JPS63288135A - Ophthalmic measuring apparatus - Google Patents

Abstract

PURPOSE:To perform accurate measurement regardless of the output variation of a laser beam source, by controlling the quantity of the laser beam projected on the predetermined point in an eye by a beam quantity control means so as to make the same almost constant regardless of the output variation of the laser beam source. CONSTITUTION:A polarizing plate 2a has a polarizing direction P and an He-Ne laser beam source 1 has a linear polarizing direction shown by Q and, therefore, the quantity of transmitted beam can be arbitrarily controlled by revolving the polarizing plate 2a. The signal from a photodiode 3' is inputted to a beam control circuit 42 containing a motor and the automatic control of the quantity of laser beam is performed so as to make the quantity of the laser beam incident to the photodiode 3' constant. That is, when the quantity of beam is desired to increase, the polarizing plate 2a is rotated so that the polarizing direction Q of laser coincides with the polarizing direction P of the polarizing plate 2a and, when the quantity of beam is reduced, the polarizing plate 2a is rotated in a direction wherein the direction P, Q become 90 deg.. As mentioned above, the almost constant quantity of beam is obtained through adjustment regardless of the power variation of the laser beam source.

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 1 Measuring anterior chamber protein concentration is extremely important in determining the intraocular rim, ie, the aqueous humor shelf. Conventionally, visual judgment by grading using a slit lamp microscope has been frequently used,
A photometric method 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 carried out by performing constant 1-positive analysis.

[Problems to be Solved by the Invention] Normally, the power of the laser light source that emits the above-mentioned laser light varies by several percent, and as a result, the intensity of scattered light obtained from within the eye also varies. Since there is a strong correlation (straight line) between the scattered light intensity and the meat protein concentration, changes in the scattered light intensity immediately lead to measurement errors, resulting in poor reproducibility and poor measurement accuracy.

Therefore, in order to solve these problems, the present invention has the following features:
It is an object of the present invention to provide an ophthalmological measuring device that can perform accurate measurements regardless of output fluctuations of a laser light source.

[Means for Solving the Problems] In order to solve these problems, the present invention provides a light amount adjusting means in the emission part of the laser light source, and [I[! A configuration was adopted in which the amount of laser light projected onto a predetermined point within the area is adjusted to be approximately constant regardless of fluctuations in the output of the laser light source.

[Function] With such a configuration, fluctuations in the amount of laser light are almost eliminated, making it possible to measure with high precision.

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

FIG. 1 and FIG. 2 show a schematic configuration of an ophthalmological measuring device according to the present invention, and in the same figure, what is indicated by the symbol l is a laser light source made of, for example, helium neon,
This laser light source 1 is arranged on a pedestal 2. The light from the laser light source 1 is transmitted through light amount adjusting means such as a polarizing plate or a variable transmittance ND filter. Beam splitter 3, prism 4,
5°6, lens 7, beam splitter 8. The light is imaged through the lens 9 and prism 10 so as to be focused on one point 11a of the eye 11 to be examined. The laser light separated by the beam splitter 3 is incident on, for example, a photodiode 3' which functions as a light amount sensor provided to monitor the amount of laser light emitted from the laser light source 1. The output of the photodiode 3' is input to the automatic light control circuit 42 and fed back to the light amount adjusting means 2 to adjust the laser light q to a predetermined light amount.

This laser projector is provided with a slit light 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. Since this slit image is formed by light from the laser light source described above into a point shape, the slit image is used to illuminate the periphery of the slit image to easily confirm the position of the point image.

Also, the slit width and slit length of the slit 14 are
! They can be adjusted or switched via the J adjustment knob 15 and the switching knob 16, respectively.

A part 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 and is split by a half mirror or beam splitter 21, and part of it is sent to the lens 22 and the mask 26 having a slit 26a. The light passes through a shutter 26' and enters a photomultiplier tube (photomultiplier) 27 which 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, it can be observed by the examiner 33 through the eyepiece 32 through the prisms 31 and 34.

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 samplings and the total number of pulses, is stored in the memory 25 allocated for each intermediate time. The data stored in the memory 25 is subjected to arithmetic processing as described later by the arithmetic unit 41, and the intracameral whitening density is calculated.

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

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. 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, the slit light shutter 13, the photomarshutter 26', etc. It 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 beam splitter 8.
．． 10. A slit image of the pickpocket 7) 14 is formed on a portion of the anterior chamber 11a including the measurement point P via the lens 9. Subsequently, the light from the laser light source is focused on the measurement point P via the optical system.

Normally, a laser light source has a power fluctuation of several percent, and in order to avoid measurement errors caused by this, a means is provided to adjust the amount of laser light to a constant level. Light A 31 When the dividing means 2 is composed of a polarizing plate 2a, as shown in FIG. 3(A)
As shown in the figure, the polarizing plate 2a is attached so as to rotate around the optical path 1a. The polarizing plate 2a has a polarization direction P as shown in FIG.
Since the e-laser light source 1 has a linear polarization direction indicated by Q, the amount of transmitted light can be arbitrarily adjusted by iA by rotating the polarizing plate 2a.

For example, a signal from the photodiode 3' is inputted to a dimming circuit 42 including a motor, etc., and automatic dimming is performed so that the amount of light incident on the photodiode 3' is constant.
That is, when it is desired to increase the amount of light, it is rotated so that the polarization direction Q of the laser and the polarization direction P of the polarizing plate 2a match, and when it is desired to decrease it, it is rotated so that P and Q are 90 degrees.

The laser beam focused on the measurement point P in this way has an almost constant light intensity regardless of the power fluctuation of the laser light source2.
Verse 11 is given.

Measurement w A part of the light scattered at point p is beam
At the same time, the lens 22 is directed toward the examiner 33 by the lens 21. The light enters a photomultiplier tube 27 via a prism 23 and a mask 26.

The photomultiplier tube 27 receives the laser scattered light incident through the slit 26a, detects the intensity of the scattered light scattered by protein particles in the anterior chamber 11a, and converts it into a pulse train according to the intensity of the scattered light for a unit time. The number of pulses per pulse is counted by a counter 40, and the counted value is stored in the memory 25 allocated for each unit time. Arithmetic device 41
Now, the data stored in the memory 25 is operated to calculate the previous protein concentration.

In Figures 4 (A) and (B), the light amount of 2g1ft'1 is 4
IIir:#, an embodiment is shown. In this case, the laser light source 1 does not necessarily have linear polarization, but may have any polarization characteristics, as shown in FIG. 4(A).
The D filter 2b is mounted so as to be able to rotate about 0, which is offset from the optical axis, so that its transmission density changes from Sl to 32, and the ND filter 2c shown in FIG. It is attached to the shaft 1a so that it can be moved in and out of the shaft 1a, and is similarly constructed as a filter whose density is variable from 51 to 52.

As in the embodiment shown in FIG. 3, each filter is rotated or moved so that the amount of light incident on the photodiode 3' becomes a predetermined value, and automatic light adjustment is performed.

Note that in the above embodiment, when the light cannot be adjusted to a predetermined level even if the amount of transmitted light is maximized, it is determined that the life of the laser light source has come to an end.

[Effects of the Invention] As explained above, in the present invention, the light amount adjusting means is disposed at the emission part of the laser light source, so that even if there is an output fluctuation in the laser light source, fluctuations in the laser light can be eliminated. , it becomes possible to perform ophthalmological measurements with improved accuracy and good reproducibility.

[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. Figure 3 (B) is an explanatory diagram showing the dimming state depending on polarization characteristics, and Figure 4 (A
) and (B) are explanatory diagrams showing a dimming state when an ND filter is used. l...Laser light source 2...Light amount adjustment means 3'.
...Photodiode 12...Light source for slit light

Claims (1)

[Claims] 1) A laser projecting unit that focuses light from a laser light source on a predetermined point within the eye, a light amount adjusting means disposed at the output unit of the laser light source, and a laser scattering unit from within the eye. A photoelectric conversion element that receives light and a processing means that processes a signal from the photoelectric conversion element to perform an ophthalmological measurement are provided, and the light amount adjustment means adjusts the amount of laser light projected to a predetermined point within the eye from the laser light source. An ophthalmological measuring device characterized in that the light is adjusted to be almost constant regardless of output fluctuations. 2) The light amount adjusting means is a polarizing plate or a variable transmittance type N.
The ophthalmological measurement device according to claim 1, which is constructed from a D filter. 3) The ophthalmological measuring device according to claim 1 or 2, wherein a beam splitter for monitoring light amount is disposed after the light amount adjusting means.