JPH03184525A - Ophthalmological apparatus - Google Patents

Abstract

PURPOSE:To remove measuring errors generated from a change in working distance otherwise caused by a difference in diopter by adjusting a position of an alignment optical member to the diopter of an eye to be inspected beforehand. CONSTITUTION:A luminous flux is projected to an eye E to be inspected through a ens 8 from a light source 7 and the luminous flux reflected from a cornea Ec is received with a photoelectric sensor 10 through a lens 9 to measure an eye pressure by detecting a deformation of the cornea Ec caused by a jet of a current. Light from the cornea Ec becomes parallel with a lens 3 to be reflected on a convex mirror 4 and is made parallel again with the lens 3 to form an image on an eye ground Er. Prior to the measurement, a person to be inspected has a position of an optical member 5 for alignment set to an own diopter using a scale plate 6 beforehand. At the measurement, the person to be inspected has the eye E to be inspected moved forward and backward slightly and when the eye E to be inspected reaches a fixed position from a nozzle 2, the person to be inspected is allowed to recognize an image of his own eye clearly with eyes. But as the image blurs besides this position, it is possible to adjust the eye E to be inspected to a fixed working distance from the apparatus. This enables the adjusting of the eye to be inspected to a fixed working distance irrelevant to the diopter of the eye to be inspected, thereby reducing measuring errors due to a difference in diopter.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to a non-contact device that deforms the cornea by, for example, blowing an airflow onto the eye to be examined, and optically detects this deformation to measure the intraocular pressure value. This is about eye +4 devices Wi such as contact-type tonometers.

[Prior Art] Recently, a self-eye alignment device has been announced for ophthalmic instruments such as non-contact tonometers, in which the subject himself/herself aligns the subject's eye to the proper position of the ophthalmic instrument and performs the measurement. This is disclosed, for example, in Japanese Patent Laid-Open No. 61-276533.

In this device, a reflective optical system such as a half mirror, a concave mirror, or a convex mirror is placed in front of the eye to be examined, aligned with the optical axis of the ophthalmological equipment, and the eye to be examined is placed within a predetermined working distance of the ophthalmological equipment, that is, the eye to be examined and the main body. When positioned at a predetermined distance from the housing, the light emitted from the anterior segment of the subject's eye becomes a parallel beam of light and returns to the subject's eye. Positioning is performed by looking at the image of the eye to be examined or the corneal reflection image.

[Problems to be Solved by the Invention] Such a device allows the patient to easily align his/her own eyes with the predetermined working distance of the ophthalmological device, so it can be used, for example, as a non-contact tonometer for home use. However, if the diopter of the eye to be examined is different, the working distance will be different, resulting in an error in measurement.

The purpose of the present invention is to improve such problems and, when a subject performs alignment by himself/herself, by adjusting the position of the alignment optical member in advance to the diopter of the subject's eye, the working distance due to the difference in diopter can be reduced. An object of the present invention is to provide an ophthalmological instrument that can eliminate measurement errors caused by changes in

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the ophthalmological instrument according to the present invention, an alignment optical member including a mirror surface coupled to the main body housing and arranged on the optical axis has a self-alignment optical member. In an ophthalmological instrument that reflects an eye to be examined and adjusts a working distance between the eye to be examined and the main body housing to a constant value, at least a portion of the optical member for alignment is movable in the optical axis direction; The present invention is characterized in that it includes means for setting the optical member at a position corresponding to the diopter of the eye to be examined.

[Operation 1] The ophthalmological instrument having the above configuration is adjusted in advance to the diopter of the eye to be examined by slightly moving at least a part of the alignment optical member including the mirror surface in the optical axis direction, and the working distance is adjusted to the diopter of the eye to be examined. Regardless of the diopter, the examinee aligns himself so that he can clearly see the image of his own eye on the alignment optical member during measurement. The working distance remains at its original reference value.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows a first embodiment, in which 1 is a main body casing consisting of a known compressed gas generator, 2 is a main body housing that is configured to direct the airflow to the cornea of the eye E to be examined.
An alignment optical member 5 consisting of a lens 3 and a convex mirror 4 is arranged around this nozzle 2, and the subject is allowed to use the alignment optical member 5.
Alignment is performed by projecting the patient's own eye E on the screen. The lens 3 and the convex mirror 4 constituting the alignment optical member 5 are integrally formed, or at least one of them is movable in the airflow direction as shown by arrow A, and its position can be adjusted. For example, the diopter of the eye E to be examined is adjusted by setting it in accordance with a scale plate 6 graduated with diopter values. on the other hand,
By projecting a light beam from the light source 7 onto the subject IllE through a lens 8, and allowing the photoelectric sensor 10 to receive the light beam reflected by the cornea Ec through the lens 9, the deformation of the cornea Ec caused by the jet of airflow is detected and cerebral pressure is measured. Measurement is the same as before.

FIG. 2 shows the optical relationship of the alignment optical member 5,
The light from the cornea Ec becomes parallel with the lens 3 and then passes through the convex mirror 4
After being reflected by lens 3, it becomes parallel again to the fundus Er.
form an image. Note that F indicates the focal point of the lens 3 and convex mirror 4. Prior to measurement, the subject sets the position of the alignment optical member 5 to his or her diopter using the scale plate 6. During measurement, the subject moves the subject E slightly back and forth, and when the subject's eye E reaches a certain position from the nozzle 2, the subject clearly sees the image of his or her own eye. be able to. Since the image is blurred at positions other than this position, it is possible to align the eye E to be examined with respect to the apparatus at a constant working distance.

FIG. 3 shows a second embodiment, in which a concave mirror 11 is arranged as an alignment optical member in place of the lens 3 and convex mirror 4 shown in FIG. Alignment can be performed by showing E. In this case, the concave mirror 11 is a guichroic mirror, which has the characteristics of blocking visible light and transmitting the light beam from the light source 7 that emits near-infrared light.

Therefore, by projecting a light beam from the light source 7 onto the eye E through the lens 8 and the concave mirror 11, and allowing the photoelectric sensor 10 to receive the light beam reflected by the cornea Ec via the concave mirror 11 and the lens 9, the cornea Ec is deformed. can be detected to determine the intraocular pressure value. In this case as well, by adjusting the concave mirror 11 to the diopter using the scale plate 6 and setting the position by moving it in the direction of the arrow A, when the eye E to be examined reaches a certain position from the device. Since the image of the eye E to be examined is clearly reflected on the concave mirror 11, and the image is blurred at other positions, the eye E to be examined can be adjusted to a certain working distance.

FIG. 4 shows a third embodiment, which is applied to an eye refractometer. A concave mirror 13 is attached to the front of the measurement system 12 and is automatically moved along the optical axis in the direction of arrow B by the output of the control system. This concave mirror 13 preferably transmits near-infrared light and reflects visible light;
A concave half mirror may also be used.

At the time of measurement, the eye E to be examined faces the concave mirror 13, and the measurement system 12 directly measures the eye refraction. Through this measurement, the diopter of the eye E to be examined is determined, and the concave mirror 13 is moved and adjusted in the optical axis direction via the control system in accordance with this diopter.

In this state, the subject places his/her own eye E on the concave mirror 13.
The position that can be clearly seen is set as the appropriate working distance.
Perform eye refraction measurement again.

In this way, by first measuring the approximate refractive power and then adjusting the position of the concave mirror 13 according to the diopter, the subject can accurately adjust the working distance. Therefore, the eye refraction value can be measured with high precision by repeating the measurement.

Although it is a necessary condition for the alignment optical member to include a mirror surface, it goes without saying that its specific configuration may be modified in various ways other than the embodiments. When the alignment optical member is composed of a mirror surface and a lens system, at least a part of this lens system may be moved in the optical axis direction instead of moving the mirror surface in the optical axis direction to adjust the diopter.

[Effects of the Invention] As explained above, the ophthalmological instrument according to the present invention can adjust the subject's eye to a constant working distance regardless of the diopter of the subject's eye, thereby eliminating measurement errors due to diopter differences. Can be made smaller.

[Brief explanation of drawings]

The drawings show embodiments of the ophthalmological instrument according to the present invention, FIG. 1 is an optical layout diagram of the first embodiment, FIG. 2 is an optical relationship diagram of alignment optical members, and FIG. 3 is a diagram of the second embodiment. FIG. 4 is an optical layout diagram of the third embodiment. Vertebrae 1 is a main body housing, 2 is a nozzle, 3 is a lens, 4 is a convex mirror, 5 is an optical member for alignment, 6 is a scale, 7 is a light source, 8 and 9 are lenses, 10 is a photoelectric sensor, 11.13
is a concave mirror; 12 is a measurement system;

Claims (1)

[Claims] 1. An ophthalmological instrument that adjusts the working distance between the eye to be examined and the main body casing to a constant value by reflecting the patient's eye on an alignment optical member that includes a mirror surface that is coupled to the main body casing and arranged on the optical axis. An ophthalmological instrument, wherein at least a portion of the alignment optical member is movable in the optical axis direction, and includes means for setting the alignment optical member at a position corresponding to the diopter of the eye to be examined. .