JP2012217683A - Ophthalmologic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase in the whole size of an apparatus and to make a safe measurement by preventing the apparatus from having contact with a subject.SOLUTION: The ophthalmologic apparatus includes: a parallel plate 13 (optical path changing means) 13 which partially has a wedge prism shape and deflects return light from an eye 1 to be examined irradiated with light from a slit light source 2 toward the slit light source 2; and a cornea cross section image acquiring section 102 which leads the deflected light to an imaging element 18 through a cornea thickness measuring optical system and acquires a cornea cross section image of the eye 1 to be examined.

Description

  The present invention relates to an ophthalmologic apparatus for measuring an intraocular pressure value of a subject eye. Further, since the intraocular pressure value deviates from a true value due to the corneal thickness, the corneal thickness is measured in the ophthalmologic apparatus of the present invention in order to correct this. In the measurement of the corneal thickness, the light emitted from the light source for cross-sectional image photography is projected toward the anterior eye portion of the eye to be examined, and slit light is projected. In particular, the present invention relates to an ophthalmic apparatus having a corneal cross-sectional image photographing function in which the slit light becomes scattered light in the cornea, and the corneal cross-sectional scattered light is received by a light receiving optical system to obtain a corneal cross-sectional image and use it as a correction value. Is.

  The conventional non-contact tonometer (ophthalmologic apparatus) having a corneal thickness measurement function is configured so that slit light is transmitted through the inside of the gas blowing nozzle when measuring the corneal thickness, and the scattered light is scattered in the cross section of the cornea. Is received and received by an image sensor set at a predetermined position. In the conventional ophthalmologic apparatus, the corneal thickness obtained here is used as a correction value.

  Here, an imaging device that captures an anterior segment cross-sectional image and an imaging lens that guides reflected light from the anterior segment by the projection optical system to the imaging device, and an optical section of the projection image by the projection optical system, the imaging lens Japanese Patent Application Laid-Open No. H11-228707 discloses that the main plane of the imaging device and an imaging surface of the imaging device extend in a uniaxial manner.

  Further, the corneal thickness measuring means is a projection optical system having a slit and a projection lens for projecting a slit light beam from the first axis in the oblique direction of the eye to be examined onto the cornea of the eye to be examined. Patent Document 2 discloses that a slit and a projection lens have a projection optical system arranged based on the principle of Scheinproof so that it is the same as when projected onto the cornea of the eye to be examined.

  Patent Document 3 discloses that a projection optical system having a slit and a projection lens for projecting a slit light beam from a first axis in the oblique direction of the eye to be examined onto the cornea of the eye to be examined.

JP 2009-201636 A JP 2008-11878 A JP 2000-70224 A

  An optical system that receives scattered light from the corneal cross section of the anterior eye portion of the eye to be examined has a weak light scattered from the cornea, and therefore requires a light flux that provides a contrast ratio of about 60. Conventionally, a considerable amount of space was used for the receiving optical system and the holding member and the exterior member that were placed near the side of the subject's nose, so that some of them touched people with high noses and people with large noses. There was a possibility of giving discomfort. In order to avoid this, if the light receiving optical system and the holding member arranged near the side of the subject's nose are moved and arranged to the position below the subject's nose, the received light beam further spreads to increase the lens diameter and the lens. The holding member is also enlarged, the image forming position is extended, and the image sensor is disposed at this position. Therefore, the conventional ophthalmic apparatus has a problem that the entire apparatus is enlarged due to the enlargement of the light receiving system.

  The present invention has been made in view of such problems, and provides an ophthalmologic apparatus that prevents the apparatus from becoming large and prevents the apparatus from coming into contact with a subject to realize safe measurement. With the goal.

  An ophthalmologic apparatus of the present invention guides an optical path changing means for refracting return light from a subject's eye irradiated with light from a light source toward the light source, and the refracted light to an image sensor via a corneal thickness measurement optical system. Acquisition means for acquiring a corneal cross-sectional image of the eye to be examined.

  According to the present invention, it is possible to prevent an increase in the size of the entire apparatus and to realize safe measurement by preventing the apparatus from coming into contact with a subject.

It is a schematic diagram which shows an example of schematic structure of the ophthalmologic apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows 1st Embodiment and shows an example of the cornea cross-sectional image displayed on the monitor screen. It is a schematic diagram showing a positional relationship between the position of the subject's nose and the light receiving optical system, showing a conventional example. It is a schematic diagram which shows 1st Embodiment and shows the positional relationship of the position of a subject's nose and a light reception optical system. It is a schematic diagram which shows 2nd Embodiment and shows the positional relationship of the position of the to-be-tested eye 1, and a light reception optical system.

  Hereinafter, embodiments (embodiments) for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram illustrating an example of a schematic configuration of the ophthalmologic apparatus according to the first embodiment. Here, in FIG. 1, the configuration related to the intraocular pressure measurement similar to the conventional configuration is shown in combination with the configuration related to the corneal thickness measurement.

  Here, first, the configuration related to the intraocular pressure measurement similar to the conventional one will be described first.

<Observed eye observation>
At the start of measurement, the fixation lamp light source 38 which is visible light is turned on, and the eye 1 to be examined is fixed with light based on the fixation lamp optical axis 39 of the fixation lamp light source 38. In this state, the eye observation is advanced. First, the anterior eye image of the eye 1 to be examined is transmitted from the plane part of the parallel plate 13 having a partially wedged prism shape, the optical path is changed by the observation light receiving lens 11, transmitted through the air chamber partition glass 10, and transmitted through the half mirror 9. To do. An anterior eye image of the eye 1 to be examined (an image based on the observation optical axis 21 transmitted through the half mirror 9) is transmitted through the inner diameter side of the split wedge prism A23 and the split wedge prism B24 and observed by the observation imaging lens 25. The image is formed on the image pickup device 26. The image of the anterior segment can be observed with a monitor (not shown).

<Eye alignment>
Subsequently, the eye 1 is irradiated with infrared light from the intraocular pressure measurement light source 31 in a state where an image of the anterior segment is displayed in the vicinity of the approximate center of a monitor (not shown) in the eye observation. This luminous flux is irradiated onto the cornea of the eye 1 to be examined, and is formed at a substantially pupil position as a cornea reflection image, and is observed together with the eye 1 as a corneal bright spot 20. The corneal bright spot 20 passes through the observation / split diaphragm 22 through the parallel plate 13 in the form of a wedge prism, the observation light receiving lens 11, the air chamber 46, the air chamber partition glass 10, and the half mirror 9 as corneal reflection light. To do. The corneal bright spot 20 is divided by the split wedge prism A 23 and the split wedge prism B 24 and imaged on the observation imaging element 26 by the observation imaging lens 25. Based on this corneal bright spot information, the eye 1 to be inspected is driven by driving a drive mechanism (not shown) so as to be placed on the axis with respect to the Y axis in an even distribution with respect to the X axis of the observation imaging device 26. The eye alignment for the observation light receiving lens 11 is completed.

<Intraocular pressure measurement function>
Subsequently, when the eye alignment is completed, the light beam from the tonometry light source 31 is first shaped into a predetermined shape by the projection aperture 32 and passes through the projection lens 33. The light beam based on the projection optical axis 34 that has passed through the projection lens 33 further passes through the half mirror 40 and is reflected by the half mirror 35. Further, the light beam is reflected by the half mirror 9 by the imaging lens 8, passes through the air chamber partition glass 10, passes through the gas blowing nozzle 12, and is condensed on the corneal bright spot 20.

  In this state, when the piston drive source 41 is rotationally driven and the piston 43 is pushed out via the connecting arm 42, the gas inside the cylinder 44 passes through the connecting pipe 45 and the pressure in the air chamber 46 is increased at the same time. The eye 1 is sprayed through the inside. The configuration of the piston drive source 41 to the gas blowing nozzle 12 constitutes a gas blowing means for blowing gas from the inside of the gas blowing nozzle 12 to the cornea of the eye 1 to be examined. Due to the pressure of the gas, the cornea of the eye 1 to be examined is deformed and changed from a flat surface to a concave surface, and then returns to the flat surface, and further returns to a normal state. Then, the pressure value in the air chamber 46 in the initial corneal plane state is read by the pressure gauge 47. The time when the pressure value is read by the pressure gauge 47 is a time when the light beam is narrowed by the light receiving aperture 36 in the initial corneal plane state, and the amount of reflected light from the light receiving element 37 is maximized. The intraocular pressure value measurement unit 101 obtains an intraocular pressure value by converting it into an intraocular pressure value based on the pressure value of the air chamber 46 at that time (pressure value by the pressure gauge 47). As for the relationship between the pressure value and the intraocular pressure value, a conversion formula between the pressure value is determined by the eye to be examined and the clinical data, and the intraocular pressure value is obtained based on the pressure value.

  Next, corneal thickness measurement according to the present invention will be described.

<Corner thickness measurement function>
The corneal thickness measurement function measures the corneal thickness of the eye 1 based on the corneal cross-sectional image of the cornea.
When the eye alignment is completed, the light beam from the slit light source 2 is first made into a substantially uniform light amount by the diffusion plate 3. Thereafter, the light beam having a substantially uniform light quantity passes through the narrow slit having a uniform width formed on the projection chart 4 and further passes through the projection lens 5. Thereafter, the light beam based on the post-projection axis 6 that has passed through the projection lens 5 is reflected by the two half mirrors 7 and 9 and irradiated onto the cornea of the eye 1 to be examined.

  This irradiation light becomes scattered light inside the cornea of the eye 1 to be examined and can be observed from an oblique direction on the optical axis. When the scattered light passes through the wedge-shaped prism of the parallel plate 13 having a partially wedge prism shape as the received light beam 14, the light path is bent and enters from the vertical direction of the light-receiving objective lens 15. At this time, the objective lens holding barrel 19 that holds the parallel plate 13 having a partially wedge prism shape is opened so as not to interfere with the received light beam 14 of the light receiving optical system, the received light objective lens 15, and the optical axis 16 after the optical path change. Is provided. More specifically, the gas blowing nozzle 12 is provided with an opening that transmits scattered light from the anterior segment (cornea) of the eye 1 to be examined in the vicinity of the light receiving objective lens 15. Further, the scattered light is collected by the imaging lens 17, imaged on the image sensor 18 and captured as an image. Here, the captured image is displayed on the monitor screen 66 of FIG.

  Here, the partially wedged prism-shaped parallel plate 13, the light-receiving objective lens 15 and the imaging lens 17 constitute a corneal thickness measuring optical system. A wedge-shaped prism that refracts the scattered light away from the subject is provided. This wedge-shaped prism constitutes an optical path changing means. In other words, the optical path changing means, which is a wedge-shaped prism, refracts the return light from the eye 1 irradiated with light from the slit light source 2 toward the slit light source. More specifically, the optical path changing means, which is a wedge-shaped prism, refracts the scattered light from the subject eye 1 irradiated with light from the slit light source 2 from the inside of the gas blowing nozzle 12 toward the gas blowing nozzle. It is. Then, the corneal cross-sectional image acquisition unit 102 acquires a corneal cross-sectional image of the eye 1 to be examined from the imaging device 18 that has led the refracted light through the corneal thickness measurement optical system. In addition, a light receiving objective lens 15 is disposed in the vicinity of the wedge-shaped prism.

  The corneal thickness measuring unit 103 measures the corneal thickness of the eye 1 based on the corneal cross-sectional image acquired by the corneal cross-sectional image acquiring unit 102. The intraocular pressure correction unit 104 corrects the intraocular pressure value based on the corneal thickness of the eye 1 measured by the corneal thickness measurement unit 103.

FIG. 3 is a schematic diagram illustrating a positional relationship between the position of the subject's nose and the light receiving optical system, showing a conventional example.
The received light beam 52 has the same spread angle as that of the received light beam 14 in FIG. 1, and the base spreads in proportion to the distance that the light receiving lens 53 is away from the eye 1 to be examined, and the diameter of the light receiving lens 53 is increased. For this reason, the light receiving lens 53 is likely to approach and come into contact with the subject's nose 51.

FIG. 4 is a schematic diagram illustrating the positional relationship between the position of the subject's nose and the light receiving optical system according to the first embodiment. In FIG. 4, the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals.
The angle of the received light beam 14 obtained from the eye 1 is the same as that shown in FIG. The wedge-shaped prism (optical path changing means) of the parallel plate 13 having a partially wedged prism shape on the outer periphery of the gas blowing nozzle 12 refracts the optical axis away from the subject (that is, toward the gas blowing nozzle 12 side). And away from the position of the subject's nose 51.

  Further, since the image plane is moved away from the position of the subject's nose 51 by making the optical axis 16 after the optical path change by the light receiving objective lens 15 substantially parallel light, the imaging element 18 is also moved away from the subject. Therefore, the holding member (not shown) can also be configured at a position sufficiently away. Thereby, when performing intraocular pressure measurement and corneal cross-sectional image photography (corneal film thickness measurement), it is possible to perform safe measurement so that the apparatus does not contact the subject.

(Second Embodiment)
FIG. 5 is a schematic diagram showing the positional relationship between the position of the eye 1 to be examined and the light receiving optical system according to the second embodiment. In FIG. 5, the same components as those in FIG.
In the second embodiment, the eye observation, the eye alignment, and the intraocular pressure measurement of the first embodiment are the same, and the imaging method of the corneal cross-sectional image is also the same. In the second embodiment, the difference from the first embodiment is that the parallel plate 13 having a partially wedge prism shape is used in the first embodiment, but the optical path changing means of the light receiving system in the second embodiment. The point is that the parallel plate 54 and the wedge-shaped prism 55 are separately manufactured and joined.

(Third embodiment)
In the first and second embodiments described above, the measurement is performed through the corneal thickness measurement optical system using the scattered light from the eye 1 irradiated with light from the light source from the inside of the nozzle. The invention is not necessarily limited to this form.
For example, as shown in FIG. 1 of Japanese Patent Laid-Open No. 2000-60801, the scattered light from the eye 1 irradiated from a light source provided obliquely above the eye to be examined is provided obliquely below the eye to be examined. The measurement may be performed via the corneal thickness measurement optical system according to the first and second embodiments. That is, the measurement may be performed using scattered light that is regularly reflected from the eye to be examined.

In each of the embodiments of the present invention described above, the optical path changing means that refracts the scattered light from the anterior segment to the corneal thickness measurement optical system so as to be away from the subject (that is, toward the slit light source 2 side). I made it. According to such a configuration, in the non-contact tonometer that performs intraocular pressure measurement and corneal thickness measurement, it is possible to prevent an increase in the size of the entire apparatus and to realize a safe measurement by preventing the apparatus from contacting the subject. Has the effect of being able to.
In the second embodiment of the present invention, the wedge-shaped prism 55 is separately joined to a part of the parallel plate 54 on the outer periphery of the gas blowing nozzle 12 as the optical path changing means. According to such a configuration, in addition to the operations and effects described above, the degree of freedom in manufacturing the optical path changing means can be increased.
In the first and second embodiments of the present invention, the gas blowing nozzle 12 has an opening that transmits scattered light from the anterior segment in the vicinity of the light receiving objective lens 15. According to such a configuration, it is possible to reduce arrangement restrictions for avoiding interference between the light beam changed by the optical path changing means and the holding member (objective lens holding barrel 19).
Further, in each embodiment of the present invention, the optical path from the light receiving objective lens 15 is configured to be substantially parallel light, and the imaging element 18 is disposed so as to be away from the subject. According to such a configuration, in addition to the operations and effects described above, the degree of freedom in arrangement of the image pickup element 18 is increased by the parallel light beam means of the light receiving objective lens 15, so that the entire apparatus can be reduced in size.

  Note that each of the embodiments of the present invention described above is merely an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 1 Eye to be examined, 11 Observation light-receiving lens, 12 Gas spray nozzle, 13 Parallel plate of a partly wedge prism shape, 14 Light-receiving light beam, 15 Light-receiving objective lens, 16 Optical axis after optical path change, 17 Imaging lens, 18 Imaging element, 51 Subject's nose

Claims (10)

An optical path changing means for refracting return light from the eye to be examined irradiated with light from the light source toward the light source;
An acquisition means for acquiring the corneal cross-sectional image of the eye to be examined by guiding the refracted light to an imaging device via a corneal thickness measurement optical system;
An ophthalmologic apparatus comprising:   The ophthalmologic apparatus according to claim 1, further comprising gas spraying means for spraying gas from the inside of a nozzle to the cornea of the eye to be examined.   The ophthalmic apparatus according to claim 2, wherein the optical path changing unit refracts scattered light from the eye to be inspected that is irradiated with light from the light source from the inside of the nozzle. An intraocular pressure value measuring means for measuring an intraocular pressure value based on the pressure value of the air chamber in the planar state of the cornea when the gas is blown by the gas blowing means;
Corneal thickness measuring means for measuring the corneal thickness of the eye based on the corneal cross-sectional image;
Correction means for correcting the intraocular pressure value based on the corneal thickness;
The ophthalmologic apparatus according to claim 2, further comprising:   The said acquisition means acquires the cornea cross-sectional image of the said to-be-tested eye based on the scattered light from the cornea of the said to-be-tested eye irradiated with the light beam through the said nozzle. The ophthalmic apparatus according to item.   6. The ophthalmologic apparatus according to claim 2, wherein the optical path changing unit is configured such that a part of a parallel plate on an outer periphery of the nozzle is formed of a wedge-shaped prism.   6. The optical path changing unit according to claim 2, wherein a wedge-shaped prism is joined separately to a part of a parallel plate on an outer periphery of the nozzle. Ophthalmic equipment.   The ophthalmologic apparatus according to claim 2, wherein an objective lens is disposed in the vicinity of the optical path changing unit in the corneal thickness measurement optical system.   The ophthalmic apparatus according to claim 8, wherein the nozzle has an opening that transmits scattered light from the eye to be examined in the vicinity of the objective lens.   10. The ophthalmologic apparatus according to claim 8, wherein an optical path from the objective lens is configured to be substantially parallel light, and the imaging element is arranged to be away from the subject.

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