JP3068626B2 - Objective eye refractometer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective refraction measuring apparatus for objectively measuring a refraction value of an eye to be examined.

[Prior Art] In a conventional device of this type, a fixation target for fixation of an eye to be inspected is provided so as to be movable on an optical axis of an objective lens, and is mainly involved in fixing and adjusting the visual axis of the eye to be inspected. Has been removed. A method of removing the intervention of accommodation is called a fogging method, in which the fixation target is moved from the negative side to the positive side with respect to the diopter of the eye to be examined, and the subject is gazed at the fixation target to thereby fix the eye to be examined. It is used to accurately measure the far point.

[Problems to be Solved by the Invention] Such a conventional apparatus measures a refraction abnormal value of an eye to be examined at a far point, and does not have a function of simply checking presbyopia. It is well known to move the fixation target to check for presbyopia and measure the adjustment state at that time with an optometer.However, it is necessary to perform measurement continuously in time and determine the far point. It has drawbacks such as difficulty and difficulty in easily grasping the relationship between the far point and the adjustment amount.

FIG. 6 shows an example of the measurement results obtained with this optometer.
The fixation target is moved at a normal (diopter / time = constant) speed, and the accommodation response to it is recorded on an XY recorder or the like, but the accommodation response of the subject's eye is usually unstable, and as shown in the figure, The noise rises and falls with the amplitude. Therefore, a skilled diagnostician must determine the far point D0 and the accommodation power DN-D0.

In addition, in order to perform such a measurement stably, the moving speed of the fixation target must be sufficiently low that the subject's eye can follow, and the measurement takes a long time. Fixation becomes unstable, and the above-mentioned noise is generated more and more. Furthermore, since the burden on the subject is large, it is currently not used much for ordinary medical treatment.

SUMMARY OF THE INVENTION An object of the present invention is to provide an objective eye refraction measuring apparatus that can easily perform near vision refraction measurement using an internal fixation device of a conventional objective eye refractometer so that presbyopia can be checked. Is to provide.

[Means for Solving the Problems] To achieve the above object, an objective eye refraction measuring apparatus according to the present invention comprises: a presentation optical system having a fixation target for presenting a fixation image to an examinee's eye; Driving means for moving the fixation target on the optical axis, measuring means for measuring the refractive power of the eye to be examined, and moving the fixation target from the negative side to the positive side with respect to the diopter of the eye by the presentation optical system. A first measurement mode for inducing fog on the subject's eye and measuring the far point position and the far point refractive power of the subject's eye by the measuring means, and the far point refraction from the far point position by the presentation optical system. Switching means for presenting the fixation image at a predetermined near point position based on force, and switching to a second measurement mode for measuring eye refractive power for the near point position by the measuring means, The near point measured in the second measurement mode Display means for displaying information on the refractive power on the side and the position of the presented fixation image.

[Operation] The objective eye refraction measuring apparatus having the above-described configuration controls the near vision refraction value measured by the measuring device as a reference to change to the set near vision position, thereby providing the near vision by the measuring device. Enables refraction measurement.

Embodiment The present invention will be described in detail based on an embodiment shown in FIGS.

FIG. 1 shows an embodiment of an eye refractometer according to the present invention, in which an imaging optical system is provided on an optical axis L1 which coincides with a supporting axis of the eye E to be examined.
A spot light source 1 composed of an LED or the like is provided.
From the lens 2 to the eye E in order, and FIG.
A projection system diaphragm 3 having a circular aperture 3a on the optical axis, a perforated mirror 4 having a hole at the center, a dichroic mirror 5, and an objective lens 6 are arranged as shown in FIG. The spot light source 1 is preferably disposed on the conjugate plane of the eye E to be examined for emmetropia, and the projection system stop 3 is substantially conjugated to the pupil Ep of the eye E by the objective lens 6.

On the reflection-side optical axis L2 of the perforated mirror 4, three apertures 7a, 7b, which are arranged at equal distances around the optical axis L2 as a light receiving optical system as shown in FIG. A light receiving system diaphragm 7 having a 7c, a lens 8, a deflecting prism 9 in which three wedge prisms 9a, 9b, 9c are combined as shown in FIG. 3, and a two-dimensional sensor array 10 such as a CCD are sequentially arranged. Have been. Here, the light receiving system stop 7 is conjugate with the pupil Ep of the eye E, and the two-dimensional sensor array 10 is arranged on a conjugate plane with the fundus Er of the eye E.

On the optical axis L3 on the reflection side of the dichroic mirror 5, a fixation target 12 and an illumination lamp 13, which are driven on the optical axis L3 in the direction of arrow A by a stepping motor 11, are arranged. The output of the two-dimensional sensor array 10 is connected to a controller 15 via a processing circuit 14, and the controller 15 has a stepping motor 11, a measurement switch 16, a mode switch 1,
7. Printer 18 is connected. The controller 15 is programmed with an operation procedure according to a flowchart described later.

In measuring the eye refractive power, the light beam emitted from the spot light source 1 is transmitted through the lens 2 to the lens 2 and the objective lens 6.
Then, a spot beam is projected on the fundus Er of the eye E by the objective lens 6. Then, the spot light beam reflected by the eye E is reflected by the perforated mirror 4 through the objective lens 6 and reaches the light receiving system stop 7 at a position conjugate with the pupil Ep. Since the light receiving system stop 7 has three openings 7a, 7b, and 7c, light beams are taken out from three places around the pupil Ep. The light is deflected away from the optical axis by the wedge prisms 9a, 9b, 9c.

That is, the light beams passing through the openings 7a, 7b, 7c pass through the corresponding wedge prisms 9a, 9b, 9c to reach the two-dimensional sensor array 10, and as shown in FIG. The spot images 7A, 7B and 7C are formed on the spots.
For example, the light beam from the opening 7a passes through the wedge prism 9a, and is deflected in a direction perpendicular to the dividing line D of the wedge prisms 9b and 9c shown in FIG. The light beams passing through the other openings 7b and 6c are similarly deflected away from the optical axis.

In FIG. 4, dotted lines and arrows indicate directions in which the spot images 7A, 7B, and 7C move when the diopter of the eye E changes. When diopter changes in the opposite direction, spot images 7A and 7
B and 7C move in the direction opposite to the arrow, and if there is astigmatism, they will move out of the dotted line. In order to obtain the refraction value of the eye E, first, the two-dimensional coordinates of the spot images 7A, 7B, 7C are obtained. If the two-dimensional sensor array 10 is an image pickup device of a television camera, the video signal may be used, an appropriate threshold level may be determined and binarized, and the center position of the spot may be obtained by calculation. Further, in order to obtain an accurate value, a signal for each element can be used. After calculating coordinates by binarizing or multi-valued, diopters are calculated from the coordinates.

The refraction value of the eye is composed of three values of spherical power, astigmatism power and astigmatism angle, and the change in the radial direction is assumed to be sinusoidal. Therefore, once the refraction value of the three meridians is obtained, it is calculated by calculation. can do. Various methods for selecting the three meridians are known. For example, in FIG.
By taking the direction connecting the optical axis L2 and each of the openings 7a, 7b, 7c, the movement of the spot images 7A, 7B, 7C in the direction of the dotted line in FIG. 4 may be calculated. In this case, the amount of movement from the spot position for normal vision is proportional to the refraction value in each meridian direction. The processing circuit 14 performs the above-described processing on the output of the two-dimensional sensor array 10 and sends a measurement result to the controller 15.

The examiner sets the mode changeover switch 17 to the arrow B side,
Select the measurement mode of the refractive error value. In this mode, the apparatus operates in the same manner as a conventional objective ophthalmic refractometer, and measures the far point of the eye E to be examined. That is, when the measurement switch 16 is turned on, the fixation target 12 is moved by the stepping motor 11 in accordance with a command for performing the fogging method from the controller 15, and during this time, the measurement system repeats the measurement in a timely manner, and the distance of the eye E to be examined becomes longer. The point is determined and its value is displayed on the printer 18.

Next, when the mode changeover switch 17 is switched to the arrow C side in this state, a command is issued from the controller 15 to the stepping motor 11 to move the fixation target 12 to a position corresponding to the far point measured just now. When the fixation target 12 reaches this position, the subject gazes clearly at the position. The examiner checks the alignment of the device here and presses the measurement switch 16. The measurement system repeats the measurement multiple times and checks the far point. Normally, 4 to 5 measurements are performed at 0.5 second intervals. It suffices to perform this, but the controller 15 selects the numerical value closest to the current position of the fixation target 12 from these numerical values, determines the adjustment state of the eye E to be examined in this state, and displays it together with the position of the fixation target. The display at this time is preferably a diopter unit (D) with the origin of the fixation target position.

After the display, the controller 15 instructs the stepping motor 11 to move the fixation target 12 to a position requiring adjustment by, for example, −2D with respect to the far point position, and instructs the eye E to move the fixation target 12. Accompaniment is induced. The fixation target 12 stops at the predetermined value. In this state, the examiner reconfirms the alignment of the apparatus and presses the measurement switch 16 again. The measurement system repeats the measurement a plurality of times again, measures the adjustment state of the eye E in this state, and sends data to the controller 15.

The controller 15 selects and displays these numerical values as before. The examiner can objectively check the progress of presbyopia of the subject by seeing the difference between this value and the amount of movement of the fixation target 12. At the same time, the subject
By confirming the degree of blur, you can also understand it subjectively. Further, after that, the controller 15 instructs the stepping motor 11 to move the fixation target 12 to, for example, a position requiring adjustment by −3D with respect to the initial target position. Hereinafter, the operation when the measurement switch 16 is pressed repeats the above operation.

If the mode changeover switch 17 is returned to the arrow B side halfway, the mode returns to the normal mode of the objective refractometer at any time. When the measurement of about 2 to 4 points is completed for the test target position, the fixation target 12 returns to the far point position and can be measured again. The procedure of the presbyopia check mode is the fifth
This is as shown in the flowchart of FIG.

In the above-described embodiment, first, the confirmation at the far point position is performed. However, in order to perform the inspection in a shorter time, when the mode change switch 17 is switched to the C side, the confirmation is performed at a position corresponding to −2D. The fixation target 12 may be moved. In addition, the fixation target position to be inspected is set to a point that requires 0D, −2D, and −3D adjustment with respect to the far point of the eye E. However, 0D, −1D, −2D, and −3D are finer.
Can also be measured. It is also effective to be able to input the position to be measured in advance.

Further, the embodiment is configured so that the fixation target 12 is moved immediately after the measurement is completed. However, this is because the presbyopic check mode can be operated with one measurement switch 16, so that the fixation is performed. If a switch for moving the target 12 is separately provided, the measurement can be repeated at each fixation target position. Further, in the method of selecting a plurality of measured values, in addition to the above-described embodiment, it is also useful to select a measured value indicating the maximum accommodation power, for example, from the viewpoint of determining the accommodation power of the eye to be examined. Further, the measurement principle of the measurement system is not particularly limited to this method, as long as it can measure the refractive power.

[Effects of the Invention] As described above, the objective eye refraction measuring apparatus according to the present invention may have a configuration using the internal fixation system of a conventional objective eye refractometer, so that the configuration is simple, and Since the target position to be inspected is specified based on the measured far point, a near vision load stimulus corresponding to the diopter of the subject can be given. And the burden on the examiner and the examinee is reduced.

[Brief description of the drawings]

1 to 5 show an embodiment of an objective eye refraction measuring apparatus according to the present invention. FIG. 1 is a block diagram, FIG. 2 is a front view of an aperture, and FIG. 3 is a side view of a deflecting prism. FIG. 4 is a view for explaining a measurement light beam, FIG. 5 is a flowchart of a presbyopia check mode, and FIG. 6 is a graph showing measurement results obtained by a conventional optometer. 1 is a light source, 3 and 7 are apertures, 4 is a perforated mirror, 5 is a dichroic mirror, 6 is an objective lens, 9 is a deflection prism, 10 is a two-dimensional sensor array, 11 is a stepping motor, 12 is a fixation target, 13 is an illumination lamp, 14 is a processing circuit, 15 is a controller, 16 is a measurement switch, and 17 is a mode switch.

Claims (1)

(57) [Claims] 1. A presentation optical system having a fixation target for presenting a fixation image to an eye to be examined, a driving unit for moving the fixation target on an optical axis, and a measurement unit for measuring a refractive power of the eye to be examined. Moving the fixation target from the negative side to the positive side with respect to the diopter of the subject's eye by the presentation optical system to induce fog on the subject's eye, and measuring the far point position and far point refraction of the subject's eye by the measuring means. A first measurement mode for measuring force, and the presenting optical system presents the fixation image from the far point position to a predetermined near point position on the basis of the far point refracting power, and the measuring unit Second to measure eye refractive power for near point position
Switching means for switching between the first and second measurement modes;
Display means for displaying information on the refractive power on the near point side measured in the measurement mode and the position of the presented fixation image.