JP2010184048A - Eye dimension measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce burden on a subject by shortening a measurement time. <P>SOLUTION: The eye dimension measuring instrument is provided with an interference optical system including: a measurement light source; a light division member; a light path length changing member movably arranged in one optical path divided by the light division member; and a photodetector. As the other optical paths divided by the light division member, the instrument includes: the first light path with the first light path length; and the second light path having the second light path length and offsetting a light path difference which is generated when the light path length changing member is moved by a predetermined amount. A first interference signal and a second interference signal, which are outputted from the photodetector when the light path length changing member is moved in a predetermined direction, are acquired, so as to respectively measure the dimensions of the predetermined portions of the eye of the subject, based on the respective first and second interference signals. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an eye size measuring device that measures the size of a predetermined part of an eye to be examined.

  As an eye dimension measuring apparatus for measuring the axial dimension (for example, axial length, anterior chamber depth) of a predetermined part of the eye to be examined, low coherent light emitted from a light source exists at different axial positions of the eye to be examined 2 A first optical beam divided by an optical path splitting member, and a first optical beam divided by an optical path dividing member. The optical path length changing member capable of adjusting the optical path difference between the two lights is moved in the optical axis direction, and the eye dimension is measured based on the moving position of the optical path length changing member when the interference light is detected by the light receiving element. An apparatus is known (see, for example, Patent Document 1).

JP-A-2-297332

  By the way, in the case of a conventional apparatus, when a trigger signal for starting measurement is output, the optical path length changing member is moved in the predetermined direction from the origin position, and the optical path lengths of the first light and the second light coincide with each other. When this is done, an interference signal is output from the light receiving element. Then, the eye size is measured based on the movement position of the optical path length changing member when this interference signal is detected. The optical path length changing member is moved in the opposite direction after reaching the movement limit position, and returned to the origin position.

  However, in the case of the conventional apparatus, in order to measure the eye dimension twice or more, since the optical path length changing member is moved back and forth twice or more, the measurement time is long, which is a burden on the subject. It was.

  In view of the above problems, an object of the present invention is to provide an eye dimension measuring device that can shorten the measurement time and reduce the burden on the subject.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) A measurement light source that emits low-coherent light, a light splitting member that splits the light emitted from the measurement light source, and the light for changing the optical path length of a part of the light emitted from the measurement light source An optical path length changing member arranged to be movable along one optical path divided by the dividing member, and a light receiving element, irradiating the eye to be examined with low coherent light, and using reflected light from the eye to be examined as interference light An interference optical system for receiving light by the light receiving element;
A drive unit for moving the optical path length changing member;
In an eye dimension measuring apparatus comprising: an operation control unit that controls driving of the driving unit and measures a dimension of a predetermined part of the eye to be examined based on an interference signal output from the light receiving element.
As the other optical path divided by the light splitting member, a first optical path having a first optical path length and a second optical path difference that can be offset when the optical path length changing member is moved by a predetermined amount are offset. A second optical path having an optical path length is formed,
The calculation control means acquires a first interference signal and a second interference signal output from the light receiving element when the optical path length changing member is moved in a predetermined direction, and the first interference signal The size of a predetermined part of the eye to be examined is measured based on each interference signal of the second interference signal.
(2) In the eye dimension measuring device according to (1), when the optical path length changing member is moved in a predetermined direction, an optical path to be used is selected from the first optical path and the second optical path. An optical path selection unit, wherein the calculation control unit controls the optical path selection unit and selects one of the first optical path and the second optical path according to a movement position of the optical path length changing member. Features.
(3) In the eye dimension measuring device according to (2), the interference optical system is configured to divide the optical path into the first optical path and the second optical path into the other optical path divided by the light dividing member. It has two light splitting members.
(4) In the eye dimension measuring device of (3),
The arithmetic control means includes a third interference signal and a fourth interference signal output from the light receiving element when the optical path length changing member is moved in the opposite direction after the optical path length changing member is moved in the predetermined direction. And measuring the dimensions of predetermined portions of the eye to be examined based on the interference signals of the third interference signal and the fourth interference signal.

  According to the present invention, the measurement time can be shortened and the burden on the subject can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an optical system of an eye dimension measuring apparatus according to this embodiment. In the following embodiments, a case where the present invention is applied to an ocular axial length measurement apparatus will be described.

  An irradiation optical system 10 disposed to irradiate the eye cornea and the fundus of the eye to be measured with a measurement light source 1 (for example, SLD) that emits low-coherent light and a light beam emitted from the measurement light source 1 in parallel. A collimator lens 3 as a light beam, a beam splitter 5 that divides the light emitted from the light source 1, a dispersion correction glass 7 and a first triangular prism (corner cube) 9 disposed in the reflection direction of the beam splitter 5, A beam splitter 11 (for example, a half mirror) arranged in the transmission direction of the beam splitter 5, a second triangular prism 13 arranged in the transmission direction of the beam splitter 11, and a third arranged in the reflection direction of the beam splitter 11. A triangular prism 15, a polarization boom splitter 17, and a ¼ wavelength plate 19 are provided.

  The light emitted from the light source 1 is collimated by the collimator lens 3 and then divided into first measurement light (reference light) and second measurement light by the beam splitter 5. Here, the first measurement light is reflected by the triangular prism 9 through the glass 7 and is turned back. Thereafter, the first measurement light is incident on the beam splitter 5 through the glass 7. The second measurement light is split by the beam splitter 11 and then reflected and folded by the second triangular prism 13 and the third triangular prism 15. Thereafter, the second measurement light is incident on the beam splitter 5 via the beam splitter 11. In this way, the first measurement light and the second measurement light are combined by the beam splitter 5.

  The synthesized light is reflected by the polarization beam splitter 17, converted into circularly polarized light by the quarter wavelength plate 19, and then irradiated to the eye to be examined through the dichroic mirror 21. At this time, when the measurement light beam is reflected by the cornea and the fundus of the subject's eye, the phase is converted by ½ wavelength.

  The light receiving optical system 20 arranged to receive the corneal reflection light by the measurement light irradiated by the irradiation optical system 10 and the interference light by the fundus reflection light includes a quarter-wave plate 19, a polarization beam splitter 17, a collecting beam. An optical lens 25 and a light receiving element 27 are included.

  The cornea reflection light and fundus reflection light are converted into linearly polarized light by the quarter wavelength plate 19 via the dichroic mirror 21. Thereafter, the reflected light transmitted through the polarizing beam splitter 17 is collected by the condenser lens 25 and then received by the light receiving element 27.

  The triangular prism 9 is used as an optical path length changing member that is movably disposed in one optical path divided by the beam splitter 5 in order to change the optical path length of a part of the light emitted from the measurement light source 2. The triangular prism 9 is moved with respect to the beam splitter 5 by driving of a driving unit 71 (for example, a motor). In this case, the movable range of the triangular prism 9 includes the first movement range M1 (P1 to P2) set to obtain the first (fourth) interference signal by the interference light and the second ( It is divided into a second movement range M2 (P2 to P3) set to obtain a third) interference signal (details will be described later). Note that the first movement range M1 and the second movement range M2 are set so that the subject is included in the measurement range even for a subject having a relatively large ocular axial length and a small ocular axial length. In addition, it is preferable that the run-up distance of the prism 9 is ensured so that the interference signal is detected in a state where the speed of the inverted prism 9 reaches a constant speed sufficient for measurement. The optical path length changing member may be a triangular mirror, a corner prism, or the like. The drive position of the prism 9 is detected by a position detection sensor 72 (for example, a potentiometer, an encoder, etc.).

  The other optical path divided by the beam splitter 5 includes a first optical path having a first optical path length and a second optical path capable of offsetting an optical path difference generated when the prism 9 is moved by a predetermined amount. A second optical path having a length. In the case of FIG. 1, in the other optical path divided by the beam splitter 5, a second light splitting member (beam splitter 11) for further splitting the other optical path into a first optical path and a second optical path is arranged. Yes.

  The 2nd triangular prism 13 and the 3rd triangular prism 15 are arrange | positioned so that the distance with respect to the beam splitter 11 may mutually differ. Thereby, a predetermined optical path difference is generated between the optical path of the second measurement light passing through the second triangular prism 13 and the optical path of the second measurement light passing through the third triangular prism 15. This optical path difference can be set to be substantially equal to the amount of change in the optical path length caused by the movement of the first triangular prism 9 from the start point position P1 to the end point position P2 in the first movement range M1. In this case, the configuration is not limited to the configuration in FIG. 1, and the configuration may be such that the optical path in the reflection direction of the beam splitter 11 is short and the optical path in the transmission direction of the beam splitter 11 is long.

  In the above description, the optical path length changing member is arranged in one of the measurement optical paths divided by the optical path dividing member (beam splitter 5), and moved so that the optical path difference between the divided measurement optical paths is adjusted. It only has to be done. Specifically, the optical path length changing member and the optical path dividing member are arranged in the optical path of the irradiation optical system 10 as shown in FIG. 1, or the optical path of the light receiving optical system 20, or the irradiation optical system 10 and the light receiving optical system 20. It may be arranged in the common optical path.

  In the reflection direction of the dichroic mirror 21, an anterior ocular segment imaging optical system 30 arranged for imaging the anterior ocular segment of the eye to be examined is provided. The imaging optical system 30 transmits the light emitted from the light source 1 and reflects the light emitted from the anterior segment illumination light source 40, the dichroic mirror 21, the objective lens 31, the total reflection mirror 33, and the imaging lens 35. And a two-dimensional image sensor 37. Here, the anterior ocular segment image illuminated by the illumination light source 40 is imaged on the two-dimensional imaging device 37 via the dichroic mirror 21, the objective lens 31, the total reflection mirror 33, and the imaging lens 35.

  Next, a control system of the apparatus according to the present embodiment will be described. The control unit 80 is connected to the display monitor 81, the light source 1, the light receiving element 27, the drive unit 71, the position detection sensor 72, the control unit 84, the memory 85, and the like. The control unit 80 processes the interference signal output from the light receiving element 27 and obtains the axial length of the eye to be examined by calculation. The memory 85 stores the obtained measurement value and the like. In addition, the control unit 84 is provided with various switches such as a measurement start switch 84a that generates a measurement start trigger signal.

  A case where the axial length of the subject's eye is measured using an apparatus having the above configuration will be described. While looking at the alignment state of the subject's eye displayed on the monitor 81, the examiner moves the device up / down / left / right and front / rear using an operation means such as a joystick (not shown) to move the device relative to the subject eye E. Put it in the positional relationship. Further, the examiner fixes a fixation target (not shown) to the subject's eye.

  Here, when a trigger signal for starting measurement is generated and the measurement light source 1 is turned on by the control unit 80, measurement light is irradiated onto the eye to be examined by the irradiation optical system 10, and reflected light from the eye to be examined by the measurement light. Is incident on the light receiving element 27 of the light receiving optical system 20.

  The control unit 80 controls the driving of the driving unit 71 to move the first triangular prism 9 back and forth. Then, the control unit 80 calculates the axial length based on the timing when the interference light is detected by the light receiving element 27.

  More specifically, the prism 9 is moved with the initial position (reference position) P1 as the starting point, moved in the A direction through the first moving range M1 and the second moving range M2, and then moved in the end position P3. Is reversed. Thereafter, the prism 9 is moved in the B direction through the second movement range M2 and the first movement range M1, and returned to the initial position P1.

  Here, in a state where the prism 9 is moved on the first movement range M1, the optical path length of the first measurement light irradiated onto the cornea via the prism 9 and the second irradiated onto the fundus via the prism 13 are shown. When the optical path lengths of the measurement light coincide with each other, interference light caused by corneal reflection light and fundus reflection light is received by the light receiving element 27. At this time, a first interference signal due to the interference light is output from the light receiving element 27 to the control unit 80.

  Further, even after the first interference signal is detected by the light receiving element 27, the control unit 80 continues to move the prism 9 in the A direction. Then, in a state where the prism 9 is moved on the second movement range M2, the optical path length of the first measurement light irradiated to the cornea via the prism 9 and the second measurement irradiated to the fundus via the prism 15 When the optical path lengths of the light coincide with each other, the light receiving element 27 receives the interference light by the cornea reflection light and the fundus reflection light. At this time, the second interference signal due to the interference light is output from the light receiving element 27 to the control unit 80.

  When the prism 9 reaches the end point position P3 after detecting the second interference signal, the control unit 80 reverses the movement direction of the prism 9 and moves the prism 9 from the end point position P3 to the B direction. Then, in a state where the prism 9 is again moved on the second movement range M2, the optical path length of the first measurement light irradiated onto the cornea via the prism 9 and the second irradiated onto the fundus via the prism 15 When the optical path length of the measurement light matches, the interference light is received by the light receiving element 27. At this time, a third interference signal due to the interference light is output from the light receiving element 27 to the control unit 80.

  Further, even after the third interference signal is detected by the light receiving element 27, the control unit 80 continues to move the prism 9 in the B direction. Then, in a state where the prism 9 is again moved on the first movement range M1, the optical path length of the first measurement light applied to the cornea through the prism 9 and the second applied to the fundus through the prism 13 When the optical path length of the measurement light matches, the interference light is received by the light receiving element 27. At this time, a fourth interference signal due to the interference light is output from the light receiving element 27 to the control unit 80.

  The movement position of the prism 9 when the first to fourth interference signals are detected can be detected based on the signal output from the position detection sensor 72, respectively. Therefore, when calculating the axial length value, a relationship between the movement position of the prism 9 and the axial length may be obtained in advance using a predetermined arithmetic expression or a table. In this case, the relationship between the movement position of the prism 9 and the axial length in the first movement range M1 and the relationship between the movement position of the prism 9 and the axial length in the second movement range M2 are respectively obtained. . In addition, it is not restricted to the said method, You may make it measure an axial length based on the time when the interference signal was detected during the movement of the prism 9.

  The control unit 80 calculates the axial length value of each eye based on the first to fourth interference signals, and obtains the first to fourth measurement results. Thereby, the axial length of the subject's eye can be measured twice while the prism 9 is moved (scanned) once in a predetermined direction. Further, the axial length of the subject's eye can be measured four times while the prism 9 is reciprocated once.

  The acquired information about the axial length of the subject's eye is stored in the memory 85 and displayed on the monitor 81. Further, when the predetermined number of measurements are completed (or when a predetermined number of eye length values of the subject are obtained), the control unit 80 ends the reciprocating movement of the prism 9 and sets the movement position of the prism 9 to the initial position. Return. When a plurality of measurement values of the axial length are acquired as described above, each measurement value may be output, or an average value of the plurality of acquired measurement values may be output. .

  With the above configuration, continuous measurement at least four times or more can be smoothly performed. In addition, since the measurement is performed a plurality of times, the measurement result is stabilized and good measurement accuracy is obtained. Note that the control unit 80 similarly detects the fifth, sixth,... Interference signals by the reciprocating movement of the prism 9 even after detection of the fourth interference signal, and the interference signal is detected. It is also possible to measure the axial length based on the moving position of the prism 9 and to perform further continuous measurement.

  In the above configuration, a half mirror is used as an example of the beam splitter 11, but a polarizing beam splitter 11a may be used (see FIG. 2). Note that components having the same numbers as those in FIG. 1 have the same functions and configurations as those in FIG. 1 unless otherwise specified. Here, it is assumed that linearly polarized light having a polarization component perpendicular to the paper surface is emitted from the light source 1 toward the beam splitter 5.

  In FIG. 2A, the polarization beam splitter 11a is configured to be rotated about the rotation axis R1 by the rotation driving unit 75. Here, by adjusting the rotation angle of the polarization beam splitter 11a every 90 degrees, the light emitted from the light source 1 is transmitted toward the prism 13 and the light emitted from the light source 1 is converted into the prism 15. It is possible to switch to the state of being reflected toward the.

  In FIG. 2B, the half-wave plate 14 can be inserted and removed between the polarizing beam splitter 11 a and the beam splitter 5 by driving of the driving unit 76. In this case, the polarization component of the light is changed by 90 degrees by the insertion of the half-wave plate 14. Thereby, when the half-wave plate 14 is inserted / removed, the light emitted from the light source 1 is transmitted toward the prism 13 and the light emitted from the light source 1 is reflected toward the prism 15. It is possible to switch to the state to be performed.

  In FIG. 2 (c), the half-wave plate 41 and the half-wave plate 42 are detachably disposed in the optical path of the irradiation optical system 10, and are inserted by driving the drive unit 77 and the drive unit 78. It has a removable configuration. In this case, the polarization component of the light incident on the polarization beam splitter 11a is changed by 90 degrees by the insertion of the half-wave plate 41. Further, the polarization component of the light is changed every 90 degrees by the insertion of the half-wave plate 42.

  Here, when the half-wave plate 42 is disposed in the optical path and the half-wave plate 41 is out of the optical path, the light emitted from the light source 1 is transmitted through the polarization beam splitter 11a and then the prism 13. After being converted to S-polarized light by the half-wave plate 42 via the polarizing beam splitter 11 a and the beam splitter 5, the light is directed to the polarizing beam splitter 17.

  When the half-wave plate 41 is disposed in the optical path and the half-wave plate 42 is out of the optical path, the light emitted from the light source 1 is reflected by the polarization beam splitter 11a, then the prism 15, the polarization It goes to the polarization beam splitter 17 through the beam splitter 11a and the beam splitter 5.

  2A to 2C, when performing continuous measurement, the control unit 80 controls the drive unit 71 to move the prism 9 as described above. At this time, when the prism 9 is moved within the first movement range M1, the control unit 80 sets the light emitted from the light source 1 to be reflected by the prism 13, and the prism 9 within the second movement range M2. When moved, the light emitted from the light source 1 is reflected by the prism 15. That is, the control unit 80 controls the driving unit to select the optical path to be used from either the first optical path or the second optical path in a state where the prism 9 is moved in a predetermined direction, and the movement of the prism 9 Depending on the position, either the first optical path or the second optical path is selected. Accordingly, the optical path of the second measurement light that interferes with the first measurement light is switched according to the movement position of the prism 9.

  In FIG. 2A, the control unit 80 may change the rotation angle of the polarization beam splitter 11a every 90 degrees in accordance with the movement position of the prism 9. In FIG. 2B, the control unit 80 may insert and remove the half-wave plate 14 in accordance with the movement position of the prism 9. In FIG. 3C, the half-wave plate 41 and the half-wave plate 42 may be respectively inserted and removed according to the movement position of the prism 9.

  With the configuration as described above, in the configuration in which the second measurement light is divided by the beam splitter 11, it is possible to avoid a decrease in the amount of the second measurement light compared to the half mirror. The S / N ratio of the interference light can be improved. In addition, it is possible to prevent disturbance light from entering the light receiving element 27. That is, it is possible to avoid the reflected light from the prism 15 being received by the light receiving element 27 when the prism 9 passes through the first movement range M1. It is possible to avoid the reflected light from the prism 13 being received by the light receiving element 27 when the prism 9 passes through the second movement range M1.

  Further, the configuration is not limited to the above configuration, and an optical path switching unit for selectively switching the optical path of the second measurement light that interferes with the first measurement light may be arranged. In this case, as the optical path dividing member arranged to divide the second measurement light, the optical path of the second measurement light is a reflected optical path (first optical path) formed in the reflection direction and a transmitted optical path formed in the transmission direction ( You may make it provide the optical path switching member which selectively switches between (2nd optical paths). More specifically, in the configuration of FIG. 1, instead of the beam splitter 11, a total reflection mirror that can be flipped up by a drive unit (for example, a motor) is used. In this case, when the prism 9 is moved within the first movement range M1, the total reflection mirror is flipped up, and the second measurement light is folded back by the prism 13. Further, when the prism 9 is moved within the second movement range M2, the second measurement light is reflected by the total reflection mirror and is turned back by the prism 15. In the case of switching the optical path as described above, a moving range for switching may be provided between the first moving range M1 and the second moving range M2 in consideration of the time required for the optical path switching. .

  In the configuration of FIG. 1, a light shielding member that can be inserted and removed may be provided in the optical path between the half mirror 11 and the prism 13 and the optical path between the half mirror 11 and the prism 15. In this case, when the prism 9 is positioned in the first movable range M1, a light blocking member is inserted in the optical path between the half mirror 11 and the prism 15. Further, when the prism 9 is positioned in the second movable range M2, a light shielding member is inserted in the optical path between the half mirror 11 and the prism 13.

  In the above description, the optical path of the second measurement light is divided. However, the present invention is not limited to this, and the total optical path length of the second measurement light (light source 1 to eye to be examined to light receiving element 27) is predetermined. The first optical path having the optical path length and the second optical path having the optical path length longer than the first optical path over the measurement range of the axial length may be used. In this case, the optical path difference between the total optical path length of the first measurement light to be adjusted and the total optical path length of the second measurement light by the first optical path (or the second optical path) corresponds to the axial length of the eye to be examined. At this time, the interference light is detected by the light receiving element 27.

  For example, as another method of forming the first optical path and the second optical path, as shown in FIG. 3, the second measurement light in the optical path of the second measurement light after the first measurement light and the second measurement light are divided is A configuration is conceivable in which the position of the reflecting member arranged for turning back the measurement light is selectively switched between the first position and the second position with respect to the traveling direction of the second measurement light. In FIG. 3, prisms 53a and 53b for turning back the second measurement light are arranged in the transmission direction of the beam splitter 5 and can be inserted and removed by the drive unit 79a and the drive unit 79b, respectively. In this case, when the prism 9 is moved within the first movement range M1, the prism 53a is disposed in the optical path, and when the prism 9 is moved within the second movement range, the prism 53b is disposed in the optical path. .

  In the above description, the optical path length is divided into the first measurement optical path and the second measurement optical path through which the first measurement light passes by the optical path dividing member (for example, the beam splitter 5), and is arranged in the divided optical path. Although the optical path difference between the first measurement light and the second measurement light is generated by the changing member (prism 9), the present invention is not limited to this. In this case, a beam splitter (light splitting member) that splits the light emitted from the light source, a sample arm (irradiation optical system) arranged to irradiate the measurement eye with the measurement light, and a reference light A reference arm (reference light optical system) arranged and a light receiving optical system having a light receiving element for receiving interference light, and irradiating the eye to be examined through the sample arm by moving the optical path length changing member The light receiving element may receive the interference light caused by the measured light and the reference light from the reference arm.

  In the above description, the configuration for measuring the axial length has been described. However, the configuration is not limited to this, and the dimension between two predetermined parts existing at different positions in the axial direction of the eye to be examined is measured. The configuration is not limited to this. For example, the present invention can also be applied to a configuration in which measurement light is applied to the subject's cornea and the crystalline lens, and the reflected light is received as interference light to measure the anterior chamber depth.

It is a schematic block diagram of the optical system of the eye dimension measuring apparatus which concerns on this embodiment. It is a figure which shows the 1st modification of the optical system of the eye dimension measuring apparatus which concerns on this embodiment. It is a figure which shows the 2nd modification of the optical system of the eye dimension measuring apparatus which concerns on this embodiment.

1 Measurement light source 5 Beam splitter 9 Triangular prism (optical path length changing member)
10 Irradiation optical system 11 Beam splitter 13 Second triangular prism 13
15 third triangular prism 20 light receiving optical system 27 light receiving element 53a, 53b prism 71 driving unit 80 control unit

Claims (4)

A measurement light source that emits low-coherent light, a light splitting member that splits the light emitted from the measurement light source, and a light splitting member that changes the optical path length of a part of the light emitted from the measurement light source. An optical path length changing member disposed so as to be movable in one of the divided optical paths, and a light receiving element. An interference optical system that receives light at
A drive unit for moving the optical path length changing member;
In an eye dimension measuring apparatus comprising: an operation control unit that controls driving of the driving unit and measures a dimension of a predetermined part of the eye to be examined based on an interference signal output from the light receiving element.
As the other optical path divided by the light splitting member, a first optical path having a first optical path length and a second optical path difference that can be offset when the optical path length changing member is moved by a predetermined amount are offset. A second optical path having an optical path length is formed,
The calculation control means acquires a first interference signal and a second interference signal output from the light receiving element when the optical path length changing member is moved in a predetermined direction, and the first interference signal An eye dimension measuring apparatus for measuring a size of a predetermined part of an eye to be examined based on each interference signal of the second interference signal. 2. The optical path selecting device according to claim 1, wherein the optical path length changing member is configured to select an optical path to be used from either the first optical path or the second optical path in a state where the optical path length changing member is moved in a predetermined direction. Have
The arithmetic control means controls the optical path selection means, and selects one of the first optical path and the second optical path according to the movement position of the optical path length changing member. . 3. The eye dimension measuring apparatus according to claim 2, wherein the interference optical system further divides the optical path into the first optical path and the second optical path into the other optical path divided by the light dividing member. An eye dimension measuring device comprising a member. In the eye dimension measuring device according to claim 3,
The arithmetic control means includes a third interference signal and a fourth interference signal output from the light receiving element when the optical path length changing member is moved in the opposite direction after the optical path length changing member is moved in the predetermined direction. And measuring the dimensions of a predetermined part of the eye to be inspected based on the interference signals of the third interference signal and the fourth interference signal.

Images