JPS63288134A - Ophthalmic measuring apparatus - Google Patents

Abstract

PURPOSE:To enhance the use efficiency of a laser beam source and to reduce the load of a patient by making it possible to use a low output laser beam source, by providing a treatment means for treating the signal from a beam receiving part to perform ophthalmic measurement and converting laser beam to one almost having only the linear polarized beam component of scattering beam. CONSTITUTION:In measurement, a slit beam source 12 is allowed to light and the slit image of a slit 14 is formed to the part including a measuring point P of the anterior chamber 11a through a polarizing beam splitter 8, a lens 9 and a prism (or mirror) 10. Continuously, the beam from a laser beam source 1 is condensed to the measuring point P through the optical system thereof. A part of the beam scattered at the measuring pint P is turned to the direction of an examine 33 by a beam splitter 21 to perform observation and, at the same time, allowed to be incident to a photomultiplier tube 27 through a lens 22, a prism 23 and a mask 26. Since only an S-polarized beam component is contained in the laser beam from the laser beam source 1, the incident quantity of beam can be reduced by the portion of a P-polarized beam component.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ophthalmological measurement device, and more specifically, a laser beam is irradiated into the eye, particularly at a predetermined point in the anterior chamber, through an optical system, and a laser beam is emitted from the eye. The present invention relates to an ophthalmological measurement device that measures ophthalmological diseases by detecting laser scattered light.

[Prior Art] Measuring anterior chamber protein concentration is extremely important in determining intraocular inflammation, ie, blood aqueous humor shelf. Conventionally, visual judgment by grading using a slit lamp microscope has been frequently used, while photographic measurement has been reported as a quantitative method, but a method that can be easily applied clinically has not yet been developed.

Conventional visual judgment has the problem that the judgment standard differs due to individual differences and the data lacks novelty.To solve this problem, a laser beam is irradiated into the eye and the scattered light from it is received. Ophthalmological measurements are performed by quantitatively analyzing the

[Problems to be Solved by the Invention] In the above-mentioned ophthalmological measurements, normally the optical axes of the laser projecting system L1 and the light receiving system L2 are approximately 90° as shown in FIG.
Since the measurement is performed with the setting set to
Therefore, if a randomly polarized laser light source is used as the laser light source, P
The polarized light component A (the linear component indicated by the double arrow) passes through the eye 11 to be examined, which poses a problem in that it is a burden on the patient and the efficiency of use of the laser light source is reduced.

Therefore, the present invention has been made to solve these conventional problems, and improves the usage efficiency of the laser light source.
It is an object of the present invention to provide an ophthalmological measuring device that can use a low-power laser light source and that reduces the burden on the medical groove.

[Means for Solving the Problems] In order to solve these problems, the present invention provides an ophthalmological measuring device in which a light receiving section is arranged on an optical axis substantially perpendicular to the optical axis of a laser projecting section. A configuration was adopted in which the light is a laser beam having almost only a linearly polarized component of scattered light.

[Function] With such a configuration, the laser beam becomes a laser beam having only an S-polarized component, so the amount of the P-polarized component can be reduced, and the amount of incident light can be reduced to nearly half.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

:i'S Figures 1 and 2 show the schematic configuration of the ophthalmological measuring device according to the present invention, and in the figures, the reference numeral 1 indicates a linearly polarized laser composed of helium neon, argon, etc. A laser light source that emits a beam of light, and this laser light source 1 is placed on a pedestal 2. The light from the laser light source 1 passes through a laser filter 3, a prism 4, a movable mirror 5° prism 6, a lens 7, a polarizing beam splitter 8, a lens 9. An image is formed through the prism 10 so as to condense the light onto one point on the eye 11 to be examined.

This laser projector is provided with a slit light source 12, and the light from this light source 12 is transmitted to a slit light shutter 13.
．． Beam splitter 8. via slit 14. Lens 9.
A slit image is formed on the mirror 11a through the prism 10. This slit image is formed by light from the above-mentioned laser light source into a point image, and is used to illuminate the periphery of the slit image to easily confirm the position of the point image.

Further, the slit width and slit length of the slit 14 can be adjusted or switched via the adjustment knob 15 and the switching knob 16, respectively.

A portion of the laser scattered light from the measurement point at the comparison point 11a passes through the objective lens 20 of the detection unit 29, is split by a half mirror or beam splitter 21, and a portion is sent to the lens 22. Mask 26 with slit 26a. The light passes through the shutter 26' and enters a photomultiplier tube 27 that functions as a photoelectric conversion element. The other scattered light split by the beam splitter 21 is sent to the variable magnification lens 3.
0. i5! by the examiner 33 through the prisms 31 and 34 and the eyepiece 32! can be understood.

The output of the photomultiplier tube 27 is input to a counter 40 via an amplifier 28, and the intensity of scattered light detected by the photomultiplier tube is counted as the number of pulses per unit time. The output of this counter 40, ie, the number of sampling times and the total number of pulses, is stored in the memory 25 allocated for each unit time. The data stored in the memory 25 is subjected to arithmetic processing as described later by the arithmetic unit 41, and the anterior chamber meat protein concentration is calculated as rA'n.

Furthermore, the movable mirror 5 is oscillated via a mirror drive circuit 60 connected to the controller 41, thereby scanning the laser light and moving the laser light spot in the anterior chamber.

Further, the detection unit 29 houses an optical system that aligns the eye to be examined and the apparatus by receiving the corneal reflected light 51. The corneal reflected light 51 is received through a prism 61, a prism 62, a shutter 64 . Mask 63. It passes through the lens 65 and is reflected by the half mirror 21 to the examiner 33.
be guided in the direction of The prisms 61 and 62 are adjusted to efficiently receive corneal reflected light. Note that this shutter 64 and a shutter 26' disposed in front of the photomultiplier tube 27 are interlocked, and the shutter 64 is configured to be closed while the shutter 26' is open.

Note that the detection unit 29 is attached to a support 70, and the support 70 and the laser emitting unit are attached so that they can rotate relative to each other around an axis 71, so the optical axes of the laser emission system and the light receiving system can be set at any angle. can be set to approximately 9 in the embodiment of the present invention.
The measurement is performed with the setting set to 0'.

Further, in the present invention, a fixation lamp 90 made of a light emitting diode or the like and supplied with power from a power source 91 is arranged at a position where the subject can fixate the fixation lamp. The colored light of the fixation lamp 9o is selected to be different from the colored light of the laser light source 1, such as green if the light from the laser light source is red. Also, this fixation light 9
0 can be rotated in the direction of the arrow by a link mechanism 92 and adjusted to a suitable position for the subject.

Further, an input device such as a joystick 45 equipped with a push button 46 is provided on the pedestal 2, and by operating the input device, the laser filter 3. Slit light shutter 13. Photomar shutter 26',
A positioning shutter weighing 64 kg can be inserted into or removed from each optical system.

Next, the operation of the device configured as described above will be explained. For measurement, first turn on the light source 12, then turn on the polarizing beam splitter 8. A slit image of the slit 14 is formed on a portion of the anterior chamber 11a including the measurement point P via the lens 9 and the prism (or the mirror 10).

Subsequently, the light from the laser light source is focused on the measurement point P via the optical system.

A part of the light scattered at the measurement point P is directed towards the examiner 33 by the beam splitter 21 and is detected at the same time as it enters the photomultiplier tube 27 via the lens 22, prism 23, and mask 26. be done.

According to the embodiment of the present invention, since the laser beam from the laser light source 1 contains only the S-polarized component, the amount of incident light can be reduced by the amount of the P-polarized component A in FIG.

5. In the embodiment of the present invention, a polarizing beam splitter 8 is used in the laser projector, but since a halogen lamp is used as the slit light source 12, the optical axis of the halogen illumination system and the laser beam If a polarization beam splitter is used to combine the axes, the light intensity attenuation of the laser light can be small, and the polarization direction of the laser is made to enter the polarization beam splitter as P-polarized light.

The photomultiplier tube 27 receives the laser scattered light incident through the pickpocket 7) 26a, detects the intensity of the scattered light scattered by the protein particles in the front EIl a, and converts it into a pulse train accordingly. The counter 40 counts the number of pulses per unit time, and the counted value is stored in the memory 25 allocated for each unit time. In the operation type 2141.

The anterior chamber meat protein concentration is calculated by calculating the data stored in the memory 25.

In this case, as shown in FIG. 4, a condensing lens 66 is arranged in front of the shutter 64, and an aperture having a transmitting part or a diffusing surface 63'a is used as the aperture 63', so that the corneal reflected light 51
It is preferable that the light is focused on the transmission part 63'a. In this embodiment, the corneal reflected light image becomes brighter, and this brightness is related to the working distance, so there is an advantage that the working distance can be approximately monitored. .

In addition, in FIG. 2, the prisms 61 and 62 may be connected by a light guide, a diffuser plate may be used instead of the prism 62, and the light emitting system and the light receiving system may be arranged in a predetermined arrangement relationship ( For example, the leading axis is 9 as described below.
0'), it is also possible to fix the light-receiving surface of the corneal reflected light to the light projector.

Also, see Figure 5 (
As shown in A) and (B), the examiner may observe with the naked eye a light receiving plate 72 made of ground glass or the like with scales or marks attached. , the size and position differ depending on the positional relationship between the test region 11 and the device, as shown by dotted lines, so positioning can be done in a simple manner. Also, Figure 5 (C)
, (D), it is also possible to arrange a plurality of light receiving elements (photodiodes) on the light receiving plate 72 and align them in one position. In the example of FIG. 5(C), four light receiving elements 7 are used.
When the light receiving element 3a does not receive light and the four light receiving elements 73b receive light, the position is aligned and the state shown in FIG. 5 (D
), the light receiving element 74a does not receive light, and the light receiving element 74b and 74c, which are divided into four parts, are aligned when receiving light.

In each of the embodiments shown in FIG. 5, three-dimensional alignment is possible with a simple configuration, and there is no need for anything related to the alignment light projection system, such as an index light source or index. Furthermore, when using a light receiving element, it becomes possible to perform positioning display according to the light receiving state of the light receiving element.

Note that the radius of curvature of the cornea is about 6 to 8 degrees, and the depth of the cornea is about 3 Ilffi, so the corneal reflection of light that is focused on the anterior aqueous humor is concentrated once and then diffused. Becomes light. Using this focused point for positioning has high brightness and is convenient for obtaining positioning information, but depending on where the anterior aqueous humor is measured, the light may be focused quite close to the cornea. Therefore, it is preferable to select a light-receiving surface in a place where the light is in a diffused state.

Further, in this embodiment, the light receiving section and the light projecting section are arranged so that their front axes 81 and 82 are at approximately 90 degrees, as shown in Fig. f56. At this time, an image 26' of the mask 26 by the light receiving lens 22 is formed on the beam waist 80 at a position conjugate with the mast and on the optical axis of the light projection system.

[Effects of the Invention] As explained above, in the present invention, the laser beam is
Since the laser beam has only the linearly polarized component (S) of the side scattered light from 0°, the amount of the P-polarized component can be reduced and the amount of incident light can be halved. Therefore, a low-output laser light source can be used, the burden on the TB person can be reduced, and the laser light source can be made low-cost and compact.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the appearance of the device according to the present invention [ffl
, Figure 2 is a configuration diagram showing the optical arrangement of the device, Figure 3 is an explanatory diagram explaining the incidence and reception of P and S polarized components of laser light, and Figure 4 is a diagram of the optical system for observing corneal reflected light. Layout diagram, FIG. 5(A) is another embodiment of the optical system for observing corneal reflected light, FIGS. 5(B) to (D) are explanatory diagrams showing different embodiments of the light receiving plate, and FIG. The optical axis arrangement of the emitter and receiver is approximately 90
FIG. 1... Laser light source 8... Polarizing beam splitter 12... Light source for slit light

Claims (1)

[Scope of Claims] 1) A laser light source that generates linearly polarized laser light; a laser projector that focuses the light from the laser light source on a predetermined point within the eye; and an optical axis of the laser projector. A light receiving section arranged on optical axes that are substantially orthogonal to each other and receiving laser scattered light from within the eye, and a processing means that processes the signal from the light receiving section to perform ophthalmological measurements are provided, and the laser light is divided into substantially scattered light. An ophthalmological measuring device characterized by using a laser beam having only a linearly polarized component. 2) Claim 1 in which a polarizing beam splitter is used to combine the optical axis of the illumination system and the optical axis of the laser beam.
The ophthalmological measuring device described in Section.