JPH0580898B2 - - Google Patents

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 protein concentration in the anterior chamber 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 criteria vary depending on individual differences and the data lacks freshness.To solve this problem, we irradiate the inside of the eye with a laser beam and receive the scattered light from it. Ophthalmological measurements are performed through quantitative analysis.

[Problems to be Solved by the Invention] In the above-mentioned ophthalmological measurements, the optical axes of the laser projecting system L1 and the light receiving system L2 are usually set at approximately 90° as shown in FIG. ,
The light receiving unit receives the side scattered light as a signal, which is approximately S polarized light component B (linear component perpendicular to the paper surface).
It has become only. Therefore, if a randomly polarized laser light source is used as a laser light source, the P polarized light component A
(the straight line component of the double arrow) passes through the subject's eye 11. There are problems in that it places a burden on the patient and reduces the efficiency of using the laser light source.

Therefore, the present invention has been made to solve these conventional problems, and provides an ophthalmological measuring device that increases the efficiency of use of a laser light source, allows the use of a low-power laser light source, and reduces the burden on patients. The purpose is to

[Means for Solving the Problems] In order to solve the above 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.

Figures 1 and 2 show a schematic configuration of the ophthalmological measurement device according to the present invention, and the one designated by the reference numeral 1 emits a linearly polarized laser beam composed of helium neon, argon, etc. This laser light source 1 is placed on a pedestal 2. The light from the laser light source 1 passes through the laser filter 3, prism 4, movable mirror 5, prism 6, lens 7, polarizing beam splitter 8, lens 9, and prism 10 to one point in the eye chamber 11a of the eye 11 to be examined. The image is focused so as to condense the light.

This laser projector has a light source 12 for slit light.
The light from this light source 12 passes through a slit light shutter 13, a slit 14, a beam splitter 8, a lens 9, and a prism 10, and enters the eye chamber 1.
A slit image is formed on 1a. Since this slit image is formed by the light from the laser light source described above into a dot, the slit image is used to easily confirm the position of the dot image by illuminating its surroundings.

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

A part of the laser scattered light from the measurement point in the eye chamber 11a passes through the objective lens 20 of the detection unit 29 and is split by a half mirror or beam splitter 21, and part of it is sent to the lens 22 and the slit 26a.
The light passes through a mask 26 and a shutter 26', and enters a photomultiplier tube 27 that functions as a photoelectric conversion element. Also, beam splitter 2
The other scattered light divided by 1 is transmitted through variable magnification lens 3
0, it can be observed by the examiner 33 through the prisms 31 and 34 through the eyepiece 32.

Further, the output of the photomultiplier tube 27 is inputted 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 protein concentration is calculated.

Furthermore, the movable mirror 5 is oscillated via a mirror drive circuit 60 connected to the arithmetic unit 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. Corneal reflected light 51 is received through prism 61, passes through prism 62, shutter 64, mask 63, and lens 65, is reflected by half mirror 21, and is guided toward examiner 33. The prisms 61 and 62 are adjusted to efficiently receive corneal reflected light. Note that this shutter 64 and the shutter 26' arranged in front of the photomultiplier tube 27 are interlocked, and the shutter 26' is arranged in front of the photomultiplier tube 27.
The shutter 64 is configured to be closed while the shutter 6' 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. In the embodiment of the present invention, the angle is set to approximately 90° and measurements are performed.

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 this fixation lamp 90 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. Further, this fixation lamp 90 can be rotated in the direction of the arrow by a link mechanism 92 and can be adjusted to a suitable position for the subject.

Further, an input device such as a joy stick 45 equipped with a push button 46 is provided on the pedestal 2, and by operating this input device, the laser filter 3, the slit light shutter 13, the photo printer 26', the position Matching shutter 6
4 etc. can be inserted into or removed from each optical system.

Next, the operation of the device configured as described above will be explained. In the measurement, first, the light source 12 is turned on, and a slit image of the slit 14 is formed on a portion of the anterior chamber 11a including the measurement point P via the polarizing beam splitter 8, lens 9, and prism (or 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 toward the examiner 33 by the beam splitter 21 and observed, and at the same time, the light is transmitted to the lens 22 and the prism 2.
3. The light enters the photomultiplier tube 27 through the mask 26.

According to the embodiment of the present invention, since the laser light 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.

In the embodiment of the present invention, a polarizing beam splitter 8 is used in the laser projecting section, but since a halogen lamp is used as the light source 12 for slit light, the optical axis of the halogen illumination system and the laser beam If a polarizing beam splitter is used to combine the optical axes, the attenuation of the amount of laser light can be kept small. Note that the polarization direction of the laser is such that it enters the polarization beam splitter as P-polarized light.

The photomultiplier tube 27 receives the laser scattered light incident through the slit 26a, and
The intensity of the scattered light scattered by the protein particles inside is detected and converted into a pulse train accordingly, which is counted by a counter 40 as the number of pulses per unit time, and the counted value is allocated to a memory for each unit time. 25. In the arithmetic unit 41,
The protein concentration in the anterior chamber is calculated by calculating the data stored in the memory 25.

In this case, as shown in FIG.
A condensing lens 66 is placed in front of the aperture 6.
It is preferable to use a diaphragm having a transmitting part or a diffusing surface 63'a at 3' so that the corneal reflected light 51 is focused on the transmitting part 63'a. In this embodiment, the observed corneal reflected light image becomes brighter, and since this brightness is related to the working distance, 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, and the prism 6
A diffuser plate may be used instead of 2.
Also, since the light emitting system and the light receiving system have a predetermined arrangement relationship (for example, the optical axis is set at 90 degrees as described later), the receiving surface of the corneal reflected light is fixed to the light emitting part. You can also do that.

In order to align the light receiving portion of the measurement site, the examiner may visually observe a light receiving plate 72 made of ground glass or the like with scales or marks attached, as shown in FIGS. 5A and 5B. The size and position of the corneal reflected light image 72a observed on the light receiving plate 72 vary depending on the positional relationship between the eye 11 and the apparatus, as shown by the dotted lines, so positioning can be performed by a simple method. It is also possible to arrange and align a plurality of light receiving elements (photodiodes) on the light receiving plate 72 as shown in FIGS. 5C and 5D. In the example of FIG. 5C, there are four light receiving elements 73.
When the light receiving element 74a does not receive light and the four light receiving elements 73b receive light, the aligned state is reached, and in the example of FIG. When the light receiving element 74c is receiving light, it is in an aligned state.

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 a light receiving element is used, alignment display can be performed according to the light receiving state of the light receiving element.

The radius of curvature of the cornea is approximately 6 to 8 mm.
On the other hand, since the depth of the anterior aqueous humor is about 3 mm, the corneal reflected light of the light beam that is focused on the anterior aqueous humor becomes diffused light after being focused once. 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 optical axes 81 and 82 of the light receiving section and the light projecting section are approximately parallel to each other, as shown in FIG.
placed at 90°. 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, since the laser beam is a laser beam having only the linearly polarized component S of the side scattered light from approximately 90 degrees, the P polarized component is reduced and the incident The amount of light can be halved. Therefore, a low-output laser light source can be used, reducing the burden on the patient, and making it possible to provide a low-cost and compact laser light source.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the external appearance of the device according to the present invention, Fig. 2 is a configuration diagram showing the optical arrangement of the device, and Fig. 3 is an explanation explaining the incidence and reception of P and S polarized components of laser light. Figure 4 is a layout diagram of an optical system for observing corneal reflected light, Figure 5 A is another embodiment of the optical system for observing corneal reflected light, and Figures 5 B to D are different implementations of the light receiving plate. An explanatory diagram showing an example, FIG. 6 is an arrangement diagram when the optical axis arrangement of the light projecting part and the light receiving part is about 90 degrees. DESCRIPTION OF SYMBOLS 1... Laser light source, 8... Polarizing beam splitter, 12... Light source for slit light, 25... Memory, 26... Mask, 26a... Slit, 27
...Photomultiplier tube, 40...Counter, 41...
...Arithmetic device, 50...Cornea, 51...Corneal reflected 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; A light receiving section arranged on orthogonal optical axes to receive laser scattered light from within the eye, and a processing means for processing a signal from the light receiving section to perform an ophthalmological measurement are provided, and the laser light is converted into a substantially straight line of the scattered light. An ophthalmological measuring device characterized by using a laser beam having only a polarized component. 2. The ophthalmological measuring device according to claim 1, wherein a polarizing beam splitter is used to combine the optical axis of the illumination system and the optical axis of the laser beam.