JP3114819B2 - Ophthalmic measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art When measuring the eye refractive power of a subject, an index (a visual acuity chart or a fixation target, etc.) is generally used so that no adjustment is required.
(Hereinafter referred to as a fixation target) is placed in the apparatus main body, optically placed at a far point or further away from the subject, and measurement is performed by so-called cloud vision.

In this case, since the far point of each subject is different, pre-measurement is performed, and based on the result, a fixation target is set at the far point of the subject or further away before measurement. Is going.
Therefore, it takes time to move the fixation target to the far point of the subject or farther after the pre-measurement. In addition, 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 make the target fixate with both eyes, a mirror that reflects infrared light and transmits visible light is disposed in the subject positioning section (the chin support section), and the external fixation target is viewed. Those which have been made semi-capable have already been proposed in JP-A-55-143129 or JP-A-56-60530.

[0005]

However, Japanese Patent Application Laid-Open No. 55-143
No. 129, the one proposed in JP-A-56-60530, merely collimates the outside, or performs a pre-measurement, and then moves to the far point of the subject or further away according to the result. The fixation target was presented and fogged.

For this reason, in the case of a hyperopic eye, when the external fixation target at a finite distance is collimated, it is adjusted to look at the fixation target at a finite distance, so that the measurement result corresponding to the distance is obtained. Or near-measurements, making it difficult to detect hyperopia. Further, in order to make the far-point or cloud of the subject look at the fixation target according to the subject, as described above, perform the pre-measurement to move the fixation target to that position. This necessitates a mechanism for moving the fixation target in accordance with the result, and the mechanism is complicated when both eyes are simultaneously or separately or even with a single eye.

[0007] In view of such circumstances, the present invention has two eyes.
While observing in a state closer to natural vision, there is no fog mechanism for moving the subject so as to present the fixation target at the far point of the subject or based on the result of the previous measurement, or Without allowing a test lens or the like to be applied in accordance with the pre-measurement of the subject, it is possible to detect hyperopia, and to screen for a refractive error of a certain value or more. .

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a flexion of a subject's eye.
It has a measurement main body for measuring the bending force, and fixes a mirror of infrared light transmission and visible light reflection to the subject positioning part to both eyes of the subject, and with both eyes through the mirror the external indication to enable collimation, the measuring body and the between of the eye were alternatively arranged lenses known values between the mirror and the external index ophthalmic
Measuring device, the diopter of the known lens
Ratio for comparing the value with the measurement result from the measurement body
A comparison operation unit .

[0009]

The operation of the comparison unit is caused by the bending of the subject's eye by the measurement main unit.
Comparison of bending force measurement result with diopter value of known lens
Then, the magnitude of both values is determined, and if the measurement result is small, the measurement is continued as it is, and if the measurement result is large, a display such as re-measurement is performed.

[0010]

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

As the measuring device body, for example, various conventionally known eye refractive power measuring devices can be used, but in the present embodiment, it is disclosed in Japanese Patent Application No. 2-214811. The description will be made assuming that the above is used.

Reference numeral 1 denotes a projection system for projecting a measurement light source image onto the fundus 7 of the eye 3 to be inspected. Reference numeral 2 denotes a light receiving system for receiving the light beam 10 reflected by the fundus 7. The system 2 is arranged to face the subject's eye 3.

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

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 a 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 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 eye 3 with respect to the objective lens 8.

[0016] The In the optical path of the light receiving system 2, a position eye refractive power of the eye 3 the measurement light source image in the case of the reference diopter value is formed, the aforementioned light-shielding member 12 is perpendicular to the optical axis plane Is placed within.

Two of the light source sections 4a, 4b, 4c, 4d are selected except for those on the same meridian, and are lit one by one, and the light quantity distribution and the light quantity distribution in the direction perpendicular and parallel to the edge ridge line. The inclination angle of is calculated, and the calculation is performed.
If the light sources 4a, 4b, 4c, and 4d are all turned on sequentially for measurement, and the measurement results on the same meridian are averaged, the effects of eyelashes and the effects of turbidity of the crystalline lens can be almost eliminated. This will improve the measurement system.

An arithmetic unit 13 is connected to the light receiving element 9. 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 displays the result on the display 14. It is designed to output.

Measurement of refractive power and further astigmatism is described in Japanese Patent Application No. Hei.
As shown in No. 4811, for example, it is obtained by measuring two meridians and a light quantity distribution in a direction orthogonal to each of the two meridians.

According to Japanese Patent Application No. 2-214811, the light quantity distribution of the pupil image is calculated by the following equation.

[0021]

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]

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 a spherical power S 1 / l ₁ −1 / l ₂ is a cylindrical power C θ _A is an astigmatic axis angle A.

[0023]

Equation 3] a ₁ = Table as _{(LC sin2A) / 2 a 2} = L {2 / L- (2S + C) + C cos2A} / 2 a 3 = L {2 / L- (2S + C) -C cos2A} / 2 When a ₁ , a ₂ , and a ₃ are obtained, a known two meridians and a light quantity distribution in a direction orthogonal to each of the two meridians are measured by the above equation, and the spherical power S, the astigmatic power C, 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 quantity distribution in the direction orthogonal to each of the two meridians, as is clear from the calculation formula, in the case of a certain angle combination, for example, a combination of 0 ° and 90 ° In the case of (1), it is possible to use any three data.

In this case, in order to observe or aim and measure both eyes at the same time, if one tries to receive the light receiving element 9 with one, there is a distance between the pupils of the subject, and the magnification on the light receiving surface is naturally limited. It will be. In order to measure with high accuracy, it may be possible to increase the magnification, but there is a limit from the above. For this reason, a light receiving element, for example, a light receiving range of an area sensor such as an individual CCD or the like is provided at a light receiving position substantially conjugate with the subject's pupil, a substantially alignment range of each of the two eyes, or a margin that allows easy aiming. The magnification is set to correspond to the range held, and two light receiving elements are placed at that position. In this case, when processing and calculating signals from both light receiving elements,
A common processing system / memory may be used, or separate processing systems / memory may be used. Alternatively, one of them may be common. In any case, the magnification at the light receiving position cannot be reduced by the light receiving element, and the measurement can be performed while increasing the magnification to improve the measurement accuracy. Needless to say, one light-receiving element may be used as in the related art.

When displaying on the display, the images on both light receiving elements, the stored images are combined and displayed on the display, or displayed on separate displays. In this case, a process other than the displayed portion, such as a portion outside the alignment range, is performed so that only black is displayed, and characters such as a measurement result are displayed at a necessary portion (see FIG. 2).

Referring to FIG. 1, the main part of the present apparatus will be described.

The main body 16 is configured as described above, and the subject positioning section 17 is provided in front of the main body to stabilize the face of the subject.
Is placed, the face of the subject is stabilized, and the target is observed by the fixation target 18 or an optotype such as a visual acuity chart.

At this time, a mirror 19 for transmitting infrared light and reflecting visible light is arranged on a column 22, for example, of a subject positioning portion 17 (a chin receiving portion, etc.) via a support frame, and a mirror 19, for example, is provided above the mirror. A total reflection mirror or a mirror 20 that reflects visible light and transmits infrared light is disposed via a support frame for holding the support 22 so that the fixation target 18 outside the measurement main body can be seen. . At this time, the mirror 19 that transmits infrared light and reflects visible light is used.
And a lens 21 having a known value is disposed between the total reflection mirror 20 and the like, for example, via a support frame to be held on a support. At this time, the upper fixation target may be directly viewed without using the total reflection mirror 20 or the like. Either mirror may correspond to both eyes and may have a sufficient width. Further, the lens 21 may have a marginal width corresponding to both eyes, or may be a separate lens corresponding to the subject's eye for each eye.

In the measurement, the subject places the face on the subject positioning section 17 (the chin support section), and when the binocular vision is closer to natural vision, the subject and the mirror are compared with a known value. The fixation target 18 is seen through the lens 21. In this state, the examiner moves the measurement main body 16 and performs measurement by aligning the subject's eye with the measurement main body 16 through the mirror 19 that transmits infrared light and reflects visible light. The measurement main body at this time may be of a conventionally known type of a monocular measurement or a type of a binocular measurement. In the case of monocular measurement, it goes without saying that the mirror lens may be for a single eye.

Further, in order to make the observer look closer to natural vision, the user looks at the fixation target 18 with both eyes, adjusts to the refracting power of the subject by the pre-measurement, and sets the far point or the cloud position. When the fixation target 18 is moved optically, the convergence angle is set to about 0 ° as if the subject is looking at infinity, that is, parallel viewing, It is necessary to change the angle so that adjustment or the like does not cause a problem. In this case, the convergence adjusting prism is arranged separately for the left and right eyes near the lens, and adjustment is performed in accordance with the position of the measurement unit main body and the fixation target.

When an external fixation target is viewed, the convergence angle is approximately 0 only when the measurement unit main body and the fixation target are set.
The convergence adjusting prism may be adjusted so that the angle does not cause a problem in adjustment by convergence or the like. Alternatively, in place of the convergence adjusting prism, reflecting mirrors may be provided separately for the left and right eyes, and their inclinations may be adjusted.

[0033] While computing the eye <br/> refraction power of the eye by light distribution from the light receiving element 9 by the calculator 13, this calculator 13 has been set and input the diopter value of the known lens 21 The arithmetic unit 13 calculates the refractive power of the eye, further compares the diopter value with the diopter value of the eye to be obtained by the calculation, determines the magnitude of both diopter values, and further displays the result. Is displayed on the container 14.

When measurement is performed in such an arrangement, a subject having a refractive power more negative than that of the lens 21 having a known value will look at the fixation target in a cloudy state. Become. A subject having a refractive power on the positive side adjusts the amount by the amount of difference from the known diopter and sees the value, which is almost a value close to the known diopter. Alternatively, if the accommodation power is smaller than the difference or if the intensity is hyperopia, the value becomes larger than the known value (see FIG. 4).

For example, a spectacle lens usually has a lens
Since it is common to place the lens at 2 mm, the known lens 21
Is set to a value equivalent to +2.5 diopters when the lens is placed 12 mm in front of the eyes, the refractive power of the lens to be added to form an image on the retina when the subject is farsighted is determined by The true value when a person is farsighted is +1 diopter,
In the case of a subject of minus diopter, the value appears approximately at that value. However, in the case of a subject of +7 diopter, if the subject has accommodation power and the fixation target 18 is clearly seen, then +2.
It is measured as a value near 5 diopters. In addition, in the case of a subject having the same +7 diopter but having only 3 diopters or insufficient adjustment, for example, the subject is measured as a numerical value near +4 diopter or a numerical value of +2.5 diopter or more. It is measured as

In such a case, if a measurement result that exceeds a predetermined refraction value, for example, +2.5 diopter or +1 diopter is obtained, it is possible that hyperopia is greater than that. Use it to make measurements or use another method to measure again.

Alternatively, when screening is further performed by a group examination or the like, a predetermined refractive power (± both directions), a difference between left and right refractive powers, a range of cylindrical power, and the like are stored in a measuring instrument. If it exceeds the range, some caution mark may be displayed on the display unit or displayed when printed out, or may be displayed on the display unit and printed out at the same time. When this mark is displayed, it may be determined that there is some abnormality, and a separate detailed inspection may be performed. The predetermined range can be changed later.

[0038] In this way, while observing with binocular vision in a state closer to natural vision, based on the pre-measurement and the result of the pre-measurement,
Without the need for a fogging mechanism to move the subject to present the fixation target at the far point or farther away, and without having to hang the test lens in time for the subject's pre-measurement In the case of a subject on the minus side of the known value lens 21 only by disposing the known value lens 21, the same measurement as in the case where the cloud fog mechanism is provided is possible. In the case of the subject on the more positive side, it is measured as a diopter near or above the same value as a lens of a known value, so that hyperopia can be found, and whether there is a certain degree of refractive error or more It is possible to carry out a screening such as seeing

When the known lens 21 is not only disposed but also changed to another known lens, or when a fixed fixation target is placed inside the main body, the position of the lens is changed between the subject and the subject. It may be arranged between the mirrors 19 transmitting infrared light and reflecting visible light, which are attached to the positioning part 17 (the chin 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. An error caused by tilting the lens may be corrected. In this case, correction is performed because the refractive power of the lens is also added.

[0040]

As described above, according to the present invention, a binocular vision and a near-natural vision are used, and a pre-measurement is performed. Without a fog mechanism to move to present the fixation target further away,
Its without causing over the test lenses and the like in accordance with the measurement before the subject, it is possible to discover hyperopia, Ri Do and can be screened whether there is ametropia above a certain value, further there also The comparison operation unit determines the refraction of the eye to be examined.
Compare the force measurement result with the diopter value of the known lens,
The magnitude of both values is determined, and if the measurement result is small,
Continue measurement, and if the measurement result is large,
Because the display is displayed, measurement is simplified and no unnecessary work is performed.
It becomes.

[Brief description of the drawings]

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

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

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

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

6 is a view as viewed in the direction of arrows AA in FIG. 5;

FIG. 7 is a view taken in the direction of arrows BB in FIG. 5;

[Explanation of symbols]

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

Claims (1)

(57) [Claims] 1. A measuring book for measuring an eye refractive power of an eye to be examined.
Having a body part , fixing a mirror of infrared light transmission and visible light reflection to the subject positioning portion to both eyes of the subject, enabling collimation of an external index with both eyes via the mirror, Apart from between the eye to be examined and the measuring body, in the ophthalmic measuring apparatus arranged lenses known values between the mirror and the external indicators, the
The known diopter value of the lens and the
An ophthalmologic measuring device comprising a comparison operation unit for comparing a measurement result .