JPH06292653A - Ophthalmoic device - Google Patents

Abstract

PURPOSE:To exactly diagnose glaucoma, for example, by imaging or digitizing the retina thickness distribution and detecting the running direction of nerve fibers. CONSTITUTION:Light from a light source 1 passes through a polarizing plate 3, lens 4 of an illumination optical system, pupil conjugate hole mirror 5 and objective lens 6 to be rotated around an illumination system optical axis S1 and illuminates the fundus Er of the eye E to be examined, the reflected light of the fundus is passed through a polarizing plate 9 to be rotated around a light reception system optical axis S2 synchronously with the objective lens 6, central hole of the hole mirror 5, image formation lens 7 and polarizing plate 3 of the illumination system, a signal from an imaging device 10 is fetched into an image storage device inside a signal processor 11, and the polarizing characteristic of the fundus Er is detected from the stored data signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometry apparatus for detecting a polarization characteristic of a fundus used for diagnosis of glaucoma, for example.

[0002]

2. Description of the Related Art As is well known, when glaucoma occurs, the nipple is pressed by the intraocular pressure so that the retinal nerves die and the retina in that part becomes thin, and the birefringence decreases accordingly.

Therefore, it is possible to diagnose glaucoma by knowing the retinal polarization characteristics. Conventionally, a device for inspecting the birefringence of the retina is generally a system in which a laser light is spotwise applied to a retina measurement point and the reflected light thereof is polarized.

[0004]

In the conventional device for determining the birefringence of the retina, only one point can be known at a time.
It is unsuitable to diagnose a wide area distribution as an image. Further, the defect of the nerve fiber layer appears in a strip shape along the running of the nerve, but the fundus in that portion has a small change in reflectance, so that it is difficult to understand in a general photograph.

An object of the present invention is to make it possible to visualize or quantify the retinal thickness distribution by utilizing the phenomenon that the polarization characteristics change greatly when the transparent retinal thickness changes.
Another object of the present invention is to provide an optometry apparatus capable of accurately detecting a defect in the nerve fiber layer.

[0006]

An optometry apparatus according to the present invention for achieving the above object comprises an illumination system for illuminating a fundus by rotating a polarization direction of a polarized light beam, and a fundus reflected light of the illumination system. It is characterized in that it has a storage means for storing together with the rotation, and detects the polarization characteristic of the fundus oculi by the signal of the storage means.

[0007]

The optometry apparatus having the above-described structure uses polarized light to represent a partial change in the retinal thickness as an image in the image, and simultaneously quantitatively analyze a relatively large area.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 shows an embodiment of the optometry apparatus according to the present invention,
On the optical path from the light source 1 such as a lamp or strobe to the eye E to be inspected, a deflection plate 3 rotated by a motor 2 along an optical axis S1, a lens 4, and a perforated mirror 5 which is a total reflection mirror having no polarization characteristic. , The objective lens 6 is arranged.

Behind the perforated mirror 5, there is an optical axis S2.
An imaging lens 7, a polarizing plate 9 that rotates in synchronization with the deflecting plate 3 by a motor 8, and an image pickup device 10 that is arranged in conjugation with the fundus Er of the eye E to be inspected are arranged along. The output of the image sensor 10 is connected to the signal processing device 11, and the output of the signal processing device 11 is connected to the television monitor 12, the motor 2, and the motor 8.

The light from the light source 1 passes through the polarizing plate 3, the lens 4, the perforated mirror 5 and the objective lens 6 and the fundus of the eye E to be examined.
Illuminate Er. The fundus reflected light passes through the objective lens 6, the central hole of the perforated mirror 5 and the imaging lens 7 and reaches the polarizing plate 9 of the light receiving system. The polarizing plate 9 is synchronized with the polarizing plate 3, and the motor 8
Is rotated about the optical axis S2 of the light receiving system by the
It is desirable that the polarization direction of the polarizing plate 9 be 90 degrees. The light flux that has passed through the polarizing plate 9 is received by the image pickup device 10, which is, for example, a CCD. The signals from the image sensor 10 are sequentially taken into the image storage device provided inside the signal processing device 11.

FIG. 2 is a graph showing the change in the amount of reflected light with respect to the polarization angle from one point on the fundus Er. The angle θ on the horizontal axis indicates the rotation angle of the polarizing plates 3 and 9, and the vertical axis indicates the amount of reflected light. Of the stored data, if the difference between the images is calculated, only the AC component is extracted. This AC component changes depending on the direction of the nerve fiber layer and the incident polarization direction, and becomes a sine wave with a period of 90 degrees, the phase thereof indicates the direction of the nerve fiber layer, and the amplitude A serves as retinal thickness information.

It is necessary to rotate the polarizing plates 3 and 9 by at least 90 degrees, and the phase, that is, the direction and thickness of the nerve fiber layer can be calculated for each point if at least three screens are captured. When the fundus image F along with the traveling direction line is displayed on the television monitor 12 with the amplitude A of each point as the brightness, the place with the defect or atrophy appears dark, so that the defect or atrophy part of the nerve fiber layer is accurately displayed. Can be detected. Also, the amplitude A and the phase can be digitized.

The light source 1 may be caused to emit light in synchronization with the loading into the image storage device. The shorter the wavelength of the light source 1 used, the more it reflects without entering the pigment epithelium.
It is preferable because the polarization is maintained. If the wavelength band is wide, the phase difference varies depending on the wavelength, which is not preferable. Therefore, it is preferable to use a filter or the like to narrow the wavelength band or use monochromatic laser light.

Even if the polarizing plate 9 of the light receiving system is omitted, a certain amplitude A can be obtained, and the amplitude A appears even if the direction of the polarizing plate 9 is not necessarily orthogonal to the direction of the polarizing plate 3. In addition,
It is also possible to attach the polarizing plates 3 and 9 to the non-mydriasis type fundus camera and also serve as a television camera for alignment.
Furthermore, when the fundus is photographed, by removing the polarizing plate or by making the polarization directions parallel, it is possible to record on a recording medium such as a film.

[0015]

As described above, since the optometry apparatus according to the present invention can visualize or digitize the retinal thickness distribution, it is effective for diagnosing glaucoma, for example. Further, since the running direction of the nerve fiber is known, it is possible to accurately grasp the defect portion or atrophy portion of the nerve fiber layer.

[Brief description of drawings]

FIG. 1 is an optical layout diagram of an example.

FIG. 2 is a graph showing a relationship between a light amount of fundus reflected light and a rotation angle of a polarizing plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 3, 9 Polarizing plate 5 Perforated mirror 6 Objective lens 10 Imaging element 11 Signal processing device 12 Television monitor

Claims (1)

[Claims] 1. An illumination system that rotates the polarization direction of a polarized light flux to illuminate the fundus of the eye, and a storage unit that stores the fundus reflected light of the illumination system together with the rotation. An optometry device for detecting polarization characteristics.