JPH0191828A - Ophthalmic measuring apparatus - Google Patents

Abstract

PURPOSE:To rapidly and accurately measure the refractivity of an intraocular lens, by mounting a optical measuring means for obtaining the cornea shape data of an eye to be examined and an ultrasonic measuring means for obtaining the length of the predetermined region of the eye to be examined by an ultrasonic probe. CONSTITUTION:When the shape of the cornea is measured, the cornea reflected images of light sources 7a-7d are brought to almost parallel beams by the objective lens 1 opposed to an eye E to be examined and reflected by mirrors 2, 3 to be formed into an image on an imaging element 6 by an iris 4 and a relay lens 5. Next, when the axial length of the eye to be examined is measured, the objective lens 1, the mirrors 2, 3 and the light sources 7a-7d move downwardly and an ultrasonic probe 8 advances along a slide guide member 10 guiding a probe holder 9 and approaches the cornea Ec of the eye E to be examined or is brought into contact therewith to measure the axial length of said eye. A microprocessor unit 28 calculates the refractivity of an intraocular lens from the cornea shape and eye axial length thus measured according to the predetermined operation formula written in a read-on memory 29 and the calculation result is displayed on a television monitor 25 through an image memory 24 and a mixer circuit 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention optically measures the corneal shape of an eye to be examined, and also measures lens thickness and vitreous length using ultrasound.

The present invention relates to an ophthalmological measuring device that measures various parts of an eye to be examined, such as axial length.

[Prior Art] Conventionally, spectacle lenses or contact lenses have been used to correct refractive power, for example after cataract surgery, but in recent years, intraocular lenses have been inserted into the position of the removed crystalline lens.

In order to select an appropriate intraocular lens for patients with aphakic eyes, it is necessary to know the corneal refractive power and the axial length, that is, the length from the cornea to the retina. Therefore, in the past, corneal refractive power was measured using a corneal shape measuring device, while axial length was measured using a separate ultrasonic measuring device, and the refractive power of the intraocular lens was calculated after each measurement was completed. This was inconvenient and required a considerable amount of effort and time to measure.

In addition, devices that have both of these two functions are also known, but in such devices, an ultrasound probe for measuring the axial length is present in the optical path when measuring the corneal shape, so the corneal reflection image is It has drawbacks such as being eclipsed by the image of the sonic probe, making it difficult to make accurate measurements.

[Object of the Invention] An object of the present invention is to provide optical measurement means for obtaining information on the corneal shape of the eye to be examined, and ultrasonic measurement means for obtaining the length of a predetermined part of the eye to be examined using an ultrasonic probe. An object of the present invention is to provide an ophthalmological measuring device that can quickly and accurately measure the refractive power of an intraocular lens using a calculation means based on the refractive power and the length of a predetermined portion.

[Summary of the Invention] The gist of the present invention to achieve the above-mentioned object is to provide an optical measuring means for obtaining information on the corneal shape of the eye to be examined, and an ultrasonic probe for obtaining a length signal of a predetermined part of the eye to be examined using an ultrasonic probe. a driving mechanism for selectively moving the optical measuring means and the ultrasonic measuring means to a position facing the eye to be examined; A storage means for storing the length of the region, a calculation means for calculating the refractive power of the intraocular lens from the corneal refractive power stored in the storage means and the length of the predetermined region, and a display means for displaying the output of the calculation means. This is an ophthalmological measuring device characterized by comprising:

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

1 and 2 show the optical system of the ophthalmological measuring device according to the present invention, FIG. 1 shows the state when measuring the shape of the cornea, and FIG. 2 shows the state when measuring the axial length of the eye. In Figure 1, the eye to be examined E
An objective lens 1 is provided facing the cornea Ec, and a mirror 2.3, a 4% aperture relay lens 5, and a two-dimensional imaging device 6 such as a CCD are arranged behind the objective lens 1 along the optical path.

Further, a plurality of light sources 7a to 7d are arranged around the objective lens 1, as shown in FIG. The objective lens l, the mirror 2.3, and the light sources 1a to 1d are integrally constructed, and a drive mechanism (not shown) changes the state from the state shown in FIG. 1 to the second state.
It is possible to move to the state shown in the figure or vice versa. Further, an ultrasonic probe 8 is held by a sliding guide member 10 via a probe holder 9 so as to be movable back and forth along the optical axis of the objective lens 1 shown in FIG.

In the case of the corneal shape measurement shown in FIG. An image is formed on the image sensor 6. In this case, the ultrasonic probe 8 is located behind the mirror 2 and removed from the optical path.

Next, in the case of measuring the ocular axial length, as shown in FIG. 2, the objective lens 1. As the mirror 2.3 and the light sources 7a to 7d move downward, the ultrasound probe 8 moves forward along the sliding guide member lO that guides the probe holder 9, approaches or contacts the cornea Ec of the eye E to be examined. Axial length measurements are taken.

FIG. 4 shows a circuit configuration for performing the above-described operation. Here, the output of the two-dimensional image sensor 6 is connected to an image signal processing circuit 21 and a mixer circuit 22.
1 is connected to the internal bus 23. In addition, internal bus 2
An image memory 24 is connected to 3, an output of the image memory 24 is connected to a mixer circuit 22, and an output of the mixer circuit 22 is connected to a television monitor 25. The ultrasonic probe 8 includes an ultrasonic transmitting/receiving circuit 26. It is connected to the internal bus 23 via an ultrasonic signal processing circuit 27 .

Also, microprocessor unit (MPU) 28,
The outputs of read-only memory (ROM) 29, random access memory (RAM) 30, and nonvolatile memory 31 are connected to internal bus 23, and the output of bus circuit 25 is connected to interface 32 and printer 33. Further, the interface 32 includes a measurement switch 34, a changeover switch 35 for switching between the optical measurement means and the ultrasonic measurement means, light sources 7a to 7d, and electric motors 36 and 37 for driving the optical measurement means and the ultrasonic measurement means, respectively. It is connected.

When performing corneal topography measurement, as shown in FIG. Next, when the measurement switch 34 is pressed, the corneal reflection images IA to ID of the light sources 7a to 7d, which are imaged on the image sensor 6 by the signal from the ink face 32, are stored on the image memory 24. Ru. By measuring the coordinates of the four stored corneal reflection images IA to ID, the corneal shape can be determined by a known method.

As a result, the microprocessor 2217 calculates corneal shape information such as maximum radius of curvature, minimum radius of curvature, average radius of curvature, degree of corneal astigmatism, and astigmatism using a predetermined calculation formula written in read-only memory 29. The axial angle, the spherical refractive power, the ocular refractive astigmatism, and the astigmatic axial angle, which are subordinate power information, are calculated, and the calculation results are displayed on the television monitor 25 via the image memory 24 and the mixer circuit 22 as shown in FIG. is displayed numerically. In FIG. 5, L represents the left eye and R represents the right limit information.

Next, when measuring the length of a predetermined portion of the eye E to be examined using ultrasound, the ultrasound probe 8 is brought into contact with the corner MEc of the eye E to be examined, as shown in FIG. At this time, a driving pulse is applied to the ultrasound probe 8 from the ultrasound transmitting/receiving circuit 26, and an ultrasound pulse signal is emitted into the eyeball of the eye E to be examined. If there is an echo from within the eyeball, it is amplified by the ultrasonic transmitting/receiving circuit 26, converted into a digital signal by the A/D converter in the ultrasonic signal processing circuit 27, and then sent to the image memory 24 via the internal bus 23. As a result, an ultrasonic reflection signal S as shown in FIG. 6 is displayed on the television monitor 25. In this case, the eye to be examined E
The eye E to be examined is guided in the direction of the visual axis or the angle of the ultrasound probe 8 is changed so that the echoes from the crystalline lens and retina are maximized.

Then, when the measurement switch 34 is pressed, the interface 32
An echo from within the eyeball of the eye E to be examined is measured using a known method. As a result, the microprocessor unit 28 calculates the axial length, anterior chamber depth, crystalline lens thickness, and vitreous thickness using a predetermined calculation formula written in the read-only memory 29, and the results are stored in the image memory 24. It is displayed on the television monitor 25 via the mixer circuit 22.

Based on the corneal shape information and the measured value of the axial length thus measured, the microprocessor unit 28 calculates the refractive power of the intraocular lens using a predetermined calculation formula written in the read-only memory 29, and calculates the refractive power of the intraocular lens. The result is image memory 24
, and is displayed on the television monitor 25 via the mixer circuit 22.

Only one of the corneal shape measurement and the length measurement of a predetermined region of the eye E to be examined can be selectively performed;
After finishing one of the measurements, it is possible to automatically continue the measurement of the other one or prepare for the other one. Further, when the corneal refractive power and the length of the predetermined region of the eye E to be examined are ITIII determined, the refractive power of the intraocular lens can be automatically calculated and displayed next.

Furthermore, the optical system for measuring corneal shape and the ultrasonic measuring means are
The drive mechanism for moving from the state shown in the figure to the state shown in FIG. 2, or vice versa, can be automatically driven by a calculation means.

[Effects of the Invention] As explained above, the ophthalmological measuring device according to the present invention can measure corneal shape and axial length etc. with one device, so that, for example, selecting an intraocular lens can be performed accurately and quickly. Is possible. Furthermore, in the case of corneal shape measurement, since the ultrasound probe is removed from the optical path, the corneal reflection image is not obscured by the image of the ultrasound probe, allowing accurate measurement.

[Brief explanation of the drawing]

The drawings show an embodiment of the ophthalmological measuring device according to the present invention, and the first embodiment
The figure is a block diagram of the state of corneal topography measurement, Figure 2 is a block diagram of the state of ultrasonic measurement, Figure 3 is a light source arrangement diagram, Figure 4 is a block circuit diagram, and Figures 5 and 6 are FIG. 3 is a front view of the television monitor. 1 is an objective lens, 2 and 3 are mirrors, %4 is an aperture, 5 is a relay lens, and 6 is a two-dimensional image sensor. 7a to 7d are light sources, 8 is an ultrasonic probe, 9 is a probe holder, 10 is a sliding guide member, and 25 is a television monitor. Patent applicant Canon Co., Ltd. Drawings Figure 1 Collection 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. An optical measurement means for obtaining corneal shape information of the eye to be examined, an ultrasonic measurement means for obtaining a length signal of a predetermined part of the eye to be examined using an ultrasonic probe, and a combination of the optical measurement means and the ultrasound probe. a drive mechanism for selectively moving the acoustic wave measuring means to a position facing the subject's eye; a storage means for storing the corneal refractive power based on the corneal shape information and the length of the predetermined region based on the signal of the predetermined region; An ophthalmological measurement characterized by comprising a calculation means for calculating the refractive power of an intraocular lens from the corneal refractive power stored in the storage means and the length of a predetermined region, and a display means for displaying the output of the calculation means. Device. 2. The ophthalmological measuring device according to claim 1, wherein the selection between the optical measuring means and the ultrasonic measuring means is performed by moving an optical system around an objective lens of the optical measuring means. 3. The ophthalmological measuring device according to claim 1, wherein when either the corneal refractive power or the length of the predetermined region is measured, the other is automatically measured next. 4. Ophthalmological measurement according to claim 1, wherein when either the corneal refractive power or the length of the predetermined region is measured, preparations for the next measurement of the other are automatically performed. Device. 5. The ophthalmological measuring device according to claim 1, wherein the length of the predetermined portion is the axial length of the eye. 6. The ophthalmological measuring device according to claim 5, wherein when the corneal refractive power and the axial length are measured, the refractive power of the intraocular lens is then calculated and displayed. 7. The ophthalmological measuring device according to claim 6, wherein a plurality of constants of the refractive power of the intraocular lens are stored, and the refractive power of the intraocular lens is calculated and displayed using each constant.