JPH0431254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fixation device for ophthalmological equipment for fixing the line of sight of an eye to be examined.

[Prior Art] Ophthalmological devices that measure or record various constants of the subject's eye include a fixation device that presents a fixation lamp to the subject's eye and causes the subject's eye to fixate in order to improve the accuracy or fix the recording site. There are some that have Such a fixation device usually has a diopter correction mechanism because if the subject's eye has a refractive error, the fixation lamp cannot be clearly observed and fixation becomes unstable. However, such a diopter correction mechanism is not only complicated to operate, but also difficult to use in ophthalmological equipment that does not have a means to objectively grasp the refractive error of the subject's eye. It is often not used on a case-by-case basis. In such cases,
As mentioned above, the fixation of the subject's eye is insufficient,
This results in the inconvenience of not being able to accurately measure and record.

As an example for solving the above-mentioned disadvantages, Japanese Patent Application Laid-Open No. 61-288824 is known. This device presents a plurality of fixation lights on the optical axis, and the subject's eye is designed to naturally observe the fixation lights located at positions corresponding to its refractive error value. FIG. 3 shows its configuration, in which fixation lights 5, 6, and 7 made of LEDs are arranged behind the projection lens 1 in front of the eye E to be examined via half mirrors 2, 3, and 4. The optical positions of the fixation lights 5, 6, and 7 are such that the lengths of the optical paths L1, L2, and L3 are set to correspond to the refractive error values of the eye E to be examined -10, 0, and +10 diopters.

However, the above-mentioned conventional example is an image of approximately the same object, and when presented with an overlapping image of a clear image and an unclear, out-of-focus image, the human brain Since the eye uses the visual characteristics of selecting a potentially clear image to fixate, in order for the subject's eye to fixate accurately, it is necessary to make sure that the adjacent optotype is sufficiently blurred and 2
Visual targets must be presented at ~3 diopter intervals, and fixation lights 5, 6, 7 and half mirrors 2, 3,
4 actually requires a considerable number of devices, which has the drawback of making the device large and expensive.

[Object of the Invention] An object of the present invention is to provide a plurality of apertures between the eye to be examined and the fixation lamp light source when presenting a fixation lamp through a projection lens facing the eye to be examined, and to emit a luminous flux. To provide a fixation device for ophthalmological equipment, which can ensure fixation regardless of the refractive error of an eye to be examined by presenting a fixation lamp in a sufficiently narrowed state.

[Summary of the invention] The gist of the present invention for achieving the above object is as follows:
In a fixation device of an ophthalmological device that includes a projection lens facing the eye to be examined, a light source arranged behind the projection lens, and a light beam of the light source to the eye to be examined via the projection lens, a plurality of light sources are provided in the projection optical path. This is a fixation device for ophthalmological equipment characterized by having an aperture of

[Embodiments of the Invention] The present invention will be explained in detail based on the embodiments shown in FIGS. 1 and 2.

FIG. 1 is an embodiment of the present invention, and is a configuration diagram of the device incorporated into a non-contact tonometer. Eye to be examined E
A nozzle 10, which is an air pulse outlet for deforming the cornea of the eye E to be examined, and a projection lens 11 are provided on the optical axis 01 in front of the projection lens 11.
A dichroic mirror 12 that reflects visible light and transmits infrared light is installed obliquely behind the
2. It is separated into a reflection optical axis 03. Transmitted optical axis 0
2 is used for observing the eye E to be examined, and the members arranged on the transmission optical axis 02 to configure the tonometer are:
Illustrations are omitted because they are not directly related to the present invention. On the optical axis 03 where the fixation device is provided, a light source 17 consisting of a first circular aperture 13, a mirror 14, second and third circular apertures 15, 16, an LED, etc. is arranged in order from the dichroic mirror 12. has been done.

In the above arrangement, the light beam emitted from the light source 17 passes through the first, second and third circular apertures 13 and 1.
5, 16 and the nozzle 10, the diameter of the light beam is limited, and the light beam enters the pupil P of the eye E to be examined as a small diameter light beam and reaches the fundus Er. If the second circular aperture 15 is arranged so that the focal position of the projection lens 11 on the light source 17 side is set so that it has an appropriate aperture as a fixation target, if the eye E to be examined is an emmetropic eye, The aperture image of the circular aperture 15 of 2 is the light source 1
7 and can be clearly observed. In addition, when the eye E to be examined is an ametropic eye, since the spread of the light flux is restricted by the other first and third circular apertures 13 and 16 and the nozzle 10, the second eye, which is the fixation target, is Since the amount of blur of the circular aperture 15 is regulated, the function as a fixation lamp can be substantially satisfied.

In order to further improve this function, it is effective to adjust the positions and sizes of the first and third circular apertures 13 and 16 as follows. That is, as shown in FIG. 2, consider the light beam that can enter the pupil image P' of the subject's eye having a predetermined pupil diameter through the projection lens 11. In the non-contact tonometer shown in FIG. 1, the nozzle 10 acts as an artificial pupil instead of a natural pupil, so the pupil diameter is determined by the inner diameter of the nozzle 10.

If only the second circular aperture 15 at the focal point of the projection lens 11 exists, the light flux forming the edge a2 of the circular aperture 15 is r1'-
r2', where non-optometry E is a predetermined refractive error value,
For example, the eye to be examined E in the case of −5 and +5 diopters
Edges a1 and a3 of the first and third circular apertures 13 and 16 placed at positions conjugate with the fundus Er of
The edge a1 is adjusted to limit r1' to r1, and the edge a3 is adjusted to limit r2' to r2, and the luminous flux r1-r- forming the edges a1 and a3, respectively.
4. Adjust so that r-3-r2 can enter the pupil image P' of the eye E to be examined.

With this configuration, the light source 17 illuminates the -5 diopter eye E with the aperture image of the first circular aperture 13, and the +5 diopter eye E with the aperture image of the third circular aperture 16. It will be clearly observed. In addition, the eye E to be examined having a refractive error value between the two has a circular aperture 13,
15 and 16, but even in this state it is possible to satisfy the fixation function as described above.

In the above-described embodiment, a non-contact tonometer in which the nozzle 10 located in front of the projection lens 11 acts as an artificial pupil has been described as an example, but the member that determines the predetermined pupil diameter of the eye E is conjugate with the pupil P. It may be an aperture provided at a certain position, or it is also possible to adopt a configuration in which circular apertures 13, 15, 16 limit the luminous flux r3, r4 limited by the pupil P' in FIG. 10 is not an essential component. Furthermore, by limiting the dichroic portion of the dichroic mirror 12, an aperture can be used instead.

Of course, the positions of the first and third circular apertures 13 and 16 are not limited to the rear of the projection lens 11, but may be located in front. In addition, by increasing the number of circular apertures, determining the luminous flux forming the edge of each circular aperture as described above, and adjusting its diameter, the range of refractive error values that can clearly observe the fixation target can be expanded. However, in practice, 3 to 4 locations are sufficient, and it is desirable to distribute the locations for plus and minus refractive errors.

Further, although the second circular aperture 15 is arranged at the focal position of the projection lens 11 in order to accommodate emmetropic eyes, the second circular aperture 15 is not particularly limited to this position. It may also correspond to −1 to −2 diopters, which are abnormal values. Also,
The aperture shape of each circular aperture 13, 15, 16 does not need to be limited to circular, but for the eye E between the corresponding refractive error values of the circular apertures,
Since this is handled by limiting the blurring of the light beam, it is more desirable to use a circular shape because it is perceived as the same shape by all eyes.

In the embodiment, the fixation of the eye E to be examined is guided in the optical axis direction of the projection lens 11, but it is of course possible to guide the fixation in an oblique direction.

[Configuration of the Invention] As described above, the fixation device for an ophthalmological device according to the present invention has a simple configuration in which a plurality of apertures are provided between the eye to be examined and the light source, and has necessary and sufficient functions. This has a great effect in realizing miniaturization and cost reduction of the main body without impairing the original measurement or recording functions of the ophthalmological device. Furthermore, the position and size of each aperture is adjusted so that the light flux forming each edge of each aperture can pass through the pupil of the eye to be examined, and a clear fixation target is set for a specific refractive error value. can give.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the fixation device for ophthalmological equipment according to the present invention, Figure 1 is a configuration diagram when applied to a non-contact tonometer, and Figure 2 is an explanation of luminous flux restriction. FIG. 3 is a configuration diagram of a conventional example. 10 is a nozzle, 11 is a projection lens, 12 is a dichroic mirror, 13, 15 and 16 are circular apertures, and 17 is a light source.

Claims (1)

[Scope of Claims] 1. A fixation device for an ophthalmological instrument that includes a projection lens facing an eye to be examined, a light source arranged behind the projection lens, and projects a light beam from the light source onto the eye to be examined via the projection lens. A fixation device for an ophthalmological device, characterized in that a projection optical path includes a plurality of apertures. 2. The fixation device for ophthalmological equipment according to claim 1, wherein the plurality of apertures are arranged between the projection lens and the light source. 3. The fixation device for ophthalmological equipment according to claim 2, wherein the plurality of apertures are arranged in front and behind the light source side focal position of the projection lens. 4. The fixation device for ophthalmological equipment according to claim 2, wherein the plurality of apertures are arranged at a focal position on the light source side of the projection lens and at least three positions before and after the focal position on the light source side. 5. The fixation of the ophthalmological equipment according to claim 1, wherein the position and size of the aperture are adjusted so that the light beam forming the edge of each of the plurality of apertures can pass through the pupil of the eye to be examined. Visual device. 6. The fixation device for ophthalmological equipment according to claim 1, wherein the aperture has a circular opening.