JPS60116324A - Eyeball azimuth determining apparatus of ophthalmotonometer - 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 a. Field of Industrial Application The present invention relates to an eyeball orientation determining device in a tonometer.

b. Conventional configuration and its problems Tonometers measure intraocular pressure by using the deformation of the eyeball due to the pressure of air pulses, and at this time, it is important to check whether the eyeball direction is aligned with the traveling direction of the air pulses. , a critical factor for accurate measurements. For this reason, various optical systems for determining eyeball orientation have been developed. However, in all of these conventional optical systems, the air flow axis of the air pulse reservoir and the observation optical system are placed on the same axis. There are limitations due to the relationship, and it has been difficult to create an ideal design for each.

In addition, the observation optical system had a single spectral distribution. This association judges that the direction matches the reference direction (range) when the amount of incident light exceeds a certain set level, so when the reflectance of the eyeball surface changes, the incidence (of reflected light) on the detector changes. There is a drawback that the amount of light changes, and therefore, changes in the ocular surface reflectance affect the orientation determination accuracy.

C.Object of the Invention The present invention eliminates the above-mentioned problems in determining the direction of the eyeball, substantially eliminates the problem of functional competition between the air system and the optical system in design, and improves the reflectance of the eyeball surface. It is an object of the present invention to provide an eyeball orientation determination device that improves the accuracy of orientation determination by ensuring that the detected amount does not change as a whole even if the amount changes.

d.Structure of the Invention In order to achieve the above object, the present invention comprises a binary non-generating portion for generating two light fluxes with different wavelength distributions;
Injecting the compressed air q from a direction different from the air flow axis so that 10,000 of the two light beams emitted from the two light flux generating parts are focused on the apex of the eyeball surface and the other on the center of curvature of the eyeball surface, a pair of incident and reflection optical path sections for returning and guiding the two reflected beams retroreflected from the apex and the center of curvature to respective incident optical paths, and extracting the two reflected beams from the optical path to measure the amount of each light beam. a light beam combining section for extracting the two reflected light beams from the optical path in a direction different from the photometry section and combining these two light beams on an equivalent wavefront; By using an observation station to visually observe the beam combination state in the beam combining section, the two reflected beams are combined, the wavelength distribution of this combined light is detected, and the light intensity of each component is determined. This constitutes an eyeball orientation determination device for a tonometer that can determine the reference orientation of the eyeball at the point where the maximum value or the point where the value exceeds a predetermined level.

e Description of Embodiments Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
Explain in detail.

In FIG. 1 showing the main parts of the embodiment, (1) is a white light source, (2) is a pinhole element having a pinhole through which light from the light source 11) passes, (3) is a field lens, and (4) is is a half mirror, and part of the pinhole light incident on the half mirror (4) via the field lens (3) is reflected here in the direction toward the eyeball (5) of the subject. A deflection prism (6), a Kester prism (7), and a pair of telemeter lenses (8) and (9) are arranged on the path approaching the eyeball (5) from the half mirror (4), and the deflection prism (6) The reflected light that entered the Kester prism (7) iC through the prism is reflected by the divided pieces (
Telemeter lenses t8) and (
9). Therefore, the prism bonding fabric of the Kesku prism (7) forms a so-called dichroic mirror in which the reflected light beam and the transmitted light beam have different wavelength distributions. A second half mirror LD is arranged behind the telemeter lenses (8) and (9) (only the second telemeter lens (9) is via a correction lens aO), and a pair of mirrors placed on the transmission side of the second half mirror LD are arranged behind the telemeter lenses (8) and (9). objective lens u21. t
i31 makes one light beam incident on the vertex P of the eyeball surface, and the other light beam enters the center of curvature O of the eyeball surface.

Note that the objective lens 11.21. (131 and eyeballs (5)
A compressed air nozzle I is installed between the two on the central axis of the two incident optical axes, and the eyeball direction is adjusted to align with the air flow axis from this nozzle.

When the incident light flux to the eyeball (5) accurately reaches the apex P and the center of curvature O of the eyeball surface (cornea), these incident lights are retroreflected toward the objective lenses u21 and (131), and the incident optical system is Therefore, the principle of this orientation determination device is to ensure that the eyeball orientation in which the optical system can detect these retroreflected lights as the maximum value (or around it) is aligned with the air flow axis of the tonometer. It is something.

Now, the two light beams reflected along the optical system and going in opposite directions are transmitted through the second half mirror +tn'f for visual observation, and are further transmitted through the telemeter lenses (8) and (9) (however, before reaching the latter pass through a correction lens (10)) and enter the bottom surface of each part of the Kester prism (7), where they are synthesized at equal wavefronts, enter the deflection prism (6), and pass through the first half mirror. (4) is reached. A focusing plate (15) and an eyepiece (I6) are arranged further in front of the half mirror (4), and a part of the combined light that has also passed through the half mirror (4) is reflected as the final image of the pinhole (2). The image is formed on the focus plate ([9], and the measurer can observe the combined state of the image through the eyepiece (161).

Figures 2 and 3 show the photoelectric photometry system branched from the second half mirror (1]), a7), (18
1 is an eyepiece lens, (19), I20) is a photoelectric conversion element.

That is, the light reflected by the half mirror (111) is reflected by the field lens (12), (131) and the eyepiece lens σ7, respectively.
), (181 through the photoelectric conversion element (191, (2C〃
The wavelength distribution is detected here.

Since the embodiment of the present invention is configured as described above, the eyeball orientation can be quickly and accurately determined by performing the fine adjustment using the photoelectric groove after the rough adjustment using visual observation.

FIG. 4 shows a mode of visual observation, and a in the figure is, for example, a pinhole image (211
coincides with the line of sight and does not coincide with the center of curvature O. Figure 4 shows the result of adjusting the line of sight, etc., to obtain a pinhole image f211, (22+ is fairly shaped (i.e., the white area indicating a straight line is large), and the eyeball direction is aligned with the air flow axis. Although it shows that it is approaching, it is still insufficient and the pinho/L' image (
This visual observation and rough adjustment are completed when the 2B and 2B completely overlap to form one circle.

Next, the light from the corneal apex P reflected by the second half mirror (111) enters the first photoelectric conversion element (19,
Similarly, since the light from the center of curvature O of the cornea that is reflected by the half mirror 111 is incident on the second photoelectric conversion element (20), these two luminous fluxes with different wavelength distributions are converted into Measurements are made using the probes (191, 1201), the line of sight of the eyeball (5) is finely adjusted, the direction in which each light amount is maximum or exceeds a predetermined level is determined, and this direction is determined as the reference direction. It is.

f. Effects of the Invention The present invention allows light amounts of two light fluxes having different wavelength distributions to be projected onto the eyeball without difficulty along a pair of incident and reflected optical paths symmetrically inclined with respect to the airflow axis, Moreover, since it is a reflective device, it is possible to effectively perform dual-wavelength measurement, and it is possible to accurately and quickly determine the orientation of the eyeball axis without being affected by differences in the reflectance of the corneal surface of the eyeball or changes in the light intensity of the light source. This is what makes it possible.

[Brief explanation of the drawing]

Fig. 1 is a line diagram showing the main parts of the optical system in an embodiment of the present invention, Fig. 2 is a side view showing a photoelectric photometry section branched from the optical system shown in Fig. 1, and Fig. FIG. 4 is a schematic diagram showing a combined state of a pair of pinhole images observed on the focusing plate of the optical system shown in FIG. ti)----Single white light source (2)--11--Pinhole element (3), αη, (181--Single field of view lens (4), tt
n---Half mirror (6)---One declension prism (force---Kessler prism (8), (9)---Telemeter lens QO)---
--One correction lens nz, uai---One objective lens (141---One compressed air lens (151---One focal plate (161---One eyepiece (19), 1201--- One photoelectric conversion element 1l---
-Final image from point P (corneal apex) (221-----0
Final image from a point (center of corneal curvature) Patent applicant Agent for the subsidiary Yanagimoto Seisakusho Niimi Other departments (1 other person)

Claims (5)

[Claims] (1) In a tonometer that measures intraocular pressure using the deformation of the eyeball caused by the pressure of compressed air pulses, one of each light beam is retroreflected from the apex of the ocular surface, and the other from the apex and center of curvature of the ocular surface. a pair of incident and reflective optical path sections for returning and guiding the two reflected light beams to respective incident optical paths; and a pair of photoelectric conversion elements for extracting the two reflected light beams from the optical paths and measuring the respective amounts of light. By being equipped with a photometering section, it is possible to determine the reference direction for measuring the intraocular pressure of the eyeball by adjusting the direction of the eyeball and determining the point at which the light intensity of each of the two reflected light beams reaches a maximum or exceeds a predetermined level. A tonometer eyeball orientation determining device characterized by: (2) The two light beams in the incident and reflected optical path sections pass through optical axes that are substantially symmetrically arranged upward with respect to the air flow axis line.
The device described in section 1). (3) A tonometer that measures intraocular pressure using the deformation of the eyeball due to the pressure of compressed air parnu, which includes a two-beam generation section for generating two light beams with different wavelength distributions, and from the two-beam generation section. The compressed air is made to enter the apex of one of the two ocular surfaces, from a direction different from the air flow axis, so that it converges on the center of curvature of the other ocular surface, and from the apex and the center of curvature. a pair of incident and reflective optical path sections for guiding the two retroreflected beams back to each incident optical path; and a photoelectric conversion element for extracting the two reflected beams from the optical path and measuring the amount of each light beam. a pair of photometric sections, each of which includes a pair of photometric sections, a beam combining section for extracting the two reflected beams from the optical path in a direction different from the photometry section and combining these two beams on an equivalent wavefront, and a beam in the beam combining section. By providing an observation station for visually observing the combined state, the two reflected light beams are combined, the wavelength distribution of this combined light is detected, and the light intensity of each component is maximized or reaches a predetermined level. 1. An eyeball orientation determining device for a tonometer, characterized in that the reference orientation of the eyeball can be determined by the point above. (4) The two light beams in the incident and reflected optical path sections pass through optical axes that are substantially symmetrically arranged above with respect to the air flow line.
). (5) The beam combining section is obtained by optically reversing the use of the beam splitting section in the binary non-generating section for splitting a single beam into the two beams having different wavelength distributions. Device according to claim 3 or 4, characterized in that: