JPH08280623A - Ophthalmologic apparatus - Google Patents

Abstract

PURPOSE: To eliminate adjusting action of eyes to be inspected by a Placido pattern by providing a pattern projection means with an infrared projection means to project a Placido pattern on a cornea using infrared rays while a photodetecting means is so arranged to be sensitive to an infrared reflection image from the cornea. CONSTITUTION: An infrared light emitting diode of a Placido pattern projection system 100 and infrared light emitting diodes 122 and 132 of a mark projection optical system 120 are lit by manipulating an operating section and a light source 21 of a scale projection system 20 is turned ON. Luminous fluxes of a ring reflection image and a mark reflection image by reflection on a cornea EC of an eye to be inspected to form images on an area sensor 18 together with an anterior ocular segment image and the ring reflection image and the mark reflection image are displayed on a monitor together with the anterior ocular segment image. With the light source 21 of the scale projection system 20 ON, a scale image is formed on the area sensor 18 and the scale image is also displayed on the monitor. Thus, an inspector establishes an alignment viewing the scale image and the ring reflection image displayed on the monitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus capable of measuring the refractive power of an eye and the corneal shape of an eye to be examined.

[0002]

2. Description of the Related Art Conventional ophthalmologic devices include, for example, an autorefractometer (eye refractometer) for objectively measuring the refractive power of the eye and an autokeratometer (corneal curvature measuring device) for measuring the curvature of the cornea of the eye to be examined. There is. Both of these devices provide the data necessary for the ophthalmologist to make an appropriate diagnosis.

By the way, in recent years, the installation area of the device has been reduced,
Attempts have been made to combine a plurality of devices that perform different measurements in order to shorten the inspection time and reduce the device cost. For example, a combination of the above-mentioned autorefractometer and autokeratometer has been attempted. With this combination, the eye refractive power and the corneal curvature can be measured with a single device, which facilitates the examination.

On the other hand, it is necessary to precisely measure the shape of the cornea before performing cataract surgery or other surgery for inserting a knife into the cornea. For this reason, it is required to measure the shape of the cornea in a wider range as compared with the autokerato that measures the corneal curvature.

As an apparatus for precisely measuring the corneal shape, a placido pattern, that is, a concentric circular pattern by visible light is projected onto the cornea of the eye to be inspected, and the reflection shape from the cornea of the eye to be inspected in this concentric circular pattern is projected. There is known a corneal shape measuring apparatus which recognizes how much the shape of the projected pattern changes and how much the shape of the cornea changes based on the shape change.

[0006]

However, in the conventional corneal shape measuring apparatus, in addition to projecting the placido pattern by visible light onto the cornea of the eye to be inspected, the placido pattern is very large. When measuring one of them, a part of the outer pattern of the Placido pattern can be recognized by the eye to be examined, which is not measuring the other, which attracts the subject's attention. It should be noted that the placido pattern on the pattern board was visible even when the placido pattern was not projected, which attracted the subject's attention.

This is because the subject's line of sight is not stable, which is inconvenient in measuring the shape of the cornea. That is, in the apparatus for evaluating the regular reflection image of the cornea, when the line of sight changes in this way, the appearance position of the pattern image on the cornea changes,
The shape of each part of the cornea did not appear, which was not preferable.

Further, conventionally, since there have been few operations on the cornea of the eye to be inspected, the corneal shape measuring apparatus has been used alone, and a combination with an autorefractometer has not been considered.

However, in recent years, cataract surgery and other operations for inserting a knife into the cornea have become very popular, and in consideration of reduction of the installation area of the device, reduction of inspection time, reduction of the device cost, etc. Therefore, it has been attempted to combine a cornea shape measuring device and an autorefractometer.

However, as in the corneal shape measuring apparatus as described above, since the placido pattern of the pattern plate is visible, when the subject's attention is ventilated, an adjusting action of the subject's eye occurs, so this placido If the refractive power of the subject's eye is also measured at the same time when the corneal shape is measured using the pattern, there is a possibility that the refractive power cannot be accurately measured.

Therefore, a main object of the present invention is to provide an ophthalmologic apparatus in which the action of adjusting the eye to be inspected by the Placido pattern does not occur.

Another object of the present invention is to provide an ophthalmologic apparatus which does not cause the accommodation action of the eye to be inspected by the Plactide pattern when measuring the eye refractive power even if the configurations of the autorefractometer and the corneal shape measuring apparatus are combined. .

[0013]

In order to achieve the above-mentioned main object, in the invention of claim 1, the plactide pattern is projected onto the cornea by the pattern projection system, and the reflected light of the plactide pattern on the cornea is received by the optical system. In the ophthalmologic apparatus in which the shape of the cornea is obtained in a wide range from the output of the light receiving means by the calculating means, the pattern projection means projects the plactide pattern onto the cornea using infrared light. In addition to the infrared projection means, the light receiving means is an ophthalmologic apparatus having sensitivity to an infrared reflection image from the cornea.

In order to achieve the above-mentioned other object, the invention of claim 2 is provided with a measurement light beam projection optical system for projecting a measurement light beam for eye refraction measurement onto the fundus of the eye to be inspected, and the light beam reflected from the fundus is reflected. An ophthalmologic apparatus which is provided with a light receiving optical system for guiding to a light receiving means, and which is provided with a computing means for obtaining an eye refractive power of the eye to be inspected based on an output from the light receiving means. A placido pattern projection system for projecting an outer placido pattern is provided, and the computing means is an ophthalmologic apparatus for computing a corneal shape from a reflection image of the placido pattern by the cornea.

According to a third aspect of the present invention, the placido pattern has a size facing both eyes in a state where the center of the placido pattern is aligned with the optical axis of one of the two eyes of the subject. It is characterized by being formed.

According to a fourth aspect of the present invention, the plactide pattern projection system comprises a plactide pattern plate, and a visible cut or a filter having a low visible transmittance is arranged between the eye to be examined and the plactide pattern plate. And

The invention of claim 5 is characterized in that an antireflection coating layer is provided on the surface of the filter on the eye side.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ophthalmologic apparatus according to the present invention, which is integrated with a corneal shape measuring apparatus for projecting a Placido pattern (that is, a Placido ring pattern) to measure a corneal shape, will be described below with reference to the drawings.

FIG. 4 (c) shows the relationship between the ophthalmologic apparatus 1 according to the present invention and the subject 2. This ophthalmologic apparatus 1 includes a base 3, a device book 4 mounted on the base 3 so as to be movable back and forth and left and right, and a joystick lever 5 mounted on the device body 4 to move the device body 4 back and forth and left and right.
(Operating lever), frame 6 attached to the front end of the base 3, chin rest 7 provided on the frame 6 so as to be movable up and down, and operation knob for holding the frame 6 to move the chin rest 7 up and down. Have eight.

As shown in FIG. 1, the apparatus main body 1 includes an anterior ocular segment observing optical system 10 for observing the anterior ocular segment of the eye E and a fixation target projection optics for projecting a fixation target on the eye E. A system 50, a measurement projection optical system 70 that projects measurement light for measuring eye refractive power onto a fundus Er of the eye E, a light receiving optical system 90 that receives measurement light reflected by the fundus Er, and an eye to be examined. Cornea E
It is provided with a placido pattern projection system 100 for projecting a placido pattern for measuring the shape of the cornea on c, and a mark projection optical system 120 for projecting a mark for detecting the working distance toward the cornea Ec.

The anterior segment observation optical system 10 includes an objective lens 11
, A dichroic mirror 60, a mirror 13, a relay lens 14, a dichroic mirror 15, a relay lens 16, an imaging lens 17, and C as a light receiving means.
An area sensor (imaging device) 18 including a CD is provided.

Further, the anterior segment observation optical system 10 is provided with a scale projection system 20 for forming a cross-shaped scale image P (see FIG. 7) on the area sensor 18. The scale projection system 20 includes a light source 21, a condenser lens 22,
A scale plate 23 having a scale (not shown) is provided, and the light emitted from the light source 21 is condensed by the condenser lens 22.
The scale plate 23 irradiates the scale plate 23 and the cross-shaped luminous flux reaches the imaging lens 17 via dichroic mirrors 15, 92 (described later). A scale image P is formed on the image 18. Then, the scale image P is displayed on the monitor 202 (see FIG. 7) together with the anterior segment.

The fixation target projection optical system 50 includes a light source 51, an infrared cut filter F, and a condenser lens 52.
, Fixation target plate 53, relay lens 54, and mirror M1
, Dichroic mirror 55, relay lens 56
, Mirror M2, relay lens 57, mirror M3,
The dichroic mirror 60 and the objective lens 11 are provided. The fixation target plate 53 is at a conjugate position with the fundus Er, and a mark (not shown) serving as a fixation target is formed on the fixation target plate 53, and this mark is projected on the fundus Er. By projecting this mark, the eye E to be inspected is directed in a predetermined direction and is viewed as a cloud.

Measurement projection optical system 70 (measurement light beam projection system)
Is a light source 71, a condenser lens 72, a conical prism 73, a ring aperture plate 74 having a ring aperture (not shown), a relay lens 75, a mirror 76, a relay lens 77, and a dichroic mirror 78. The mirror 79, the dichroic mirror 80, the dichroic mirror 60, and the objective lens 11.

The conical prism 73 is a condenser lens 7
Light from the light source 71 collected by the ring aperture plate 7
The light is focused on the ring opening of No. 4. The ring aperture plate 74 and the fundus Er are in a conjugate position, and the ring aperture plate 74 is
Ring image (not shown) by the light flux that passes through the ring aperture of
Is projected onto the fundus Er.

The reflected light flux of the ring image projected on the fundus Er is the objective lens 11, the dichroic mirror 60, the dichroic mirror 80, the mirror 79, the dichroic mirror 78, the dichroic mirror 91, and the relay lens 5.
An image is formed on the area sensor 18 via the mirror 7, the mirror M2, the relay lens 56, the dichroic mirror 55, the dichroic mirror 92, and the imaging lens 17 to form a ring image.
An arithmetic and control unit 20 for calculating the eye refractive power from this ring image, which will be described later.
3 calculates and obtains.

Then, the light receiving optical system 90 includes the objective lens 1
1, dichroic mirror 60, dichroic mirror 80, mirror 79, dichroic mirror 7
8, 91, a relay lens 57, a mirror M2, a relay lens 56, dichroic mirrors 55, 92, an image forming lens 17, and an area sensor 18.

As shown in FIG. 2, the placido pattern projection system 100 includes a disc-shaped pattern plate 101 (placido pattern plate), a plurality of infrared light emitting diodes 102 (light source (light projection means)), and a visible cut. It is composed of a filter 103 and the like. The plurality of light emitting diodes 102
Are attached to the PC board 104 (printed circuit board) along rings C1 to C9 (light transmitting ring pattern) described later.

Moreover, even if the infrared light emitting diode 102 projects a placido pattern (that is, a plurality of concentric ring (concentric circle) transparent ring patterns having different diameters) on the pattern plate 101 onto the eye to be examined, Because it is projected with infrared light, it does not ventilate the attention of the subject's eye.

A white reflective layer (not shown) is provided on the surface of the PC board 104 on which the infrared light emitting diode 102 is provided (the surface facing the pattern board 101). This reflective layer can be easily formed by applying a white coating on the PC board 104 (printed board) using a printing means for performing white silk printing on the PC board 104 (printed board) for the purpose of explaining the parts.

The visible cut filter 103 may be replaced with a filter having a low visible transmittance. An antireflection coating layer 103a is applied to the surface of the visible cut filter 103 on the eye E side. Moreover, such a visible cut filter 103 is used for the eye E and the pattern plate 10 to be inspected.
1 is provided to prevent the Placido pattern of the pattern plate 101 from being seen by outside light such as indoor illumination light, and the antireflection coating layer 103a prevents the subject's confidence from being visible. It is prevented from reflecting in the image.

Thus, in the eye refraction measurement, the placido pattern and the image of the subject do not attract the attention of the subject's eye and the accommodative action of the subject's eye does not occur, and accurate eye refraction can be measured. Become.

A diffusion plate capable of transmitting and diffusing light is used as the base of the pattern plate 101. This pattern board 10
1 is attached to the cylindrical portion 4a at the front end of the device body 4 as shown in FIG. 4 (c), and as can be seen from FIGS. 1 and 2, the eye EC (one eye) is In a state where it is aligned with the optical axis O of the apparatus, the portion near the edge is the other eye (opposite eye) E
It is formed so as to face C '. As a result, both eyes (both eyes) EC, EC ′ of the subject 2 are exposed to the pattern plate 10
Facing 1.

Moreover, the pattern plate 101 has a structure shown in FIG.
As shown in FIG. 3, a circular hole 101a is opened in the center, and nine concentric rings C1 to C9 (light-transmitting ring patterns) concentrically provided around the hole 101a are formed.

As shown in FIGS. 4 (a) and 4 (b), the rings C1 to C9 are light-shielding portions D1 to D9 composed of a white paint layer 101c (white reflective layer) and a black paint layer 101d (black layer). Formed on the surface 101b of the pattern plate 101 at concentrically spaced intervals so that the light-shielding portions D1 to D9 are formed between adjacent ones (that is, portions where the paints 101c and 101d are not applied). Is.

As a result, the plurality of infrared light emitting diodes 1
Of the light emitted from 02, the light traveling toward the rings C1 to C9 is generated by the action of the light shielding portions D1 to D9 and the PC board 104, as shown in FIG.
Diffusion and reflection are repeated as indicated by L, L1 and L2 in (b). That is, the effect of this diffusion and reflection will be described using the ring C1 and one infrared light emitting diode 102. From the infrared light emitting diode 102 to the ring (transparent ring pattern).
Most of the light flux L directed to C1 passes through the ring C1 as diffused light L1 when passing through the pattern plate 101 which is a diffuser, and the rest is reflected to the PC plate 104 side as reflected light L2. The reflected light L2 and the light directly traveling from the infrared light emitting diode 102 to the light shielding portions D1 to D9 are reflected as the reflected light L3 by the PC board 104, and then the white paint layer (white reflective layer) 101c and the PC board 104. After being reflected a number of times between and, the image is projected from one of the rings C1 to C9 to the eye E side. With this, the light emitted from the infrared light emitting diode 102 is used for projecting a placido pattern (placido ring pattern) without waste, and uniform illumination light can be projected on this placido pattern.

In this embodiment, the pattern plate 101 is formed of the diffusion plate, but the present invention is not limited to this. For example, a pattern plate and a diffusion plate (not shown)
May be separately formed and overlapped with each other, and the light-shielding portions D1 to D9 described above may be formed between the pattern plate and the diffusion plate.

On the pattern plate 101, two circular marks Q1 and Q2 arranged in the horizontal direction are formed.
These marks Q1 and Q2 are also paints 101c and 101d as above.
Is the unpainted part.

The infrared light emitting diode 102 is composed of each ring C.
1 to C9 and along each ring C1 to C9,
As shown in FIG. 5, they are attached to the PC board 104 at predetermined intervals. The PC board 104 is fixed to the unit base 105, and the surface 104a of the PC board 104 is white and reflects infrared light forward. The unit base 105 is fixed to the lens barrel portion 106 holding the objective lens 11. 107 is a PC board 104 and a visible cut filter 103
It is a reflector placed between and.

The mark projection optical system 120 includes the pattern plate 1
01 and the pair of parallel projection units 121 and 131 (see FIG. 1) arranged on the same horizontal plane.
Reference numeral 1 denotes a lens barrel 125 including infrared light emitting diodes 122 and 132, and projection lenses 123 and 133 which convert the infrared light emitted from the infrared light emitting diodes 122 and 132 into parallel light beams and emit the parallel light beams toward the marks Q1 and Q2. , 135 respectively.

Optical axis 1 of parallel projection units 121 and 131
21a and 131a pass through the marks Q1 and Q2 and the cornea Ec of the eye to be examined.
The marks Q1 and Q2 are projected from the infinity distance toward the cornea Ec of the eye to be inspected by the parallel light beams from the projection lenses 123 and 133. That is, the marks Q1 and Q2 from different distances from the pattern plate 101
Is projected onto the cornea Ec of the eye to be examined.

Case 125 of parallel projection unit 121
Is inserted into a recess 104c of a hole 104b formed at the center of the PC board 104 (printed circuit board) and is fixed to the lens barrel 106 with a screw N. The parallel projection unit 131 is also fixed to the lens barrel portion 106 as described above.

FIG. 6 is a block diagram showing the configuration of the control system of this ophthalmologic apparatus. In FIG. 6, 201 is a frame memory for storing an image received by the area sensor 18, and 20 is a frame memory.
Reference numeral 2 is a monitor for displaying an image received by the area sensor 18, and 203 is a corneal shape calculated from each ring image Ca to Ci (see FIG. 7) of the image stored in the frame memory 201, and the ring image Cb is calculated. Diameter L1 and mark image Qa,
This is an arithmetic control device (arithmetic means) that detects the working distance of the apparatus main body from the ratio to the distance L2 between Qb and corrects the corneal shape based on this working distance. The arithmetic and control unit 203 has functions as a corneal shape calculating means, a working distance detecting means, and a correcting means.

Then, the Placido pattern projection system 100
, Mark projection optical system 120, and anterior segment observation optical system 10
And the arithmetic and control unit 203 constitute a cornea shape measuring device for measuring the shape of the cornea.

Further, the arithmetic and control unit 203 is configured so that the printer 206 and the recording unit 20 can be operated based on the operation of the operation unit 205.
7, controlling the light sources 21, 51, 71, 102, 122, 132 and the like. Further, the arithmetic and control unit 203 controls the fundus Er
The eye refractive power is calculated from the ring image projected on the eye.

Next, the operation of the above embodiment will be described.

By operating the operation unit 205, the infrared light emitting diode 102 of the Placido pattern projection system 100 and the infrared light emitting diodes 122 and 132 of the mark projection optical system 120.
Lights up. Further, the light source 21 of the scale projection system 20 is turned on.

When the infrared light emitting diode 102 is turned on, a ring luminous flux of infrared light is emitted from the rings C1 to C9 of the pattern plate 101 through the visible cut filter 103,
This ring luminous flux is projected onto the cornea Ec of the eye to be examined and the ring C1
A reflected image of C9 is formed.

Similarly, the infrared light emitting diodes 122, 13
The infrared light emitted from 2 is converted into a parallel light beam by the projection lens and irradiates the marks Q1 and Q2, and is converted into a circular parallel light beam by the marks Q1 and Q2, and is projected onto the cornea Ec of the eye to be inspected to generate the marks Q1 and Q2. A reflected image is formed by.

Then, the light fluxes of the ring reflection image and the mark reflection image due to the reflection of the cornea Ec of the eye to be examined are the objective lens 1
1, dichroic mirror 60, mirror 13, relay lens 14, dichroic mirror 15, relay lens 16,
The image is formed on the area sensor 18 together with the anterior segment image through the dichroic mirror 92 and the image forming lens 17. Then, as shown in FIG. 7, the anterior segment image Ea is displayed on the monitor 202.
Together with the ring reflection images Ca to Ci and the mark reflection image Qa,
Qb is displayed.

Since the scale image is formed on the area sensor 18 by turning on the light source 21 of the scale projection system 20, the scale image P is also displayed on the monitor 202.

While inspecting the scale image P and the ring reflection image Ca displayed on the monitor 202, the examiner moves the apparatus main body vertically and horizontally so that the intersection point Pa of the scale image P is located at the center of the ring reflection image Ca. Then, alignment in the XY directions is performed. Further, the apparatus main body is moved in the front-rear direction so that the mark reflection images Qa and Qb and the ring reflection image Cb substantially coincide with each other to perform Z-direction alignment.

Since the marks Q1 and Q2 are projected from infinity, the distance L2 between the mark reflection images Qa and Qb is constant regardless of the distance in the Z direction of the apparatus body, while the ring reflection image is Since the diameter L1 of Cb varies depending on the distance in the Z direction, by comparing the distance L2 between the mark reflection images Qa and Qb shown in FIG. 7 and the diameter L1 of the ring reflection image Cb, the alignment in the Z direction is performed. Can be adjusted and the working distance can be determined.

In this way, the scale image P is displayed on the monitor 202.
Is displayed, alignment can be performed by looking at the scale image P, which is very easy to perform.

After these alignments are completed, when the measurement switch (not shown) of the operation unit 205 is pressed, the image shown in FIG. 7 is displayed in the frame memory 201 in step 2 shown in FIG.
Is stored.

The arithmetic control unit 203 is connected to the frame memory 20.
The ratio between the diameter L1 of the ring reflection image Cb stored in 1 and the distance L2 between the mark reflection images Qa and Qb is calculated, and the working distance of the apparatus main body is calculated from this ratio. Then, the difference between this working distance and the preset working distance, that is, the alignment error in the Z direction is calculated (step 3). Whether or not this error is within a predetermined range is determined in step 4, and if YES, the corneal shape is obtained from the ring reflection images Ca to Ci stored in the frame memory 201, and further,
The corneal shape is corrected according to the above error (step 5). By this correction, an accurate corneal shape can be obtained even if the alignment in the Z direction is not accurately performed.

The corneal shape before correction, the corneal shape after correction, and the working distance are displayed on the monitor 202, and these data are printed out by the printer 206.
It is recorded in the recording device 207 together with the image shown in FIG. 7 (step 6).

As described above, even if the alignment in the Z direction is not accurately performed, the alignment error is obtained, and the corneal shape is corrected based on the error to obtain the accurate corneal shape. Therefore, the working distance is short. However, it is possible to set a wide allowable range of alignment and to obtain an accurate corneal shape.

When the eye refractive power is measured, the light source 51 of the fixation target projection optical system 50 is turned on to direct the eye E to be examined in a predetermined direction and to make a cloudy vision. Then, the light source 71 of the measurement projection optical system 70 is turned on to project a ring image (not shown) on the fundus Er, and this ring image is objective lens 11, dichroic mirror 60, dichroic mirror 80, mirror 79, dichroic mirror 78. , Dichroic mirror 91, relay lens 57, mirror M2, relay lens 56,
Dichroic mirror 55, dichroic mirror 92,
Form an image on the area sensor 18 via the imaging lens 17,
The arithmetic control device 203 calculates the eye refractive power from this ring image.

In the above embodiment, the placido pattern projection system 100 is integrally provided in the eye refractive power device.
For example, the placido pattern projection system 100 may be integrally provided in an ophthalmologic apparatus such as a fundus camera, or a corneal shape measuring apparatus that measures only the corneal shape based on the Placido pattern by removing the optical system for eye refraction measurement from the above apparatus. May be

In the above embodiment, the frame memory 2
Although the scale image P is also stored in 01, the light source 21 of the scale projection system 20 may be turned off when the measurement switch is pressed so that the scale image P is not stored in the frame memory 201. By doing so, the scale image P does not get in the way when calculating the corneal shape and working distance. Further, the marks Q1 and Q2 are projected from the infinite distance toward the cornea Ec of the eye to be examined.
The marks Q1 and Q2 may be projected onto the cornea Ec of the eye to be examined from a distance different from 01.

In the above embodiment, when the measurement switch is pressed, an image is captured in the frame memory 201 to calculate the corneal shape and working distance. However, without pressing the measurement switch,
It is also possible to always capture an image, calculate the working distance, and when the working distance is within an appropriate range, calculate and output the corneal shape.

[0063]

As described above, according to the first aspect of the invention, the plactide pattern is projected onto the cornea by the pattern projection system, and the reflected light of the plactide pattern on the cornea is guided to the light receiving means by the light receiving optical system. In the ophthalmologic apparatus configured to obtain the shape of the cornea from the output of the light receiving means in a wide range by the calculation means, the pattern projection means has an infrared projection means for projecting a Placido pattern onto the cornea using infrared light. Along with that, since the light receiving means is configured to have sensitivity to an infrared reflection image from the cornea, since the placido pattern due to infrared light is not visible to the eye to be inspected, when measuring the corneal shape, the eye to be inspected by the placido pattern is measured. It is possible to obtain a stable line of sight and thus an improvement in measurement accuracy.

Further, in the invention of claim 2, a measurement light beam projection optical system for projecting a measurement light beam for eye refraction measurement is provided on the fundus of the eye to be inspected, and the light receiving optical system for guiding the reflected light beam from the fundus to the light receiving means is provided. An ophthalmologic apparatus which is provided with an arithmetic means for obtaining an eye refractive power of the eye to be inspected based on an output from the light receiving means, wherein a Placido pattern for projecting an infrared Placido pattern toward the cornea of the eye to be inspected. Since the projection system is provided and the computing means is configured to compute the corneal shape from the reflection image of the Placido pattern by the cornea, the Placido pattern by infrared light is invisible to the eye to be inspected. Accurate measurement of the eye refractive power can be achieved by reducing the adjustment action of the subject's eye due to the Plactide pattern during measurement.

According to a third aspect of the present invention, the size of the placido pattern is such that the center of the placido pattern is aligned with the optical axis of one of the two eyes of the subject and the two eyes are exposed. Although it is a configuration that is formed, since the placido pattern by infrared light is not visible to the eye to be inspected, when measuring the corneal shape and eye refractive power, the stability of the line of sight of the eye to be inspected by the placido pattern, and thus the measurement accuracy An improvement is obtained.

According to a fourth aspect of the present invention, the plactide pattern projection system comprises a plactide pattern plate, and a visible cut or a filter having a low visible transmittance is arranged between the eye to be inspected and the plactide pattern plate. Therefore, the external light (visible light) from the side of the eye to be examined is absorbed by the filter before reaching the pattern plate, or hardly reaches the pattern plate. As a result, since the Placido pattern provided on the pattern plate becomes invisible to the eye to be inspected, it is possible to reduce the adjustment action of the eye to be inspected due to the Plactide pattern during the measurement of the eye refractive power, and to measure the eye refractive power accurately .

Further, according to the invention of claim 5, since the antireflection coating layer is provided on the surface of the filter on the side of the eye to be inspected, the face and eyes of the person to be examined are confident due to external light such as indoor lighting. Is no longer reflected on the surface of the filter, and the eye refracting power can be accurately measured by more reliably eliminating the adjusting action of the eye to be inspected due to the reflection image of the filter surface when measuring the eye refractive power.

[Brief description of drawings]

FIG. 1 is an optical layout diagram showing the layout of an optical system of an ophthalmologic apparatus according to the present invention.

FIG. 2 is a sectional view showing a configuration of a Placido pattern projection system.

3 is a front view showing a pattern plate of the Placido pattern projection system of FIG.

4A is an enlarged cross-sectional view showing a part of the structure of the pattern board of FIG. 3, FIG. 4B is an explanatory view showing the relationship between the pattern board and the PC board, and FIG. It is a perspective view which shows the relationship between an ophthalmologic apparatus and a subject.

FIG. 5 is a front view of a PC board showing an arrangement of infrared light emitting diodes.

FIG. 6 is a block diagram showing a configuration of a control system of the ophthalmologic apparatus.

FIG. 7 is an explanatory diagram showing an image displayed on a monitor.

FIG. 8 is a flowchart showing the operation of the ophthalmologic apparatus.

[Explanation of symbols]

 10 Anterior Eye Observation Optical System 18 Area Sensor (Light Receiving Unit) 30 Alignment Projection Optical System (Projection Optical System) 70 Measurement Projection Optical System (Measurement Light Beam Projection Optical System) 90 Light Reception Optical System 100 Placido Pattern Projection System 101 Pattern Plate (Plactide) Pattern board) 120 mark projection optical system 202 monitor 203 arithmetic and control unit (arithmetic means) E eye to be examined Ec cornea

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Yasuhisa Ishikura 75-1 Hasunumacho, Itabashi-ku, Tokyo Topcon Co., Ltd. (72) Inventor Kenji Hayashi 75-1 Hasunumacho, Itabashi-ku, Tokyo Topcon Co., Ltd. Within

Claims (5)

[Claims] 1. A pattern projection system projects a placido pattern onto a cornea, and the reflected light of the placido pattern on the cornea is guided to a light receiving means by a light receiving optical system, and the shape of the cornea is calculated from the output of the light receiving means. In an ophthalmologic apparatus adapted to obtain a wide range by means, the pattern projection means has an infrared projection means for projecting a placido pattern onto the cornea using infrared light,
The ophthalmologic apparatus, wherein the light receiving means is sensitive to an infrared reflection image from the cornea. 2. A measurement light beam projection optical system for projecting a measurement light beam for eye refraction measurement is provided on the fundus of an eye to be inspected, and a light receiving optical system for guiding a reflected light beam from the fundus to a light receiving means is provided.
It is an ophthalmologic apparatus provided with a calculation unit for obtaining the eye refractive power of the eye to be inspected based on the output from the light receiving unit, wherein a Placido pattern projection system for projecting an infrared Placido pattern toward the cornea of the eye to be inspected is Is provided,
The ophthalmologic apparatus, wherein the calculating means calculates a corneal shape from a reflection image of a Placido pattern by the cornea. 3. The plactide pattern is formed to have a size facing the two eyes in a state where the center of the plactide pattern is aligned with the optical axis of one of the two eyes of the subject. The ophthalmologic apparatus according to claim 1 or 2, characterized in that. 4. The placido pattern projection system comprises a placido pattern plate, and a visible cut or low visible transmittance filter is arranged between the eye to be examined and the placido pattern plate. Or the ophthalmologic apparatus according to 2. 5. The ophthalmologic apparatus according to claim 4, wherein an antireflection coating layer is provided on the surface of the filter on the eye side.