JPH11253403A - Ophthalmic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmic device which can provide observation images allowing clear distinction of measured portions, without overburdening a subject. SOLUTION: An ophthalmic device is fitted with an observation system for observing the fundus oculi of the eye to be examined 50, having a confocal optical system including galvanomirrors 16, 18 for scanning infrared rays output by an LD 1, and a measuring system for obtaining cross-sectional images of the eye to be examined 50 by causing low coherent light beams of short interference lengths output from an SLD 26 to be introduced into the eye to be examined 50 by use of the confocal optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ophthalmologic apparatus for obtaining a tomographic image of an eye using low coherent light having a short interference length.

[0002]

2. Description of the Related Art As a device for obtaining a tomographic image of an eye, a low coherent light having a short interference length called an optical coherent tomography (OCT) is used as a light source.
2. Description of the Related Art A measuring apparatus (hereinafter, referred to as an OCT apparatus) using a method of obtaining a tomographic image using an interferometer is known. OC
According to the T device, using the infrared light in which the subject's eye does not mydriasis,
Highly accurate tomographic images of the eye can be measured, but when deciding which part to measure, that is, when observing before and after the measurement, observation using the principle of a fundus camera or slit lamp separately from the optical system for measurement An optical system is added to the apparatus to observe the subject's eye. For more information about OCT, see D. Huan
g et al., "Optical Coherence Tomography", Science 19
91, 254, pp. 1178-1181 and the like.

[0003]

When a tomographic image of an eye is obtained by using an OCT apparatus, it is necessary to determine a site for measuring the tomographic image. For this reason, the OCT apparatus is usually provided with a function for observing the fundus. However, this function added to the conventional OCT apparatus has not been capable of obtaining an observation image in which a measurement point can be clearly understood without imposing a burden on a subject.

For example, in a conventional OCT apparatus having a function of observing a fundus by irradiating an eye with infrared light and visualizing the reflected light, the fundus observation does not burden the subject. Since infrared light is light having good penetration into the retina, the displayed fundus image is inside the fundus surface. That is, the OCT apparatus is an apparatus that can obtain only an observation image in which the location of the macula, which is important when determining the measurement site, is difficult to understand.

In a conventional OCT apparatus having a function of performing observation using visible light, an image of the fundus surface can be obtained because visible light is light having good reflectivity on the fundus surface. However, in order to prevent miosis, the amount of light must be considerably weakened.
The device cannot obtain a clear observation image.
When a mydriatic agent is used, a clear observation image can be obtained, but in this case, a burden is imposed on the subject.

It is an object of the present invention to provide an ophthalmologic apparatus capable of obtaining an observation image in which measurement points can be clearly understood without imposing a burden on a subject.

[0007]

According to the present invention, there is provided an ophthalmologic apparatus comprising: (a) a confocal optical system including a scanning means for scanning a laser beam;
Using a confocal optical system, the observation laser light is scanned over a predetermined surface of the eye to be inspected, and the intensity of the observation light laser light reflected from the predetermined surface of the eye to be inspected is detected, whereby the predetermined surface is detected. Observation image forming means for forming an observation image of
(C) observation image display means for displaying the observation image formed by the observation image formation means on the screen of the display device, and (d) low-coherent light for measurement, which is infrared light and has a short interference length, as a light source;
It is configured using measurement means for performing measurement using an interferometer on an eye to be inspected.

That is, in the present invention, a function as a so-called confocal laser scanning microscope is provided to an ophthalmologic apparatus so that a fundus surface having good infrared light transmission can be observed without a mydriatic pupil. .

In realizing the ophthalmologic apparatus of the present invention, a means using a scanning means in a confocal optical system is used as a measuring means in order to introduce low coherent light having a short interference length to a measuring position of an eye to be examined. It is desirable to adopt it. By employing such a measuring means, an optical system of an ophthalmologic apparatus can be formed with a small number of optical components. Therefore, an ophthalmologic apparatus employing the above-described measuring means can obtain an observation image in which a measurement location can be clearly seen without imposing a burden on a subject, and can be manufactured at low cost.

[0010] Further, a point designation means for designating a point in the screen of the display device, and a display device using the point designation means while the observation image is displayed on the screen of the display device by the observation image display means. When two points in the screen are specified, a specifying means for specifying a portion of the observation image displayed on a line segment connecting the two points, and measuring the portion specified by the specifying means A measurement control means to be performed by the means may be added.

According to the ophthalmologic apparatus to which these means are added, it is possible to easily specify the measurement site. In addition,
When realizing the ophthalmologic apparatus of the present invention, in the case of adding a specifying unit or the like, as the measurement control unit, the observation image forming unit forms the observation image and stores the observation image, and then the measurement unit uses the specifying unit. It is also possible to employ a means for causing the specified portion to be measured, and after the measurement is completed, causing the observation image forming means to form an observation image and storing the observation image.

In addition, without providing any specific means or the like, the observation image forming means forms an observation image and stores the observation image, and then the measurement means performs measurement. After the measurement is completed, the observation image formation means The ophthalmologic apparatus according to the present invention may be realized by adding a measurement control unit for forming an observation image to the camera and storing the observation image.

By using an ophthalmologic apparatus to which such measurement control means is added, it is possible to easily detect eye movement during measurement by the measurement means.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below based on examples. FIG. 1 shows a configuration of an optical system provided in an ophthalmologic apparatus according to an embodiment of the present invention.
1 shows an overall configuration of the ophthalmologic apparatus of the embodiment.

As shown in FIG. 1, the optical system of the ophthalmologic apparatus according to the embodiment includes a semiconductor laser (LD) 1
Is a light source, and the subject's eye 50 is a measurement target.
An optical system (an optical system composed of elements from the LD 1 to the objective lens 19; hereinafter, referred to as an observation optical system) for functioning as a confocal laser scanning microscope is included.

Further, the position of the optical system in the field of ophthalmology is controlled by a superluminescent diode (SLD) 26, an optical multiplexer / demultiplexer 27, and a moving mechanism (see FIG. 2) as a light source of low coherent light having a short interference length. An optical system including a movable mirror 31 (from the relay lens 21 to the mirror 3)
An optical system comprising up to one element; hereinafter, referred to as an optical interference system) is also included. The optical interference system is an optical system for controlling the spot position of the laser beam, which forms a part of the observation optical system (from the focusing mirror section 14 to the objective lens 19).
(Hereinafter, referred to as a scanning optical system) is provided in the ophthalmologic apparatus so as to be used via a dichroic mirror (DM) 13. That is, the ophthalmologic apparatus is controlled by the SLD by the optical interference system, the DM 13 and the scanning optical system.
An optical system (hereinafter, referred to as a measurement optical system) for functioning as a device for obtaining a tomographic image of the eye 50 to be inspected by OCT using the light source 26 is realized.

As schematically shown in FIG. 2, in the ophthalmologic apparatus of the embodiment, various drivers and signal processing circuits, a control device 40 for integrally controlling them, and the like are added to the optical system. Device.

Hereinafter, the operation of the ophthalmologic apparatus of the embodiment and the functions (roles) of each component of the ophthalmologic apparatus will be specifically described with reference to these drawings. As is apparent from the above description, the present ophthalmologic apparatus includes low coherent light (hereinafter referred to as observation laser light) output from the LD 1 and low coherent light (hereinafter referred to as measurement low coherent light) output from the SLD 26. ) Can be introduced into the eye 50 to be examined. However, the ophthalmologic apparatus does not operate in a state where both laser beams are introduced into the eye 50, and operates in a state where at least one laser beam is not introduced into the eye 50.

That is, the ophthalmologic apparatus has a state in which only the observation laser light is introduced into the eye 50, a state in which only the low coherent light for measurement is introduced into the eye 50, and a state in which both lights are introduced into the eye 50. Operate in one of the states that do not. Then, the ophthalmologic apparatus determines that the transition between the states is L
The apparatus is performed by changing the operation state of the acousto-optic modulator (AOM) 3 and the optical shutter 24 while the respective lights are being output to the D1 and the SLD 26.

For example, when the power of the ophthalmic apparatus is turned on,
The control device 40 causes the LD 1 and the SLD 26 to start outputting the respective light, supplies the control signal to the AOM 3 to cut the laser light from the LD 1 to the AOM driver 33, and sets the optical shutter 24 to the SLD 26.
Of the control signal to cut the low coherent light from the optical shutter 24 is started. That is,
The control device 40 sets the operation state of the ophthalmologic apparatus to a state in which both lights are not introduced to the subject's eye 50 and the galvanometer mirrors 16 and 18 are not driven (hereinafter, referred to as an initial state). .

After that, the control device 40 operates the input device 41
When a transition is made to a state of monitoring signals from the (keyboard, mouse) and it is detected that a measurement start instruction has been given, the image of the fundus 51 of the subject's eye 50 is displayed almost in real time on the screen of the monitor device 42. The control process for fundus observation for displaying by is started.

At the start of the fundus observation control process, the control unit 4
0 changes the level of the control signal supplied to the AOM driver 33, thereby causing the AOM 3 to output a laser beam obtained by attenuating the laser beam output from the LD1.
Also, galvanometer (GM) drivers 35 and 36
The galvanomirror 16 and the galvanomirror 1 respectively
8 (the drive pattern will be described later).

As a result of these controls, the observation laser light
After passing through the lens 2 and the AOM 3, the light is introduced into the photodetector (PD) 5 and the beam shaping optical system 6 by the half mirror 4.

The output of PD 5 is supplied to AOM driver 33.
2 (see FIG. 2), the AOM driver 33 is a circuit that controls the AOM 3 so that the output of the PD 5 becomes a level corresponding to the level of the control signal from the control device 40. ing).

The observation laser light introduced into the beam shaping optical system 6 passes through the perforated mirror 7, is reflected by the DM 13, and is introduced into the scanning optical system. The observation laser light (reflected by the DM 13) introduced into the scanning optical system is used to adjust the position of the pinhole 11 to the conjugate position of the fundus 51, the focusing mirror unit 14, and the spherical mirror 1.
5. The light is reflected by the galvanomirror 16, the spherical mirror 17, and the galvanomirror 18, passes through the objective lens 19, and is introduced into the eye 50 to be examined. The driving pattern of the galvanomirrors 16 and 18 described above is determined by the observation laser light introduced into the eye 50 through such a path.
Is set to be raster-scanned at predetermined time intervals.

The observation laser light introduced into the eye 50 is diffused and reflected by each part of the eye 50. Its diffusion
As a result of the reflection, the observation laser light returned in the direction of the objective lens 19 reverses the same path as that at the time of incidence, and the perforated mirror 7
Leads to. The observation laser light reflected by the perforated mirror 7 passes through the condenser lens 8 and is a filter for removing disturbance light, and an interference filter 9 having a light opaque portion at the center thereof. An avalanche photodiode (APD) 12 passes through a transmission glass (only the light opaque portion 10 is shown) provided with a light opaque portion 10 at the center thereof and a pinhole 11 arranged at a conjugate position of the fundus. Will be introduced.

The pinhole 11 and the like are provided between the condenser lens 8 and the APD 12 so that only light necessary for forming a fundus image is incident on the APD 12. That is, the light reflected by the perforated mirror 7 includes, in addition to the reflected light of the observation laser on a predetermined surface of the fundus 51, the reflected light on the cornea of the eye 50 to be examined, which is reflected light that deteriorates the fundus image. The reflected light from the objective lens 19 and the reflected light from a portion other than the predetermined surface of the fundus 51 are included. Therefore, in the present ophthalmologic apparatus, by providing the interference filter 9 having the light opaque portion, the reflected light from the cornea
12 is prevented. Further, by providing the light non-transmissive portion 10, the pinhole 11 is prevented so that the reflected light from the objective lens 19 does not enter the APD 12.
Is provided so that the reflected light from the portion other than the predetermined surface of the fundus 51 is not incident on the APD 12 as much as possible (so that only the reflected light from the predetermined surface of the fundus 51 is incident).

The output of the APD 12 is supplied to the observation signal processing circuit 3
4, after the noise is removed, the galvanomirror 1
6 is converted into a digital signal at a cycle corresponding to the scanning cycle. The control device 40 causes the monitor device 42 to display a fundus image by processing the digital signal in accordance with the scanning cycle of the galvanometer mirrors 16 and 18.

The operator of the ophthalmologic apparatus adjusts the focus by adjusting the position of the focus mirror unit 14 if necessary while watching the fundus image displayed on the monitor 42. Then, the operator uses the input device 41 (mouse) to specify the positions of both ends of the portion for performing the tomographic measurement on the fundus image displayed on the monitor device 42, and
Instructs execution of CT measurement.

When the control unit 40 detects that the above designation has been made during the execution of the fundus observation control process, the control unit 40 sends a control signal to be supplied to the AOM driver 33 to the observation laser beam spot. When it is located on the portion corresponding to the line segment connecting the two designated points, the control signal is switched to a control signal that causes the level of the laser light output from the AOM 3 to drop to a predetermined level.

That is, as shown schematically in FIG. 3, the control device 40 outputs the AOM 3 from the AOM 3 so that the observation image 45 in which the section 46 where the cross-section measurement is performed can be identified by light and dark is displayed on the monitor device 42. The intensity of the laser beam to be modulated is applied. FIG. 3 is a diagram showing an example of the display contents of the monitor device 42 when the OCT measurement is completed. When the designation of the measurement section is completed, the monitor device 42 displays:
Only the observation image 45 is shown.

Thereafter, when it is detected that the start of the OCT measurement has been instructed, the control device 40 stores the fundus image displayed at that time and continues to display the fundus image on the monitor device 42. To perform the necessary processing. In addition, the control device 40 controls the AOM driver 33 and the galvanometer drivers 35 and 36 to return the states of the AOM 3 and the galvanometer mirrors 16 and 18 to the initial state.

Next, the control device 40 opens the optical shutter 24 in order to perform OCT measurement. Further, the portion where the fundus 51 is to be measured (the portion designated by the mouse) is scanned at a set speed by the low coherent light for measurement, and the mirror 31 is schematically indicated by an arrow in FIG. 1 or FIG. As shown in the figure, the galvanometer drivers 35 and 36 and the moving mechanism driver 37 are controlled so as to repeat the reciprocating operation within the set range in the set pattern. The setting of the scanning speed of the low coherent light for measurement used in the OCT measurement and the operation pattern (moving distance, speed, etc.) of the mirror 31 are separately performed prior to the execution of the OCT measurement.

With this control, the APD 29 is configured to combine the low coherent light for measurement whose frequency has been shifted by the movement of the mirror 31 and the low coherent light for measurement diffused and reflected in the eye 50 into the optical multiplexer / demultiplexer 27. The multiplexed and interfered light is incident. The light is converted into an electric signal corresponding to the level by the APD 29, and is converted into a digital signal after unnecessary wavelength components are removed in the measurement signal processing circuit 38. The control device 40 performs predetermined signal processing on the digital signal from the measurement signal processing circuit 38 in consideration of the introduction position of the low coherent light for measurement and the speed and position of the mirror 31, thereby obtaining the eye 50 to be examined.
The reflectance of each part inside is calculated. Then, points having a luminance (or color) corresponding to the determined reflectance are displayed at positions corresponding to the respective portions for which the reflectance has been determined in the screen of the monitor device 42. As a result, when the OCT measurement is completed, the screen of the monitor device 42 displays, as shown in FIG.
An observation image 46 at the start of the OCT measurement and a tomographic image 47 obtained by the OCT measurement are displayed.

After that, the control device 40 closes the shutter 24 and executes the same control as in the control processing for fundus observation after the completion of designation of the measurement section, thereby obtaining and storing the fundus image at that time. I do. Next, the control device 40
Returns the state of the AOM 3 and the galvanometer mirrors 16 and 18 to the initial state, and displays various conditions from the operator, that is, displays the fundus image and tomographic image stored in the control device 40 on the monitor device 42. The state shifts to a state in which a display instruction which is an instruction to be performed, a print instruction to print a fundus image or a tomographic image by a printer (not shown), a measurement start instruction, and the like are received.

When the control device 40 is in this state, the operator examines the measurement results and the like. For example, the operator displays whether or not the eyeball has moved during the measurement by displaying the fundus images before and after the OCT measurement on the monitor device 42. When measurement is required, a measurement start instruction is issued.

As described above, the ophthalmologic apparatus according to the embodiment has a function as a so-called laser scanning microscope using infrared laser light. For this reason, if the present ophthalmologic apparatus is used, it is possible to obtain a fundus image necessary for determining a site for performing OCT measurement without imposing a burden on the subject.
In addition, since the position for performing the cross-sectional measurement on the fundus image can be designated, a desired portion can be easily measured. Furthermore, since the apparatus has a function of capturing and storing fundus images before and after OCT measurement, the use of the present ophthalmologic apparatus makes it easy to detect eye movement during OCT measurement.

By providing the observation optical system and the measurement optical system completely separately, a device equivalent to the ophthalmologic apparatus of the embodiment can be manufactured. However, in this case, more optical components will be required to manufacture the device,
As in the optical device of the embodiment, an optical system for scanning the observation laser light and the measurement coherent light is commonly used, and the ophthalmologic apparatus is implemented so that the observation optical system and the measurement optical system are realized. It is desirable to configure.

Further, O which can be provided in the present ophthalmologic apparatus
The configuration for performing the CT measurement is not limited to the configuration shown in the embodiment. For example, the configuration disclosed in Japanese Patent Application No. 9-73916-8 may be used instead of the configuration shown in the embodiment. Can also.

[0040]

According to the ophthalmologic apparatus of the present invention, it is possible to obtain an observation image in which measurement points can be clearly understood without imposing a burden on a subject, so that various measurements can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical system included in an ophthalmologic apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically illustrating the configuration of an optical system for explaining the overall configuration and operation of the ophthalmologic apparatus according to the embodiment.

FIG. 3 is a diagram showing an example of display contents of a monitor device provided in the ophthalmologic apparatus of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 semiconductor laser (LD) 2, 21, 22, 25, 28 lens 3 acousto-optic modulator (AOM) 4 half mirror 5 photodetector (PD) 6 beam shaping optical system 7 perforated mirror 8 focusing lens 9 interference Filter 10 Non-transmitting part 11 Pinhole 12, 29 Avalanche photodiode (APD) 13 Dichroic mirror 14 Focusing mirror part 15, 17 Spherical mirror 16, 18 Galvano mirror 19 Objective lens 23, 30 Mirror 24 Optical shutter 26 Super luminescent diode ( SLD) 27 Optical multiplexer / demultiplexer 31 Moving mechanism 33 AOM driver 34 Observation signal processing circuit 35, 36 Galvanometer (GM) driver 37 Moving mechanism driver 38 Measurement signal processing circuit 40 Control device 41 Input device 42 Monitor device 50 Eye to be examined 51 Fundus

Claims (5)

[Claims] 1. A confocal optical system including a scanning unit for scanning a laser beam, and a laser beam for observation is scanned on a predetermined surface of an eye to be inspected by using the confocal optical system. An observation image forming unit that forms an observation image of the predetermined surface by detecting the intensity of reflected light of the observation light laser light from the predetermined surface of the eye to be inspected; and an observation formed by the observation image forming unit. Ophthalmology, comprising: an observation image display unit for displaying an image on a screen of a display device; and a measurement unit for performing measurement using an interferometer with the low coherent light having a short interference length as a light source on the subject's eye. apparatus. 2. The scanning unit in the confocal optical system for introducing low coherent light having a short interference length to a measurement position of the eye to be inspected, wherein the measuring unit uses the scanning unit in the confocal optical system. The ophthalmic apparatus according to any of the preceding claims. 3. A point designating unit for designating a point on a screen of the display device, and the point designating unit in a state where the observation image is displayed on a screen of the display device by the observation image display unit. When two points in the screen of the display device are designated by using, a specifying means for specifying a portion of the observation image displayed on a line segment connecting the two points, The ophthalmologic apparatus according to claim 1, further comprising: a measurement control unit that causes the measurement unit to measure the measured portion. 4. An observation image is formed by the observation image forming means, and the observation image is stored. The measurement image is measured by the measurement means. After the measurement is completed, an observation image is formed by the observation image forming means. The ophthalmologic apparatus according to claim 1, further comprising a measurement control unit configured to store the observation image. 5. The measurement control unit, after causing the observation image forming unit to form an observation image and storing the observation image, causes the measurement unit to measure a portion specified by the specifying unit. The ophthalmologic apparatus according to claim 3, wherein after the measurement is completed, the observation image forming means forms an observation image and stores the observation image.