JPH07255678A - Optometrical instrument - Google Patents

Abstract

PURPOSE:To provide a device which can measure the radius of curvature of a cornea and can also photograph cornea endothelium cells. CONSTITUTION:The reflection light on the cornea Ec from a light source 1a for measurement of the cornea size is reflected on dichroic mirrors 2 and 9 and received by a TV camera 19. And according to the light reception signal obtained there, a signal process circuit 21 calculates the radius of curvature of the cornea Ec. The reflection beam on the cornea Ec from the light source 25 for photograph are split in two directions by a beam splitting part 27. The split light at the beam splitting part 27 is received at the one-dimensional CCD31 as a slit image, and the shooting depth is detected. On the other hand, the beam going through the beam splitting part 27 is reflected on a mirror 29 and a dichroic mirror 17, and photographed by the TV camera 19 as a cornea endothelium cell image, and the image is projected on a TV monitor 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometry apparatus used in an ophthalmology clinic or the like.

[0002]

2. Description of the Related Art A keratometer and a corneal endothelial cell imaging device are often used as a cornea inspection device for an eye to be inspected.

[0003]

Although these are devices for examining the vicinity of the same corneal center, they are separate devices. In order to perform these inspections at the same time, two devices are required and a wide inspection space is required. Also, it takes time to move the subject for each different examination,
Furthermore, there is a problem in that the inspection parts cannot be dealt with if the inspection devices are different.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an optometry apparatus that can measure the shape of the cornea of an eye to be inspected and image the corneal endothelium with a single apparatus, and can take correspondence of those examination sites.

[0005]

An eye examination apparatus according to a first aspect of the present invention for achieving the above object is to project a light flux from a light source on a circumference centered on an optical axis onto a cornea of an eye to be inspected. The corneal shape measuring means for receiving the reflected light at the light receiving element by the light receiving element and the slit light is projected from the direction inclined to the optical axis to the part on the optical axis of the cornea, and the reflected light is reflected here. It is characterized in that it has a corneal photographing means for receiving light with a light receiving element from a direction symmetrical with respect to the projection direction with respect to the axis, and a fixation means having a fixation target commonly used for the corneal shape measuring means and the corneal photographing means. .

Further, the optometry apparatus according to the second aspect of the present invention includes a position detecting means for projecting a light beam on a predetermined position of the cornea of the eye to be examined and receiving the reflected light beam to detect the position of the apparatus, and an optical axis. A cornea shape measuring means for projecting a light flux from a light source on a circumference centered on the eye onto the cornea of the eye to be inspected and receiving the reflected light with a light receiving element to obtain the shape of the cornea of the eye to be inspected, and tilted to the optical axis. And a cornea photographing unit for photographing a cornea image from a direction symmetrical to the projection direction with respect to the optical axis.

[0007]

The eye examination apparatus according to the first aspect of the present invention having the above-mentioned configuration fixes the eye to be inspected by a common eye fixation target, and transmits the light flux from the light source on the circumference around the optical axis to the cornea of the eye to be inspected. Project the light onto the cornea, receive the reflected light from the cornea on the light receiving element to determine the shape of the cornea, project the slit light onto the cornea from the direction inclined to the optical axis, and the reflected light here is symmetrical with the projection direction with respect to the optical axis. The cornea is imaged by the light receiving element from different directions.

The optometry apparatus according to the second invention is a position detecting means for projecting a light beam to a predetermined position on the cornea of an eye to be examined and receiving the reflected light beam to detect the position of the apparatus. The corneal shape measuring means having a light source on the circumference of the center and the corneal photographing means having the symmetrical illuminating optical path and photographing optical path are aligned.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a configuration diagram of the first embodiment, which is an optometry apparatus having three functions of a refractometer, a keratometer, and a corneal endothelial cell imaging apparatus, which is opposed to an eye E to be inspected and as shown in FIG. Optical path 01 behind four corneal shape measuring light sources 1a to 1d symmetrically arranged with respect to the optical path O1
A dichroic mirror 2, an objective lens 3, a perforated mirror 4, a central aperture stop 5 conjugate with the pupil Ep, a lens 6, and a refractive power measuring light source 7 are sequentially arranged on the upper side.

Optical path of dichroic mirror 2 in incident direction
A lens 8, a dichroic mirror 9, a lens 10, and a fixation target 11 that can move along the optical path O2 are sequentially arranged on O2 to form a fixation target projection system. On the optical path O3, a 6-hole diaphragm 12 conjugate with the pupil Ep,
A separation prism 13 composed of six wedge prisms, a lens 14, and a dichroic mirror 15 are sequentially arranged. On the optical path O4 in the reflection direction of the dichroic mirror 9 on the optical path O2, the diaphragm 16, the dichroic mirror 17, the dichroic mirror 15, the lens 18, and the TV camera 19 provided in the rear focal plane of the lens 8 are sequentially arranged. , The output of the television camera 19 is connected to a television monitor 20 and a signal processing circuit 21 including a symbol generating circuit,
The output of the signal processing circuit 21 is also connected to the television monitor 20.

On the optical path O5 inclined with respect to the optical path O1, there are arranged a lens 23, a slit plate 24 conjugate with the cornea Ec, a photographing light source 25 such as a lamp or a strobe from the eye E side, and the optical path O1 is arranged. With respect to the optical path O5 that is symmetrical with respect to the optical path O5, a lens 26, a light beam splitting member 27, a slit plate 28 conjugate with the cornea Ec, and a mirror 29 are arranged from the eye E side, and the optical path O5 is disposed.
Light sources 30a and 30b for anterior ocular segment illumination are arranged near the lenses 23 and 26 on 5 and O6, respectively. A one-dimensional CCD conjugate with the cornea Ec in the reflection direction of the light beam splitting member 27.
31 is arranged, and the lens 32, the dichroic mirror 17, the lens 33, and the lens 33 are provided on the optical path O7 in the reflection direction of the mirror 29.
The half mirror 34 and the four-leaf photoelectric element 35 including four light receiving elements as shown in FIG.
An alignment light source 36 is arranged in the incident direction of No. 4. The outputs of the four-leaf photoelectric element 35 and the one-dimensional CCD 31 are connected to the signal processing circuit 21.

Here, the light source 7 for measuring the refractive power and the light sources 30a and 30b for illuminating the anterior segment emit light beams of different wavelengths, and the dichroic mirror 2 transmits the light beam from the light source 7 for measuring the refractive power and transmits it to the anterior eye. The dichroic mirror 15 reflects the luminous flux from the light source 7 for refractive power measurement and reflects the luminous flux from the light sources 30a and 30b for anterior ocular segment illumination. It has a wavelength division characteristic of transmitting. The light source 25 for photographing is the light sources 1a to 1d for measuring corneal shape and the light sources 30a and 30b for illuminating the anterior segment.
Emits a light beam with a wavelength different from that of the dichroic mirror 17
Has a wavelength division characteristic that reflects the light flux from the imaging light source 25 and transmits the light flux from the corneal shape measurement light sources 1a to 1d and the anterior ocular segment illumination light sources 30a and 30b.

When performing alignment of the apparatus, the anterior segment illumination light sources 30a and 30b and the alignment light source 36 are turned on while the fixation target 11 is used to fixate the eye E to be examined. Observe. The light flux from the fixation target 11 passes through the lens 10, the dichroic mirror 9, and the lens 8 and is reflected by the dichroic mirror 2 to be projected onto the fundus Er of the eye E, and the fixation target 11 is presented to the eye E. Fixation target 1
1 shows a design that is a fixation target on the optical path O2.
The examiner moves the fixation target 11 along the optical path O2 to adjust the diopter of the eye E, and causes the subject to fixate the fixation target of the fixation target 11 to determine the visual axis of the eye E. And the optical path O1.

The light fluxes emitted from the anterior ocular segment illumination light sources 30a and 30b illuminate the anterior ocular segment Ef of the eye E to be examined. From the anterior segment Ef, the light is reflected by the dichroic mirror 2, passes through the lens 8, and is reflected by the dichroic mirror 9, and the diaphragm 16, the dichroic mirror 17, the dichroic mirror 15,
The television camera 19 passes through the lens 18 and serves as the anterior segment image Pf.
And is displayed on the TV monitor 20.

The light flux from the alignment light source 36 is reflected by the half mirror 34, passes through the lens 33, is reflected by each of the dichroic mirrors 17, 9 and 2, and is reflected as a corneal reflection image Pa 'on the cornea Ec of the eye E to be examined. Form an image. The reflected light flux here is reflected by the dichroic mirror 2,
It is reflected by the dichroic mirror 9 through the lens 8,
Further, after passing through the diaphragm 16, the light is reflected by the dichroic mirror 17, passes through the lens 33, passes through the half mirror 34, and is converted into a corneal reflection image Pa as shown in FIG.
Is received by. The light reception signal obtained here is taken into the signal processing circuit 21, and the position of the corneal reflection image Pa is obtained from the light reception amount ratio of the four light receiving elements of the four-leaf photoelectric element 35, and the three-dimensional position of the device is determined. Calculated and this result is used as an alignment mark AM consisting of two cross images on the TV monitor 2
It is projected on 0.

Furthermore, the signal processing circuit 21 also projects a spot-shaped reference mark SM representing the optical path O1 on the television monitor 20. A part of the light reflected by the alignment light source 36 on the cornea Ec passes through the dichroic mirror 17, is captured by the television camera 19 as a cornea reflection image Pa, and is displayed on the television monitor 20. The examiner is this TV monitor 20
While observing, align the device.

In the television monitor 20, the deviation of the two cross images of the alignment mark AM represents the deviation from the working distance in the optical path O1 direction.
The deviation from the SM represents the magnitude and direction of the deviation in a plane perpendicular to the optical path O1. While observing the television monitor 20, the inspector adjusts the device in the direction of the optical path O1 to match the two cross images of the alignment mark AM, and also adjusts the device in a plane perpendicular to the optical path O1 to display the alignment mark AM. Align the center of the cross with the fiducial mark SM. When the alignment is completed, the corneal reflection image Pa is aimed at the four-leaf photoelectric element 35 and comes to be positioned at the center thereof. Therefore,
In the signal processing circuit 21, the received light signals of the four-leaf photoelectric element 35 are sequentially captured, and the aiming and received light positions of the corneal reflection image Pa are monitored to determine whether or not the alignment is completed.
It is also possible to start the measurement / imaging automatically.

At the time of measuring the refractive power, the light beam emitted from the light source 7 for measuring the refractive power passes through the lens 6, the central aperture stop 5, the aperture of the perforated mirror 4, the objective lens 3 and the dichroic mirror 2, and then the eye E to be inspected. It is projected as dots on the fundus Er. Fundus
The reflected light flux at Er returns through the same optical path O1 and has a perforated mirror 4
Is reflected by the 6-hole stop 12, divided into 6 light beams by the 6-hole diaphragm 12, passed through the separation prism 13, the lens 9, reflected by the dichroic mirror 15, passed through the lens 18, and picked up by the television camera 19 as six small circular spot images. The light is received by the element. This received light signal is taken into the signal processing circuit 21, and the internal computer analyzes the respective light receiving positions of the six spot images to obtain the refractive power of the eye E to be inspected. At this time, it is preferable that the anterior ocular segment illumination light sources 30a and 30b be turned off.

When measuring the corneal shape, the light fluxes from the corneal shape measuring light sources 1a to 1d are focused on the cornea Ec of the eye E to be examined. This reflected light beam is reflected by the dichroic mirror 2, passes through the lens 8, and is reflected by the dichroic mirror 9, passes through the diaphragm 16, the dichroic mirror 17, the dichroic mirror 15, and the lens 18, and then the television camera 1
The image pickup device 9 receives the light as four small circular spot images. The received light signal obtained here is taken into the signal processing circuit 21, and the internal computer calculates the radius of curvature of the cornea Ec from the positional relationship of the spot images. In this case, it is desirable that the anterior segment illumination light sources 30a and 30b be turned off.

When photographing a corneal endothelial cell, a photographing light source 25
The light flux emitted from the laser beam passes through the slit plate 24 and the lens 23 and is projected in a slit shape on the cornea Ec of the eye E to be examined. This reflected light flux passes through the lens 26 and is split into two directions by the light flux splitting member 27. The light flux transmitted through the light flux splitting member 27 is reflected by the mirror 29 through the slit plate 28, passes through the lens 32, is reflected by the dichroic mirror 17, passes through the dichroic mirror 15 and the lens 18, and is transmitted to the television camera 19 as a corneal endothelial cell image. It is imaged. On the other hand, the light beam reflected by the light beam splitting member 27 is a one-dimensional CC as a slit image.
The light is received by D31. The slit plate 28 serves to remove the reflected light generated on the cornea Ec and the surface.

Here, the slit plate 24 is slit in a direction perpendicular to the paper surface, and the one-dimensional CCD 31 has light receiving elements arranged in parallel on the paper surface, so that the slit image and the one-dimensional CCD 31 are substantially orthogonal to each other. Therefore, a part of the slit image is received by the one-dimensional CCD 31. Therefore, when the shooting depths match, the slit image is a one-dimensional CC.
Light is received by the light receiving element in the center of D31, but if the depth of field is shifted, depending on the magnitude and direction of the shift,
The slit image is received off the center of the one-dimensional CCD 31. Therefore, the signal processing circuit 21 takes in the received light signal of the one-dimensional CCD 31 to obtain the deviation of the slit image and the direction thereof, and displays the result as the separation of the two cross images of the alignment mark AM on the television monitor 20 again. While observing the television monitor 20, the examiner again fine-adjusts the optometry apparatus in the optical path O1 direction so that the cross images of the alignment marks AM match.

In this way, the corneal reflection image Pa from the alignment light source 36 is detected to perform the primary alignment, and the slit image from the photographing light source 25 is detected to again use the alignment mark AM to perform the secondary alignment. Since the alignment is performed as described above, it is possible to improve the alignment accuracy at the time of photographing a corneal endothelial cell.

The light beam may be split by using a switching mirror instead of the dichroic mirror 17. In this case, first retract the switching mirror from the optical path O4,
An image of the anterior segment image Pf is captured by the TV camera and the TV monitor 20
Then, the first alignment is performed. When this alignment is completed, the switching mirror is automatically inserted into the optical path O4, a corneal endothelial cell image is captured by the television camera 19 and displayed on the television monitor 20, and the secondary alignment is performed.

When recording an image of corneal endothelial cells, the light sources 1a to 1d, 7, 30a, 30 other than the photographing light source 25 are used.
b and 36 are extinguished, and the strobe light of the photographing light source 25 is caused to emit light. Only the corneal endothelial cell image is captured by the television camera 19 and displayed on the television monitor 20.

In the present embodiment, the corneal reflection image Pa from the alignment light source 36 is detected by the four-leaf photoelectric element 35 to perform the alignment, but the refractive power measuring light source 7 may be used instead. Further, instead of reflecting the cornea reflected light from the alignment light source 36 by the dichroic mirror 17 and guiding it to the four-leaf photoelectric element 35, a dichroic mirror is separately provided on the optical path O1 so as to lead to the four-leaf photoelectric element 35. You can also

Since the accuracy of alignment increases in the order of refractive power measurement, corneal shape measurement, and corneal endothelial cell imaging, if the detection accuracy of alignment is increased in this order in the signal processing circuit 21, measurement / imaging can be performed smoothly and automatically. It becomes possible to do it. Particularly, during the refractive power measurement and the corneal shape measurement, only the corneal reflection image Pa of the alignment light source 36 is detected to perform the alignment. Therefore, if the alignment detection accuracy is increased as described above, the corneal shape It is possible to more accurately adjust the position of the device to the proper working distance during measurement. For alignment in the optical axis 01 direction at the time of corneal measurement, a one-dimensional CCD using the light source 25 for photographing is used.
31 signals may be used.

When the alignment can be performed with high accuracy in this way when measuring the shape of the cornea, the light source for cornea measurement 1
Since the light beams from a to 1d do not have to be parallel to each other,
No lens is required to collimate the light flux. For example,
As shown in FIG. 2, four corneal shape measurement light sources 1 are arranged on the circumference.
When a ring-shaped light source is used instead of arranging a to 1d, it is possible to remarkably simplify the lens configuration, and the diaphragm 16 for measuring the corneal shape is not required, and the diameter of the lens 8 is reduced. Can be made smaller.

The four corneal shape measuring light sources 1a to 1 are provided.
The corneal shape measurement and the corneal endothelium imaging may be performed while appropriately selecting the wavelengths of d and sequentially illuminating each of them to present the eye E as the peripheral fixation lamp. In this case, the radius of curvature of the cornea Ec and the corneal endothelium image can be recorded for the same site, so more effective diagnostic data can be obtained for the eye E to be examined.

In the present embodiment, the television camera 19 is used not only for observing the anterior segment of the eye but also for measuring the refractive power and the corneal shape. However, a light receiving element and a light beam splitting unit are separately provided for measuring the refractive power and the corneal shape. It is also possible to provide a member and guide each measurement light beam to the light receiving element via the light beam dividing member.

FIG. 4 is a block diagram of the second embodiment.
A ring-shaped light source 41 for measuring corneal shape centering on O8 faces the eye E to be inspected, and a lens 42, a half mirror 43, a diaphragm 44, and a television camera 45 are sequentially arranged in an optical path O8 behind the eye E, and a half mirror. An alignment light source 46 is arranged in the incident direction of 43. Further, on the optical path O9 that is inclined with respect to the optical path O8, the lens 4 from the eye E side is examined.
7, slit plate 48 conjugated with cornea Ec, light source 49 for photographing,
The lens 50 and the illumination light source 51 are arranged in sequence, and the optical path O8
On the optical path O10 which is symmetrical with respect to the optical path O9, the lens 52 and the two-dimensional CCD 53 are sequentially arranged from the eye E side.

The light beam from the alignment light source 46 is reflected by the half mirror 43, passes through the lens 42, and forms a cornea reflection image Pa 'on the cornea Ec of the eye E to be examined. This reflected light flux returns through the same optical path, passes through the half mirror 43 and the diaphragm 44, and is received by the image pickup element of the television camera 45 as a cornea reflection image Pa. The computer detects a video signal in the vicinity of the center of the image pickup element of the television camera 49, obtains the deviation of the corneal reflection image Pa from the sighting and the optical path O8, and determines the optical path O8 direction and the optical path O8.
Determine the position of the device in the plane perpendicular to the
It is displayed on the TV monitor as the alignment mark AM as shown in. The examiner performs alignment while observing the television monitor. At this time, the alignment light source 46
If the wavelength of is properly selected, the alignment light source 46 can be presented to the eye E as a central fixation lamp. The position in the direction of the optical axis 08 is C by the illumination light source 51.
It may be obtained from CD53.

The light beam emitted from the ring-shaped light source 41 for measuring corneal shape is projected on the cornea Ec of the eye E to be examined. The reflected light flux passes through the lens 42, the half mirror 43, and the diaphragm 44, and is received by the image pickup element of the television camera 45 as a ring image. The obtained video signal is taken into a built-in computer, the shape of the ring image is analyzed, and the radius of curvature of the cornea Ec is obtained.

The luminous flux emitted from the illumination light source 51 is reflected by the lens 5
0 forms an image near the photographing light source 49, and the slit plate 4
8. It passes through the lens 47 and is projected in a slit shape into the cornea Ec of the eye E to be examined. Part of the reflected light flux here is the lens 4
2, TV camera 4 through half mirror 43 and diaphragm 44
5, and a part of the other light flux passes through the lens 52 and is received as a corneal image Pc by the two-dimensional CCD 53 as shown in FIG. The computer detects the received signal on the central dividing line m of the two-dimensional CCD 53 and monitors the imaging depth in the optical path O8 direction based on the light receiving position of the corneal image Pc on the central dividing line m. The examiner finely adjusts the apparatus so that the corneal image Pc is positioned symmetrically with respect to the perpendicular bisector of the center dividing line m.

When recording a corneal endothelial cell image, the image on the television monitor 20 is switched from the television camera 45 to the image on the CCD 53, that is, the endothelial cell image as shown in FIG. When the positions are well aligned, only the photographing light source 49 emits light, the corneal endothelial cell image is captured by the CCD 53, and the image is displayed on the television monitor 20.

[0035]

As described above, the optometry apparatus according to the first and second inventions can measure the shape of the cornea and image the corneal endothelial cells with a single apparatus, thus shortening the examination time. The space occupied by the device is also reduced. Further, the first invention has a common fixation target, and the second invention uses the common position detection system to align the corneal shape measuring means and the corneal imaging means. It is possible to measure the radius of curvature and take an image.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a light source for measuring corneal shape.

FIG. 3 is an explanatory diagram of a four-leaf photoelectric device during alignment.

FIG. 4 is a configuration diagram of a second embodiment.

FIG. 5 is an explanatory diagram of a two-dimensional CCD capturing a corneal image.

[Explanation of symbols]

 1, 41 Corneal shape measurement light source 7 Refractive power measurement light source 11 Fixation target 19, 45 TV camera 20 TV monitor 21 Signal processing circuit 24, 28, 48 Slit plate 25, 49 Imaging light source 30 Anterior eye light source 31 one-dimensional CCD 35 four-leaf photoelectric element 36 alignment light source 51 illumination light source 53 two-dimensional CCD

Claims (5)

[Claims] 1. A corneal shape measuring means for projecting a light flux from a light source on a circumference centered on an optical axis onto a cornea of an eye to be inspected and receiving reflected light from the cornea with a light receiving element to obtain the shape of the cornea. A cornea photographing means for projecting slit light from a direction inclined to the optical axis to a portion on the optical axis of the cornea, and receiving reflected light with a light receiving element from a direction symmetrical with the projection direction with respect to the optical axis; An optometry apparatus having a fixation target having a fixation target which is commonly used for the shape measuring unit and the cornea photographing unit. 2. The optometry apparatus according to claim 1, wherein the light receiving element of the cornea photographing unit photographs corneal endothelial cells of an eye to be examined. 3. The optometry apparatus according to claim 1, further comprising the corneal reflected light detecting means, and aligning the corneal shape measuring means based on a signal obtained by the corneal reflected light detecting means. 4. A position detecting means for projecting a light beam to a predetermined position on the cornea of an eye to be inspected and receiving the reflected light beam to detect the position of the device, and a light source on a circumference centered on the optical axis. A corneal shape measuring device that projects the light flux from the eye onto the cornea of the eye to be examined and receives the reflected light with a light receiving element to obtain the shape of the cornea of the eye to be examined, and a portion on the optical axis of the cornea from the direction inclined to the optical axis. An ophthalmologic apparatus comprising: a corneal photographing unit that projects slit light onto the eye and captures a corneal image from a direction symmetrical with the projection direction with respect to the optical axis. 5. The optometry apparatus according to claim 4, wherein the position detecting unit aligns the corneal shape measuring unit and the corneal photographing unit.