JPH0249632A - ophthalmological model eye - Google Patents

Abstract

PURPOSE:To rapidly perform the measurement of the refractivity of the cornea and the axial length of an eye by performing alignment only once by sealing an ultrasonic wake transmitting substance for transmitting an ultrasonic wave at a low speed in a housing having an optical spherical reflecting surface provided to the front part thereof and an ultrasonic wave reflecting surface provided to the rear part thereof. CONSTITUTION:The ultrasonic wave reflecting surface 1a of a housing 1 is composed of material quality well reflecting an ultrasonic wave and the axial length of an ultrasonic wave transmitting substance 2 is set to a dimension almost near to the length from the cornea of a human eye to the retina thereof as an ultrasonic measured conversion value. The spherical reflected images of a plurality of spot light sources 17 arranged around an objective lens 16 are formed by the spherical reflecting surface 3a of a model eye M. The mutual positional relation of said spot light sources 17 is detected by a photodetector through an optical system containing the objective lens 16 and, further, signal processing and operational processing are performed to calculate the refractivity of the cornea. Next, a part of an optical system containing the objective lens 16 or a mirror 18 is retracted while an ultrasonic probe 19 is advanced to be lightly applied to the spherical reflecting surface 3a of the model eye M and an ultrasonic wave is oscillated into the model eye and the reflecting signal of said ultrasonic wave is detected to measure the axial length of an eye.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a complex ophthalmological measurement system that has two measurement functions: corneal refractive power measurement using optical means and axial length measurement using ultrasonic waves. The present invention relates to an ophthalmological model eye that is effective for use in an apparatus.

[Prior Art] Conventionally, a complex ophthalmological measuring device has been developed which has two measurement functions: corneal refractive power measurement using optical means and axial length measurement using ultrasound. The model eyes used to test or demonstrate such a complex device have traditionally been steel balls or spherical lenses for measuring corneal refractive power, and eye models for measuring axial length. Model eyes that are used underwater and model eyes that use columnar metal members are each used individually.

In this way, in the past, separate eye models were used for each of the two measurements, which caused the hassle of having to attach and align the eye to the ophthalmological measuring device for each measurement, which required equipment certification and demonstration training. There is a problem in that it is not possible to quickly carry out an action.

[Object of the Invention] In order to improve such problems, the object of the present invention is to enable one model eye to be used both for corneal refractive power measurement and axial length measurement, and to perform alignment only once. An object of the present invention is to provide a composite ophthalmological model eye that can quickly perform both measurements.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to transmit ultrasonic waves at a low velocity into the interior of a housing having an optical spherical reflecting surface in the front and an ultrasonic reflecting surface in the rear. This is an ophthalmological model eye characterized by enclosing an ultrasonic conductive substance that transmits ultrasonic waves.

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

FIG. 1 shows an example of an ophthalmological model eye according to the present invention,
Inside the cylindrical casing l, which is open at the front and has an ultrasonic reflecting surface 1a at the rear bottom, is an ultrasonic conductor made of water or other liquid material that conducts ultrasonic waves well at low speeds. A substance 2 is enclosed, and the front opening is closed by a meniscus lens-shaped spherical reflective member 3. This spherical reflective member 3 corresponds to the cornea of the human eye, and it is desirable that the radius of curvature of the spherical reflective surface 3a on the front side be as close to the radius of curvature of the cornea of the human eye as possible. The spherical reflecting member 3 is made of a material capable of transmitting ultrasonic waves, and the spherical reflecting surface 3a may be within a range of about 5 to 10 mm.
If the reflectance of the material is comparable to that of the cornea of the human eye, there is no problem even if it is made of an opaque material. O-rings 5.6 are interposed between the spherical reflective member 3 and the lid member 4 and the housing 1 to prevent leakage of the ultrasonic conductive material 2. The ultrasonic reflecting surface 1a of the housing 1 is made of a material that reflects ultrasonic waves well, and the axial length of the ultrasonic conducting material 2 is approximately II4 from the cornea at the time of falling asleep in terms of ultrasonic measurement conversion value.
The dimensions are almost the same as the length to the membrane. That is, the spherical reflecting member 3 corresponds to the cornea of a deep sleep, and the ultrasonic reflecting surface 1a of the housing 1 corresponds to the retina.

FIG. 2 shows another embodiment of the ophthalmological model eye according to the present invention, and the same reference numerals as in FIG. 1 indicate the same or equivalent members. In this case, two thin films 7 and 8 are placed near the opening in the casing 1 with an appropriate interval between them. As shown in FIG. 3, these thin films 7 and 8 have small holes 9 near their periphery for allowing the ultrasonic conductive substance 2 to flow, and have a spacing 10 that corresponds to the thickness of the human eye lens. spacing is maintained. In this case, the ultrasonic conductive material 2 inside the casing 1 is sealed by the spherical reflective member 3 and the lid member 4, but the internal pressure is adjusted to approximately the same level as the intraocular pressure of the human eye by the pressure adjustment plug ti. It is possible to adjust the degree.

This pressure adjustment means can be achieved by, for example, making a pressure adjustment plug 11 made of a material with good elasticity such as rubber, and inserting the needle of a well-known syringe 12 into the pressure adjustment stopper 11 to inject or expel the ultrasonic conductive substance 2. The pressure can be increased or decreased.

FIG. 4 shows the relationship between the human eye E and the waveform S of the ultrasonic reflection signal at regular intervals on the long side of the eye axis. In Figure 2, the fourth
A spherical reflective member 3 corresponding to the cornea C of the human eye in the figure is formed of a flexible material with a glossy surface, such as silicone rubber, and thin films 7 and 8 are respectively formed on the anterior capsule L of the human eye lens.
By placing it at a position corresponding to f and after meal Lb,
It is possible to approximate the waveform of the ultrasonic reflected signal when measuring the axial length of the eye to the waveform when measuring the actual human eye. Therefore, in the embodiment shown in FIG. 2, not only the axial length A shown in FIG. 4 but also the anterior chamber depth B
, lens thickness C1, vitreous length, etc. can also be measured.

FIG. 5 shows an example of how this model eye M is used, and 13 shows the main body of a complex ophthalmological measuring device that has two functions of corneal refractive power measurement and axial length measurement. The face rest is fixed to the pillar 14 with a mounting bracket 15.

When measuring the corneal refractive power, first, an alignment operation is performed to properly align the device main body 13 and the model eye M. When the alignment is properly performed, a spherical reflection image of a plurality of point light sources 17 arranged around the objective lens 16 is formed by the spherical reflection surface 3a of the model eye M. The mutual positional relationship of the point light source images is detected by a light receiving element (not shown) through an optical system including the objective lens 16, and further electrical signal processing and arithmetic processing are performed to determine the corneal refractive power.

Next, in the case of measuring the ocular axial length, the objective lens 16 and the mirror 1 are
After retracting a part of the optical system including 8, the ultrasound probe 19 is advanced and lightly applied to the spherical reflective surface 3a of the model eye M to oscillate ultrasound into the model eye. The axial length is measured by detecting the reflected signal.

As mentioned above, the model eye according to the present invention is most effective when used in a complex ophthalmological measuring device that has two functions of corneal refractive power measurement and axial length measurement, but it is not necessarily limited to the complex type. For example, it goes without saying that the present invention can also be used in a device that only measures the axial length of the eye or a device that only measures the corneal refractive power.

In addition, if the front spherical reflective member 3 is made of a material with elasticity and flexibility, and the internal pressure is made to be about the same as the internal pressure of the human eyeball, the dent will appear when the tip of the ultrasound probe is pressed against it. Since the conditions are close to those during actual human eye measurement, testing and demonstrations of ophthalmological measuring devices such as tonometers can be performed with a sense of realism. In addition, even if a liquid such as water is used as the ultrasonic conductive material sealed inside, the sealed structure allows it to be installed in any direction.
Maintenance is also easy.

[Effects of the Invention] As explained above, in the ophthalmological eye model according to the present invention, one model eye can be used for two measurements: corneal refractive power measurement and axial length measurement. Furthermore, when measuring a model eye using a measurement system that matches the corneal position during corneal refractive power measurement with the corneal position during axial length measurement using a complex ophthalmological measurement device, alignment operations are only required once. It is possible to quickly proceed with both measurements.

[Brief explanation of the drawing]

The drawings show an example of the ophthalmological model eye according to the present invention, and the first
The figure is a cross-sectional view, Figure 2 is a cross-sectional view of another embodiment, Figure 3 is a front view of the thin film, Figure 4 is a diagram of the relationship between the human eye and ultrasound reflected signals, and Figure 5 is an explanation of usage conditions. It is a diagram. Symbol l is a housing, la is an ultrasonic reflecting surface, 2 is an ultrasonic conducting material, 3 is a spherical reflecting member, 3a is a spherical reflecting surface, 4 is a lid member, 5.6 is an O ring, 7.8 is a thin film, 9 is a small hole, 10 is a spacing ring, and 11 is a pressure adjustment plug.

Claims (1)

[Claims] 1. For ophthalmology, characterized in that an ultrasonic conductive material that transmits ultrasonic waves at a low speed is sealed inside a housing having an optical spherical reflecting surface in the front and an ultrasonic reflecting surface in the rear. Model eyes.