JPH0576496A - Ophthalmic measuring apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] While looking at the image in a state closer to natural vision with binocular vision, based on the results of the previous measurement and the previous measurement, the fixation target at the far point of the subject or at a further distance. It is possible to detect hyperopia without the need for a cloud mechanism to move the subject so as to present it, and without putting a test lens or the like on the subject's pre-measurement. Allows you to screen for the presence. [Structure] A mirror 19 that transmits infrared light and reflects visible light is fixed to a subject positioning portion 17 for both eyes of a subject, and an external index 18 can be collimated by both eyes via the mirrors. A lens 21 having a known value is arranged between the mirror and the external index separately from between the measurement main body 16 and the eye to be examined, and the diopter value of the known lens is used as a reference value to measure the measurement result by the measurement main body. By comparing, the diopter value of the known lens and the measurement result of the eye refractive power by the measurement main body are discriminated from each other to judge whether or not the measurement can be performed or to re-measure, or to display as appropriate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic measuring device for measuring the refractive power of a subject's eye, and particularly to an ophthalmic measurement which does not require adjustment of a fixation target in order to obtain the cloud vision state of the subject. It relates to the device.

[0002]

2. Description of the Related Art When measuring an eye refractive power of a subject, generally, an index (a visual acuity table, a fixation target, etc.) is used so that adjustment is not required.
(Hereinafter referred to as a fixation target) is placed inside the main body of the device, and is optically placed at a far point of the subject or further away, and so-called cloud vision is used for measurement.

In this case, since the far point of each subject is different, a pre-measurement is performed, and based on the result, the far point of the subject or a fixation target is placed further away and then the measurement is performed. Is going.
Therefore, it took time to move the fixation target to the far point of the subject or farther from the previous measurement. Also, a mechanism for moving the fixation target to the far point of the subject or farther away is required.

On the other hand, in order to see the fixation target with both eyes, a mirror for transmitting infrared light and reflecting visible light is arranged in the subject positioning part (jaw receiving part) to see the external fixation target. The quasi-possible one has already been proposed in JP-A-55-143129 or JP-A-56-60530.

[0005]

However, JP-A-55-143
No. 129 and the one proposed in Japanese Patent Laid-Open No. 56-60530 only aim at the outside, or after performing pre-measurement, the subject's far point or farther distance may be adjusted according to the result. It was the one to make the fixation target be presented and to be fogged.

Therefore, in the case of hyperopic eyes, when collimating an external fixation target of a finite distance, adjustment is made so that the fixation target of a finite distance is viewed. Therefore, the measurement result corresponding to the distance is obtained. It was difficult to detect hyperopia. Furthermore, in order to make the far point or cloud of the subject to see the fixation target according to the subject, as described above, the pre-measurement is performed so that the fixation target is moved to that position. In addition, it is necessary to provide a mechanism for moving the fixation target according to the result, and the mechanism is complicated even if both eyes are simultaneously or separately, or even if it is a single eye.

In view of the above situation, the present invention provides a binocular vision,
While viewing in a state closer to natural vision, without pre-measurement, or a fog mechanism for moving to present the fixation target to the far point of the subject based on the results of the previous measurement, or further away, It enables the detection of hyperopia without the need to put a test lens or the like on the subject's pre-measurement, and also enables screening for whether there is a refractive error of a certain value or more. ..

[0008]

According to the present invention, a mirror for transmitting infrared light and reflecting visible light is fixed to a subject positioning portion for both eyes of a subject, and externally visible by both eyes via the mirror. Index can be collimated, apart from between the measurement body and the eye to be examined, a lens with a known value is arranged between the mirror and an external index, and the diopter value of the known lens is used as a reference value. It is characterized in that it is compared with the measurement result by the section.

[0009]

[Function] By comparing the eye refractive power measurement result of the eye to be inspected by the measurement main body and the diopter value of the known lens, the magnitude of the two values is discriminated, and if the measurement result is small, the measurement is continued and the measurement result is continued. If is large, display such as remeasurement.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As the measuring device main body, it goes without saying that various conventionally known eye refractive power measuring devices can be used, but in this embodiment, it is shown in Japanese Patent Application No. 2-214811. The description will be made assuming that one is used.

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

The projection system 1 has slit-shaped light source portions 4a, 4b, 4c, 4d of a required length which are orthogonal to the optical axis of the projection system and orthogonal to the edge of a light shielding member 12 which will be described later, and the light shielding member. Reference numeral 12 is a member having a rectangular hole, and four edges of the hole are edge ridge lines 15a, 15b, 15c, 15d, and the measurement light source 4 also has the ridge lines 15a, 15b, 15c, 1
Slit-shaped light source units 4a, 4b, 4c, 4 corresponding to 5d
d is provided. Further, the luminous flux 1 from the measurement light source 4
The projection system 1 projects a light flux 11 from the measurement light source 4 through the pupil 6 so as to form an image of the measurement light source 4 on the fundus 7 through the pupil 6. ..

The light receiving system 2 comprises an objective lens 8 and a light receiving element 9, and a light beam 10 from the fundus 7 is reflected by the half mirror 5.
Is guided through the light receiving element 9.

The light receiving element 9 is an area CCD, an image pickup tube or the like, and the light receiving surface 9a of the light receiving element 9 is arranged at a position substantially conjugate with the pupil 6 of the subject's eye 3 with respect to the objective lens 8.

In the optical path of the light receiving system 2, the light shielding member 12 is in a plane perpendicular to the optical axis at a position where the measurement light development is formed when the eye refractive power of the eye 3 to be inspected is the reference diopter value. Is located in.

Of the light source sections 4a, 4b, 4c and 4d, two except the ones on the same meridian are selected and turned on one by one, and the light quantity distribution and the light quantity distribution are perpendicular to the edge ridge and parallel to the edge ridge. The inclination angle of is calculated and the calculation is performed.
It should be noted that if the light sources 4a, 4b, 4c, 4d are all sequentially turned on for measurement, and if the measurement results on the same meridian are averaged, it is possible to almost eliminate the effects of eyelashes and cloudiness of the crystalline lens. Therefore, the measurement system can be improved.

An arithmetic unit 13 is connected to the light receiving element 9, and the arithmetic unit 13 stores the data of the light receiving state of the light receiving element 9 at each ridge line, further calculates the result, and the result is displayed on the display unit 14. It is designed to output.

Measurement of refractive power and astigmatism is described in Japanese Patent Application No. 2-21.
As shown in Japanese Patent No. 4811, it can be obtained by measuring, for example, two meridians and a light amount distribution in a direction orthogonal to each of the two meridians.

According to Japanese Patent Application No. 2-214811, the light amount distribution of the pupil image is expressed by the following equation for performing the calculation.

[0021]

## EQU1 ## fs (xp ', yp') = {I ₀ + (a ₁ cos θ + a ₂ sin θ) xp '+ (a ₁ sin θ + a ₃ cos θ) yp'} / I ₀ xp ', yp' Any point I ₀ on the pupil is the length of the slit target,

[0022]

## EQU00002 ## a ₁ = L {(1 / l ₂ −1 / l ₁ ) sin2θ _A } / 2 a ₂ = L {2 / L− (1 / l ₁ + 1 / l ₂ ) + (1 / l _{1 -1 / l 2) cos2θ A}} / 2 a 3 = L {2 / L- (1 / l 1 + 1 / l 2) - (1 / l 1 -1 / l 2) cos2θ A} / 2 1 / l ₁ is the spherical power S 1 / l ₁ −1 / l ₂ is the cylindrical power C θ _A is the astigmatic axis angle A

[0023]

[Formula 3] a ₁ = (LC sin2A) / 2 a ₂ = L {2 / L- (2S + C) + C cos2A} / 2 a ₃ = L {2 / L- (2S + C) -C cos2A} / 2 Then, when a ₁ , a ₂ and a ₃ are obtained, the spherical power S and the astigmatic power C can be obtained by measuring the known two meridians and the light amount distribution in the direction orthogonal to each of the two meridians according to the above equation. The astigmatic axis A can be calculated, and the state of the astigmatic eye can be measured.

As is apparent from Japanese Patent Application No. 2-214811 and the above equation, the pupil diameter is not involved in the calculation of the refractive power. Similarly, when measuring the two meridians and the light amount distribution in the direction orthogonal to each of the two meridians, as is apparent from the calculation formula, in the case of a combination of certain angles, for example, a combination of 0 ° and 90 ° In the case of, it is possible if any 3 data is used.

In this case, in order to observe or aim / measure both eyes at the same time, when one light receiving element 9 is intended to be received, there is a pupil distance of the subject, and naturally the magnification on the light receiving surface is limited. It becomes a thing. For accurate measurement, it may be possible to increase the magnification, but there is a limit from the above. Therefore, the light receiving element, for example, the light receiving range of an area sensor such as an individual CCD is provided at a light receiving position substantially conjugate to the pupil of the subject, and a substantially alignment range of each eye, or a margin for facilitating aiming is provided. Make the magnification equivalent to the range you have, and place two photo detectors at that position. In this case, when processing and computing the signals from both light receiving elements,
A common processing system / memory may be used, or separate processing systems / memory may be used. Alternatively, either one may be made common. In any case, the magnification at the light receiving position cannot be changed by the light receiving element, and the magnification can be increased to improve the measurement accuracy and the measurement can be performed. Needless to say, only one light receiving element may be used as in the conventional case.

When the images are displayed on the display, the images on both light receiving elements are displayed on the display, or the images stored in memory are combined or displayed, or displayed on separate displays. In this case, in a place other than the displayed portion, for example, a portion outside the alignment range is processed to display only black, and characters such as a measurement result are displayed in a necessary portion (see FIG. 2).

The main part of this apparatus will be described with reference to FIG.

The main body 16 is constructed as described above, and in order to stabilize the face of the subject in front of the main body, the subject positioning unit 17 is provided.
Is placed, the face of the subject is stabilized, and the fixation target 18 or a visual target such as a visual acuity chart is viewed to perform measurement.

At this time, a mirror 19 which transmits infrared light and reflects visible light is arranged on the support 22 of the subject positioning part 17 (jaw receiving part, etc.) via a support frame, and above the mirror 19, for example. A total reflection mirror or a mirror 20 that transmits infrared light and reflects visible light is arranged through a support frame for holding the support 22, so that the fixation target 18 outside the measurement body can be seen. .. At this time, a mirror 19 that transmits infrared light and reflects visible light
Then, a lens 21 having a known value is disposed between the total reflection mirror 20 and the like, for example, via a support frame for holding it on a column. At this time, the fixation target of the upper portion may be directly viewed without using the total reflection mirror 20 or the like. Any of the mirrors may correspond to both eyes and may have a sufficient width. Further, the lens 21 may have a sufficient width for both eyes, or may be a separate lens for each eye.

In the measurement, the subject has his / her face placed on the subject positioning unit 17 (jaw receiving unit), and the binocular vision is closer to the natural vision and the mirror and known values are used. The fixation target 18 is seen through the lens 21. In this state, the examiner moves the measurement main body 16 and positions the eye to be inspected with the measurement main body 16 through the mirror 19 that transmits infrared light and reflects visible light to perform measurement. The measurement main body at this time may be either a monocular measurement or a binocular measurement, which is conventionally known. In the case of monocular measurement, it goes without saying that the mirror lens may also be monocular.

Further, in order to make the image look closer to the natural vision, the fixation target 18 is made to be seen by both eyes, and the far point or the cloud position is adjusted according to the refracting power of the subject measured in advance. When the fixation target 18 is optically moved to the position, the vergence angle is adjusted to about 0 ° as if the subject is looking at infinity, that is, the subject is looking parallel, depending on the position, or It is necessary to change the adjustment so that the angle does not cause any problem. In this case, the convergence adjustment prisms are separately arranged near the lens for the left and right eyes, and adjustment is performed according to the position of the measurement unit main body and the fixation target.

When the external fixation target is viewed, the vergence angle is about 0 only when the measuring unit main body and the fixation target are installed.
The convergence adjusting prism may be adjusted so that the angle is such that the adjustment due to the convergence does not pose a problem. Alternatively, instead of the convergence adjustment prism, reflection mirrors may be provided separately for the left and right eyes and the inclinations thereof may be adjusted.

The eye flexion force of the eye to be inspected is calculated by the calculator 13 based on the light distribution from the light receiving element 9. The calculator 13 has a known diopter value of the lens 21 set and input. Then, while calculating the eye refractive power, the diopter value is further compared with the diopter value of the subject's eye obtained by the calculation, the magnitude of both diopter values is judged, and the result is further displayed on the display unit 14. To do.

When the measurement is performed in such an arrangement, a subject having a negative refractive power than the lens 20 having a known value looks at the fixation target in a clouded state, and the same measurement as the conventional measurement is possible. Become. A subject having a positive refracting power will adjust the amount of the difference from the known diopter to see, and a value close to the known diopter will appear. Alternatively, when the accommodation power is smaller than the difference, or in the case of strong hyperopia, etc., the value becomes larger than the known value (see FIG. 4).

For example, a normal spectacle lens has a lens in front of the eye 1
Since it is generally placed at 2 mm, the known lens 21
If the value is equivalent to +2.5 diopters when placed at 12 mm in front of the eye, the refractive power of the lens to be added in order to form an image on the retina when the subject looks into the distance is The true value when a person looks into the distance is +1 diopter,
In the case of a negative diopter subject, the value is approximately that value, but in the case of a +7 diopter subject, there is accommodative power, and when the fixation target 18 is clearly seen, +2.
Measured as a value near 5 diopters. Also, even if the same +7 diopter, the adjustment power is, for example, only 3 diopters, or in the case of a subject who cannot adjust sufficiently, it will be measured as a value near +4 diopters or a value of +2.5 diopters or more Will be measured.

In such a case, when a measurement result that exceeds a predetermined refraction value, for example, +2.5 diopter or +1 diopter, appears, it is considered that there is hyperopia more than that. You can use it to make a measurement, or use another method to make a measurement again.

Alternatively, when further screening is performed by a mass examination or the like, a predetermined refracting power (± both directions), a difference between left and right refracting powers, a range of cylindrical power, and the like are stored in the measuring device, If it exceeds the range, some caution mark may be displayed on the display, or may be displayed at the time of printout, or may be displayed on the display and printed out at the same time. If this mark is displayed, it is possible to carry out a detailed inspection separately as if there is any abnormality. The predetermined range can be changed later.

[0038] In this way, based on the results of the pre-measurement and the pre-measurement while seeing in a state closer to natural vision with binocular vision,
Without the need for a cloud mechanism to move the subject to present the fixation target at a far point or farther away, and without having the test lens hung in front of the subject. By simply disposing the lens 21 having the known value, in the case of the subject on the negative side of the lens 21 having the known value, it is possible to perform the same measurement as in the case where the fog mechanism is provided. In the case of a subject on the more positive side, it is possible to detect hyperopia because it is measured as a diopter of about the same value as the lens of a known value or more, and whether there is a certain refractive error or more. It becomes possible to carry out a screening such as seeing.

In addition, when the known lens 21 is not only arranged but can be changed to another known lens or a fixed fixation target is placed inside the main body, the position of the lens can be set to the subject and the subject. You may arrange | position between the mirrors 19 of infrared-light transmission and visible-light reflection attached to the positioning part 17 (jaw receiving part). At this time, it is preferable to incline so that the reflection of the measurement light by the lens does not return to the main body measurement unit. The error caused by tilting the lens may be corrected. Further, in this case, since the refractive power of the lens is also added, the correction is performed.

[0040]

As described above, according to the present invention, it is possible to perform a pre-measurement or a far point of a subject based on the result of the pre-measurement while viewing with a binocular vision and a state closer to natural vision. Without the cloud mechanism to move to present the fixation target further away,
It is possible to detect hyperopia without having to attach a test lens or the like in accordance with the pre-measurement of the subject, and it is possible to screen whether there is a refractive error of a certain value or more.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an imaging state of an eye to be inspected.

FIG. 3 is an explanatory diagram of the same embodiment.

FIG. 4 is an explanatory diagram showing a relationship between an eye refractive power of an eye to be inspected and a diopter value of a known lens in the same Example.

FIG. 5 is a basic configuration diagram of a measurement main body unit used in the previous embodiment.

6 is a view taken along the line AA of FIG.

FIG. 7 is a view taken along the line BB of FIG.

[Explanation of symbols]

 13 arithmetic unit 16 measurement main body 17 subject positioning unit 18 fixation target 19 mirror 21 lens

Claims (1)

[Claims] 1. A measurement is performed by fixing a mirror that transmits infrared light and reflects visible light to both eyes of a subject at a subject positioning portion, and makes it possible to collimate an external index with both eyes through the mirrors. Separately between the main body and the eye to be examined, a lens having a known value is arranged between the mirror and the external index, and the diopter value of the known lens is used as a reference value to compare with the measurement result by the measurement main body. An ophthalmic measuring device characterized by: