JPH05285108A - Ophthalmic measuring instrument - Google Patents

Abstract

PURPOSE:To secure a sufficient illuminating light quantity, in the ophthalmic measuring instrument for executing an eye ground blood vessel measurement for illuminating simultaneously an incoherent illuminating light and a laser light. CONSTITUTION:Light of a lamp 11 is made incident on an interference filter 17 for allowing it to pass through the vicinity of 570nm. Also, as for the light of the lamp 1, only a component of its wavelength or below is synthesized by a wavelength separating mirror 5. A laser light source of 632.8nm wavelength is guided by a minute mirror 18 arranged in a cornea conjugate position corresponding to the lower eyelid side, on a ring slit 6. An area of about 1mm on an eye ground corresponding to the opening diameter of a diaphragm 15 of the lamp 11 side is an illuminating area of an incoherent light illuminated together with a laser light, and this area becomes a blood vessel diameter measurable area, and by constituting the instrument so that the light quantity of an incoherent illuminating light on the cornea exists locally in the vicinity of an incident position of the laser light, the light quantity of a necessary and sufficient incoherent illuminating light is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmic measuring apparatus, and more particularly to an ophthalmic measuring apparatus for measuring blood flow in a fundus blood vessel.

[0002]

2. Description of the Related Art A method for optically measuring the blood flow in a retinal blood vessel in real time has been proposed in JP-A-2-274220. The method is to measure the blood flow velocity with scattered light when the fundus is illuminated with a laser beam, and at the same time, image the laser beam scattered from the fundus and receive it with a scanning sensor placed on the fundus conjugate plane. This is a method in which the blood vessel diameter is measured based on the difference in the speed of spatiotemporal fluctuations in the speckles of the portion and the portion other than the blood vessel, and the blood flow rate is calculated from both of them.

[0003]

In the above-mentioned conventional method, (1) the measurement cannot be guaranteed for an affected eye whose blood flow velocity decreases.

(2) Since the blood flow velocity is slow in the blood vessel wall portion, a sufficient velocity difference with the tissue cannot be obtained. Therefore, it is difficult to recognize a stable blood vessel wall.

There are problems such as

In order to solve this problem, a method of measuring the blood flow velocity using the speckle phenomenon and performing incoherent light illumination of a predetermined wavelength at the same time and analyzing the obtained fundus image to measure the blood vessel diameter was examined. ..

At this time, it is conventionally known that when the wavelength of the incoherent illumination light is set in the vicinity of 570 nm, the contrast between the blood vessel image and the image of the surrounding tissue is increased, and this point was also confirmed as a supplementary test. However, I found the following new problems.

A laser beam for measuring blood flow velocity is applied to the cornea 1
When the light having a wavelength of 570 nm is incident on the eyeball at the same time as ring illumination and the fundus is illuminated with a spot of about 1 mm, the laser light is incident, but half of the ring illumination is eclipsed by the iris. In such alignment state, 5
In many cases, it was difficult to measure the blood vessel diameter due to the insufficient amount of illumination light with a wavelength of 70 nm.

Further, when the incident point of the laser light is set on a line that horizontally crosses the center of the pupil, there is a problem that the upper eyelid tends to close due to the glare, and the laser light is easily eclipsed by the eyelashes.

An object of the present invention is to solve the above problems, to provide a configuration of an ophthalmologic measuring apparatus which can sufficiently provide incoherent illumination light and which is free from a measurement laser beam. is there.

[0011]

In order to solve the above problems, in the present invention, in an ophthalmologic measuring apparatus for measuring the blood flow rate of the fundus blood vessel, at least incoherent light generating means of a wavelength in the vicinity of a predetermined wavelength, An illumination light generation unit including a laser light illumination unit having a wavelength other than the predetermined wavelength, and an illumination optical system that irradiates the fundus with the light emitted from the illumination light generation unit, and the predetermined wavelength light and laser light Employs a configuration in which the fundus is illuminated with a spot size sufficiently smaller than the size of the eye to be examined.

[0012]

According to the above construction, the quantity of incoherent illumination light on the cornea is localized near the incident position of the laser light. Therefore, if the laser light illuminates the fundus, a sufficient amount of incoherent illumination light can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows the structure of an ophthalmologic measuring apparatus adopting the present invention. Light emitted from the halogen lamp 1 arranged on the conjugate surface of the cornea is focused on the ring slit 6 via the lens 2, the diaphragm 3, the lens 4, and the wavelength separation mirror 5. The light passing through the ring-shaped opening of the ring slit 6 passes through the lenses 7 and 8 and is reflected by the perforated mirror 9. The objective lens 10 forms a ring-shaped image in the vicinity of the cornea Ep of the eye E to be inspected. The fundus Er of the eye is illuminated.

At the same time, the light emitted from the halogen lamp 11 also arranged on the corneal conjugate surface passes through the lens 12, the light blocking plate 13, the lens 14, the diaphragm 15, the lens 16 and the interference filter 17, and from the wavelength separation mirror 5. Guided to the illumination optics.

As shown in FIG. 2, the interference filter 17 has a characteristic of transmitting only light having a wavelength near 570 nm.

On the other hand, as shown in FIG. 3, the wavelength separation mirror 5 has a characteristic of reflecting light having a wavelength shorter than 560 nm and reflecting light having a wavelength longer than 560 nm.

Further, the diaphragms 3 and 15 are arranged substantially on the conjugate plane of the fundus oculi, and the aperture diameter of the diaphragm l5 corresponds to about 1 mm on the fundus, which is sufficiently smaller than the aperture diameter of the diaphragm 3 and is equal to the aperture diameter of the diaphragm l5. A region of approximately 1 mm above the fundus becomes the blood vessel diameter measurable region.

Further, a minute mirror 18 is arranged at one portion of the ring of the ring slit 6 shown in FIG.
Light radiated (wavelength 632.8 nm) is guided to the illumination optical system.

The ring slit 6 is arranged on the corneal conjugate plane, and the laser light of the laser light source 19 is caused by the micro mirror 18 arranged at the corneal conjugate position corresponding to the lower eyelid side on the cornea on the ring opening. Is reflected.

The light scattered by the fundus Er of the eye E to be examined is the objective lens 10, the aperture of the perforated mirror 9 and the lens 20.
To reach the wavelength separation mirror 21.

The wavelength separating mirror 21 is, as shown in FIG.
It has a characteristic of transmitting light having a wavelength shorter than 560 nm and reflecting light having a wavelength longer than 560 nm.

Light having a wavelength shorter than 560 nm passes through the wavelength separation mirror 21, is reflected by the flip-up mirror 22, passes through the mirror 23 and the eyepiece lens 24, and reaches the eye S of the examiner.

Light having a wavelength longer than 560 nm is reflected by the wavelength separation mirror 21 and reaches the wavelength separation mirror 26 via a lens 25 movable in a plane perpendicular to the optical axis.

The wavelength separation mirror 26, as shown in FIG.
The laser light source 19 has a characteristic that it transmits light of a wavelength emitted by it and reflects light of other wavelengths.

The laser light is reflected by the wavelength separation mirror 26, forms an image on the detection aperture 27 arranged on the fundus conjugate plane, and the light passing through the detection aperture 27 is detected by the photomultiplier tube 28.

Light having a wavelength near 570 nm passes through the wavelength separation mirror 26 and is separated by the half mirror 29, one of which is a line sensor F arranged on the fundus conjugate plane.
The other one passes through the reticle 30 arranged on the fundus conjugate plane and reaches the examiner's eye S ′ through the eyepiece lens 31.

With this structure, a blue image of the entire fundus of the eye is observed from the eyepiece lens 24, and an enlarged yellow image of the measurement region is observed from the eyepiece lens 31.

Also, 57 obtained from the line sensor F
A fundus blood vessel image is recognized from the fundus image data with a wavelength near 0 nm, and the blood flow velocity of the fundus blood vessel is measured by processing the output of the photomultiplier tube 28.

The light shielding plate 13 is arranged almost on the corneal conjugate plane,
It blocks the light flux that enters the eyeball from the upper eyelid side of the cornea and illuminates the fundus.

FIG. 6 shows an illumination state of the conventional apparatus, and since the eyeball incident point 32 of the laser light is close to the upper eyelid, when the upper eyelid is closed due to glare, the laser light for illumination is easily eclipsed by the eyelashes. Conventionally, since the minute mirror 18 for laser light is arranged at one end of the ring slit, the observation illumination light 33 (ring illumination) lacks the laser incident point 32.

On the other hand, FIG. 7 shows an illumination state in the device of the present invention, in which the eyeball incident point 32 ′ of the laser light is the minute mirror 18.
The position is changed to the lower eyelid side of the cornea of the eye to be examined. That is, since the eyeball incident point 32 'of the laser light is farther than the upper eyelid, there is an advantage that the illumination laser light is less likely to be shaded even when the upper eyelid is closed to some extent.

The illumination light 34 having a wavelength of 570 nm is
By using the light shielding plate 13 and using the lower half of the ring illumination, the amount of the illumination light of 570 nm is concentrated near the eyeball incident position of the laser light, so that it is less affected by the alignment state.

[0034]

As is apparent from the above, according to the present invention, in the ophthalmologic measuring apparatus for measuring the blood flow in the fundus blood vessel, at least the incoherent light generating means having a wavelength in the vicinity of the predetermined wavelength and the other than the predetermined wavelength are used. An illumination light generation unit including a laser light illumination unit having a wavelength, and an illumination optical system for irradiating the fundus with the light emitted from the illumination light generation unit,
The light of the predetermined wavelength and the laser light are used to illuminate the fundus with a spot size sufficiently smaller than the size of the eye to be inspected. That is, since the light quantity of the incoherent illumination light on the cornea is localized near the incident position of the laser light, if the laser light illuminates the fundus, the necessary and sufficient incoherent illumination light There is an excellent effect that the amount of light can be obtained. Furthermore, by setting the incident position of the laser light on the side of the lower eyelid of the cornea, the laser light is prevented from being eclipsed by the eyelashes.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a structure of an ophthalmologic measuring apparatus adopting the present invention.

FIG. 2 is a diagram showing a characteristic of an interference filter 17.

FIG. 3 is a diagram showing characteristics of the wavelength separation mirror 5.

FIG. 4 is a diagram showing the characteristics of the wavelength separation mirror 21.

5 is a diagram showing the characteristics of the wavelength separation mirror 26. FIG.

FIG. 6 is an explanatory diagram showing a problem of the conventional device.

FIG. 7 is an explanatory view showing the operation of the device of the present invention.

[Explanation of symbols]

 1 Halogen Lamp 2 Lens 3 Aperture 4 Lens 5 Wavelength Separation Mirror 6 Ring Slit 7 Lens 8 Lens 9 Hole Mirror 10 Objective Lens 11 Halogen Lamp 12 Lens 13 Light Shield 14 Lens 15 Aperture 16 Lens 17 Interference Filter 18 Micro Mirror 19 Laser Light Source 22 Flying mirror 23 Mirror 24 Eyepiece lens 25 Lens 26 Wavelength separation mirror 27 Detection aperture 28 Photomultiplier tube 29 Half mirror 31 Eyepiece lens 32 Eyeball incident point 33 Observation illumination light 32 'Eyeball incident point 34 Illumination light F line sensor

Claims (4)

[Claims] 1. An ophthalmologic measuring device for measuring blood flow in a fundus blood vessel, comprising: incoherent light generating means having a wavelength at least near a predetermined wavelength; and illumination light generating means including a laser light illuminating means having a wavelength other than the predetermined wavelength. , Having an illumination optical system for irradiating the fundus with the light emitted from the illumination light generating means, the light of the predetermined wavelength and the laser light are compared to the measurement region size of the fundus, the fundus with a sufficiently small spot size. An ophthalmologic measuring device characterized by being illuminated. 2. The illumination optical system comprises a ring slit arranged substantially on a corneal conjugate plane, and a micro mirror arranged at a corneal conjugate position corresponding to the lower eyelid side on the cornea on the ring opening of the ring slit. The ophthalmic measurement device according to claim 1, further comprising: a micro mirror that guides the laser light. 3. The illuminating means includes illuminating means for illuminating light of a predetermined wavelength, and the illuminating means for illuminating light of a predetermined wavelength is substantially a light flux regulating means for limiting an illuminating light flux on the upper eyelid side half of the cornea. The ophthalmologic measuring apparatus according to claim 1, wherein the ophthalmologic measuring apparatus is included in a corneal conjugate position. 4. The ophthalmologic measuring apparatus according to claim 2, wherein the illuminating means of the light of the predetermined wavelength includes a wavelength separation mirror.