JPS61220626A - Non-contact type tonometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention, which is an industrial scale system, deforms the cornea by injecting a fluid for corneal deformation toward the cornea, and measures intraocular pressure based on the deformation of the cornea. This relates to non-contact intraocular pressure d1, and more specifically, alignment 1 for the cornea of the eye to be examined.
- Concerning coordination.

One conventional technique.

Conventionally, as a non-contact type intraocular pressure measurement M1, for example, the one disclosed in Japanese Patent Publication No. 56-6772 has been known.

This conventional non-contact intraocular pressure side utilizes air pulses as the fluid for corneal deformation. This conventional non-contact intraocular pressure d
1 has a fluid ejection nozzle that ejects the air pulse. The axis of this fluid ejection nozzle is one for corneal observation.
It is aligned with the optical axis of the sensing optical system. This fluid ejecting nozzle is designed to help
・When the alignment is completed and the distance from the center of corneal curvature to the tip of the fluid ejection nozzle has reached a predetermined distance, send an air pulse toward the cornea of the eye to be examined, assuming that alignment is complete. It is something that is ejected. The cornea of the eye to be examined is applanated by the air pulse, and the applanation deformation of the cornea of the eye to be examined is caused by the detection light emitting optical system that emits the corneal deformation detection light for detecting applanation deformation, and the reflected light of the corneal deformation detection light. It is detected by a light-receiving optical system that receives the light. The non-contact intraocular pressure side measures intraocular pressure based on a predetermined amount of deformation of the cornea.

By the way, what is disclosed in this Japanese Patent Publication No. 56-6772 is based on the corneal axis connecting the corneal curvature center and the corneal apex and the observation optical system. It has an aligner 1 adjustment device that adjusts the alignment with the optical axis of the system and adjusts the distance from the center of corneal curvature to the tip of the fluid ejection nozzle (hereinafter referred to as the working distance). The alignment optical system has an index projection optical system that projects an index spot light toward the cornea, and in the one disclosed in Japanese Patent Publication No. 56-6772, the objective lens of the observation optical system is used as the index projection optical system. In this alignment optical system, an objective lens projects an index spot light so as to form an image on the center of curvature of the cornea, and the reflected light of the projected light due to specular reflection of the cornea is again passed through the objective lens and observed. Return to optical system and aim plate
This is to form an index spot image on L. In this conventional non-contact intraocular pressure control, alignment 1 to the cornea is performed based on the sharpness of the index spot 1 and the position of the index image on the aiming plate.

However, with this conventional alignment adjustment device,
Even if only l1ffi- fiducial images are formed, it is difficult to finely judge their sharpness and position on the aiming plate.・There is a problem that it is difficult to perform accurately.

Furthermore, since the index spot light is focused on the center of the corneal curvature, there is a drawback that the working distance depends on the radius of corneal curvature of the eye to be examined, resulting in an error.

Therefore, the first object of the present invention is to provide a non-contact type intraocular pressure i1 that can obtain an accurate working distance without depending on the radius of curvature of the cornea of the eye to be examined. The second object of the present invention is to
It is an object of the present invention to provide a non-contact tonometer that can serve as both a target projection optical system and a corneal deformation detection optical system for detecting corneal deformation.

= 4- One feature of the non-contact type intraocular pressure M1 according to the present invention is that the observation optical system is has an illumination means for illuminating the anterior ocular segment of the subject's eye, an objective lens for forming an image of the anterior ocular segment as an intermediate image, and an I-observation means for observing the intermediate image; having an optical system attached to two pairs of alignment members 1 disposed at symmetrical positions with respect to the optical axis of the observation optical system so that their respective optical axes intersect at one point on the optical axis of the observation optical system; Each alignment optical system includes an index spot light forming means, an index projection optical system that projects the index spot light as a parallel light beam onto the cornea, and a virtual image of the index spot light generated by specular reflection of the cornea of the eye to be examined. and an index detection system that guides the indicator to the observation means via an index projection optical system, and the pair of index spot lights are infrared lights having different wavelengths, and the illumination light of the illumination means is visible light. .

B1 The non-contact method for reducing intraocular pressure M1 according to the present invention is such that when a pair of index projection optical systems project light from a pair of index spora 1 to the cornea, a pair of indexes are formed on the cornea by specular reflection of the cornea of the eye to be examined. A virtual image ahead of Subono is formed.

When the optical axis of the observation optical system passes through the corneal vertex and coincides with the center of corneal curvature, the pair of virtual images are generated at symmetrical positions with respect to the optical axis of the l1llrN optical system. Each alignment optical system is arranged at a symmetrical position with respect to the optical axis of the observation optical system, so when a pair of virtual images is formed at a symmetrical position 16, the specularly reflected light from the cornea is transmitted to the index detection system. is guided to the observation means through the polymerization system. Therefore, this pair of 1. u
Similar polymerization can be observed by observation means to adjust the alignment to the cornea.

Example: Below, the non-contact type intraocular pressure n1 according to the present invention will be explained (with reference to the drawings).

1 and 2 show a non-contact type intraocular pressure side optical system according to the present invention, where 1 is an observation optical system, Q is its front axis, 2 is an eye to be examined, and 3 is its cornea. 11 The observation optical system 1 includes an illumination means 4 for illuminating the anterior segment of the subject's eye, an objective lens 5 for forming an intermediate image of the anterior segment, and an observation means 6 for observing the intermediate image. There is. The illumination means 4 is composed of four green light emitting diodes F4a to 4a. The green light emitting diodes 4a to 4a are arranged around the optical axis Q at equal angles. Here, an imaging tube 7 is used as the observation means 6, and the anterior segment image of the eye to be examined 2 is formed as an intermediate image on the imaging surface 7a of the imaging tube 7 by the objective lens 5. There is. A reticle image is also formed on this imaging surface 7a by a reticle image projection optical system, which will be described later. A fluid ejection nozzle 8 is provided on the optical axis Q of the observation optical system 1, and 8a is the tip of the nozzle.

As shown in FIG. 3, this fluid ejection nozzle 8 has a function of ejecting a corneal deforming fluid from its nozzle tip 8a toward the cornea in the six directions of arrows. The cornea 3 is applanated and deformed into a flat state by this fluid as shown by the broken line in FIG. Here, an air pulse is used for this fluid, and the injection conditions for this air pulse will be described later.

The subject undergoes an intraocular pressure measurement test while gazing at the target, and in FIG. 2, reference numeral 9 denotes a fixation target projection optical system. This fixation target projection optical system 9 includes a green light emitting diode 10 as a same vision light source, a fixation target plate 1.1, and a total reflection mirror 1.
2 and a half mirror 13, and a diopter correction optical system I4 is provided between the total reflection mirror 12 and the half mirror 13.
Or is provided. The diopter correction optical system 14 consists of a lens group mounted on a turret plate 15, and the turret 1 to plate 15 are provided with diopter correction lenses 15a in the circumferential direction.
~15e is installed, and 516 is its turret plate I
5 rotation axis.

Here, the lens 15a is for O diopter;
b is for 13 diopters, lens 15c is for 110 diopters, I-nozzle 15d is for +IO diopters, and lens 15e is for +3 diopters.By rotating the plates 1 to 15, lenses], 5a to
15e is selectively added to the visual target projection optical system 9 to perform diopter correction.

The air pulse is emitted from the corneal curvature center 01 to the corneal apex 02.
This is performed when the corneal axis 1 connecting the corneal axis 1 and the optical axis Q are aligned, and the distance Ωl from the corneal apex 02 to the nozzle tip 8a is a predetermined distance 1-L. . The non-contact type intraocular pressure B1 is provided with an alignment adjustment device for aligning the corneal axis m and the optical axis Q 11 and adjusting the position from the nozzle tip 8a to the corneal apex 02. This alignment device 1 is roughly composed of a pair of first alignment optical system 17 and second alignment optical system 18. In this pair of alignment optical systems 17°18, each optical axis is ll'! The optical axis Q of the observation optical system 1 is arranged at a symmetrical position with the optical axis Q of the observation optical system 1 as the axis of symmetry, so that the optical axis Q and the axis of the observation optical system 1 intersect at one point.

The first alignment optical system 17 includes an infrared light emitting diode 19 as an index spot light forming means, an index projection optical system 20 that projects infrared light as an index spot light toward the cornea 3 as a parallel light beam, and It is composed of an index detection system 21 that directs a virtual image of the index spot light generated by the specular reflection of the cornea of the optometrist 2 onto the imaging surface 7a via the index projection optical system (described later) of the other alignment optical system 1B. The second alignment optical system 18 includes an infrared light emitting diode 22 as a light forming means to the index spoiler 1, and a parallel beam of infrared light from the index spoiler 1 to an angle II! 4
an index projection optical system 23 that projects toward the subject's eye 2;
An index detection system 24 that guides the Ik image of the index spot light generated by specular reflection from the corner 11 of
It is composed of. The target projection optical system 20 is a pan 1
~Puff filter 25, lens 26, and half mirror 2
7, an objective lens 28, and the target projection optical system 2:3 includes a bandpass filter 29 and a lens 30.
, a half mirror 31 , and an objective lens 32 .

Infrared light emitting diode 19 and infrared light emitting diode 22
generates infrared light having different wavelengths, and here, the emission wavelength of the infrared light emitting diode 19 has a center wavelength near 760 nm, and the emission wavelength of the infrared light emitting diode 22 is: The center wavelength is said to be around 830 nm. The bandpass filter 25 has a function of selectively transmitting infrared light in a wavelength band as shown by the symbol C in FIG. It has the function of selectively transmitting infrared light in a band. In addition, in this Figure 9,
Symbol E indicates the transmission characteristic of the bandpass filter 34, which is provided between the objective lens 5 of the observation optical system 1 and the half mirror 13, and filters infrared light. It has the function of transmitting reflected green light reflected at the anterior segment of the eye. Apertures 25a and 29a are formed in the bandpass filter 25 and the bandpass filter 29 using a through-air vapor deposition film. The infrared light emitted from the infrared light emitting diode 19 and the infrared light emitted from the infrared light emitting diode 22 are
5a and 20a converge the light beam to the lens 26.
30 respectively.

Lens 26. The lens 31 transforms each infrared light into an intermediate image P1
．． The objective lens 28.32 has the function of forming an image as an intermediate image Pt, P2, and the objective lens 28.32 has a focal point at the position where the intermediate image Pt, P2 is formed, and focuses the infrared light formed as an intermediate image Pi, P2. It has the function of converting into parallel light beam.

As shown in FIG. 1, on the cornea 3, a virtual image j1.
j:a is formed, and is formed at a symmetrical position with the corneal axis m and the optical axis Q as boundaries when the corneal axis m and the optical axis a coincide. Note that the virtual image 11 is formed by the index spot light projection of the first alignment optical system 17, and the virtual image j2
is formed by the index spot light projection of the second alignment system 1-optical system]8. The target projection optical system 20 has a function of guiding the reflected light forming the virtual image j2 to the target detection system 2/l via the half mirror 27, as shown in FIG. It has a function of guiding the reflected light forming the index to the index detection system 21 via the half mirror 31. 35 filters, center wavelength 760 nm
It has the function of transmitting infrared light with a center wavelength of 830 nm and transmitting infrared light with a center wavelength of 830 nm. The filter 37 is
It has a function of cutting red evening I light with a center wavelength of R3n nm and transmitting infrared light with a center wavelength of 760n Il+. On the imaging surface 7,1 of the image pickup tube 7, virtual images j1. j
The reflected light forming the = is guided by the index detection system 21.24, and this reflected light is formed into a pair of index images S1 as shown in FIGS. 5 to 7. The pair of index images S1 will be described later, and then the reticle image projection optical system 39 will be described.

The reticle image projection optical system 39 includes an illumination light source 40, a reticle plate 41, a projection lens 42, and a half mirror 43. On the imaging surface 7a of the imaging tube 7, a reticle image 44 is formed by the reticle image projection optical system 39, as shown in FIG.

In FIG. 10, 44a is a crosshair, 44b is a boundary frame for determining completion of alignment, and a pair of index images S
1 enters this boundary frame 44b, an air pulse generator (not shown) is driven by a detector to be described later, and an air pulse is ejected from the nozzle tip 8a.

The half mirror 43 detects a portion of the corneal specularly reflected light as a detector 45.
The detector 45 has a function to guide the half mirror 4.
3 is located at a conjugate position with the imaging tube 7. A filter 46 that blocks the illumination light from the illumination light source 40 and transmits infrared light is provided between the half mirror 43 and the detector 45.
is provided. As a result, detection 17:'j 1
15 is a scale that receives only corneal specular reflection light without being affected by the illumination light from the illumination light source 40.

A pair of indexes S1 are such that the optical axis Q and the corneal axis m coincide, and the distance Ω from the nozzle tip 7 days to the corneal apex 02
When l is sensed at a predetermined distance, as shown in FIG. If there is a mismatch or the nostle tip 8
, 1 to the corneal apex 02 is not set to a predetermined distance, as shown in FIGS. 6 and 7, the pair of index images S1 are separated and recognized as The image S1 becomes out of focus 1-. Therefore, by checking through the IPi image tube 7 whether the superposition of the index image S1 of -.2J and the intersection with the crosshair 44a match, alignment run 1 can be adjusted.

The 17th Ramen I optical system 17 is a detection light emitting optical system that emits corneal deformation detection light when the cornea is deformed.
A part of the second alignment optical system 18 constitutes a part of a light receiving optical system that receives the anti-n·1 light of the corneal deformation detection light, and the index sub-1 light from the infrared light emitting diode 19 is As shown in FIG. 3, an aperture 25a is used as corneal deformation detection light.
The milk is guided by the diaphragm 25a and guided to the lens 26, where it is imaged by the lens 15 as an intermediate image P1. Note that in this embodiment, the beam width of the infrared light as the corneal deformation detection light and the beam width of the infrared light as the index spot light are the same. The intermediate image P1 is converted into a parallel beam of light by the objective lens 28 and projected onto the cornea 3. The corneal deformation detection light is reflected by the cornea 3 and guided to the objective lens 32, as shown in FIG.

A half mirror 47, which constitutes a part of the light receiving optical system, is provided between the objective lens 32 and the half mirror 31. The half mirror 47 has a function of reflecting the corneal deformation detection light toward the direction where the aperture 48 is present. The aperture 48 constitutes a part of the light receiving optical system, and is arranged at a position conjugate with the focal position of the objective lens 32.

The corneal deformation detection light is transmitted to the aperture 48 by the objective lens 32.
The intermediate image P3 is formed at the position .beta.. The size of the intermediate image P3 is the same as the aperture 48a of the diaphragm 48. This intermediate image P-1 is formed on the detector 50 via the relay lens 49, whereby the applanation state is electrically detected from the change in the amount of light reflected by the cornea 3.

Note that 51 is a glass plate.

In this device, the filter 35 cuts the reflected infrared light forming the virtual image 11 and transmits only the reflected infrared light forming the virtual image 12, and the filter 37 cuts the reflected infrared light forming the virtual image j2. Since only the reflected infrared light forming the virtual image 11 is transmitted, the virtual image j1. An index projection optical system 21.2 that projects an index spot light that forms a virtual image jt, i2 of the corneal specularly reflected light that forms j2.
3 The cornea and iris as harmful components that return to themselves,
It is possible to cut reflected light from the anterior segment of the eye such as the crystalline lens, and the imaging surface 7a of the imaging tube 7 and the light receiving surface 45a of the detector 45
This makes it possible to prevent image deterioration of the index image S1 that is formed.

Note that in each of the embodiments described above, the fluid ejection nozzle 8 and the optical axis α of the observation optical system 1 are made to coincide, but the present invention is not necessarily limited to this.

114 ■Lya As explained above, the present invention includes an observation optical system that includes an illumination means that illuminates the anterior segment of the subject's eye, an objective lens that forms an intermediate image of the anterior segment of the subject's eye, and an intermediate image thereof. and an alignment adjustment device arranged in a symmetrical position with respect to the optical axis of the observation optical system so that each optical axis intersects at a point on the optical axis of the observation optical system. The alignment optical system has a pair of alignment optical systems, each of which is connected to an index spot light forming means, an index projection optical system that projects the index spot light as a parallel light beam onto the cornea, and a beam generated by corneal specular reflection of the eye to be examined. Since it is composed of an index detection system that guides a virtual image of the index spot light to the observation means via the index projection optical system of the other alignment optical system, the corneal axis connecting the optical axis of the observation optical system, the corneal apex, and the center of corneal curvature If these do not match and the distance from the corneal apex to the nozzle tip is not set to a predetermined distance,
A pair of index images corresponding to the virtual image based on corneal specular reflection are separated and visually recognized, and 11! By checking the superposition/non-polymerization of a pair of target images through a detection means, the alignment adjustment between the optical axis of the observation optical system and the corneal axis and the distance adjustment from the tip of the fluid injection nozzle to the corneal apex are simultaneously performed. This has the effect that alignment adjustment can be performed accurately. In addition, the cornea of the eye to be examined is aligned so that the vertex of the cornea of the eye to be examined coincides with the point where the optical axes of the first and second alignment optical systems and the optical axis of the observation optical system intersect. It has the advantage that the working distance does not depend on the radius of curvature.

Further, one side of the alignment optical system is a detection light emitting optical system that emits corneal deformation detection light when the cornea is deformed, and the other side of the alignment optical system is a part of the light receiving optical system that receives reflected light of the corneal deformation detection light. Because of this configuration, compared to a system in which a corneal deformation detection optical system consisting of a detection light emitting optical system and a light receiving optical system is provided separately, the configuration is more compact. Here, we introduce a filter that directs the reflected infrared light of the light to the index spora 1 emitted from one index projection optical system and transmits only the reflected infrared light of the index spot light emitted from the other index projection optical system. is provided in the index detection system constituting a part of the other alignment optical system, and the reflected infrared light of the index spot light emitted from the other index projection optical system is captured. Reflection of light to the index spora 1 By providing a filter that transmits only infrared light in the index detection system that constitutes a part of one of the alignment optical systems, each virtual image of the corneal specularly reflected light that forms each virtual image is The index projection optical system that projects the index spot light that forms the image can cut out the harmful components of light reflected from the anterior segment of the eye, such as the cornea, iris, and crystalline lens, which return to itself, making it possible to improve the observation method. This has the effect of preventing image deterioration of the index image confirmed through the image.

[Brief explanation of drawings]

Fig. 1 is an optical system diagram showing the main part configuration of the non-contact type intraocular pressure N1 according to the present invention, and Fig. 2 is a 1/ticle image projection optical system and diopter correction optical system for the non-contact type intraocular pressure n1 according to the present invention. An optical system diagram for explaining the system, FIG. 3 is a non-contact intraocular pressure n system according to the present invention.
1. Optical system diagram for explaining the detection optical path during corneal deformation,
FIG. 4 is an optical system diagram for explaining the reflected light flux of the non-contact ++a pressure H1 according to the present invention, and FIGS. 5 to 7 are alignment adjustment of the non-contact intraocular pressure n1 alignment adjustment device according to the present invention. FIG. 8 is a diagram for explaining the diopter correction optical system shown in FIG. 2.
FIG. 10 is an explanatory diagram of a reticle image formed on the imaging surface by the reticle image projection system shown in FIG. 2. ...observation optical system, 2.eye to be examined, :3.cornea,
4...Lighting means. 5. Observation means, 8. Fluid injection nozzle, 17. First alignment optical system, 18. Second alignment 1-optical system, 19. Infrared light emitting diode, 20. - Indicator projection optical system, 21... Indicator detection system, 22... Infrared light emitting diode, 23... Indicator projection optical system, 24... Indicator detection system. District 5, Figure 6, Figure 71! l Figure 8 j510 figure m9 figure

Claims (2)

[Claims] (1) The axis of the fluid ejection nozzle that ejects fluid for corneal deformation of the eye to be examined toward the cornea is positioned in a predetermined arrangement relationship with the optical axis of the observation optical system for observing the eye to be examined, and the fluid ejection nozzle a non-contact type eye, wherein when the alignment of the eye to be examined is completed based on the alignment adjustment device, the fluid is injected to deform the cornea, and the intraocular pressure is measured based on the deformation of the cornea. The observation optical system is a pressure meter, and the observation optical system includes an illumination means for illuminating the anterior segment of the eye to be examined, an objective lens for forming an image of the anterior segment as an intermediate image, and an observation means for observing the intermediate image. The alignment adjustment device has a pair of alignment adjustment devices arranged at symmetrical positions with respect to the optical axis of the observation optical system such that their respective optical axes intersect at one point on the optical axis of the observation optical system. It has an alignment optical system, and each alignment optical system has
An index spot light forming means, an index projection optical system that projects the index spot light as a parallel light beam onto the cornea, and an index projection optical system of the other alignment optical system that projects a virtual image of the index spot light generated by specular reflection of the cornea of the eye to be examined. and an indicator detection system that guides the indicator light to the observation means via the indicator, the pair of indicator spot lights are infrared lights having mutually different wavelengths, and the illumination light of the illumination unit is visible light. Non-contact tonometer. (2) One of the alignment optical systems is a detection light emitting optical system that emits corneal deformation detection light when the cornea is deformed, and the other of the alignment optical systems is a light receiving optical system that receives reflected light of the corneal deformation detection light. The non-contact tonometer according to claim 1, wherein the non-contact tonometer forms part of a system.