light emitting surfaces, and the light blocking member may be simply a knife-edge shaped light emitting section.

In addition, the light source unit is arranged linearly using a point light source as the light emitter, but may be replaced with a surface-emitting LED light emitter. When a surface-emitting luminous body is used, the diffusion plate and the aperture plate can be omitted.

[Effects of the Invention] As described above, according to the present invention, a measurement light beam is projected on the fundus, a reflected light beam is received in a state where a part of the reflected light beam is blocked, and the light amount distribution of the received light beam is used as an eye. An excellent effect of realizing a light source necessary for an eye refractive power measuring device for measuring a refractive power and contributing to realization of the eye refractive power measuring device is exhibited.

[Brief description of the drawings]

FIG. 1 is a basic schematic diagram showing one embodiment of the present invention, FIG. 2 is a view taken on line AA of FIG. 1, FIG. 3 is a view taken on line BB of FIG. 1, and FIG. FIG. 2 is an explanatory view showing the relationship between the light source unit and the eye to be inspected. 1 is a projection system, 2 light receiving systems, 3 is an eye to be examined, 4 is a measurement light source unit,
7 fundus, 9 is a light receiving element, 10 and 11 are luminous flux, 12 is a light shielding member, 1
3a, 13b, 13c, 13d are slit holes, 15 is a diffusion plate, 16a, 16b, 16
c, 16d, 16e are small lenses, 18a, 18b, 18c, 18d, 18e are luminous bodies,
20a, 20b, 20c, and 20d indicate apertures, and 21 indicates an aperture plate.

Continued on the front page (72) Inventor Akio Umeda 75-1, Hasunumacho, Itabashi-ku, Tokyo Inside Topcon Co., Ltd. (72) Inventor Noriyuki Nagai 75-1, Hasunumacho, Itabashi-ku, Tokyo Topcon Co., Ltd. (58) Survey Field (Int.Cl. ⁶ , DB name) A61B 3/103

Claims (4)

(57) [Claims] 1. A projection system for projecting a measurement light source image onto a fundus of a subject's eye having a slit-shaped measurement light source, a pupil of the subject's eye, and reflection from a fundus of the subject's eye on a light receiving element arranged at a substantially conjugate position. A light-receiving system for guiding the light beam, and a light-blocking member disposed in the light-receiving system to block a part of the reflected light beam; In an eye-refractive-power measuring device that measures the eye refractive power of
An eye-refractive-power measuring apparatus, characterized in that the slit-shaped measuring light source is constituted by a slit hole and a plurality of light emitters arranged along the slit hole. 2. An eye refractive power measuring apparatus according to claim 1, wherein a lens is provided between the slit hole and the luminous body so that each luminous body and the anterior ocular segment of the eye to be examined have a substantially conjugate positional relationship. 3. An eye refractive power measuring device according to claim 1, wherein a diffusing plate is provided between the slit hole and the luminous body. 4. An eye refractive power measuring apparatus according to claim 2, wherein a stop is provided between the light emitting body and the lens so that light from the light emitting body does not enter another adjacent lens.