JP3386613B2 - Objective eye refractometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an objective eye refractive power measuring device, and more particularly, in an objective eye refractive power measuring device provided with a fixation target projection system for making an eye to be inspected cloudy. The present invention relates to a technique capable of further improving the above.

[0002]

BACKGROUND ART In recent years, as an apparatus for measuring the refractive power of the eye,
BACKGROUND ART Objective eye refractive power measurement devices, which allow quick measurement, require no skill in measurement, and have a small measurement difference by an examiner, have become popular. This device generally has a projection optical system that projects a measurement light beam onto the fundus of the eye to be inspected, while detecting reflected light from the fundus of the eye to be inspected by a light receiving element,
Although it is provided with a measurement optical system for obtaining the eye refractive power information of the eye to be inspected, such an apparatus further includes:
For the purpose of stabilizing the line of sight of the subject at the time of measurement, it is arranged at a position branched from the optical path of the projection optical system and the measurement optical system, and a fixation target projection system for fixing the eye to the subject is provided. There is.

However, in the objective eye refractive power measuring device equipped with such a fixation target projection system, when the examinee looks into the fixation target in the device, accommodation force acts on the eye to be examined. Therefore, accurate refractive power measurement cannot be performed as it is.
Therefore, in the conventional device, the refractive power is measured in the state where the adjustment power is working at the start of the measurement, and then the fixation target is set so as to be positioned only at an appropriate diopter, so that the eye to be inspected is fogged. It is in the visual state, and the adjustment power is removed.

Therefore, even in the method of bringing the eye to be examined into the clouded state, it is difficult to apply it to some eyes. For example, when the eye to be examined has strong astigmatism, the blurring of the fixation target is caused. There was a problem that it was not possible to expect a sufficient fog effect for the eye to be examined of a child with a large amount of eyes that could not gaze at the fixation target in a stable manner and had large accommodation power. In Japanese Patent Publication No. 3-49445, an optical member that creates a cylindrical component with a cylindrical lens is arranged on the optical path of the fixation target projection system, and the refractive power of the fixation target projection system is continuously or stepwise set manually. The objective automatic eye refractive power measurement device that has a cloud effect for subjects with strong astigmatism and children with large accommodation power has been proposed. Using the optical member to change the refractive power of the fixation target projection system Is from where in was achieved, inevitably complicated in apparatus structurally.

Further, the accommodation power of the subject's eye is easily affected by the psychological effect of the subject, and when the target image is in a cloudy state, the contour of the target image becomes blurred and becomes large. Has an inherent problem that it causes an illusion that the target image is approaching, causing tension, which may prevent accurate measurement.
The conventional device does not sufficiently respond to such a problem.

[0006]

The present invention has been made in view of such circumstances, and its object is to provide a cloudy state in which it is difficult to cause an illusion that a target image approaches a subject. It is an object of the present invention to provide an objective-type eye refractive power measuring device capable of generating a high-precision measurement.

[0007]

In order to solve such a problem, the present invention detects a projection optical system that projects a measurement light beam onto the fundus of the eye to be inspected and a light receiving element to detect light reflected from the fundus of the eye to be inspected. With the measurement optical system for obtaining the eye refractive power information of the eye to be examined, a fixation target projection system is provided at a position branched from the optical path of the optical system to fixate the eye. In the objective eye refractive power measuring device, the fixation target projection system is positioned between the fixation target and the objective lens on the side of the eye to be imaged on the fundus of the eye. By disposing variable diaphragm means capable of continuously or stepwise changing the size of the diaphragm, the eye refractive power information obtained first and the eye refractive power information previously obtained by other means are compared. Based on the above, the size of the diaphragm in the variable diaphragm means can be changed. The objective type eye refractive power measuring apparatus according to symptoms, it is an gist thereof.

Further, in the objective eye refractive power measuring device according to the present invention, it is advantageous to provide a moving means for moving the fixation target back and forth on the optical path of the fixation target projection system. At the same time as changing the size of the diaphragm in the variable diaphragm means to a small value, the diopter value is also changed to a small value based on the movement of the fixation target by the moving means.

[0009]

As described above, in the objective eye refractive power measuring device according to the present invention, the fixation target and the fixation target on the retina of the eye to be examined are connected to the fixation target projection system. Since the variable diaphragm means that can change the size of the diaphragm continuously or stepwise is arranged so as to be located on the optical path between the objective lens on the eye side to be imaged, In the objective eye refractive power measuring device, the eye refractive power information obtained by first measuring, in other words, the measurement result with the diaphragm of a predetermined size set by the variable diaphragm means, and other Eye refractive power information previously obtained by the means, specifically, the subjective eye refractive power measurement value obtained by the subjective eye refractive power measurement device, or the eyeglasses or contact lenses worn by the subject's eye In contrast to refractive power information, if there is a certain degree of difference between them, The subject's illusion that the fixation target is approaching by changing the aperture by the variable aperture means to a smaller predetermined aperture value, increasing the optical depth of focus, reducing blurring of the outline of the fixation target This is to prevent the above, and by doing so, it has become possible to perform highly accurate measurement.

Further, on the optical path of the fixation target projection system, a moving means for moving the fixation target back and forth is provided, and as described above, the diaphragm by the variable diaphragm means is changed to a predetermined small diaphragm. At the same time, the fixation target is moved to a predetermined position, specifically, to a position where the diopter value is smaller than the diopter value at the time of the previous measurement, by the moving means. The illusion of the subject that the target is approaching, rather than simply changing the aperture,
It will be possible to prevent more effectively,
It is possible to measure with higher accuracy.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the present invention more specifically, representative embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a block diagram of an objective eye refractive power measuring device having a structure according to the present invention. In this figure, reference numeral 100 denotes an observation optical system. Then, in the observation optical system 100, the reticle 26 located at a position substantially conjugate with the cornea of the subject's eye 2 is illuminated by the rear light source 24, passes through the cold mirror 4, the half mirror 28, and the observation lens 30, and is further reflected. The light is reflected by the mirror 32 so that an image is formed on the image forming surface 34 of the CCD camera. On the other hand, the luminous flux from the illumination light 48 is reflected by the cornea of the eye 2 to be inspected, further reflected by the cold mirror 4, passes through the same optical path as described above, and is imaged on the image forming surface 34 of the CCD camera. Then, the above-mentioned reticle 26
While looking at the monitor (not shown) on which the image and the cornea image of the subject's eye 2 are projected, the examiner moves the device up, down, left, right, and front and back to perform alignment so that the focus becomes clear. Do it.

Further, in the fixation target projection system 200 in such an objective eye refractive power measuring apparatus, while the light source 36 illuminates the fixation target 38, the fixation target 38 is fixed. Is transmitted through the lens 40 and the variable diaphragm 42, is reflected by the mirror 44, is transmitted through the objective lens 46, and is made into a substantially parallel light beam by the lens 40 and the objective lens 46. The light is reflected by the mirror 28 and the cold mirror 4 and reaches the retina of the eye 2 to be inspected, so that the eye 2 is configured to fixate the fixation target 38.

The variable diaphragm 42 provided on the optical axis of the fixation target projection system 200 has a circular aperture diameter of 2 mm, 3 mm, and 1 mm on a straight line, as shown in FIG. A non-translucent plate 58 having an aperture 50 is provided, and a rack 56 provided on the side of the plate 58.
The pinion 54 meshing with the pinion 54 is driven to rotate by the motor 52, so that the plate 58 is moved in the longitudinal direction (arrangement direction of the rack 56), and thereby the three kinds of opening diameters provided in the plate 58. Any desired aperture hole 50 can be selected and positioned on the optical axis of the fixation target projection system 200.

That is, the variable aperture 42 has an aperture diameter of 1 mm or 2 mm by pressing or of the aperture change switch Sp in the operation panel as a setting means for setting the size of the aperture as shown in FIG. The diaphragm hole 50 is positioned on the optical axis. In other words, when the aperture change switch Sp of the operation panel in FIG. 4 is pushed in, the aperture hole 50 having an opening diameter of 1 mm is located on the optical axis, and when the aperture change switch Sp is pushed in, the aperture change switch Sp of 2 mm is opened. The motor 52 is rotated so that the aperture 50 having the aperture is located on the optical axis. Then, here, at the start of the measurement, the diaphragm hole 50 having an opening diameter of 3 mm is controlled to be positioned on the optical axis so that the diaphragm diameter is always 3 mm.

In the fixation target projection system 200, the fixation target 38 is moved by a driving device (moving means) not shown.
It is movable along the optical axis. Then, such a driving device is controlled by the output of an arithmetic circuit (not shown) so that the fixation target 38 can be moved to a predetermined position where the eye 2 to be inspected can fix without being adjusted. Thus, a so-called automatic fog device is configured.

Further, in the projection optical system 300, the inclination angles of the first lens 18 and the slit-shaped light beam are different by two or more along the traveling direction of the light from the measurement light source 16. A chopper disk 20 having slits is provided, and a motor 22 for rotating the chopper disk 20 is further provided. Therefore, the measurement light source 16 is disposed on the same side as the first lens 18 with respect to the chopper disc 20, and the measurement light source 16 is second conjugate that is substantially conjugate with the corneal surface of the eye 2 to be inspected. The lens 6 is fixedly provided so that the measurement light beam can be projected onto the fundus of the eye 2 to be inspected.

Further, in the measuring optical system 400, of the scanning light beams projected into the pupil of the eye 2 to be inspected, the light beam reflected by the fundus of the eye is the cold mirror 4, the second lens 6,
After passing through the polarization beam splitter 8, the imaging lens 1
It is focused by 0. Further, a diaphragm 12 having a circular opening centered on the optical axis is provided behind the imaging lens 10, and a photoelectric converter 14 is provided behind it.
The diaphragm 12 is fixed, respectively, so that the diaphragm 12 is substantially conjugate with the fundus of the eye 2 and the light receiving surface of the photoelectric converter 14 is substantially conjugate with the cornea of the eye 2. , Are arranged on the optical axis.

As is well known, on the light receiving surface of the photoelectric converter 14 in the measuring optical system 400,
As shown in FIG. 6, the photoelectric conversion element 14 which is a light receiving element.
Each of a, 14b, 14c, and 14d is arranged outside the optical axis. Then, the pair of photoelectric conversion elements 14a,
14 c is a direction of one measurement meridian, that is, a plane including one of the directions in which the slit-shaped light beam scans the eye 2 to be inspected (Y direction) and the optical axis passes through each center, and each is substantially symmetrical to the optical axis. And another pair of photoelectric conversion elements 14b and 14d.
Is the other of the direction of the measurement meridian orthogonal to the direction of the measurement meridian, that is, the direction (X
The plane including the (direction) and the optical axis passes through the respective centers, and each is arranged symmetrically with the optical axis on a line orthogonal to the optical axis. Then, the photoelectric conversion element 14 forming these pairs
The target eye refractive power information is calculated based on the output signals from a, 14c and 14b, 14d. The calculation method is well known, for example, Japanese Patent Laid-Open No. 62-5147. It is clarified in the official gazette.

When measuring the eye refractive power of the subject's eye 2 using the objective type eye refractive power measuring device having such a configuration, when the variable diaphragm 42 of the fixation target projection system 200 is operated, In the case of measurement of, first, the plate 58
The eye-refractive-power value is measured with the aperture diameter of 3 mm so that the aperture hole 50 with an aperture diameter of 3 mm is located on the optical axis of the fixation target projection system 200. Then, the eye refractive power value obtained by the measurement, and the eye refractive power information separately obtained in advance by another means, for example, the value measured by the subjective eye refractive power measuring device or the glasses worn by the subject. And the eye refractive power value of the contact lens are compared with each other, and the difference between the refractive power values is a predetermined value or more, specifically, 1 diopter or more, the aperture change switch of the operation panel shown in FIG. When the switch of Sp or is pushed in,
As shown in FIG. 5, a plate 58 having three kinds of aperture holes 50 of 1 mm, 2 mm, and 3 mm in aperture size is moved by a motor 52, and an aperture having a desired aperture size of 1 mm or 2 mm is changed from the aperture size of 3 mm. Therefore, the corresponding aperture hole 50 is selected and arranged on the optical axis. The selected diaphragm diameter (diaphragm hole 50) of the variable diaphragm 42 is displayed at one corner of a monitor (not shown) on which the cornea image of the eye 2 to be inspected and the reticle 26 are displayed simultaneously with such selection. It has been made known to the examiner.

Next, by aligning the device with the eye 2 to be inspected by the monitor and pressing a measurement start switch (not shown), the optical depth of focus is increased under the diaphragm changed by the variable diaphragm 42. At the very least, the target eye refractive power information of the eye 2 to be inspected is measured in a state in which the blur of the outline of the fixation target is reduced. By such a diaphragm operation by the variable diaphragm 42, the optical depth of focus is increased, the blurring of the outline of the fixation target 38 is reduced, and the illusion that the fixation target of the subject approaches is effective. It is possible to prevent this, and it is possible to perform highly accurate measurement, and under the condition where the depth of focus is increased, the target eye refractive power information of the subject's eye 2 is collected. Of. At the same time as the completion of the measurement, the diaphragm diameter of the variable diaphragm 42 automatically returns to 3 mm.

In the specific example described above, the plate 58 provided with the diaphragm hole 50 having a predetermined opening diameter is linearly moved, but instead, it is a non-translucent rotating plate. A configuration in which diaphragm holes having a plurality of different opening diameters are provided on the concentric circles of the disk to be obtained, and the diaphragm holes can be changed by switching the diaphragm holes located on the optical axis by the rotation of such a disk. Etc. can be appropriately adopted, and in any case, any known structure can be adopted as long as a desired diaphragm hole can be selected by moving a member provided with a plurality of diaphragm holes having different sizes. A structure can also be adopted.

However, in the case of the variable diaphragm 42 having a plurality of aperture diameters as in the above example, it is unavoidable that the inside of the apparatus that the examinee is looking into becomes dark when the aperture diameters are changed. It is desirable to use an iris diaphragm whose aperture diameter can be continuously changed as the variable diaphragm 42 in order to eliminate the anxiety of the subject caused thereby.

FIG. 3 shows an example of such an iris diaphragm, in which a lever 62 of the iris diaphragm 60 is fixed while a gear 64 is attached to the outer periphery of the iris diaphragm 60. The gear 68 that engages with the motor 64 is attached to the shaft of the motor 66. The rotation of the motor 66 causes the gear 64 to rotate via the gear 68, thereby opening the iris diaphragm 60. The aperture (diaphragm) is continuously changed. Such an operation panel of the iris diaphragm 60 serves as setting means for setting the size of the diaphragm so that the diaphragm diameter is continuously reduced by continuously pressing the diaphragm changing switch Sp as shown in FIG. It is controlled, and even in this case, the aperture diameter is displayed in one corner of the monitor described above, and at the same time as the completion of the measurement,
The aperture diameter automatically returns to 3 mm.

When the objective eye refracting power measuring device as described above is started, the refracting power is measured while the eye 2 to be inspected has an adjusting power, and thereafter, an appropriate diopter (usually +3 diopter) is measured. By moving and arranging the fixation target 38 so as to give only the amount, the eye to be inspected is made into a fog state and its accommodation force is removed, but at a position where +3 diopter is given, The contour of the optotype image is greatly blurred, and there is a case in which the subject feels an illusion that the optotype image is approaching and looks at the near side, and accurate measurement cannot be performed. Therefore, in the above-described specific example, the variable aperture 42 is provided and the amount of blur is reduced to reduce the blur amount. However, the aperture amount (diaphragm diameter) of such a variable aperture 42 is reduced. If it is made too small, the amount of light of the fixation target 38 image becomes insufficient, and the subject gazes at the fixation target 38, which may make accurate measurement difficult.

In such a case, the variable diaphragm 42
The aperture amount is not less than a predetermined amount (1 mm in the above specific example).
Since there is no diaphragm hole 50 having an aperture diameter smaller than 1 mm, a diaphragm amount of 1 mm or less cannot be selected), and the amount of movement of the fixation target 38 by the drive device is concerned with the subject. Instead, the fixation target 38 is moved by the driving device without being fixed as a fixed amount of the initially determined amount, for example, +3 diopter, and the movement amount of +2 diopter is reduced by +1 diopter. The amount of blurring of the image of the target 38 does not become insufficient and the amount of blurring can be reduced, and thus accurate measurement can be performed.

The operation method is carried out by continuously pressing the diopter switch Dp provided on the operation panel as the aperture setting means shown in FIGS. 4 and 5, whereby the movement amount of the fixation target 38 is moved. Is controlled so that the position of the fixation target 38 is fixed by stopping the pressing operation of the diopter switch Dp when the fixation target 38 reaches the target movement amount. The Rukoto. Also in this case, the movement amount of the fixation target 38, in other words, the diopter value is displayed together with the diaphragm diameter of the variable diaphragm 42 in one corner of the monitor, and the fixation target 38 is moved to the +3 diopter position at the same time when the measurement is completed. In addition, the variable diaphragm 42 is automatically returned so that the diaphragm diameter becomes 3 mm.

In the above measurement operation, the measurement result when the diaphragm diameter of the variable diaphragm 42 in the fixation target projection system 200, which is a normal measurement condition of the present apparatus, is 3 mm, and the movement amount of the fixation target 38 is +3 diopter. Between (eye refractive power value) and the eye refractive power information obtained by other means, such as the previously-obtained subjective eye refractive power measurement value and the refractive power value of eyeglasses or contact lenses worn by the subject. When there is a predetermined amount of difference, for example, a difference of 1 diopter, after the measurement under such normal conditions (diaphragm diameter 3 mm, +3 diopter),
5. Using the operation panel of FIG. 5 or by manually operating or automatically reducing the diaphragm diameter of the variable diaphragm 42 and the moving amount of the fixation target 38, for example, diaphragm diameter: 1 mm, moving amount: +
As the diopter, the target eye refractive power information is obtained by repeating the measurement under the condition.

When the difference between the two eye refractive power values obtained as described above is too extreme, it is determined that a subject who is unsuitable for the objective eye refractive power measuring apparatus is aware of the eye refractive power. It is judged that it is desirable to obtain the eye refractive power information based on the measurement values obtained by other means such as the force measuring device.

Although one embodiment of the objective eye refractive power measuring device having the structure according to the present invention has been described above, it is a literal example, and the present invention is not limited to such an embodiment. Needless to say, it should not be construed as limiting, and the present invention is carried out in variously modified, improved, modified, etc. embodiments, and such embodiments do not depart from the gist of the present invention. It is to be understood that, to the extent, both are within the scope of the invention.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an objective eye refractive power measuring device having a structure according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a variable diaphragm arranged in the fixation target projection system shown in FIG.

FIG. 3 is an explanatory diagram showing another example of a variable diaphragm provided in the fixation target projection system shown in FIG.

FIG. 4 is an explanatory diagram of an operation panel that controls the variable aperture and the like shown in FIG.

5 is an explanatory diagram of an operation panel that controls the variable aperture and the like shown in FIG.

6 is an explanatory diagram showing an arrangement form of photoelectric conversion elements of a photoelectric converter arranged in the measurement optical system shown in FIG. 1. FIG.

[Explanation of symbols]

2 eye to be inspected 4 cold mirror 6 second lens 8 polarization beam splitter 10 imaging lens 12 diaphragm 14 photoelectric converters 14a, 14b, 14c, 14d photoelectric conversion element 16 light source for measurement 18 first lens 20 chopper disk 22, 52 , 66
Motors 24, 36 Light source 26 Rectangle 28 Half mirror 30 Observation lens 32 Reflection mirror 34 CCD camera image plane 38 Fixation target 40 Lens 42 Variable aperture 44 Mirror 46 Objective lens 48 Illumination light 50 Aperture hole 54 Pinion 56 Rack 58 Plate 60 Iris diaphragm 62 Lever 64, 68 Gear 100 Observation optical system 200 Fixation target projection system 300 Projection optical system 400 Measurement optical system

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) A61B 3/10-3/18

Claims (2)

(57) [Claims] 1. A projection optical system that projects a measurement light beam onto the fundus of the eye to be examined, and light reflected from the fundus of the eye to be detected is detected by a light receiving element to obtain eye refractive power information of the eye to be examined. In the objective eye refractive power measuring device, which is provided with the measurement optical system and the fixation target projection system which is arranged at a position diverging from the optical paths of the optical systems so as to fixate the eye to be examined, In the fixation target projection system, the size of the diaphragm is continuously or stepwise so that it is located between the fixation target and the objective lens on the side of the eye to be imaged on the fundus of the eye. A variable aperture means that can be changed to a variable aperture means is provided, and the size of the aperture in the variable aperture means is determined based on the comparison between the eye refractive power information obtained first and the eye refractive power information previously obtained by another means. The objective eye refractive power measuring device characterized in that the height can be changed. 2. A moving means for moving the fixation target back and forth on the optical path of the fixation target projection system is provided, and the size of the diaphragm in the variable diaphragm means is changed to a small size, and at the same time, the fixation means is fixed. The objective eye refractive power measuring device according to claim 1, wherein the diopter value is also changed to be small based on the movement of the target.