JP2836873B2 - Eye axial length probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used in an eye axial length measuring device that obtains the axial length of an eyeball by irradiating an ultrasonic wave into the eyeball and resolving the echo. And a probe for measuring the axial length of the eye.

[Related Art] For example, an intraocular lens transplantation operation is performed for the treatment of cataract. In this case, the implanted intraocular lens must have a refractive power compatible with the patient. In order to obtain this refractive power, it is generally necessary to know the axial length of the eye as well as the radius of curvature of the cornea. Conventionally, as an apparatus for measuring the axial length, an axial length measuring apparatus that irradiates an ultrasonic wave into an eyeball and analyzes its echo is known. This eye axial length measuring device uses an eye axial length measuring probe.

In short, the probe for measuring the axial length of the eye has an ultrasonic probe attached to the tip of the case. When measuring the axial length of the eye, the ultrasonic probe directly on the cornea of the eyeball,
Alternatively, the ultrasonic wave is made to come into contact with a predetermined medium, an ultrasonic wave is made to enter the eyeball, and the echo is detected. The detected echo is analyzed by a predetermined circuit means, and the target distance, that is, the axial length, is determined from the time from the ultrasonic wave incident time to the echo detection time, or the time difference between the echoes and the sound speed.

By the way, in order to accurately determine the axial length of the eye, the ultrasonic axis of the ultrasonic probe (the center axis of the ultrasonic beam) must coincide with the visual axis. Conventionally, this axis alignment, while observing the position and shape of the echo peak on the CRT display, so that the echo peak at a predetermined position and shape,
The contact angle of the ultrasonic probe to the cornea was adjusted. This adjustment requires skill and is likely to cause pain for the patient. Therefore, as a method that can be adjusted more easily, a method using a so-called fixation lamp has been proposed.
In this method, a through-hole is provided along the center axis of the ultrasonic probe, and light (fixation lamp) is emitted forward from the through-hole, so that the patient can fixate the light. It is. As a result, the visual axis coincides with the optical axis of the light, and consequently coincides with the ultrasonic axis coincident with the optical axis (for example, Japanese Utility Model Application Laid-Open No. 61-111409, Kosho 63
-16131, Japanese Utility Model Publication No. 1-121010, etc.).

[Problems to be Solved by the Invention] However, in the above-described conventional probe for measuring the axial length of the eye, a through-hole must be provided along the center axis of the ultrasonic probe. When a through hole is provided in the ultrasonic probe, transmission and reception of ultrasonic waves are not performed at that portion. For this reason, the transmission and reception efficiency of the ultrasonic wave decreases, and the detection sensitivity of the echo decreases. Moreover,
Since the intensity of the center portion of the ultrasonic beam is small and the intensity distribution of the beam becomes non-uniform, the shape of the echo is adversely affected and analysis becomes difficult.

In addition, since the patient stares at the light, in some cases, the iris is closed due to feeling dazzling, and there is a problem that an iris echo or the like harmful to the analysis is generated.

The present invention has been made under the above-mentioned background,
It is an object of the present invention to provide a probe for measuring the axial length of an ultrasonic probe that does not have a through hole in the ultrasonic probe, enables alignment with a fixation lamp, and does not cause a patient to feel dazzling during alignment. [Means for Solving the Problems] The present invention solves the above-described problems by adopting the following configuration.

An eye axis length measuring probe used in an eye axis length measuring device for obtaining an eye axis length of the eyeball by irradiating an ultrasonic wave into an eyeball and analyzing an echo thereof, comprising: a case part; An ultrasonic probe attached to a distal end of the ultrasonic probe, a light guide formed around the ultrasonic probe, and a light source for supplying light to the light guide. From the periphery of the distal end portion of the ultrasonic probe through the light guide section toward the front.

[Operation] In the above-described configuration, the ultrasonic probe is brought into contact with the corneal surface of the eyeball, the ultrasonic wave is made incident on the eyeball, and the echo is detected. At this time, the patient can see an image formed by the light emitted from the light guide. This image is
When the ultrasonic probe is away from the cornea, the ultrasonic probe part is dark, the surrounding light guide is bright,
In addition, the outside appears dark. However, as the ultrasonic probe gradually approaches the cornea, the dark part of the ultrasonic probe becomes smaller, and conversely, the bright part (hereinafter referred to as a bright part) increases. When the ultrasonic probe comes into contact with the cornea, the dark portion of the ultrasonic probe becomes substantially dot-shaped, that is, the image at that time is a point-shaped dark portion (hereinafter referred to as a dark portion) in the bright region. (Called a scotoma). At this time, when the visual axis is displaced from the ultrasonic axis of the ultrasonic probe, the scotoma appears to be displaced from the center of the bright region, and is located at the center when these axes coincide. become. Therefore, if the patient fixes his / her eyes on the dark spot and makes the dark spot appear at the center, the visual axis and the ultrasonic axis coincide.

In this case, it is not necessary to provide a through-hole or the like in the ultrasonic probe as in the related art. Therefore, there is no reduction in echo detection sensitivity or disturbance of echo peaks due to the provision of the through-holes, and analysis is facilitated.

In addition, the patient sees a dark spot instead of a bright spot as in the past. In addition, the light portion around the dark point has a large light spread from the light guide means, and has a low light intensity. Therefore, the patient does not feel dazzling even when looking at the scotoma. As a result, since the iris does not close, a normal echo is obtained and analysis is facilitated.

[Example] FIG. 1 is a partially cutaway cross-sectional view of a probe for measuring an axial length according to an embodiment of the present invention, FIG. 2 is a diagram showing how the axial length is measured by the probe of the embodiment, FIG. 3 is a view showing an image seen by a patient, and FIG. 4 is an explanatory view of a visual axis. Hereinafter, an embodiment will be described in detail with reference to these drawings.

In FIG. 1, reference numeral 1 denotes a case portion, reference numeral 2 denotes an ultrasonic probe, reference numeral 3 denotes light guide means, reference numeral 4 denotes a light source, and reference numeral 10 denotes a probe for measuring the axial length of the eye.

The case section 1 is a rod-like body in which a storage space 11 for storing components is formed. The distal end portion (right end portion in the figure) 12 of the case portion 1 is formed in a tapered shape so as to become thinner toward the distal end. A through-hole 13 having a circular cross section with the center axis O of the case portion 1 passing through the storage space 11 and the outside is provided inside the distal end portion 12. . This through hole
13 is fitted with a cylindrical light guide means 3.

The light guide means 3 is made of a transparent material such as transparent plastic or glass, and is fitted and fixed to the through hole 13 so that a part of the light guide means 3 projects from the tip of the through hole 13 to the outside. The light guiding means 3 may be made of a material that can transmit light, and may be, for example, a ring formed by bundling a large number of optical fibers. In the case of using the transparent plastic or glass, if a light-shielding film is formed on the surface to prevent light leakage, efficient light guide can be achieved.

A cylindrical ultrasonic probe 2 is fitted to the tip of the light guide 3. The ultrasonic probe 2 transmits and receives a predetermined ultrasonic wave. In other words, an ultrasonic beam u of a predetermined frequency (for example, 10 MHz) is emitted from the right end face in the drawing by a drive signal transmitted through a terminal (not shown), and at the same time, the emitted ultrasonic waves are reflected and reflected by the external structure. The ultrasonic echo is detected and sent to an external circuit (not shown). In this case, the center axis of the emitted ultrasonic beam u, that is, the ultrasonic axis coincides with the central axis of the ultrasonic probe 2, and the central axis of the ultrasonic probe 2 is It coincides with the central axis O. That is,
The ultrasonic axis is common to the axis O.

The light source 4 may be of any type as long as it can emit visible light. In this embodiment, a light emitting diode (LED) that emits red light that is easily perceived by the eyes is employed. The light source 4 is fixed in the storage space 11 of the case unit 1 by an L-shaped fixing bracket 41. And
The light emitting section is arranged so as to face the left end surface of the light guide means 3. Therefore, the light 1 emitted from the light source 4 enters from the left end of the light guide means 3 and is emitted from the right end. That is, an ultrasonic beam u is emitted from the distal end surface of the ultrasonic probe 2 and a substantially annular light is emitted from the distal end of the light guide means 3 to which the ultrasonic probe 2 is fitted. 1 is injected.

Next, a procedure for measuring the axial length with the axial length measuring probe 10 will be described.

As shown in FIG. 2, the probe for measuring the axial length of the eye
The ultrasonic probe 2 at the distal end of 10 is gradually approached to the cornea 21 of the eyeball 20 and finally brought into contact.

In this case, the image seen by the patient is as shown in FIG. 3 (a) when the tip of the probe 10 is separated from the cornea 21. That is, the portion of the ultrasonic probe 2 looks dark and forms a dark portion A, and the portion of the light guide portion 3 around the dark portion A looks bright and forms a substantially annular bright portion B. Note that the outside of the bright portion B looks dark. However, as the ultrasonic probe 2 gradually approaches the cornea 21, the dark area A becomes smaller, and conversely, the smaller dark area becomes the light area B.
Will occupy. When the ultrasonic probe 2 comes into contact with the cornea 21, the dark area A becomes a point-shaped dark area A ′.
Becomes That is, the image at that time is an image having a point-like dark portion A 'in the region of the bright portion B'.

In this state, the patient looks at the dark area A 'so that the dark area A' is located at the center of the light area B '. Then, as shown in FIG. 4, the central axis of the light guide means 3, that is, the ultrasonic axis O
And the visual axis V match. Further, the dark portion A '
Are shifted from the center of the bright portion B 'as shown by the dotted line in FIG. 3, the ultrasonic axis O does not coincide with the visual axis V.
The visual axis V is a straight line connecting the connection point N of the crystalline lens 22 in the eyeball 20 and the fovea 23 as is well known.

Therefore, by analyzing the ultrasonic echo detected in this state, an accurate eye axial length can be obtained.

According to the above-described embodiment, it is not necessary to provide a through-hole or the like in the ultrasonic probe 2. Therefore, as before,
There is no reduction in the echo detection sensitivity or disturbance of the echo peak due to the provision of the through hole, and the analysis is facilitated. Moreover, since it is not necessary to use a special ultrasonic probe 2 having a through-hole, production is easy and the cost is low.

Further, the patient does not see the bright spot as in the conventional case, but sees the dark area A '. In addition, the light portion B 'around the dark portion A' has a low light intensity because the light emitted from the light guide means 3 is greatly spread. Therefore, the patient does not feel dazzling even when looking at the dark area A '. Thus, since the iris 24 of the eyeball 20 does not close, a normal echo is obtained and analysis becomes easy.

In the above-described embodiment, an example of a type in which the ultrasonic probe is brought into direct contact with the cornea is given. However, the present invention provides a type in which an appropriate medium is interposed between the ultrasonic probe and the cornea. Of course, it can also be applied to things. In this case, a transparent flexible bag or the like for accommodating a medium is provided at the tip of the ultrasonic probe.

[Effects of the Invention] As described in detail above, the present invention is, in short, to forward light forward from around the distal end portion of an ultrasonic probe through a light guide formed around the ultrasonic probe. It is designed to emit light, thereby enabling axial alignment with a fixation lamp without providing a through hole in the ultrasonic probe, and at the time of axial alignment, there is no danger that the patient will feel dazzling A probe for length measurement has been obtained.

[Brief description of the drawings]

FIG. 1 is a partially broken cross-sectional view of a probe for measuring an axial length according to an embodiment of the present invention, FIG. 2 is a diagram showing a state of measuring the axial length with the probe of the embodiment, and FIG. FIG. 4 is a view showing an image seen by a patient, and FIG. 4 is an explanatory view of a visual axis. DESCRIPTION OF SYMBOLS 1 ... Case part, 2 ... Ultrasonic probe, 3 ... Light guide means, 4 ... Light source, 10 ... Eye axial length measurement probe.

Claims (1)

(57) [Claims] 1. An eye axis length measuring probe used in an eye axis length measuring device for obtaining an eye axis length of an eyeball by irradiating an ultrasonic wave into the eyeball and analyzing an echo thereof. An ultrasonic probe attached to the tip of the case, a light guide formed around the ultrasonic probe, and a light source for supplying light to the light guide. The ultrasonic probe is brought into contact with the cornea directly or through a medium so that the ultrasonic wave enters the eyeball, and the light from the light source is transmitted through the light guide section to the ultrasonic probe. A probe for measuring an axial length of an eye, wherein the probe is emitted forward from the periphery of the part and enters the eyeball to form a fixation point as a dark spot on the fundus.