JP2016030181A - Ophthalmographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmographic apparatus capable of capturing a high-quality image of a fundus oculi without generating harmful light such as flare in a simple configuration.SOLUTION: An illumination dual-aperture diaphragm is disposed near a conjugate position of an anterior eye part of a subject's eye and spot-like illumination light beams 11a' and 11b' are formed on a pupillary surface 31. An illumination slit diaphragm is disposed at a conjugate position of the fundus oculi and slit-like illumination light 40 is formed on the fundus oculi. An imaging diaphragm is disposed at a conjugate position of the anterior eye part of an imaging optical path, and spot-like imaging light 40' is formed at a position that is not overlapped with the spot-like illumination light beams 11a' and 11b'. The illumination slit diaphragm is rotated about an optical axis and the fundus oculi is sequentially illuminated by the slit-like illumination light 40 rotating accordingly, and photographed. The illumination dual-aperture diaphragm is also rotated in conjunction with the illumination slit diaphragm. Consequently, in any rotation position, the illumination light and imaging light become narrow-angle light beams so as to prevent an occurrence of flare.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a fundus imaging apparatus that causes illumination light to enter the fundus of a subject's eye via an illumination optical path, and guides reflected light from the fundus of the subject's eye to an imaging element via the imaging optical path to photograph the fundus of the subject's eye.

  In the fundus imaging apparatus, the illumination light from the illumination light source enters the fundus through the pupil of the eye to be examined. The reflected light reflected from the fundus is guided to the imaging system of the apparatus through the entrance pupil of the fundus imaging apparatus to form a fundus image. Hereinafter, the return light from the fundus is referred to as photographing light. It is known that when illumination light and imaging light are superimposed in the crystalline lens of the eye to be examined, harmful light such as flare is generated and the quality of the fundus image is degraded.

  Since such harmful light is more likely to occur as the angle of view of the observation imaging system is larger, in Patent Document 1 below, a slit-shaped opening is provided at a position conjugate with the fundus of the eye to be examined, and a slit-shaped opening image is obtained. And a technique for photographing the fundus by scanning the fundus in a direction perpendicular to the optical axis with this aperture image.

  Patent Document 2 below discloses a technique for capturing a clear fundus image with indirect illumination light, in order to remove the influence of specular reflection light from the surface of the retina, etc., by partially shielding the fundus and photographing a plurality of times. Has been.

  Japanese Patent Application Laid-Open No. 2004-259542 discloses a technique for illuminating the fundus through a light-shielding unit that can change the light-shielding region, photographing the fundus a plurality of times, and connecting images without flare later to generate a single fundus image. It is disclosed.

  Patent Document 4 below provides a light-shielding point that can change the area for illuminating the anterior segment other than the ring slit for illuminating the anterior segment, and electrically masks the area corresponding to the reflected light from the crystalline lens. A technique for obtaining a high-quality fundus image without flare is disclosed.

  Patent Document 5 below discloses a technique in which a slit-like light source image is projected onto a subject, scanned in a direction intersecting the optical axis, and a member for shielding the light source image at a position conjugate with the subject in the observation system is disclosed. ing.

JP-A-55-29316 JP-A-7-51230 JP 2003-339634 A JP 2005-137484 A JP 2007-325781 A

  However, in the technique described in Patent Document 1, since the fundus is imaged by scanning a slit-shaped aperture image in a direction perpendicular to the optical axis, illumination light and imaging light are determined according to the scanning position of the aperture image. There is a problem that flare cannot be completely removed due to the difference in the degree of superposition.

  Moreover, since the techniques described in Patent Documents 2 and 5 indirectly illuminate the fundus, there is a problem that it is difficult to acquire a clear fundus image with a dark fundus.

  Further, the technique described in Patent Document 3 has a problem that a plurality of anterior-eye illumination stops must be prepared in order to change the light-shielding region.

  In addition, the technique described in Patent Document 4 has a problem that the process becomes complicated because the process of electrically masking the captured image is required.

  The present invention has been made to solve such problems, and provides a fundus imaging apparatus capable of photographing the fundus with high quality without generating harmful light such as flare with a simple configuration. Is an issue.

The present invention
A fundus imaging apparatus that irradiates illumination light to an eye fundus of a subject via an illumination optical path, guides reflected light from the fundus of the subject eye to an imaging element via an imaging optical path, and images the fundus of the eye to be examined,
A spot-shaped illumination light provided with a first opening at a predetermined position in a first direction from the center toward the periphery, and arranged near the conjugate position of the anterior segment of the anterior eye of the illumination light path, corresponding to the first opening A first diaphragm that forms a pupil plane on the eye to be examined;
A slit-shaped second opening extending in a second direction substantially perpendicular to the first direction from the center toward the periphery, and disposed near the eye fundus conjugate position of the eye to be examined in the illumination optical path. A second diaphragm for forming slit-shaped illumination light corresponding to the opening on the fundus of the eye to be examined;
A third aperture is provided in the center area, and the spot-shaped illumination light corresponding to the third aperture is disposed near the anterior ocular segment conjugate position of the imaging optical path, and the spot-shaped illumination on the eye pupil surface to be examined A third aperture formed at a position that does not overlap the light,
The first and second diaphragms are rotated in conjunction with the optical axis center, and the spot-like illumination light formed on the pupil surface by the first diaphragm and the slit-like illumination formed on the fundus by the second diaphragm It is characterized by photographing the fundus while rotating the light in conjunction.

  In such a configuration, the illumination light incident on the anterior ocular segment (pupil surface) of the eye to be examined is spot-shaped and narrow-angle light is incident on the fundus, and reflected light from the fundus, that is, imaging light is also captured by the anterior eye. The spot is narrowed into a spot shape and becomes a narrow-angle light beam, which exits the pupil surface. Accordingly, the illumination light and the photographing light are less likely to intersect with each other as a narrow-angle light beam in the lens, so that the generation of harmful light such as flare in the lens can be reduced.

(A) is an optical diagram showing a configuration when the illumination optical system is viewed from above, and (b) is an optical diagram showing a configuration when the illumination optical system is viewed from the side. (A) is an optical diagram showing a configuration when the photographing optical system is viewed from above, and (b) is an optical diagram showing a configuration when the photographing optical system is viewed from the side. (A) is explanatory drawing which showed the illumination light formed in the pupil surface of a to-be-tested eye, and the illumination light formed in a fundus, (b) is the imaging light formed in the pupil surface of a to-be-tested eye, and formed in the fundus. It is explanatory drawing which showed the imaging light. It is explanatory drawing which showed the illumination light which injects into a to-be-tested eye, and the imaging light inject | emitted from a to-be-tested eye.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

  FIG. 1A illustrates a configuration when the illumination optical system is viewed from above, and FIG. 1B illustrates a configuration when viewed from the side. What is denoted by reference numeral 10 in each figure is an illumination light source, and the illumination light source 10 is composed of light emitting diodes in three rows and columns. In FIG. 1A, three light emitting diodes in a row are shown in FIG. Each of the three light emitting diodes in the column is shown as a rectangular block.

  Illumination light from the illumination light source 10 is arranged in the vicinity of the conjugated position of the eye fundus of the subject to be examined in the illumination optical path, the two-hole illumination aperture (first diaphragm) 11 disposed in the vicinity of the anterior ocular segment conjugate position of the eye to be examined. Then, the light passes through the illumination slit stop (second stop) 12, enters the lens 13, and then passes through the perforated mirror 14 having the opening 14a at the center disposed near the conjugate position of the anterior eye portion to be examined (transmitted or transmitted). reflect.

  The illumination light that has passed through the perforated mirror 14 passes through the objective lens 15 and enters the anterior eye part (pupil) Ep of the eye E to illuminate the fundus Er of the eye E. In FIG. 1, the conjugate position of the anterior ocular segment to be examined is indicated by P, and the conjugate position of the fundus to be examined is indicated by R.

  FIG. 2A shows a configuration when the photographing optical system is viewed from above, and FIG. 2B shows a configuration when viewed from the side. As in FIG. 1, the eye anterior eye conjugate position of the eye to be examined is indicated by P, and the eye fundus conjugate position of the eye to be examined is indicated by R.

  In FIG. 1, the reflected light from the fundus Er illuminated by the illumination light source 10 becomes imaging light in FIG. 2, passes through the anterior eye segment Ep to be examined and enters the objective lens 15, and then conjugates to the anterior eye segment to be examined. It passes through a photographing diaphragm (third diaphragm) 16 having a circular opening 16a at the center disposed near the position P. The imaging light that has passed through the imaging aperture 16 passes through an imaging lens 17 and a slit plate (fourth aperture) 18 disposed in the vicinity of the fundus conjugate position R of the eye to be inspected, and an imaging device 19 composed of a CCD or a CMOS. The fundus is imaged by imaging.

  The slit plate 18 has a slit opening 18a extending in the vertical direction, similarly to the illumination slit diaphragm 12, and is disposed in front of the image sensor 19 to restrict the photographing light incident on the image sensor 19 into a slit shape. The center 18b is arranged in the photographing optical path with the optical axis O aligned. As will be described later, the slit plate 18, the illumination two-hole aperture 11, and the illumination slit aperture 12 are each rotated in conjunction (synchronized) with the optical axis O as the center.

  Note that the perforated mirror 14 disposed in the illumination optical system is disposed in the vicinity of the photographing aperture 16 and is functionally illustrated by a one-dot chain line in FIG.

  Returning to FIG. 1, the illumination two-hole aperture 11 is arranged with the center 11 c aligned with the optical axis O, and circular at a predetermined distance d 1 from the center 11 c toward the periphery in the first direction (horizontal direction). A hole (first opening) 11a is provided, and another circular hole 11b is provided at a position symmetrical to the hole 11a with respect to the center 11c.

  The illumination slit stop 12 is arranged with the center 12b aligned with the optical axis O, and extends from the vicinity of the center 12b into a slit shape (second direction) extending in a second direction (vertical direction) substantially perpendicular to the first direction. ) 12a. The slit opening 12a does not overlap each other when viewed in the optical axis direction with respect to the holes 11a and 11b of the illumination two-hole diaphragm 11, that is, the illumination two-hole diaphragm 11 and the illumination slit diaphragm 12 are centered. When overlapped, the slit opening 12a comes between the two holes 11a and 11b of the illumination two-hole stop 11 so as not to overlap the two holes 11a and 11b.

  The illumination two-hole aperture 11 is disposed in the vicinity of the anterior eye conjugate position P of the eye to be inspected in the illumination optical path, and the illumination light that has passed through one of the holes 11a is the illumination slit diaphragm 12, the lens 13, the perforated mirror 14, and the objective lens 15. Is incident on the anterior eye Ep of the eye to be examined, and spot-like illumination light 11a ′ is formed at one end of the center of the pupil 31 of the iris 30 as shown in the upper part of FIG. . The illumination light that has passed through the other hole 11b of the illumination two-hole diaphragm 11 passes through the illumination slit diaphragm 12, the lens 13, the perforated mirror 14, and the objective lens 15 and enters the anterior eye portion Ep of the eye to be examined. The spot-shaped illumination light 11 b ′ is formed at the other side end of the center of the pupil 31. Illumination lights 11a 'and 11b' incident on the anterior eye portion Ep of the eye to be examined are schematically shown in the vicinity of the anterior eye portion Ep of the eye to be examined in FIG.

  On the other hand, the illumination slit stop 12 is disposed at the fundus conjugate position R, and the slit opening 12a extends in a direction (vertical direction) orthogonal to the direction in which the two holes 11a and 11b of the illumination two-hole stop 11 are arranged. Accordingly, the fundus Er illuminated by the illumination lights 11a ′ and 11b ′ is shielded by the portions other than the slit opening 12a, and the fundus Er has an opening of the slit opening 12a as illustrated in the lower part of FIG. A slit-shaped illumination light 40 extending in the vertical direction corresponding to the image is formed.

  The reflected light from the fundus Er illuminated with the illumination light 40 becomes imaging light 40 ′, passes through the anterior eye Ep of the eye to be examined, passes through the objective lens 15, and enters the imaging aperture 16. As shown in the upper part of FIG. 3B, the photographing aperture 16 is configured so that the photographing light 40 ′ does not overlap the illumination light 11a ′ and 11b ′ at the substantial center of the pupil 31, that is, from the illumination light 11a ′ and 11b ′. It is arranged in the vicinity of the anterior eye portion conjugate position P of the eye to be examined so as to pass through the center of the pupil 31 in a separated state. Since the imaging light 40 ′ passing through the anterior eye Ep of the eye to be examined becomes imaging light passing through the opening 16 of the imaging aperture 16, the imaging light 16a ′ in the vicinity of the eye anterior eye Ep in FIG. It is schematically illustrated with a curved line indicating.

  In FIG. 4, the illumination light 40 described above passes through the anterior ocular segment Er to be examined and the crystalline lens Ec, enters the fundus Er, reflects from the ocular fundus Er, and is emitted from the anterior ocular segment Ep as imaging light 40 ′. The state is illustrated.

  As shown in FIG. 4, the illumination light 40 incident on the anterior eye portion Ep (pupil surface) of the eye to be examined is narrowed into a spot shape by the illumination two-hole aperture 11 to become narrow-angle illumination lights 11a ′ and 11b ′. Is incident on the fundus Er. Also, the reflected light from the fundus Er, that is, the imaging light 40 ', is narrowed in a spot shape by the imaging aperture 16 at the anterior eye portion Ep of the eye to be examined, and is similarly emitted as a narrow-angle imaging light 16a' from the pupil surface. Therefore, since the illumination light 40 and the photographing light 40 'are less likely to intersect with each other as a narrow-angle light beam in the lens Ec, it is possible to reduce generation of harmful light such as flare in the lens Ec. In particular, since the direction in which the illumination lights 11a ′ and 11b ′ are arranged and the direction in which the photographing light 40 ′ formed on the fundus extends in a slit shape are orthogonal to each other, even if the fundus is photographed with a wide angle of view, illumination is performed within the lens. Light and photographic light are less likely to cross, and a good fundus image with little flare can be acquired.

  As shown in the lower part of FIG. 3A, the illumination light illuminates the fundus by the illumination slit diaphragm 12 arranged at the fundus conjugate position R as shown in the lower part of FIG. Therefore, the illumination slit diaphragm 12 is rotated about 180 degrees around the optical axis O, and the fundus Er is sequentially illuminated with the slit-shaped illumination light 40 that rotates in accordance with the rotation, and the imaging element 19 shoots. During this photographing, the illumination two-hole aperture 11 is also rotated around the optical axis in conjunction with the rotation of the illumination slit aperture 12. As described above, when the illumination slit diaphragm 12 and the illumination two-hole diaphragm 11 are rotated in conjunction with each other, the relationship shown in FIGS. 3A and 3B, that is, the pupil 31 is formed at any rotational position. Further, the two spot-shaped illumination lights 11a ′ and 11b ′ and the spot-shaped photographing light 40 ′ are arranged horizontally in the center of the pupil plane without intersecting, and the fundus Er has a slit shape extending in the vertical direction to the center of the pupil plane. Since the illumination light 40 or the photographing light 40 ′ is formed, noxious light is reduced at any rotational position, and a good fundus image can be photographed.

  When the illumination two-hole aperture 11 is rotated around the optical axis in conjunction with the illumination slit aperture 12, the slit plate 18 disposed on the front surface of the image sensor 19 is also rotated around the optical axis. In addition, light other than the photographing light 40 ′ is prevented from entering the image sensor 19.

  In addition, since a slit image that rotates about the optical axis is incident on the image sensor 19, multiple exposure is performed at the center, and the brightness of the fundus image differs between the center and the periphery. Therefore, the pixel value is corrected according to the position of each pixel of the image sensor 19 when viewed in the radial direction. For example, each pixel is weighted with a coefficient corresponding to the distance in the radial direction of the pixel, and all the pixels are divided by a predetermined value as necessary to correct the fundus image with uniform brightness. As another method, the fundus image may be acquired as a moving image while being rotated, and the image of each frame may be synthesized later to form one fundus image.

  In the embodiment described above, the illumination two-hole diaphragm 11 includes the two holes 11a and 11b, but it may be a one-hole diaphragm having only one hole at a position d1 away from the center in the radial direction. In this case, the amount of illumination light is reduced, but the same effect can be obtained because the illumination light and the photographing light are narrow-angle rays.

  The slit opening 12a of the illumination slit stop 12 is a slit opening extending both in the radial direction from the center. However, even if the slit length is half of that, that is, the slit opening extending in one direction from the center in the radial direction. Good. In this case, since the slit-shaped illumination light formed on the fundus Er becomes illumination light extending in only one direction from the center in the radial direction, the illumination slit diaphragm 12 is rotated 360 degrees to illuminate the entire fundus. To be. At this time, of course, the illumination two-hole aperture 11 is rotated 360 degrees in conjunction with the illumination slit aperture 12.

DESCRIPTION OF SYMBOLS 10 Illumination light source 11 2 hole aperture for illumination 12 Slit aperture aperture for illumination 14 Perforated mirror 15 Objective lens 16 Imaging aperture 17 Imaging lens 18 Slit plate 19 Imaging element 40 Illumination light 40 'Imaging light

Claims (5)

A fundus imaging apparatus that irradiates illumination light to an eye fundus of a subject via an illumination optical path, guides reflected light from the fundus of the subject eye to an imaging element via an imaging optical path, and images the fundus of the eye to be examined,
A spot-shaped illumination light provided with a first opening at a predetermined position in a first direction from the center toward the periphery, and arranged near the conjugate position of the anterior segment of the anterior eye of the illumination light path, corresponding to the first opening A first diaphragm that forms a pupil plane on the eye to be examined;
A slit-shaped second opening extending in a second direction substantially perpendicular to the first direction from the center toward the periphery, and disposed near the eye fundus conjugate position of the eye to be examined in the illumination optical path. A second diaphragm for forming slit-shaped illumination light corresponding to the opening on the fundus of the eye to be examined;
A third aperture is provided in the center area, and the spot-shaped illumination light corresponding to the third aperture is disposed near the anterior ocular segment conjugate position of the imaging optical path, and the spot-shaped illumination on the eye pupil surface to be examined A third aperture formed at a position that does not overlap the light,
The first and second diaphragms are rotated in conjunction with the optical axis center, and the spot-like illumination light formed on the pupil surface by the first diaphragm and the slit-like illumination formed on the fundus by the second diaphragm A fundus photographing apparatus that photographs the fundus while rotating the light in conjunction with each other.   The fundus imaging apparatus according to claim 1, wherein the first diaphragm includes another opening at a position symmetrical to the position of the first opening and the optical axis.   The fundus imaging apparatus according to claim 1, wherein the second opening of the second diaphragm is an opening extending in a slit shape in both directions from the center.   The fundus imaging apparatus according to claim 2, wherein the first and second apertures are rotated about 180 degrees.   A fourth diaphragm having a slit-like opening extending in the second direction is disposed in front of the image sensor, and the fourth diaphragm is rotated in conjunction with the first and second diaphragms. The fundus imaging apparatus according to any one of claims 1 to 4, wherein the fundus imaging apparatus is characterized.