JP3708694B2 - OPERATION POSITION DETERMINING DEVICE FOR OPTICAL DEVICE AND OPERATION POSITION DETERMINING DEVICE FOR retinal Imaging Device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an operation position determination device for automatically determining an operation position of an ophthalmologic apparatus or a fundus imaging apparatus.
[0002]
[Prior art]
One of the ophthalmologic apparatuses is a fundus camera (fundus photographing apparatus). The fundus camera includes an illumination optical system and a photographing optical system, projects illumination light onto the fundus through the pupil, and photographs the fundus through the pupil. The illumination optical axis coincides with the photographing optical axis. In fundus photography, illumination and photography are performed through the pupil in this way. Therefore, alignment of the photographing optical system and the eye to be examined is important. However, manual operation requires complicated operations and skill. Moreover, since it takes time, the subject is forced to have a long time until photographing.
[0003]
In order to eliminate such a complicated operation and reduce the time required for photographing, a fundus photographing apparatus including an operation position determining device that automatically performs the alignment has been proposed (for example, Japanese Patent Laid-Open No. 8-275921). No. publication). This is done by automatically aligning the parallel light projected from the front of the subject's eye with the reflected light from the vertex of the subject's eye in the plane perpendicular to the imaging optical axis, and then applying slit light obliquely from the front to the subject's eye. Projecting is performed, and the working distance in the photographing optical axis direction is automatically adjusted using the reflected light from the vertex of the eye to be examined as an index. When the device is photographed with the eye of the eye to be examined facing in the front direction, a fundus image centered on the fundus gazing point (fovea) is photographed.
[0004]
[Problems to be solved by the invention]
In the above operating position determination device, no particular problem occurs when the eye axis is facing the front. However, in fundus photography, the target portion of the fundus may be moved to the vicinity of the center of the field of view by guiding the eye of the subject's eye with a fixation target. When the line of sight is guided and the eye axis is directed in a direction other than the front, the vertex of the eye to be examined and the pupil center do not coincide with each other in a plane orthogonal to the imaging optical axis. As described above, the fundus photographing apparatus irradiates the fundus with illumination light through the pupil and photographs the fundus through the pupil. Therefore, if the photographing optical axis does not coincide with the center of the pupil, illumination and photographing are blocked by the iris. In the above operating position determination device, since the imaging optical axis is aligned with the vertex of the eye to be examined, the fundus cannot be clearly photographed when the eye axis of the eye to be examined is directed in a direction other than the front.
[0005]
As a method for solving this problem, for example, a method of quantitatively correcting the deviation between the eye apex and the pupil center according to the angle at which the line of sight is guided and fixed can be considered. In other words, the line of sight of the eye to be examined is normally fixed at a predetermined angle by the fixation lamp, but the imaging optical axis is moved from the position of the eye to be examined by a correction amount predetermined for each fixation lamp. Move it. This method is effective when photographing a predetermined position of the fundus as in a medical examination. However, it is not possible to change the shooting position to a position other than a predetermined position. Moreover, it cannot respond to the case where the subject is strabismus. This is because, since the point of strabismus deviates from the fovea is the point of gaze, the direction of the eye axis cannot be predicted from the fixation lamp.
[0006]
In addition, as another method for solving the above problem, for example, a method of aligning with the center of the pupil of the anterior segment image instead of the apex of the eye to be examined is conceivable. This method is effective when the eye axis of the subject slightly swings from the front direction. However, if the eye axis is greatly swung from the front method, the vertex position of the eye to be examined is greatly deviated from the alignment position. As a result, the reflected light from the subject eye of the slit light for adjusting the working distance does not return to the light receiving element for detecting the working distance, and the working distance cannot be detected.
[0007]
In view of the above problems, the present invention automatically determines an appropriate operation position even if the line of sight is greatly shaken at an arbitrary angle or the subject is in perspective, and the imaging region is clearly defined. It is an object of the present invention to provide an operating position determination device for an ophthalmologic apparatus that can be photographed and observed and an operating position determination device for a fundus imaging apparatus that can capture a clear fundus image.
[0008]
[Means for Solving the Problems]
  In order to solve the above problems, an operating position determining device for an ophthalmologic apparatus according to the present invention is an operating position determining apparatus for an ophthalmologic apparatus having an optical system as a main optical system for photographing or / and observing a predetermined part of an eye to be examined. An alignment index projection optical system for projecting alignment index light onto the eye spherical surface of the eye to be examined, and an anterior eye image of the eye to be examined, and reflected light from the eye spherical surface of the alignment index light.Purkinje statueAnd an anterior ocular segment observation optical system that receives light asPurkinje statueBased on the position, the main optical system is adjusted so that the optical axis of the main optical system coincides with the vertex of the eye to be examined.MoveAlignment means and reflected light from the vertex of the subject eye of the working distance detection index light projected obliquely forward onto the eye to be examined in a state where the optical axis of the main optical system coincides with the vertex of the eye to be examined by the alignment means Working distance adjusting means for adjusting the working distance by moving the main optical system in the direction of the optical axis so that light can be received at a predetermined position;Based on the anterior ocular segment image received by the anterior ocular segment observation optical system, the main optical system in a state where the optical axis coincides with the apex of the eye to be examined while detecting the pupil center position of the eye to be examined. Alignment correction means for moving the optical axis so as to coincide with the pupil center(Claim 1). The main optical system may be an optical system having both a photographing function and an observation function, or may be an optical system having only one of the functions.
[0009]
  In order to solve the above problems, an operation position determination device for a fundus imaging apparatus according to the present invention includes an illumination optical system that illuminates the fundus of a subject's eye with illumination light, and fundus imaging optics that images the fundus based on the illumination light. An operating position determination device for a fundus photographing apparatus having an optical system, an alignment index projection optical system that projects alignment index light onto the eye spherical surface of the eye to be examined, and an anterior ocular segment image of the eye to be examined, The reflected light from the eye spherical surface of the alignment index lightPurkinje statueAnd an anterior ocular segment observation optical system that receives light asPurkinje statueBased on the position, the fundus photographing optical system is adjusted so that the optical axis of the fundus photographing optical system coincides with the vertex of the eye to be examined.MoveAlignment means, and reflection of the working distance detection index light projected from the front obliquely on the eye under examination with the optical axis of the fundus imaging optical system made coincident with the eye eye under examination by the alignment means Working distance adjusting means for adjusting the working distance by moving the fundus photographing optical system in the optical axis direction so that light can be received at a predetermined position;Based on the anterior ocular segment image received by the anterior ocular segment observation optical system, the fundus imaging optical system in a state where the optical axis coincides with the apex of the eye to be examined while detecting the pupil center position of the eye to be examined. Alignment correction means for moving the optical axis so as to coincide with the center of the pupil(Claim 2).
[0010]
The operation position determination device for the ophthalmologic apparatus or the operation position determination device for the fundus imaging apparatus includes a fixation lamp for changing and fixing the line of sight of the subject's eye, and the fixation lamp You may comprise so that the position of the fundus imaged by the fundus imaging optical system can be changed by changing the line of sight.
[0011]
The optical axis of the main optical system or fundus imaging optical system is adjusted based on the position of the reflected image (Purkinje image) of the alignment index light from the eyeball surface so that it coincides with the vertex of the eye to be examined. (Alignment adjustment).
[0012]
Once the alignment is adjusted, the working distance is then adjusted based on the working distance detection index light. Since this adjustment is performed in a state where the optical axis of the main optical system or the fundus imaging optical system is coincident with the vertex of the eye to be examined, it can be performed based on the reflected light from the vertex of the eye to be examined for the working distance detection index light.
[0013]
Once the working distance is adjusted, the optical axis of the main optical system or fundus photographing optical system that coincides with the subject's eye apex is adjusted (alignment correction) so as to coincide with the pupil center position.
[0014]
As a result, the ophthalmologic apparatus can accurately capture the position of the pupil, and in particular, when photographing and observing a part deeper than the iris of the eye to be examined through the pupil, the part is clear without being blocked by the iris. Can be photographed and observed. Further, it is possible to deal with a wide range of eye movements of the eye to be examined, and furthermore, even if the angle of the eye to be examined cannot be predicted as in the case of perspective, it is possible to capture and observe clearly. In addition, an ophthalmologic apparatus that automatically determines the operation position in the order of alignment adjustment, operation distance adjustment, and alignment correction can be configured.
[0015]
Further, the fundus imaging apparatus can project the illumination light onto the fundus without being blocked by the iris, and the reflected light from the fundus can be incident on the fundus imaging optical system without being blocked by the iris. Therefore, a clear fundus image can be taken. In addition, it is possible to deal with a wide range of eye movement of the eye to be examined, and a clear fundus image can be obtained even if the angle of the eye to be examined cannot be predicted as in the case of strabismus. In addition, it is possible to configure a fundus imaging apparatus that automatically determines the operation position in the order of alignment adjustment, operation distance adjustment, and alignment correction.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a block diagram illustrating a schematic configuration of a fundus photographing apparatus 1 which is one of ophthalmologic apparatuses. The operation position determination device for the fundus imaging apparatus is one of the operation position determination apparatuses for the ophthalmologic apparatus, and the operation position determination apparatus according to an embodiment of the present invention is applied to the fundus imaging apparatus 1. . First, a schematic configuration of the fundus imaging apparatus 1 will be described with reference to FIG.
[0018]
The fundus imaging apparatus 1 mainly includes a mirror body 3 on which various optical systems are arranged, a drive mechanism (XY axis drive mechanism 50, Z axis drive mechanism 52) for driving the mirror body 3, and the optical system. It comprises a control circuit 45 for processing signals from the system and controlling the drive mechanism.
[0019]
On the mirror body 3, mainly, an illumination optical system Sa, a fundus photographing optical system Sb, an alignment index projection optical system Sc, an anterior ocular segment observation optical system Sd, a working distance index projection optical system Se, and a working distance detection optical system Sf. A focusing index projection optical system Sg is provided. The fundus photographing optical system Sb also corresponds to the main optical system described in the claims.
[0020]
The illumination optical system Sa is an optical system for illuminating the fundus of the eye E, and includes a strobe discharge tube 11, condensing lenses 12, 13, a circular slit 14, a mirror 15, condensing lenses 18, 20, and a perforated mirror. It is comprised from 6. Visible light emitted from the strobe discharge tube 11 is focused at the position of the circular slit 14 by the condenser lenses 12 and 13, then passes through the circular slit 14, is reflected by the mirror 15, and folds the optical path on the illumination optical axis 16. Bend. Further, the visible light travels on the illumination optical axis 16, converges in the vicinity of the perforated mirror 6 through the condensing lens 18, a half mirror 19 of the focusing index projection optical system G described later, and the condensing lens 20. An image is formed on the perforated mirror 6. Further, this visible light is reflected by the perforated mirror 6, the optical path is bent on the photographing optical axis 4, passes through the objective lens 5 of the fundus photographing optical system Sb, and converges near the pupil from the apex position of the eye E to be examined. The fundus retinal surface is irradiated.
[0021]
The fundus photographing optical system Sb is an optical system for photographing the fundus based on the illumination light of the illumination optical system Sa. The objective lens 5, the focus lens 7, the relay lens 8, and the television camera (color television camera for fundus imaging) 10 Consists of. These structural members of the fundus photographing optical system Sb are disposed on the photographing optical axis 4. The fundus image passes through the objective lens 5, the perforated mirror 6 of the illumination optical system Sa, the focus lens 7 and the relay lens 8, and is imaged and photographed on the CCD light receiving surface 9 of the TV camera 10. An image signal output from the television camera 10 is input to the control circuit 45.
[0022]
The alignment index projection optical system Sc is an optical system for projecting alignment index light onto the eye spherical surface F of the eye E, and includes an alignment light emitting diode 21a, a mirror 22, a condensing lens 23, a mirror 25, and a concave lens 26. Is done. The concave lens 26 is used to perform correction for canceling the strong power of the objective lens 5, and a lens having a strong canceling power is used. Infrared light, which is alignment index light emitted from the alignment light emitting diode 21a, is reflected by the mirror 22, and the optical path is bent on the alignment index optical axis 27a. This alignment index light passes through the condenser lens 23 and the half mirror 24 of the anterior ocular segment observation optical system Sd, is reflected by the mirror 25, and the optical path is bent on the photographing optical axis 4. Further, the alignment index light passes through the concave lens 26 and the objective lens 5 of the fundus photographing optical system Sb, and is projected as parallel light toward the eye spherical surface F of the eye E to be examined. The concave lens 26 and the mirror 25 are retracted from the photographing optical axis 4 as described later when the fundus is illuminated by the illumination optical system Sa and when the fundus is photographed by the fundus photographing optical system Sb. In addition, a plurality of fixation lamps (not shown) are incorporated in the alignment index projection optical system Sc. These fixation lamps are for fixing the line of sight of the eye E by having the subject gaze. As a result, the line of sight of the eye E can be fixed in the front direction or in a direction rotated by a predetermined angle from the front direction.
[0023]
The anterior ocular segment observation optical system Sd is an optical system for receiving the reflected light of the alignment index light from the eye spherical surface F of the eye E and receiving an anterior ocular segment image of the eye E. The half mirror 24, It is composed of an anterior ocular segment observation lens 28, a television camera 30, and an anterior ocular segment illumination light source 21b. The reflected light from the eye spherical surface F of the alignment index light passes through the objective lens 5 and the concave lens 26, is reflected by the mirror 25, and bends the optical path on the alignment index optical axis 27a. Further, the reflected light is reflected by the half mirror 24, and the optical path is bent on the anterior ocular segment observation optical axis 27b. The reflected light that has passed through the anterior ocular segment observation lens 28 reaches the CCD light receiving surface 29 of the television camera 30 and forms an image. An anterior segment image formed as a bright and dark image having different luminance levels depending on the pupil and iris of the eye E is also input to the television camera 30 through the same route as the reflected light of the alignment index light. The anterior segment illumination light source 21b is provided to illuminate the eye E with infrared light so that the anterior segment image is more clearly formed. An image signal output from the television camera 30 is input to the control circuit 45.
[0024]
The working distance index projection optical system Se includes a working distance detection light emitting diode (infrared LED) 31 disposed along the working distance detection index optical axis 35a that forms 45 degrees with respect to the photographing optical axis 4, and a condenser lens. 32, a working distance detection index slit 33 and a projection lens 34. Light from the working distance detection light emitting diode 31 travels along the working distance detection index optical axis 35a, and sequentially passes through the condenser lens 32, the working distance detection index slit 33, and the projection lens 34, thereby working distance detection index. The light enters the eye spherical surface F.
[0025]
The working distance detection optical system Sf includes an imaging lens 36 for receiving the working distance detection index light reflected by the eye spherical surface F and a working distance detection light receiving element (PSD) 37. The imaging lens 36 and the working distance detection light receiving element 37 are arranged along a working distance detection optical axis 35b that is symmetrical to the working distance detection index optical axis 35a with respect to the photographing optical axis 4. The working distance detection light receiving element 37 outputs a light reception signal accompanying the reception of the working distance detection index light to the control circuit 45.
[0026]
The focus index projection optical system Sg is an optical system for focusing the fundus photographing optical system Sb on the fundus of the eye E to be examined, and includes a halogen lamp 38, a condenser lens 39, an automatic focus index slit 40, and a projection lens 41. The split prism 42, the condenser lens 44, and the half mirror 19. Among these, the halogen lamp 38, the condenser lens 39, the automatic focus index slit 40, the projection lens 41, and the split prism 42 integrally form a movable portion 60. The focusing index projection optical system Sg incorporates a plurality of fixation lamps (not shown). These fixation lamps remain at the same angle even after the mirror 25 and the concave lens 26 retract the line of sight of the eye E fixed by the fixation lamp incorporated in the alignment index projection optical system C from the photographing optical axis 4. It is provided to keep it fixed.
[0027]
An XY-axis drive mechanism 50 and a Z-axis drive mechanism 52 are interposed between the gantry of the fundus photographing apparatus 1 and the mirror body 3, and the position of the mirror body 3 with respect to the gantry is changed by these drive mechanisms. The Z-axis drive mechanism 52 is a drive mechanism for moving the mirror body 3 in the Z direction. Here, the Z direction is a direction (left-right direction in FIG. 1) in which the eye E is approached / separated. Note that the direction of the photographing optical axis 4 coincides with the Z direction. The XY axis drive mechanism 50 is a drive mechanism for moving the mirror body 3 in the XY direction. Here, the X direction refers to a direction orthogonal to the Z axis in a horizontal plane (a direction perpendicular to the paper surface in FIG. 1). The Y direction refers to the vertical direction (the vertical direction in FIG. 1).
[0028]
The control circuit 45 receives signals from the TV camera 10, the TV camera 30, and the working distance detection light receiving element 37, processes these signals in accordance with a predetermined procedure, and performs an XY axis driving mechanism 50, a Z axis driving mechanism 52, and the like. This is a circuit for sending a control signal to the.
[0029]
Next, the operation / operation procedure of the fundus imaging apparatus 1 will be described based on the flowcharts of FIGS. 2 and 3 and with reference to FIGS. The end point M in the flowchart of FIG. 2 matches the start point M in the flowchart of FIG. In addition, step numbers in the following description correspond to steps denoted by the same reference numerals in the flowcharts of FIGS. The operation / operation procedures shown in the flowcharts of FIGS. 2 and 3 are: (1) preliminary adjustment (corresponding to steps 101 to 109), (2) alignment (corresponding to steps 110 to 111), (3) Working distance adjustment (corresponding to steps 112 to 114), (4) alignment correction (corresponding to steps 115 to 117), (5) focusing (corresponding to steps 118 to 121), (6) fundus photography (step) 122). Hereinafter, description will be made for each of these stages.
[0030]
(1) Preliminary adjustment
First, when the photographing button of the fundus photographing apparatus 1 in the standby state is turned on (step 101), an anterior segment image by the anterior segment observation optical system Sd is displayed on the monitor display 47 (step 102). The subject fixes his / her head to the jaw base and looks at the fixation lamp incorporated in the alignment index projection optical system Sc through the objective lens 5 according to the doctor's instructions (step 103). At this time, whether the eye E is the right eye or the left eye is detected by the jaw table based on the position of the jaw table relative to the objective lens 5. A predetermined fixation lamp selected from a plurality of fixation lamps for the left eye or the right eye is turned on based on a signal from the jaw table (step 104).
[0031]
4A and 4B are views showing the eye E to which the line of sight is guided by the fixation lamp. FIG. 4A is a cross-sectional view of the eye E cut along the XZ plane, and FIG. FIG. Ia is the left part of the iris as seen from the subject, and Ib is the right part of the iris. PC is the center of the pupil of the eye E, and its position on the XY coordinates is (X0, Y0). ER is the apex of the eye E to be examined as viewed from the anterior ocular segment observation optical system Sd, and its position on the XY coordinates is (X1, Y1). In FIG. 4, the eye axis t of the eye E is directed in the direction of the point S, not the front direction (Z-axis direction). For example, the following cases can be considered. When an examinee who is in perspective sees the fixation light in the front (fixation lamp in the Z direction), the eye axis t is rotated slightly from the Z axis direction, for example, the direction of the point S as shown in FIG. It will turn. Further, even if the visual line is directed in the direction of the point S by turning on the fixation lamp in the direction of the point S on the subject who is not perspective, the eye axis t is directed in the direction of the point S as shown in FIG. The eye E is not only rotated in the XZ plane but also rotated in the YZ plane, but a cross-sectional view cut along the YZ plane is omitted.
[0032]
When the predetermined fixation light is turned on in this way (step 104) and the eye E is fixed in the state of FIG. 4, the doctor then operates the jaw table and the monitor display 47 displays the subject's eye. Adjustment is made so that the anterior segment of the eye E is reflected (step 105), and the imaging button is pressed again (step 106). The operation of the fundus photographing apparatus 1 from the second button pressing operation to the completion of fundus photographing is automated.
[0033]
By the second button pressing operation, the alignment light emitting diode 21a and the working distance detection light emitting diode 31 are turned on (step 107). In this state, the Z-axis drive mechanism is used until an ocular spherical reflection image (Purkinje image) by the reflected light from the eye spherical surface F of the alignment index light can be clearly recognized in the anterior segment image captured on the imaging screen of the television camera 30. 52 is driven to advance the mirror body 3 toward the eye E (steps 108 and 109).
[0034]
(2) alignment
When the Purkinje image is clearly recognized on the imaging screen of the television camera 30 as described above (step 109), alignment in the XY directions is performed next. This alignment is performed by automatically driving the mirror body 3 in the XY directions (steps 110 and 111) so that the Purkinje image falls within a predetermined range on the imaging screen of the television camera 30. The operation in steps 110 and 111 will be described in detail as follows. First, the anterior segment image and Purkinje image of the eye E are received by the television camera 30, and an image signal is input from the television camera 30 to the control circuit 45. The control circuit 45 detects the position of the Purkinje image in the imaging screen.
[0035]
FIG. 5 shows an imaging screen K by the television camera 30. The control circuit 45 sends a drive signal to the XY axis drive mechanism 50 so that the Purkinje image Q falls within a predetermined range R in the imaging screen K. For example, as shown in FIG. 5, if the Purkinje image Q is in the range of Kx1 on the X-axis coordinate on the imaging screen K, the mirror 3 is moved so that the Purkinje image Q moves to the left in the imaging screen K. The mirror body 3 is moved by sending a drive signal to the XY axis drive mechanism 50 by the control circuit 45. If the Purkinje image Q is in the range of Kx3, the XY axis drive mechanism 50 is controlled so that the Purkinje image Q moves to the right in the captured image K. As a result, the Purkinje image Q is guided in the range of Kx2 on the imaging screen K. When the Purkinje image Q is in the range of Kx2, the mirror 3 is not moved in the X direction. That is, Kx2 is an insensitive range regarding the movement of the mirror body 3 in the X direction. Similarly, in the Y direction, the XY axis drive mechanism 50 is controlled so that the Purkinje image Q enters the insensitive range ky2. In this way, the Purkinje image Q is guided within a predetermined range R in the imaging screen K. The anterior ocular segment observation optical system Sd is arranged on the mirror body 3 so that a subject to be photographed on the photographing optical axis 4 is reflected in a range R in the imaging screen K. Therefore, when the Purkinje image Q enters the range R, the imaging optical axis 4 is in a state of being coincident with the X and Y direction positions (X1, Y1) of the vertex ER of the eye E to be examined. In FIG. 5, the range R is exaggerated with respect to the size of the Purkinje image Q in order to facilitate understanding of the operation description. For the same reason, the position of the Purkinje image Q is exaggerated and greatly separated from the pupil center position.
[0036]
(3) Working distance adjustment
The alignment is completed when the Purkinje image Q enters the predetermined range R in the imaging screen K as described above (step 111). The XY axis drive mechanism 50 is controlled while following the Purkinje image Q so as to maintain the state in which the Purkinje image Q remains in the range R, that is, to maintain the aligned state. The working distance is adjusted. The working distance is adjusted by advancing the mirror body 3 toward the eye E until the working distance detection light receiving element 37 receives the working distance detection index light (eye spherical reflection light) (step 112). When the control circuit 45 detects that the working distance detection light receiving element 37 has received the working distance detection index light (eye spherical reflection light) (step 113), the control circuit 45 drives the XY axis driving mechanism 50 and the Z axis driving mechanism 52. Is stopped (step 114).
[0037]
The operation in steps 112, 113, and 114 will be described in detail as follows. First, when the alignment in the XY directions is completed (step 111), the working distance detection index light is projected onto the eye E by the working distance index projection optical system Se. However, when the alignment is completed, the fundus photographing optical system Sb is located farther from the eye E than the working distance. In such a state, the fundus photographing optical system Sb and the working distance index projection optical system Se are in the mirror body 3 in such a positional relationship that the working distance detection index light does not enter the vertex (eye vertex) EY of the eye spherical surface F. It is arranged on the top. Therefore, the reflected light from the eye spherical surface F is not received by the working distance detecting light receiving element 37. Thereafter, a drive signal is sent from the control circuit 45 to the Z-axis drive mechanism 52, and the mirror 3 is moved along the Z-axis in a direction approaching the eye E (step 112). When the mirror 3 reaches a certain distance with respect to the eye E, the index light from the working distance index projection optical system Se is incident on the eye vertex ER of the eye spherical surface F, and the reflected light is detected as the working distance. Light is received by the light receiving element 37 (step 113). In this state, the fundus photographing optical system Sb and the working distance index projection optical system Se are disposed on the mirror body 3 in such a positional relationship that the distance from the fundus photographing optical system Sb to the eye E to be examined is the working distance. When the working distance detecting light receiving element 37 receives the reflected light, it outputs a light receiving signal to the control circuit 45. Then, the control circuit 45 sends a stop signal to the Z-axis drive mechanism 52 to stop the operation of the Z-axis drive mechanism 52. This stops the movement of the mirror body 3 in the Z direction. Further, the maintenance of the alignment state in the XY directions, which has been performed while following the Purkinje image, is ended by temporarily stopping the XY axis drive mechanism 50 (step 114).
[0038]
(Four) Alignment correction
When the working distance adjustment is completed as described above, alignment correction is performed next. The alignment correction is performed so that the pupil center PC position is detected on the basis of the anterior segment image of the eye E to be examined imaged by the television camera 30 (step 115), and the mirror body is set so that the photographing optical axis 4 coincides with the pupil center PC. 3 is moved (steps 116 and 117). The movement of the mirror body 3 is performed by the control circuit 45 sending a drive signal to the XY axis drive mechanism 50.
[0039]
The operation in steps 115, 116, and 117 will be described in detail as follows. First, the anterior segment image of the eye E is received by the television camera 30, and an image signal from the television camera 30 is input to the control circuit 45. The control circuit 45 obtains the position of the pupil center PC in the photographing screen from this image signal.
[0040]
FIG. 6 is a diagram illustrating a method in which the control circuit 45 obtains the position of the pupil center PC on the imaging screen K. This figure shows how the luminance level of the anterior ocular segment image is calculated in order to obtain the position of the pupil center PC in the photographic plane K in the XY plane. 6A is an anterior segment image captured by the television camera 30, and FIG. 6B is a video signal scanning line (dotted line in FIG. 6A) L in the anterior segment image. This is the upper luminance level signal. By performing binarization at the reference level indicated by the broken line N in FIG. 6B, the pupil P portion and the iris I portion can be selected from the anterior segment image. That is, in FIG. 6B, the range p with a low luminance level corresponds to the pupil P, and the range i with a relatively high luminance corresponds to the iris I. Then, the geometric gravity center C is detected for the range p with a low luminance level, and this geometric gravity center C is obtained as the position of the pupil center PC on the imaging screen K.
[0041]
The control circuit 45 sends a drive signal to the XY-axis drive mechanism 50 so that the pupil center position thus detected falls within a predetermined range R on the imaging screen K. The method of guiding the pupil center position to the predetermined range R on the imaging screen K is the same as the method of guiding the position of the Purkinje image Q to the range R on the imaging screen K in the alignment described above. Thus, when the pupil center position enters the predetermined range R of the imaging screen K, the photographing optical axis 4 coincides with the pupil center PC of the eye E to be examined. As a result, the photographing optical axis 4 is located at an equal distance from the left part Ia and the right part Ib of the iris. In addition, when the alignment correction is completed in this way, the fundus photographing optical system Sb is guided to the operating position (the operating position in the XYZ directions).
[0042]
(Five) Focus
When the alignment correction is completed as described above, a correction completion signal is output from the control circuit 45 to the optical path switching mechanism 54. In response to this, the optical path switching mechanism 54 retracts the mirror 25 and the concave lens 26 from the photographing optical axis 4. The focusing is performed by the following known method. That is, the halogen lamp 38 is turned on by the control circuit 45 (step 118), and the movable portion 60 of the focus index projection optical system G and the focus lens 7 of the fundus photographing optical system Sb are moved in the Z direction until focus is detected. (Steps 119 and 120). The movable unit 60 and the focus lens 7 are moved by sending a drive signal from the control circuit 45 to the focusing drive mechanism 56. When focusing is completed, the halogen lamp 38 is turned off (step 121).
[0043]
(6) Fundus photography
When focusing is completed as described above, the stroboscopic light emission circuit 57 controlled by the control circuit 45 causes the stroboscopic discharge tube 11 to emit light, and in synchronization with this, the television camera 10 captures a fundus image (step 122). Since the alignment correction is performed so that the photographing optical axis 4 passes through the pupil center PC, the illumination light from the strobe discharge tube 11 is projected onto the fundus without being blocked by the iris I. In addition, the fundus image is not blocked by the iris during shooting. Therefore, the fundus image captured by the television camera 10 is clear. Even if the rotation angle of the eyeball of the eye to be examined becomes extremely large depending on the position of the fixation light to be watched, it is impossible to predict in which direction the eye E is rotated as in a perspective view. Even in such a case, a clear fundus image can be obtained. After fundus photography, the mirror 3 returns to the initial standby position (step 123) and enters the standby state.
[0044]
As described above, one embodiment of the present invention has been described based on the fundus imaging apparatus 1, but the operation position determination device for an ophthalmologic apparatus according to the present invention captures the pupil position of the eye to be examined or uses the pupil of the eye to be examined. The present invention can be widely applied to all ophthalmic apparatuses that perform inspection, observation, and photographing. Further, the fundus photographing apparatus 1 including the fundus photographing optical system Sb as the main optical system has been described. However, the main optical system may have both the photographing function and the observation function, or only one of the functions. May be provided.
[0045]
【The invention's effect】
As described above, according to the operation position determination device for an ophthalmologic apparatus of the present invention, it is possible to accurately capture the pupil position, and in particular, to shoot and observe a region deeper than the iris of the eye to be examined through the pupil. In such a case, the part can be clearly photographed and observed without being blocked by the iris. Moreover, it becomes possible to deal with a wide range of eye movements of the eye to be examined, and even when the eye line of the eye to be examined is greatly shaken at an arbitrary angle, it is possible to capture and observe clearly. Furthermore, even if the angle of the eye to be examined cannot be predicted as in the case of strabismus, it is possible to capture and observe clearly. In addition, it is possible to configure an ophthalmologic apparatus that automatically determines the operation position in the order of alignment adjustment, operation distance adjustment, and alignment correction.
[0046]
Further, according to the operation position determining apparatus for the fundus imaging apparatus of the present invention, the illumination light can be projected onto the fundus without being blocked by the iris, and the fundus image can be captured without being blocked by the iris. . In addition, it is possible to deal with a wide gaze movement range of the eye to be examined, and a fundus image can be clearly captured even if the gaze of the eye to be examined is greatly shaken at an arbitrary angle. Furthermore, even when the angle of the eye to be examined cannot be predicted as in the case of strabismus, a fundus image can be clearly captured. In addition, it is possible to configure a fundus photographing apparatus in which the working position is automatically determined in the order of alignment adjustment, working distance adjustment, and alignment correction.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a fundus imaging apparatus.
FIG. 2 is a flowchart showing an operation / operation procedure of the fundus imaging apparatus.
FIG. 3 is a flowchart showing an operation / operation procedure of the fundus imaging apparatus.
4A and 4B are diagrams showing an eye to be examined in which a line of sight is guided by a fixation lamp. FIG. 4A is a cross-sectional view of the eye to be examined cut along an XZ plane, and FIG. is there.
FIG. 5 is a diagram illustrating an imaging screen by a television camera.
6A and 6B are diagrams illustrating a method in which the control circuit obtains the position of the center of the pupil on the imaging screen. FIG. 6A is an anterior segment image captured by a television camera, and FIG. It is a figure which shows the luminance level signal on the scanning line of the video signal in an eye part image.
[Explanation of symbols]
1 Fundus photography device
3 body
4 Shooting optical axis
5 Objective lens
6 Perforated mirror
7 Focus lens
8 Relay lens
9 CCD light receiving surface
10 TV camera
11 Strobe discharge tube
12, 13 Condensing lens
14 Circular slit
15 Mirror
16 Illumination optical axis
18 Condensing lens
19 Half mirror
20 Condensing lens
21a Light-emitting diode for alignment
21b Light source for anterior segment illumination
22 Mirror
23 Condensing lens
24 half mirror
25 mirror
26 Concave lens
27a Alignment index optical axis
27b Anterior eye observation optical axis
28 Anterior segment observation lens
29 CCD light receiving surface
30 TV camera
31 Light emitting diode for working distance detection
32 condenser lens
33 Working distance detection index slit
34 Projection lens
35a Working distance detection index optical axis
35b Working distance detection optical axis
36 Imaging lens
37 Photodetector for working distance detection
38 Halogen lamp
39 Condensing lens
40 Automatic focus index slit
41 Projection lens
42 Split prism
44 condenser lens
45 Control circuit
47 Monitor display
50 XY axis drive mechanism
52 Z-axis drive mechanism
54 Optical path switching mechanism
56 Focus drive mechanism
57 Strobe light emission circuit
60 Moving parts
Sa illumination optical system
Sb Fundus photographing optical system
Sc alignment index projection optical system
Sd anterior ocular segment observation optical system
Se Working distance index projection optical system
Sf Working distance detection optical system
Sg focusing index projection optical system
K imaging screen
L Scan line
E Eye to be examined
F Eye sphere
t Eye axis
P pupil
I Iris
PC pupil center
ER vertex of eye to be examined
Q Purkinje statue

Claims (2)

An operating position determination apparatus for an ophthalmologic apparatus having an optical system for photographing or / and observing a predetermined part of an eye to be examined as a main optical system,
An alignment index projection optical system for projecting alignment index light onto the spherical surface of the eye to be examined;
An anterior ocular segment observation optical system that receives an anterior ocular segment image of the eye to be examined and receives reflected light from the spherical surface of the alignment index light as a Purkinje image ;
Alignment means for moving the main optical system based on the Purkinje image position observed by the anterior ocular segment observation optical system so that the optical axis of the main optical system coincides with the vertex of the eye to be examined;
With this alignment means, with the optical axis of the main optical system coinciding with the apex of the eye to be examined, the reflected light from the apex of the eye to be examined of the working distance detection index light projected obliquely forward to the eye to be examined is measured at a predetermined position. Working distance adjusting means for adjusting the working distance by moving the main optical system in the direction of the optical axis so that light can be received;
Based on the anterior ocular segment image received by the anterior ocular segment observation optical system, the main optical system in a state where the optical axis coincides with the apex of the eye to be examined while detecting the pupil center position of the eye to be examined. An operation position determination device for an ophthalmologic apparatus, comprising: an alignment correction unit that moves the optical axis so as to coincide with the center of the pupil . An operating position determination device for a fundus photographing apparatus having an illumination optical system for illuminating the fundus of a subject's eye with illumination light and a fundus photographing optical system for photographing the fundus based on the illumination light,
An alignment index projection optical system for projecting alignment index light onto the spherical surface of the eye to be examined;
An anterior ocular segment observation optical system that receives an anterior ocular segment image of the eye to be examined and receives reflected light from the spherical surface of the alignment index light as a Purkinje image ;
Alignment means for moving the fundus imaging optical system based on the Purkinje image position observed by the anterior ocular segment observation optical system so that the optical axis of the fundus imaging optical system coincides with the vertex of the eye to be examined;
With this alignment means, with the optical axis of the fundus imaging optical system aligned with the vertex of the eye to be examined, the reflected light from the vertex of the eye to be examined of the working distance detection index light projected obliquely forward to the eye to be examined is placed at a predetermined position. Working distance adjusting means for adjusting the working distance by moving the fundus photographing optical system in the direction of the optical axis so that it can be received by
Based on the anterior ocular segment image received by the anterior ocular segment observation optical system, the fundus imaging optical system in a state where the optical axis coincides with the apex of the eye to be examined while detecting the pupil center position of the eye to be examined. And an alignment correction means for moving the optical axis so as to coincide with the center of the pupil .

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