JP2817793B2 - 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. Fundus 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.

However, in such a photorefractive eye refractive power measuring device, a strobe light source is used to illuminate the optical axis of the camera from an oblique direction, and the pupil image at that time is simply photographed. There is a problem that there is a value and the measurable range is narrow.

In view of this, the present applicant has proposed in Japanese Patent Application No. 63-238505, an eye refractive power measuring apparatus capable of measuring any diopter value and obtaining a measurement result instantaneously.

Although the eye refractive power measuring device will be described in detail later, the eye refractive power measuring device projects a light source image on the fundus of the eye to be examined, and blocks and blocks a part of the light beam from the light source reflected by the fundus. The light beam is received by a light receiving element, and the eye refractive power is measured based on the light amount distribution state of the light beam.

[Problems to be Solved by the Invention] In the above-described eye refractive power measuring apparatus, when the eye refractive power is obtained based on the light amount distribution state as described later in detail, the pupil is considered as one of the factors of the measurement. Diameter.
In the present invention, when the eye refractive power is obtained from the light quantity distribution state, the pupil diameter is to be corrected to a predetermined value.

Means for Solving the Problems The present invention provides a projection system for projecting a light source image on the fundus of the eye to be inspected, a light receiving element arranged at a position substantially conjugate with the pupil of the eye to be inspected, and A light receiving system for condensing the light beam,
An edge-shaped light-blocking member arranged in the light path of the light receiving system so as to block a part of the light beam from the fundus; and an eye refractive power of the subject's eye based on a light amount distribution state of the light beam projected on the light receiving element. An eye refractive power measuring apparatus comprising: a calculating unit for calculating a pupil diameter from a video signal of the light receiving element, wherein the eye to be examined is adjusted to adjust the pupil diameter. And a light amount adjusting means for adjusting an illumination light amount of the illumination light source so that a pupil diameter calculated by the arithmetic processing unit matches a target value. .

[Operation] The pupil diameter is calculated from the video signal from the light receiving element, and this value is compared with a target value to increase or decrease the light amount of the light source for adjusting the pupil diameter so that the obtained pupil diameter matches the target value. .

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

First, the eye refraction device proposed in the earlier application will be described.

3A, 3B, and 3C, reference numeral 1 denotes a projection system for projecting a light source image onto the fundus 7 of the eye 3 to be examined, and 2 receives a light beam 10 reflected by the fundus 7. The projection system 1 and the light receiving system 2 are arranged to face the subject's eye 3.

The projection system 1 includes a light source 4 and a half mirror 5 for reflecting a light beam 11 from the light source 4 toward the subject's eye 3. The projection system 1 transmits the light beam 11 from the light source 4 onto a fundus 7 through a pupil 6. To form an image of the light source 4 on the
The distance between the light source 4 and the eye 3 is set so that the image of the light source 4 is focused on the fundus 7 when the eye refractive power of the eye 3 is a reference diopter value (reference refractive power).

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

The light receiving element 9 includes an area CCD, an image pickup tube, or a combination thereof.
The light receiving surface 9a of the light receiving element 9 is arranged at a position 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, an edge-shaped light shielding member 12 for shielding one side of the light flux 10 with the optical axis O of the objective lens 8 as a boundary is disposed at a position conjugate with the light source 4 with respect to the half mirror 5.

An arithmetic unit 13 is connected to the light receiving element 9. The arithmetic unit 13 calculates a diopter value from the light receiving state of the light receiving element 9 and the light quantity distribution, and outputs the result to the display 14. .

Next, the measurement of the eye refractive power in the eye refraction measuring apparatus having the above configuration is performed as follows.

As shown in FIG. 3 (A), when the diopter value of the subject's eye 3 is a negative diopter value compared to the reference diopter value, the image of the light source 4 is formed in front of the fundus 7, and this light flux causes Considering the light beam 10 reflected at one point on the optical axis among the illuminated fundus 7, the light beam 10 is condensed in front of the light shielding member 12, that is, on the side of the eye 3 to be examined, and is received by the objective lens 8. The upper half (hatched portion) of the light beam projected onto the element 9 is shielded.

On the other hand, as shown in FIG. 3B, when the diopter value of the eye to be inspected is the reference diopter value, the light beam 10 is condensed on the light shielding member 12, and the light beam 10 is blocked by the light shielding member 12. I can't.

Also, as shown in FIG. 3 (C), when the diopter value of the eye 3 to be examined is more positive than the reference diopter value, the image of the light source 4 is projected so as to form an image behind the fundus 7, and as described above. Similarly, the light beam 10 reflected by the fundus 7 is collected behind the light shielding member 12, that is, on the light receiving element 9 side, and the light beam 10 projected on the light receiving element 9 is a portion opposite to that of FIG. The light flux (the upper half in the figure) is shielded.

Thus, the light flux projected on the light receiving portion 9a changes in the light amount distribution state depending on the magnitude or the sign of the diopter value of the eye 3 with respect to the reference diopter value, and the diopter value is obtained based on the light amount distribution state.

The light receiving element 9 is for detecting the light amount distribution of the light beam formed on the light receiving surface 9a, and the arithmetic unit 13 is configured to detect the light amount distribution of the light beam formed on the light receiving surface 9a based on the signal from the light receiving element 9. Detects the light amount distribution, determines whether the eye refractive power of the subject's eye is positive or negative with respect to the reference diopter value, calculates the absolute value, outputs the calculation result to the display 14, and the display 14 calculates Display the results.

In the above embodiment, a half mirror is used as a light beam separating means. However, it is a matter of course that various light beam separating means such as a beam splitter and a polarizing prism are used.

4 (A) to 4 (E), a light quantity distribution state of a light beam formed on the light receiving surface 9a will be described.

In order to simplify the explanation in FIGS. 4 (A) to 4 (E), the optical axis of the light source 4 and the optical axis of the light receiving system are matched, and the light shielding member 12 and the objective lens 8 are matched. I have. For this reason, the light source 4 and the objective lens 8 are shown superimposed at the same position, and the light shielding member 12 is omitted.

FIG. 4 (A) ~ (E) is the light receiving surface by all reflected light beam objective lens 8 from the shows the case where the refractive power D of the eye is negative with respect to the reference power D _0, the following description fundus It shall be projected on 9a.

The distance between the light source 4 and the pupil 6 of the eye to be inspected is set to l, and the refractive power of the eye to be inspected at which the image of this light source is focused on the fundus is the reference refractive power D _0.
Then It is.

FIG. 4 (A) shows a case where the refractive power of the subject's eye is D (<D ₀ ) from one point S ₀ on the axis of the slit-like light source 4 having a length L in a direction perpendicular to the optical axis. Indicates the projected light flux,
The image of the point S ₀ is once formed on S ₀ ′,
Projected as a blurred image. Region 7a where D ₀ -D is projected in accordance with increase becomes wider.

FIG. 4 (B) shows the state of the light beam reflected from the light receiving system 2 and the fundus 7 of the eye to be examined.

As shown in FIG. 4 (B), considering the light flux from a point I- _n at the end of the projection area on the fundus 7 of the eye to be examined, an image I- _n 'of this point is considered.
Is imaged at a position 1 'away from the pupil of the eye to be examined, and this light beam is projected via the objective lens 8 onto a light receiving element 9 arranged at a position conjugate with the pupil 6 of the eye to be examined. The relational expression between l 'and the refractive power D of the eye to be examined is as follows.

On the other hand, assuming that the pupil diameter of the subject's eye is u, the spread width Δ of the light flux emitted from one point on the fundus is as shown in FIG. 4 (B). From the equations (1) and (2). Thus, as the difference between the refractive power D of the subject's eye 3 and the reference refractive power D ₀ increases, the spread on the light shielding member 12 increases.

Next, the spread of the light beam on the light receiving element 9 will be described. The light receiving element 9 is always irrespective of the refractive power of the eye 3 to be inspected.
Assuming that the diameter of the pupil 6 of the eye to be examined is u and the magnification of the objective lens 8 is β, the region of the diameter of βu on the light receiving element 9 (the refractive power of the eye to be examined) Is unaffected by the light beam.

Further, after the imaging from the light beam is similarly examined eye pupil 6 'image I _n to the position of' l from the I _-n symmetrical point I _n with respect to the optical axis, the same area on the light receiving element 9 projected onto βu. Light source 4
As a point light source, when that there is no light blocking member 12 is, those points I _-n from these fundus _{7, ... I 0, ... I} n, the integral of the light beam from determining the light intensity distribution on the light receiving element 9 It is.

Here, in order to consider the light amount distribution on the light receiving element 9, the light flux incident on the end position P _-n of the light beam projection position on the light receiving element 9, that is, the coordinate position -βu / 2 centered on the optical axis. In consideration of the above, the light beam incident on this position is limited to the light beam in the range of the oblique line A in FIG. 4 (C).
Similarly, considering the light flux incident on the position _Pn symmetrical to the P- _n position with respect to the optical axis, the light flux is limited to the light flux in the range of the hatched line A '. When an edge-shaped light-blocking member 12 that blocks one light beam A ′ of the optical axis is arranged at a distance of 1 from the pupil 6 of the eye to be examined (a position conjugate with the light source 4), P ₋ light beam incident on the position of the _n is not blocked by the light shielding member 12, the light beam toward the upper position from the position of the P _-n is gradually shading, half of the light beam is blocked by the center P ₀ position, P _n In this position, all the light beams are blocked. Therefore, the edge-shaped light shielding member 12
As a result, the light becomes darker on the light receiving element 9 as it goes upward, and the light quantity distribution has a constant slope where the light quantity becomes 0 at the point _Pn .

4 (A) to 4 (C) show only a light beam emitted from one point on the optical axis of the light source 4, but one point S- _n at the end of the light source 4 (where the size of the light source is L) Considering the luminous flux from the point (−L / 2 coordinate position), the result is as shown in FIG. 4D. Light beam from the point S _-n are projected in the area of I _n points from I _-n point on the fundus 7 shown in FIG. 4 (D), the I
_-n point, the reflected light from I _n points, the eye pupil as before 6
'I _n at a distance of' l from, after forming an image of I _n ',
The light is projected onto a region having a diameter of βu on the light receiving element 9. Here, of the luminous fluxes emitted from the end point _Sn of the light source 4, the luminous flux incident on the end position P- _n of the luminous flux projection on the light receiving element 9 corresponds to the shaded area B in FIG. 4 (D). It becomes a light beam.

Further, the S consider the light beam from one point S _n of the point symmetrical with the light source 4 _-n, of which FIG. 4 Given the light beam incident on the point P _-n on the light receiving element 9 C of (E) It becomes a light flux in the inclined area. As described above, when the light source 4 is considered to have a certain size, the amount of light at one point on the light receiving element 9 must be considered as the sum of the light flux from each point of the light source 4.

FIG. 5 (A) shows the respective light beams incident on the position of P- _n on the light receiving element 9 based on this concept, and shows the light beams emitted from the position of S- _n on the light source. Of which P _-n
Is incident on the area B (FIG. 4 (D)).
See), the light beam according to the position on the light source goes upward also moves upward, the reference becomes a light flux area of the light source position S ₀ in A on the axis (FIG. 4 (C)), on the light source the light beam C region at the position of S _n (see FIG. 4 (E)). Therefore, the light quantity at the point P- _n on the light receiving element 9 can be considered as the sum of these light fluxes.

Here, a light shielding member is provided at a position of a distance 1 from the pupil 6 of the eye to be examined.
FIG. 5B is a schematic diagram showing the light quantity at point P- _n on the light receiving element 9 when 12 is arranged. FIG. 5 (B) shows how the light beam is blocked by the light blocking member 12 as the position on the light source changes. The horizontal axis in FIG. 5 (B) shows the coordinate position on the light source, and the vertical axis shows the light amount. Considering the luminous flux from each point on the light source, -L / 2 (L is the light source The luminous flux from the point (0) to the point 0 is not blocked by the light blocking member 12, but is gradually blocked after passing the coordinate point 0, and all the luminous fluxes are blocked at the position of Δ (the spread of the luminous flux described above). It will be. Here, FIG. 5 (B) shows the contribution of the light amount from each point on the light source, where k is the light amount from each point on the light source when no light is shielded. This corresponds to the light amount value at the point P- _n . This area value T is as follows.

Similarly, other points on the light receiving element will be considered. Figure 6 (A) have the meanings indicated in the same manner as Figure 5 a light beam incident on the center point P ₀ on the light receiving element (A), an inner P of the light beam from a point S _-n on the light source light flux incident inclined region of B ₀ to a point _0, the hatched area of a ₀ is the center point S ₀ on the light source, the light flux from a point S _n on the light source is the luminous flux of the inclined region of the C ₀ That is, the amount of light incident on the center of the light receiving element 9 corresponds to the area T ₀ of the inclined region in FIG. 6B. That is, considering the light flux incident on the center point of the light receiving element from each point of the light source, -Δ /
The luminous flux is not blocked until the position of 2, and after passing the -Δ / 2 position, the luminous flux is gradually blocked, and all the luminous flux is blocked at the position of / 2. The following values are calculated.

Similarly, FIGS. 7A and 7B show the state of the light beam incident on the point _Pn on the light receiving element and the light amount value at this point. In Figure 7 (A), hatched A "is the light beam incident on the point of the inner P _n of the light beam from the point S _-n on the light source is shaded region of B ', the center point S ₀ on the light source The luminous flux from the point P- _n on the area and the light source is shown as a luminous flux in the hatched area C ". In this case, as shown in FIG. 7 (B), considering the light flux incident from each point of the light source to the point P _n of the light receiving element,
The light flux is not blocked from the position -L / 2 to -Δ on the light source, the light is gradually blocked after passing the -Δ position, and all light is blocked at the 0 position. When this area value is calculated, the following value is obtained.

As can be seen from the results of Equations (4), (5), and (6), the light amount value on the light receiving element 9 gradually decreases as going from lower to upper. When the light quantity distribution on the element is illustrated, it changes linearly as shown in FIG.

In the above description, the description has been made on the assumption that the spread width Δ on the light blocking member 12 when considering the light flux emitted from one point of the fundus is smaller than 1/2 of the size L of the light source. It is.

However In other words, if the deviation ΔD of the diopter value of the subject's eye with respect to the reference diopter value D ₀ is equal to or greater than a predetermined value,
A linear change as shown in the figure is not shown. This will be described with reference to FIGS. 5 to 7. As aforementioned In the case of FIG. 5, FIGS. 5 (B), 6 (B), and 7 (B) are as shown in FIGS. 12, 13, and 14, respectively. It does not show a linear change as shown in FIG.

Next, when the refractive power of the subject's eye shown in FIG. 3 (B) is the reference value, and when the refractive power of the subject's eye shown in FIG. 3 (C) is more positive than the reference value, the same as described above. The light amount distribution on the light receiving element 9 can be considered. In this case, when the refractive power of the eye to be examined is a reference value, as shown in FIG. As shown in FIG. 10, the distribution is opposite to that shown in FIG.

The diopter value (refractive power) is the slope of the light amount distribution described above.
And the direction of the slope represents the sign of the diopter value. This will be described below with reference to FIG.

The slope of the light distribution Is defined as The spread Δ of the luminous flux, that is, the amount of blur is Δ from the above equation (4). Therefore, from equation (7) Thus, equation (9) gives the deviation ΔD of the diopter value of the subject's eye with respect to the reference diopter value D ₀ . Are proportional. Therefore, if the pupil diameter u is known, it can be obtained from the pupil diameter u and the light amount distribution. Thus, the diopter value of the subject's eye can be obtained.

As described above, the diopter value of the subject's eye can be obtained from the light amount distribution of the light beam reflected from the fundus.

Note that the above-described light amount distribution is schematically illustrated, and in fact, the change in the light amount distribution corresponding to each part of the eyeball shown in FIG. 15 (A) (see FIG. 15 (B), FIG. 15 ( The light amount distribution shown by B) shows the light amount distribution at the reference diopter value), that is, the light amount protrusion ρ at the bright spot 19 due to the reflection of the cornea, or the light amount distribution at the iris 20 part outside the pupil 6. There is a drop σ and the like.

In the present invention, specifically, the fifteenth
From the rate of change of the light quantity shown in FIG.
Pupil diameter u is determined from the positions of the boundary points m and n,
Further, the pupil diameter u is to be corrected to a predetermined value.

In addition, the deviation ΔD of the diopter value from the light amount distribution described above.
Is not affected by the bright spot. Since the bright spot affects the measurement result, it is preferable to remove the influence of the bright spot during the measurement.

Hereinafter, the removal of the influence of the bright spot will be described.

FIG. 1 shows a basic configuration diagram of an embodiment of the present invention, and FIG.
The figure is a schematic block diagram of the embodiment.

In FIG. 1, the same components as those shown in FIGS. 3 (A), (B) and (C) are denoted by the same reference numerals.

A gaze target system 17 for projecting the light beam 16 from the gaze target 15 to the fundus 7 is provided in the above-mentioned eye refractive power measuring device shown in FIGS. 3 (A), 3 (B) and 3 (C).

The gazing target system 17 is a lens 18 for projecting a gazing target 15 and a light beam 16 from the gazing target 15 toward the fundus 7 of the eye to be examined.
A mirror 19 for reflecting the light beam 16 from the lens 18 toward the optical axis of the projection system 1; and a mirror 19 disposed on the optical axis of the measuring machine, and between the eye 3 and the first half mirror. Provided,
A second half mirror 20 for aligning the optical axis of the light beam 16 with the optical axis of the measuring device and projecting the light to the fundus 7, and an illumination light source 21 for the target 15 to be watched
And its condensing lens 22.

Next, FIG. 16 will be described. In the figure, 23 is the optical system of the above-mentioned eye refractive power measuring device, 9 is a light receiving element, 13 is a calculator, 14 is a display, 24 is a frame memory for storing the image of the light receiving element 9 and the result of the arithmetic processing unit, 25 is an arithmetic processing unit, 26
Is a control unit for issuing a synchronization command and a sequence command for the frame memory 24 and the arithmetic processing unit 25, and 27 is a light amount adjustment unit for adjusting the luminous intensity of the illumination light source 21.

Hereinafter, the operation of this embodiment will be described with reference to FIGS. 17 to 21.

First, a range including both eyes of the subject's eye is imaged by the light receiving element 9, and this image (FIG. 18A) is stored in a frame memory.
Capture and store in 24. In addition, this image is captured such that both eyes are included in a predetermined area, for example, the right eye is included in (X ₁ ; Y ₁ ). FIG. 18 (B) is an enlarged view of the area (X ₁ ; Y ₁ ).

A point where the amount of light is maximum, that is, a point where the potential is maximum, in the area (X ₁ ; Y ₁ ) of the frame memory 24 is examined.

If the point with the highest potential in the area (X ₁ ; Y ₁ ) is found,
This is the viewpoint 28, and the position of the bright point 28 is obtained from the position of the bit of the bright point in the frame memory 24.

When the bright spot 28 is obtained, a detection area (X _S ; Y _S ) near the bright spot centered on the bright spot is set as shown in FIG. 19 (B). The detection area ( _XS ; Y) is detected by a scanning line in the X direction parallel to the edge.
The light amounts at points a and b intersecting with the boundary line of _S ) are obtained, and approximated by a straight line at points a and b. The straight line connecting the points a and b shows the light quantity distribution in the detection area (X _S ; Y _S ) in which the influence of the bright spot 28 on the scanning line in the X direction is removed (FIG. 19). (See (C), the light amount distribution indicated by δ in the figure is a light amount distribution curve obtained by scanning the pupil portion in the X direction.)

Thus to a point, wherein the approximate straight line between point b L = a _{{(L b -L a) /} X s} × X + L a ... (10).

Here, scanning in the direction parallel to the edge is performed because the state of the light beam is symmetric in the direction parallel to the edge,
This is because, ideally, the light amount distribution is considered to be uniform except for the bright spot portion, so that there is little error when approximated by a straight line.

It carried over; (Y _S X _S) throughout the detection area of such scanning area; obtaining a correction value obtained by removing the influence of the bright spot 28 on (X _S Y _S). The storage value of the detection area (X _S ; Y _S ) of the frame memory 24 is replaced with the correction value, and the replacement with the correction value is newly stored in the frame memory 24 as a corrected video.

Next, the detection area is enlarged to include the pupil sufficiently (X ₂ ; Y ₂ ) (FIG. 20 (B)), and the detection area (X ₂ ; Y ₂ ) of the corrected image is moved in the Y direction (the edge). (In a direction perpendicular to the direction), and a light amount distribution is obtained on the scanned line. This Y-direction scanning line, and in particular, the light amount distribution γ (the
FIG. 20 (c)) corresponds to the light amount distribution shown in FIG.
This is the basis for calculating the diopter value.

There are various methods for obtaining the slope from the light amount distribution γ. For example, as shown in FIG. 21, a straight line is obtained by least square approximation, and the slope of this straight line is obtained.

 Next, the correction of the pupil diameter u will be described.

To correct the pupil diameter u is first from the light amount distribution, it obtains a pupil diameter u, calculated pupil diameter u of the illumination light source 21 as to meet the target pupil diameter u _O that is set previously input to the controller 26 Adjust the light intensity.

As shown in FIGS. 15 (A), (B) and (C), when the iris portion 29 is deviated from the pupil portion, the light amount sharply decreases (see FIG. 15).
(C). Therefore, when the change rate of the light amount distribution γ is obtained, the values protrude at the boundary points m and n between the pupil 6 and the iris portion 29. The pupil diameter u can be obtained by reading the coordinate positions of the boundary points m and n from the frame memory 24 and calculating the coordinates by the arithmetic processing unit 25.

When only the pupil diameter u is determined, it is not necessary to remove the influence of the bright spot 28 in particular. Since the bright point 28 is located at the center of the pupil 6, if a point with the maximum change rate, that is, two points near the bright point where the change rate protrudes and increases, is obtained, the boundary points m and n of the pupil are obtained. In the same manner as described above, the position is read from the frame memory 24, and is calculated by the arithmetic processing unit 25, whereby the pupil diameter u is obtained.

In order to reduce the influence of the eyelashes, scanning in the horizontal direction is convenient.

When the pupil diameter u is determined, and compared with the target value u _O arithmetic processing unit 25, if there is a deviation between the u and u _O, the light quantity adjusting portion an instruction to increase or decrease the amount for correcting the deviation 27, and the light amount adjustment unit 27 increases or decreases the light amount of the illumination light source in accordance with this command.

Iris 29 of the subject in response to changes in light intensity by scaling the pupil diameter u, the pupil diameter u of the measurement matches the pupil diameter u _O target value.

The value of the detected pupil diameter is displayed on the display 14,
Manually may be performed to increase or decrease the amount of light in this value as to meet the pupil diameter u _O target value.

As described above, when the pupil diameter u is obtained, the diopter value is obtained by Expression (9). By correcting the diopter value to a predetermined value by the above-described operation, the pupil diameter u in Expression (9) becomes The diopter value can be calculated as a constant, and the diopter value can be obtained directly without considering the difference in the pupil diameter due to the individual difference of the subject and the difference in the measurement environment.

As another example of correcting the pupil diameter, the anterior segment of the eye to be examined may be directly illuminated as shown in FIG.

[Effects of the Invention] As described above, according to the present invention, the pupil diameter can be easily corrected to a predetermined value based on the light amount distribution state, and the measurement conditions required for the measurement of the refractive power of the eye can be realized. An accurate measurement of the eye refractive power can always be performed without concern for differences in the measurement environment.

[Brief description of the drawings]

FIG. 1 is a basic schematic diagram of an eye refractive power measuring device according to one embodiment of the present invention, FIG. 2 is a basic schematic diagram of another embodiment of the present invention, and FIGS. 3 (A), (B) and (C) are books. FIG. 4 (A) and FIG. 4 (B) are illustrations showing the difference in the state of the light beam due to the difference in the diopter value of the eye to be examined in the eye refractive power measuring device according to the embodiment of the present invention.
(C), (D), and (E) are explanatory diagrams showing the state of light reception and the reflected light beam from the fundus of the eye to be examined, FIGS. 5 (A), 6 (A),
FIG. 7 (A) is an explanatory view showing the state of the reflected light flux at each point of the light source reaching the light receiving element, and FIGS. 5 (B), 6 (B), and 7 (B) show the state of being shielded by a light shielding member. FIG. 8, FIG. 9, FIG. 10, and FIG. 10 are explanatory diagrams showing a light amount distribution state on a light receiving surface corresponding to a diopter value, and FIG. 11 is a light amount distribution state. Explanatory diagrams for obtaining more diopter values, FIG. 12, FIG. 13, and FIG. 14 show the case where light is shielded by a light shielding member when the spread width Δ on the light shielding member is larger than half the size of the light source. FIG. 15 (A) is an explanatory diagram of the eye to be inspected, FIG. 15 (B) is a diagram showing a light intensity distribution corresponding to the eye to be inspected, and FIG. 15 (c) is a light intensity. FIG. 16 is a block diagram showing an embodiment of the present invention, FIG. 17 is a flow chart in the embodiment, and FIG. Fig. 18 (B) is an enlarged view of the eye to be examined, Fig. 19 (A) is an enlarged view of the eye to be examined as in Fig. 18 (B), FIG. 19 (B) is a diagram showing a range including a bright spot, and FIG.
FIG. 20 (C) is a light amount distribution diagram of a scanning line parallel to an edge passing through a bright point, FIG. 20 (A) is an enlarged view of an eye portion to be inspected similarly to FIG. 18 (B), and FIG. ) Is a diagram showing a scanning region including a pupil, FIG. 20 (C) is a diagram showing a light amount distribution of a scanning line in a direction perpendicular to an edge, and FIG. FIG. 1 is a projection system, 2 is a light receiving system, 3 is an eye to be inspected, 4 is a light source, 5 is a half mirror, 8 is an objective lens, 9 is a light receiving element, 13 is a calculator, 14 is a display, 24 is a frame memory, 21 Denotes an illumination light source, 25 denotes an arithmetic processing unit, 26 denotes a control unit, and 27 denotes a light amount adjustment unit.

Claims (2)

(57) [Claims] 1. A projection system for projecting a light source image on a fundus of a subject's eye, a light receiving element arranged at a position substantially conjugate with a pupil of the subject's eye, and a light receiving element for condensing a light beam from the fundus on the light receiving element. System and
An edge-shaped light-blocking member arranged in the light path of the light receiving system so as to block a part of the light beam from the fundus; and an eye refractive power of the subject's eye based on a light amount distribution state of the light beam projected on the light receiving element. An eye refractive power measuring apparatus comprising: a calculating part for calculating a pupil diameter from an image signal of the light receiving element. 2. An illumination light source for illuminating an eye to be examined for adjusting a pupil diameter, and a light amount for adjusting an illumination light amount of the illumination light source so that the pupil diameter calculated by the arithmetic processing unit matches a target value. The eye-refractive-power measuring device according to claim 1, further comprising an adjusting unit.