JPH08206069A - Ophthalmological measuring device - Google Patents

Abstract

PURPOSE: To correct sensitivity fluctuation of a device automatically and provide a highly reliable measurement result without preparing a specific correcting apparatus, by detecting output fluctuation of laser beam source and correct the measured result based on this detected result. CONSTITUTION: A shutter driving circuit 19 is operated by means of a control computer 22 and the shutter 17 is opened as well as the shutter 15 closed when correction is performed. Laser beam outputted from a laser beam source 1 transmits into a beam splitter 2 and is diffused by means of a diffusing board 16. Furthermore, a part of diffused light passes through the opened shutter 17 and is made incident from one end part 18a of optical fiber 18 and made outgoing from the other end part 18b to be made incident into a photoelectric transfer element 14 directly. On this occasion, the control computer 22 obtains a corrected value combined with output fluctuation of the laser beam source 1 and sensitivity fluctuation of the photoelectric transfer element 14, by operation-processing the output of the photoelectric transfer element 14 in an operating circuit 21. The measured result is corrected by comparing the corrected value with a standard value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system for receiving scattered light from a laser light source from a laser light source, which is converged and projected toward an eyeball of an eye to be inspected, and light scattered by molecules inside the crystalline lens by the laser light. The present invention relates to an ophthalmologic measuring apparatus that guides a photoelectric conversion element via a photoelectric conversion element and measures a crystalline lens based on an output signal of the photoelectric conversion element.

[0002]

2. Description of the Related Art A laser beam from a laser light source is converged and projected toward an eyeball of an eye to be inspected, and scattered light by molecules inside the crystalline lens by the laser beam is transmitted to a photoelectric conversion element via a light receiving optical system. There is known a device for guiding and measuring the particle size and the like inside the crystalline lens based on the output signal of the photoelectric conversion element. By the way, the laser light source and the photoelectric conversion element inevitably undergo output fluctuation and sensitivity fluctuation in actual use. In the conventional device, in order to correct the measurement result due to the fluctuation of the output of the laser light source and the light receiving sensitivity of the photoelectric conversion element, a calibration instrument such as a model eye with a certain reference value is prepared, and the measured value And a reference value are compared to obtain a correction value to calibrate the device.

[0003]

However, calibration using a calibration instrument such as a model eye is troublesome and cannot be performed frequently. Therefore, after calibrating the device, the next calibration is performed. When the output variation of the laser light source or the sensitivity variation of the electro-conversion element occurs during the period, there is a problem that the reliability of the measured data during that period is insufficient.

The present invention has been devised in view of the above-mentioned drawbacks. The sensitivity fluctuation of the apparatus is automatically corrected without providing a special calibration instrument, and a highly reliable measurement result can be obtained. It is a technical object to provide an obtained ophthalmologic measuring device.

[0005]

The present invention is characterized by having the following configuration in order to achieve the above object. (1) A laser projecting optical system for converging and projecting laser light emitted from a laser light source toward an eyeball of an eye to be inspected, and light scattered by molecules inside the crystalline lens by the laser light. A scattered light detection optical system including a photoelectric conversion element to detect, in an ophthalmologic measuring device for measuring the characteristics of the tissue of the crystalline lens based on the light intensity detected by the photoelectric conversion element, the output fluctuation of the laser light source It is characterized by having a detecting means for detecting and a calculating means for calibrating the measurement result based on the detection result of the detecting means.

(2) A laser projecting optical system for converging and projecting the laser light emitted from the laser light source toward the eyeball of the eye to be inspected, and molecules inside the crystalline lens by the laser light. A scattered light detection optical system including a photoelectric conversion element for detecting scattered light by
In an ophthalmologic measuring device that measures the characteristics of the tissue of the lens based on the light intensity detected by the photoelectric conversion element, a detection unit that detects the sensitivity of the photoelectric conversion element, and a measurement result based on the detection result of the detection unit. A calculation means for calibrating
It is characterized by having.

(3) A laser projecting optical system for converging and projecting the laser light emitted from the laser light source toward the eyeball of the eye to be inspected, and molecules inside the crystalline lens by the laser light. A scattered light detection optical system including a photoelectric conversion element for detecting scattered light by
In an ophthalmologic measuring device that measures the characteristics of the tissue of the lens based on the light intensity detected by the photoelectric conversion element,
A light guiding optical system for directly guiding the laser light to the light receiving element surface of the photoelectric conversion element; and laser light incident on the photoelectric conversion element for the light guiding optical system and the scattered light detecting optical system. It is characterized by further comprising: selecting means for selectively selecting, and calculating means for detecting the amount of light incident on the photoelectric conversion element through the light guide optical system and calibrating the measured value based on the detected value. .

(4) The light guiding optical system of (3) is characterized by including a diffusion plate and an optical fiber on which the diffused laser light is incident.

(5) The selection means of (3) is characterized in that it has a first shutter in the optical path of the scattered light detection optical system, and has a control means for closing the first shutter during calibration.

(6) The selection means of (3) is provided with a first shutter in the optical path of the scattered light detecting optical system and a second shutter in the optical path of the light guiding optical system, and the first shutter and the first shutter are provided. It has a control means for controlling the operation of the two shutters.

(7) The selection means of (3) is characterized in that the laser light of the light guide optical system is made to enter the photoelectric conversion element at least once for each measurement.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the outline of an apparatus for measuring the protein composition inside the lens, which is an example. Reference numeral 1 is a He-Ne laser light source for projecting laser light onto a crystalline lens, 2 is a beam splitter, 3 is an expander lens, 4 is a condenser lens, and 1 to 4 are irradiations for measuring the protein composition inside the crystalline lens. Configure an optical system. Reference numeral 5 is an eye to be inspected, and 6 is a lens. Reference numeral 7 is a point light source for a fixation lamp, 8 is a beam splitter, and 7 and 8 form a fixation target projection optical system for projecting the fixation target onto the fundus of the eye to be examined.

Reference numeral 9 is an imaging lens, 10 is a diaphragm, and 11 is a CC.
Reference numeral 9-11 denotes a D camera, which constitutes an observation optical system for observing the anterior segment. Reference numeral 12 is an imaging lens, 13 is an aperture, 14 is a photoelectric conversion element, and 12 to 14 constitute a light receiving optical system. 15 is a shutter, 16 is a diffusion plate, 17
Is a shutter, and 18 is an optical fiber. The beam splitters 2 and 15 to 19 of the irradiation optical system constitute a calibration optical system for device calibration. Reference numeral 19 is a shutter drive circuit, 20 is an image composition circuit, 21 is an arithmetic circuit, 22 is a control computer, 23 is a television monitor, 24 is an input means, and 25 is a storage means.

The operation of the apparatus having the above structure will be described. First, the calibration of the apparatus with respect to the output fluctuation of the laser light source and the fluctuation of the light receiving sensitivity of the photoelectric conversion element will be described. At the time of calibration, the control computer 22 operates the shutter drive circuit 19 to close the shutter 15 and open the shutter 17. The laser light output from the laser light source 1 passes through the beam splitter 2 and is diffused by the diffusion plate 16. A part of the diffused light passes through the open shutter 17, enters from the end 18a of the optical fiber 18, and exits from the other end 18b to directly enter the photoelectric conversion element 14. At this time, since the shutter 15 is closed, only a part of the laser light emitted from the laser light source 1 directly enters the photoelectric conversion element 14.

The arithmetic circuit 21 performs a predetermined arithmetic processing from the output signal of the photoelectric conversion element 14 at this time so that the control computer 22 calibrates the output fluctuation of the laser light source 1 and the sensitivity fluctuation of the photoelectric conversion element 14 together. Get the value. Based on this calibration value, the measurement result is corrected by comparing with a reference value preset at the time of manufacturing shipment. That is,
When the obtained calibration value is C, the reference value set at the time of manufacture and shipment is S, and the measurement result before correction is D, the corrected measurement result D ′ is D ′ = D * S / C.

Next, the operation of the apparatus of the embodiment in which the above-mentioned calibration is performed every measurement will be described based on the flowchart of FIG. The examiner causes the eye to be examined to fixate the point light source 7 as a fixation lamp. The image of the anterior segment of the subject's eye on the television monitor 23 is observed, the position of the light flux of the laser light source 1 is confirmed, and the joystick mechanism is operated to determine the measurement site. A trigger signal is issued by the input of the input means 24, and the measurement is started. The laser light emitted from the laser light source 1 is split by the beam splitter 2 into laser light used for measurement and laser light used for calibration of the apparatus. The control computer 22 operates the shutter drive circuit 19 to close the shutter 15 and open the shutter 17, and obtains the above-mentioned calibration value C from the output signal of the photoelectric conversion element 14. The control computer 22 which has obtained the calibration value C once stores the value in the memory in the circuit.

Subsequently, the shutter drive circuit 19 is driven,
This time, the shutter 15 is opened and the shutter 17 is closed. The laser beam reflected by the beam splitter 2 has its luminous flux expanded by the expander lens 3, and then is irradiated as a convergent luminous flux by the condenser lens 4 onto the crystalline lens 6 of the subject's eye 5 from an oblique direction. The laser light flux applied to the crystalline lens 6 of the eye 5 to be examined is scattered by the protein particles in the crystalline lens 6 to become scattered light, which is condensed at the position of the aperture 13 by the imaging lens 12 to open the aperture 13 and the open shutter 15. The light passes through and enters the photoelectric conversion element 14.

The photoelectric conversion element 14 outputs an electric signal corresponding to the intensity of the incident scattered light and inputs it to the arithmetic circuit 21. The arithmetic circuit 21 obtains the correlation function of the temporal fluctuation of the scattered light intensity based on the input signal, and the control computer 22 obtains the measurement result D of the scattered light information from various proteins inside the lens by this correlation function. Regarding this measurement, for example, as described in Japanese Patent Publication No. 6-505650 (Invention title "Method and apparatus for detecting the occurrence of cataract"), the correlation function of the temporal variation of scattered light intensity is:

[Equation 1] The protein composition inside the lens is calculated from the amounts of If (the intensity of scattered light from non-aggregated particles) and Is (the intensity of scattered light from aggregated particles) in this equation.

The control computer 22 uses the correction equation (D
After obtaining the corrected measurement result D ′ by '= D * S / C), the result is displayed on the television monitor 23 via the image synthesizing circuit 20. Further, the corrected measurement result is stored in the storage means 25. As described above, the apparatus detects the output fluctuation of the laser light source 1 and the sensitivity fluctuation of the photoelectric conversion element 14 each time the measurement is performed, and the measurement result is corrected and calculated each time.

The above embodiment can be modified in various ways. For example, the output of the laser light source 1 and the sensitivity of the photoelectric conversion element 14 may be calibrated independently. That is, the optical path divided by the beam splitter 2 is further divided by the beam splitter, a photoelectric conversion element is arranged in the one optical path, the output of the laser light source 1 is directly detected, and the detected laser light source 1 is detected. By comparing the output and the amount of light received by the photoelectric conversion element 14, the variation in the sensitivity of the photoelectric conversion element 14 can be known. Further, when the output of the laser light source 1 or the fluctuation of the sensitivity of the photoelectric conversion element 14 exceeds a predetermined reference, a display for instructing the replacement may be displayed.

[0021]

As described above, the ophthalmologic measuring apparatus according to the present invention can prevent the fluctuation of the measurement result due to the fluctuation of the sensitivity of the apparatus without preparing a special calibration tool.
Also, by incorporating correction of measurement results into the measurement procedure, accurate measurement results can always be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of an apparatus of this embodiment.

FIG. 2 is a flow chart for explaining the operation of the apparatus of the embodiment in which the calibration is performed every measurement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 laser light source 5 eye to be examined 6 crystalline lens 14 photoelectric conversion element 15 shutter 16 diffuser plate 17 shutter 18 optical fiber 19 shutter drive circuit 22 control computer

Claims (7)

[Claims] 1. A laser projecting optical system for converging and projecting laser light emitted from a laser light source toward an eyeball of an eye to be inspected, and a molecule inside a crystalline lens by the laser light. A scattered light detection optical system including a photoelectric conversion element that detects scattered light, and an ophthalmic measurement device that measures the characteristics of the tissue of the crystalline lens based on the light intensity detected by the photoelectric conversion element, wherein:
An ophthalmologic measuring apparatus comprising: a detection unit that detects an output fluctuation of the light source; and a calculation unit that calibrates the measurement result based on the detection result of the detection unit. 2. A laser projecting optical system for converging and projecting laser light emitted from a laser light source toward an eyeball of an eye to be inspected, and molecules inside the crystalline lens by the laser light. In a scattered light detection optical system including a photoelectric conversion element for detecting scattered light, in an ophthalmologic measuring device for measuring the characteristics of the tissue of the crystalline lens based on the light intensity detected by the photoelectric conversion element, the sensitivity of the photoelectric conversion element An ophthalmologic measuring apparatus comprising: a detection unit for detecting, and a calculation unit for calibrating the measurement result based on the detection result of the detection unit. 3. A laser projecting optical system for converging and projecting laser light emitted from a laser light source toward an eyeball of an eye to be inspected, and molecules inside the crystalline lens by the laser light. In a scattered light detection optical system including a photoelectric conversion element that detects scattered light, and an ophthalmologic measuring device that measures the characteristics of the tissue of the crystalline lens based on the light intensity detected by the photoelectric conversion element, laser light is used as the photoelectric conversion light. A light guide optical system that directly leads to the light receiving element surface of the conversion element, and laser light that enters the photoelectric conversion element is selectively selected from those of the light guide optical system and the scattered light detection optical system. An ophthalmologic measuring apparatus, comprising: a selecting unit for selecting the amount of light that has passed through the light guide optical system and incident on the photoelectric conversion element, and a calculating unit that calibrates a measured value based on the detected value. 4. The ophthalmologic measuring apparatus according to claim 3, wherein the light guide optical system comprises a diffusion plate and an optical fiber into which the diffused laser light is incident. 5. The selecting means according to claim 3, wherein a first shutter is provided in an optical path of the scattered light detection optical system, and the first shutter is provided at the time of calibration.
An ophthalmologic measuring apparatus having control means for closing a shutter. 6. The selection means according to claim 3, wherein a first shutter is provided in an optical path of the scattered light detection optical system, and a second shutter is provided in an optical path of the light guide optical system, and the first shutter and the second shutter are provided. An ophthalmologic measuring apparatus having control means for controlling the operation of a shutter. 7. The ophthalmic measurement according to claim 3, wherein the selection means controls the laser light of the light guide optical system to enter the photoelectric conversion element at least once for each measurement. apparatus.