JP3107236B2 - Corneal diameter measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a corneal diameter.

[0002]

2. Description of the Related Art As an easiest method for measuring a corneal diameter, a method is known in which an examiner applies a ruler to a cornea of a subject and reads the scale. Further, the photographed anterior segment image of the eye to be inspected is superimposed and projected on a plurality of marks, and the plurality of marks are symmetrically moved left and right about the center of the anterior segment display monitor, and the amount of movement There is also known an apparatus for measuring the corneal diameter from the eye.

[0003]

In the former method, there is a problem that an unnecessary feeling of pressure is given to the subject and the obtained measurement result is poor in objectivity. In addition, the latter device has a problem that the measurement is troublesome, for example, strict alignment between the subject's eye and the device is required. SUMMARY OF THE INVENTION In view of the above problems of the related art, an object of the present invention is to provide an apparatus that can easily measure an accurate corneal diameter.

[0004]

SUMMARY OF THE INVENTION The present invention is characterized by having the following configuration to achieve the above object. (1) Imaging means for photographing the anterior segment of the eye to be examined, anterior segment display means for displaying an anterior segment image by the photographing means, and a reference mark indicating a predetermined position on the anterior segment display means. Reference mark display means for displaying the mark, reference mark positioning means for positioning the reference mark to one end of the cornea of the eye to be examined,
Instruction mark display means for displaying an instruction mark whose distance from the reference mark is variable, and arithmetic means for calculating the corneal diameter from the interval between the reference mark and the instruction mark. It is characterized by doing.

(2) The corneal diameter measuring apparatus of (1) is characterized by comprising a refractive power measuring system for the eye to be examined and a corneal shape measuring system for the eye to be examined.

(3) The corneal diameter measuring apparatus of (1) is characterized in that it comprises a contact lens selecting means including a storage means for storing a type such as a material and a radius of an available contact lens and an inner radius of curvature. .

[0007]

Embodiments of the present invention will be described below with reference to the drawings. The apparatus is roughly divided into an eye refractive power measurement system, a corneal shape measurement system, an alignment observation system, and a corneal diameter measurement system. The configuration of the embodiment will be described with reference to the optical system layout diagram of FIG. 1 and the block diagram of FIG.

[0008]Eye refractive power measurement system  [Objective measurement system] 1 is for refractive power measurement having a wavelength in the infrared region.
Light sources for measurement, and 2 and 3 are condenser lenses.
Reference numeral 4 denotes a measurement target (spot opening), and the eye E to be examined
Measuring tool movable to be placed at a position conjugate with the bottom
Get board. Reference numeral 5 denotes an objective lens.
Is enlarged with respect to the fundus image at the position of the measurement target plate 4.
The optical system is selected. 6 is beam split
It is.

7 is an objective lens, 8 is a beam splitter,
9 is a mirror. 10 and 11 are relay lenses, 12 is a strip-shaped corneal reflection removing mask arranged at a position conjugate with the cornea of the eye E, 13 is a moving lens that moves together with the measurement target plate 4, and 14 is an image forming image. Lens. Fifteen
Is a light receiving element for measurement, and the light receiving element for measurement 15 rotates around the optical axis in synchronization with the light source for measurement 1, the condenser lens 2, and the corneal reflection removal mask 12.

[A subjective measurement system] The subjective measurement system is an aiming optical system,
Most of the optical elements and the fixation target optical system are shared. Reference numeral 20 denotes a dichroic mirror which branches off the optical path of a light emitting diode 21 used as aiming light. Reference numeral 22 denotes a first relay lens movable on the optical axis, and the amount of movement is proportional to the spherical refractive power of the eye to be examined. Reference numerals 23A and 23B denote positive cylindrical lenses having the same focal length, and both are rotatable about the optical axis by the same amount in the same direction or in opposite directions. In order to create a cylindrical component with two cylindrical lenses, it is necessary to perform correction in consideration of the spherical effect. Reference numeral 24 denotes a second relay lens. Reference numeral 25 denotes a turret at the focal position of the second relay lens 24, in which a fixation target for objective measurement and a target for visual acuity measurement are switchably arranged. 26 is a condenser lens, and 27 is an illumination lamp.

[0011]Corneal shape measurement system  Reference numerals 30a and 30b denote point light sources.
30b (point light sources are arranged at 90 degree intervals,
The light emitted from the sources 30c and 30d is omitted.
-Tig lenses 31a and 31b make parallel light flux,
After reflected by the mirrors 32a and 32b, the cornea of the eye E to be examined
It is projected at a predetermined angle. 33 is dichroic
Mirror, 34 is a mirror, and 35 is an imaging lens. 36
Is a beam splitter that divides the optical path into two, and 37 is an optical splitter.
This is an image rotator for rotating the bundle by 90 degrees. 38
Is a cylindrical lens with a prism, 39 is a one-dimensional position detector
Output element.

[0012]Observation system  Reference numeral 40 denotes a photographing lens, and 41 denotes a mirror. 42
Is a dichroic mirror. 43 is an imaging lens, 4
Reference numeral 4 denotes an image sensor. 45 is a relay lens, 46 is a position
A matching reticle plate 47 projects the reticle plate 46.
Reticle projection light source. 48 is a TV monitor
is there.

[0013]Corneal diameter measurement system  The corneal diameter measurement system will be described with reference to the block diagram of FIG.
You. Positioning reticle image 6 taken by observation system
0 and the anterior ocular segment image 61
The image is displayed on the Levi monitor 48 (see FIG. 3). 51 is measured
Mark for projecting the regular mark on the TV monitor 48
It is a presentation switch. The measurement mark is as shown in FIG.
It comprises a fixed mark 62 and a movable mark 63. Measurement
The shape of the marking is not particularly limited, and
Anything that can specify two fixed points is sufficient. Mark presentation
The signal from the switch is composed of a microcomputer, etc.
(The control circuit 52 is a cornea)
When controlling not only the diameter measurement system but also the operation of the entire device
Both perform various calculations). The control circuit 52 is a mark
The signal generator 53 is provided at a predetermined position on the television monitor 48.
Command to generate fixed mark 62 and movable mark 63
You. The mark signal generator 53 includes an image signal synthesizer 50.
And the measurement mark is synchronized with the image of the observation system.
It is projected on Nita 48. 54 moves the movable mark 63
Moving switch, and a mark moving switch.
TV monitor via the control circuit 52 and the like by the operation of 54
The movable mark 63 on 48 is moved. In the present embodiment,
The switch 54 is used to move two switches in the horizontal direction.
It consists of a switch, but you can move it two-dimensionally
No. The distance between the fixed mark 62 and the movable mark 63 is
Character signals are calculated sequentially based on the rate and display magnification, etc.
It is displayed on the television monitor 48 via the device 55. 56
Is a print switch, and 57 is a printer.

The operation of the apparatus having the above configuration will be described.
I will tell.Eye refractive power measurement  The target of the turret board 25 is switched to the target for fixation.
To the subject. Illuminated by illumination light (not shown)
While observing the anterior segment that has been
Light is emitted by a well-known mechanism that moves the system body and the fixed base relative to each other.
Move the main body of the system to form it with the light flux of the light emitting diode 21.
The luminescent spot formed and the reticle image of the reticle plate 46 are
Align to relationship.

After the positioning with respect to the eye E is completed, a measurement button (not shown) is pressed. The infrared light emitted from the measurement light source 1 passes through the condenser lenses 2 and 3, the measurement target plate 4, and the objective lens 5, and is condensed near the cornea of the eye E, and then reaches the fundus. In the case of a normal eye, the target image reflected by the fundus passes through the beam splitter 6 and passes through the mirror 9
After passing through the relay lenses 10 and 11, an image is formed on the measuring light receiving element 15 by the imaging lens 14. If the eye to be examined has a refractive error, the movable lens 13 is determined based on the light reception signal of the fundus reflection light received by the measurement light receiving element 15.
At the same time, the microcomputer 52 moves the measurement target plate 4 to a position conjugate with the fundus of the eye E to be examined. Next, the first relay lens 22 is moved so that the fixation target and the fundus of the eye E are conjugated to each other, and further moved by an appropriate diopter so that the fog is applied. With the fog on the eye E, the measurement light source 1, the corneal reflection removal mask 12, and the measurement light receiving element 15 are rotated by 180 degrees around the optical axis. During rotation, the target plate 4 for measurement and the transfer
The moving lens 13 moves, the refractive power value at each meridian can be known from the amount of movement, and the refractive power of each eye is obtained by performing a predetermined process on the refractive power value of each meridian.

After the above objective measurement is completed,
When a subjective measurement changeover switch (not shown) is pressed, the microcomputer 52 controls the cylindrical lens 23A and 23B to rotate together with the movement of the first relay lens 22 so as to correspond to the value obtained by the objective measurement. I do. Therefore, the subject's eye E looks at the subjective measurement target in a state where the refractive power obtained by the objective measurement is corrected. Various subjective measurements are made by operating the first relay lens 22, the cylindrical lenses 23A and 23B, the turret board 25, and the like.

When measuring the corneal shape, the point light sources 30a to 30d are turned on by pressing a measurement switch (not shown). Point light source 30
Is projected onto the cornea of the eye E at a predetermined angle. The reflected light of this point light source image is reflected by dichroic mirrors 33 and 34 and then formed into an imaging lens 35.
Leads to. The light transmitted through the imaging lens 35 is split into beams.
The light is divided into two light paths by the light source 36 , and the two light paths are emitted in parallel. In one optical path, the image is rotated by 90 degrees by the image rotator 37. The cylindrical lens 38 has a focal length that is infinite in a cross section in the cylindrical axis direction and has a focal length in which a stop (not shown) and the one-dimensional position detecting element 39 are almost conjugated in a cross section in a direction orthogonal to the cylindrical axis direction. An image from a point light source image (not shown) is formed on the original position detection element 39. The image on the one-dimensional position detecting element 39 is separated at an appropriate interval by the prism. In this manner, the corneal shape can be known by performing the arithmetic processing disclosed in JP-A-61-85920 by the microcomputer 52 based on the position data of the one-dimensional position detecting element 39.

[0018]Corneal diameter measurement  When the mark presenting switch 51 is pressed, a mark signal is generated.
The raw device 53 displays an anterior eye image by the image signal synthesizing device 50.
After synchronization with the signal, the fixed mark 62 and the movable mark 6
3 is generated on the television monitor 48. Joystick
To move the optical system body and the fixed base relative to each other.
Then, the fixing mark 62 is aligned with one end of the cornea of the anterior segment.
After one end of the cornea is aligned with the fixed mark 62, the mark is moved.
Operate the switch 54 to move the movable mark 63 to the other end of the cornea.
Match. The value displayed on the TV monitor at this time is
It becomes the corneal diameter of the optometry. This measurement result is displayed on a switch (not shown).
And stored as data of the eye to be examined.

[0019]Automatic selection of contact lenses  Available control contacts are included in the control circuit 52 of the device.
The type of lens material and radius, etc., and the radius of curvature inside are stored.
Have been. These data are converted into a refractive power measurement system and a corneal shape measurement.
By combining with the data of the constant system and the corneal diameter measurement system,
Optimal soft contours as well as hard contact lenses
Cut lens can be selected. Choice of contact lenses
Is Japanese Patent Publication No. 2-32891 by the applicant of the present application.
Ophthalmology Mook (Kanehara Publishing Co., Ltd.)
Row), the control circuit 52
Is executed. The above embodiment can be variously modified.
Thus, for example, the formation of the measurement mark in the embodiment is electrically performed.
The transparent body on which the mark was formed was optically
It is obvious to those skilled in the art that the
And these transformations are also smelling as long as the technical ideas are the same.
Are included in the present invention.

[0020]

According to the present invention, the corneal diameter of the eye to be examined can be measured very easily and accurately. Further, according to the apparatus of the present invention, the prescription value of the contact lens, that is, the refractive power, the radius of curvature of the cornea, and the corneal diameter can all be measured by one unit.

[Brief description of the drawings]

FIG. 1 is an arrangement diagram of an optical system of an apparatus according to the present embodiment.

FIG. 2 is a block diagram illustrating a control method of the apparatus according to the embodiment.

FIG. 3 is an explanatory view of a monitor showing a method of measuring a corneal diameter.

[Explanation of symbols]

 48 TV monitor 50 Image signal synthesizing device 51 Mark presenting switch 52 Control circuit 53 Mark signal generating circuit 54 Mark moving switch 55 Character signal generating device 62 Fixed mark 63 Movable mark

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-71722 (JP, A) JP-A-61-293423 (JP, A) JP-B-2-32891 (JP, B2) (58) Field (Int.Cl. ⁷ , DB name) A61B 3/10

Claims (3)

(57) [Claims] A photographing means for photographing an anterior segment of an eye to be examined;
Anterior segment display means for displaying an anterior segment image by the photographing means; reference mark display means for displaying a reference mark indicating a predetermined position on the anterior segment display means; Reference mark positioning means for positioning the mark at one end of the cornea of the eye to be examined, instruction mark display means for displaying an instruction mark at a variable distance from the reference mark, and the reference mark Calculating means for calculating the corneal diameter from the distance between the mark and the indication mark. 2. The corneal diameter measuring apparatus according to claim 1, further comprising a refractive power measuring system for the eye to be examined and a corneal shape measuring system for the eye to be examined. 3. A cornea diameter measuring apparatus according to claim 1, further comprising a contact lens selecting means including a storage means for storing a type such as a material and a radius of an available contact lens and an inner radius of curvature. Diameter measuring device.