JP3461950B2 - Ophthalmic measurement device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converges and irradiates a laser beam toward the eyeball of an eye to be inspected, and guides the scattered light by the molecules inside the crystalline lens by this laser beam to a photoelectric conversion element through a light receiving optical system. The present invention relates to an ophthalmologic measuring device that measures the properties of a crystalline lens based on the output signal of a photoelectric conversion element.

[0002]

2. Description of the Related Art A laser beam is converged and radiated toward an eyeball of an eye to be inspected, and scattered light by molecules inside the crystalline lens by the laser beam is guided to a photoelectric conversion element through a light receiving optical system to output the photoelectric conversion element. A device for measuring the protein composition and the like inside the lens based on the signal is known. In this type of device, it is necessary to take care not to damage the tissues such as the retina of the subject's eye by the irradiated laser light. Therefore, when the laser light intensity to be irradiated is set to the minimum necessary intensity, and at the same time when the laser light reaches the retina by increasing the convergence angle of the laser light flux, the laser light diverges and the laser light intensity per unit area, That is, the light density is reduced.

[0003]

However, when the converging angle of the laser light flux irradiated with the circular light flux is increased,
The converging point of the laser luminous flux, that is, the laser luminous flux size at the measurement point becomes small. Therefore, the measurement area becomes smaller,
There is a problem that a deviation from the intended measurement site is likely to occur due to the movement of the eyeball or the like. In addition, the small laser beam size at the measurement point makes it very difficult to align the same measurement site as the previous time when performing multiple measurements or later measurements, and the measured data tends to have poor reproducibility. It was

The present invention has been devised in view of the above-mentioned drawbacks, and an object of the present invention is to provide an ophthalmologic measuring apparatus in which the deterioration of the reproducibility due to the movement of the eyeball and the difference in the measurement site is improved.

[0005]

The present invention is characterized by having the following configuration in order to achieve the above object. (1) A laser irradiation optical system that converges and irradiates a laser beam toward the eyeball of the eye to be inspected, and detects scattered light of molecules inside the crystalline lens of the laser beam irradiated by the laser irradiation optical system. In a scattered light detection optical system and an ophthalmologic measuring device for measuring the tissue property of the crystalline lens based on the light intensity detected by the scattered light detection optical system, a light flux for shaping the laser light flux into an elliptical light flux in the irradiation optical system. An ophthalmologic measuring device having a shaping means.

(2) The elliptical light flux shaped by the light flux shaping means of (1) has a major axis in the optical axis direction of the scattered light detection optical system.

(3) The light flux shaping means of (1) is characterized by being a cylindrical lens.

(4) A laser irradiation optical system for converging and irradiating a laser beam toward the eyeball of the eye to be inspected, and a scattered light of the laser beam irradiated by the laser irradiation optical system by molecules inside the lens. In the ophthalmologic measuring apparatus for measuring the tissue property of the crystalline lens based on the light intensity detected by the scattered light detection optical system and the scattered light detection optical system, an elliptical laser beam is provided to the laser irradiation optical system. It is characterized by using a laser light source for emitting

(5) The elliptical laser beam emitted from the laser light source of (4) has a major axis in the optical axis direction of the scattered light detecting optical system.

(6) The laser light source of (4) is a semiconductor laser light source.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of an optical system and an electric system of an apparatus for measuring a protein composition in a lens as an example. The optical system is shown from above. Reference numeral 1 is a laser light source that emits a He-Ne visible laser light, 2 is an expander lens, 3 is a cylindrical lens having a generatrix in a direction perpendicular to the apparatus, and 4 is a condenser lens. 1 to 4 constitute a laser irradiation 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 a fixation target onto the fundus of the eye to be examined. Reference numeral 9 is an imaging lens, 10 is a diaphragm, 11 is a CCD camera, and 9 to 11 constitute 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 1
2 to 14 form a scattered light detection optical system. Reference numeral 15 is an image composition circuit, 16 is an arithmetic circuit, 17 is a control computer, 1
Reference numeral 8 is a television monitor, 19 is an input means, and 20 is a storage means.

Next, the operation of the above device will be described.
The light emitted from the point light source 7 is reflected by the beam splitter 8 toward the eye to be examined. The eye is fixed on the fixation target and the visual axis of the eye is fixed. The image of the anterior ocular segment of the subject's eye illuminated by an illumination light source (not shown) is received by the CCD camera 11 of the observation optical system, and the image is displayed on the television monitor 18.
The laser light output from the laser light source 1 has its luminous flux expanded by the expander lens 2 and is converted by the cylindrical lens 3 and the condenser lens 4 into an elliptical convergent luminous flux having a major axis in the horizontal direction with respect to the apparatus. The crystalline lens 6 of 5 is irradiated from an oblique direction. The examiner determines the measurement site while observing the laser converging light flux which is projected on the anterior eye part and the lens 6 projected on the television monitor 18 from an oblique direction, and determines the measurement site.
The measurement start switch provided at 9 is pressed to start the measurement.

As described above, the measurement light beam is an elliptic convergent light beam having a major axis in the horizontal direction with respect to the apparatus, and the eye 5 to be inspected.
The crystalline lens 6 is irradiated from an oblique direction. Figure 2 (a)
FIG. 6 is a diagram for explaining a state of a laser light flux which is irradiated onto the eye 5 as an elliptical convergent light flux by the laser irradiation optical system. In FIG. 2A, due to the action of the cylindrical lens 3, the convergent light flux has an elliptical shape that is stretched in the left-right direction.
This elliptical convergent light flux is elongated in the depth direction when viewed from the light receiving optical system. Therefore, the measurement area can be increased in the depth direction as compared with the normal circular convergent light flux shown in FIG. 2B in which the cylindrical lens 3 is not arranged.

The elliptical converging light flux applied to the lens 6 of the eye 5 to be examined is scattered by the protein particles in the lens 6 to become scattered light, which is condensed by the imaging lens 12 and the aperture 13 which limits the measurement area. After passing, it 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 the electric signal to the arithmetic circuit 16. The arithmetic circuit 16 obtains the correlation function of the temporal fluctuation of the scattered light intensity based on the input signal, and the control computer 17 obtains the measurement result of the protein composition inside the lens by this correlation function. As for this measurement, for example, Table 6-
As described in No. 505650 (Invention title “Method and apparatus for detecting occurrence of cataract”), the correlation function of the temporal variation of scattered light intensity is

The protein composition inside the lens is calculated from the ratio of If (scattered light intensity from non-aggregated particles) and Is (scattered light intensity from agglomerated particles) expressed by the following equation. It is calculated.

The measurement result is sent to the CC by the image synthesizing circuit 15.
The image output from the D camera 11 is combined and displayed on the television monitor 18. The measurement result can be stored by the storage unit 20. Although the He-Ne laser is used as the laser light source 1 in the above embodiment, a laser light source that originally emits an elliptical laser beam is used as in the semiconductor laser, and the ellipse thereof is used. The cylindrical lens 3 can be omitted by disposing the laser light source so that the laser beam has a major axis in the optical axis direction of the scattered light detection optical system.

[0017]

As described above, the ophthalmologic measuring apparatus according to the present invention can increase the laser light flux size at the measurement point without reducing the convergence angle of the laser light flux, so that a large measurement area can be secured. can do. Therefore, it is easy to align with the desired measurement site,
In addition, even when the measurement is performed a plurality of times or the measurement is performed again later, it is possible to prevent the measurement reproducibility from being deteriorated due to the influence of the movement of the eye to be inspected or the alignment shift.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an optical system and an electric system of an apparatus of this embodiment.

FIG. 2A is a diagram illustrating a state of an elliptical laser convergent light flux with which an eye to be inspected is irradiated. (B) It is a figure explaining the state of the circular laser converging light flux with which the to-be-tested eye is irradiated.

[Explanation of symbols]

1 laser light source 2 expander lens 3 cylindrical lens 4 condenser lens 5 Eye to be examined 6 crystalline lens 14 Photoelectric conversion element 16 arithmetic circuit 17 Control computer

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Claims (6)

(57) [Claims] 1. A laser irradiation optical system for converging and irradiating a laser beam toward an eyeball of an eye to be inspected, and a laser beam irradiated by the laser irradiation optical system for scattering light by molecules inside a crystalline lens. In a scattered light detection optical system for detecting, and an ophthalmologic measuring device for measuring the tissue property of the crystalline lens based on the light intensity detected by the scattered light detection optical system, a laser light flux is shaped into an elliptical light flux in the irradiation optical system. An ophthalmologic measuring apparatus, which is provided with a light beam shaping means for performing the above. 2. An ophthalmologic measuring apparatus, wherein the elliptical light flux shaped by the light flux shaping means according to claim 1 has a major axis in the optical axis direction of the scattered light detection optical system. 3. An ophthalmologic measuring apparatus, wherein the light beam shaping means according to claim 1 is a cylindrical lens. 4. A laser irradiation optical system for converging and irradiating a laser beam toward an eyeball of an eye to be inspected, and a laser beam irradiated by the laser irradiation optical system for scattering light by molecules inside a crystalline lens. In a scattered light detection optical system to detect, and an ophthalmologic measuring device for measuring the tissue property of the crystalline lens based on the light intensity detected by the scattered light detection optical system, an elliptical laser light flux to the laser irradiation optical system. An ophthalmologic measuring device using a laser light source for emitting light. 5. An ophthalmologic measuring apparatus, wherein the elliptical laser light flux emitted from the laser light source according to claim 4 has a major axis in the optical axis direction of the scattered light detection optical system. 6. The ophthalmologic measuring apparatus according to claim 4, wherein the laser light source is a semiconductor laser light source.