JP3964035B2 - Ophthalmic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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]
[Prior art]
As an apparatus for obtaining a tomographic image of the eye, a measuring apparatus using optical coherent tomography (OCT), which uses a low coherent light with a short interference length as a light source and obtains a tomographic image using an interferometer (Hereinafter referred to as an OCT apparatus) is known. According to the OCT apparatus, it is possible to measure the tomographic image of the eye with high accuracy using infrared light that is not mydriatic, but at the time of deciding which part to measure, that is, observation before and after the measurement In addition to the measurement optical system, an observation optical system using the fundus camera or the principle of a slit lamp is added to the apparatus to observe the eye to be examined. For details of OCT, see D. Huang et al., “Optical Coherence Tomography”, Science 1991, 254, pp. 1178-1181, and the like.
[0003]
[Problems to be solved by the invention]
When obtaining a tomographic image of an eye 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 able to obtain an observation image in which the measurement location can be clearly understood without burdening the subject.
[0004]
For example, in a conventional OCT apparatus having a function of observing the fundus by irradiating the eye with infrared light and visualizing the reflected light, the fundus observation is not a burden on the subject. Since the light has good penetrability 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 macular portion, which is important in determining the measurement site, is difficult to understand.
[0005]
In addition, in a conventional OCT apparatus having a function of observing using visible light, since visible light is light having good reflectivity on the fundus surface, an observation image of the fundus surface can be obtained. However, in order to prevent miosis, the amount of light must be considerably weakened, so that the OCT apparatus cannot obtain a clear observation image. If a mydriatic agent is used, a clear observation image can be obtained, but in this case, a burden is imposed on the subject.
[0006]
Accordingly, an object of the present invention is to provide an ophthalmologic apparatus capable of obtaining an observation image in which a measurement location can be clearly understood without imposing a burden on a subject.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, an ophthalmologic apparatus is
(A ) a confocal optical system including a first light source that emits observation laser light, and a scanning unit that scans the observation laser light emitted from the first light source ;
(B) both performed scanning on a predetermined surface of the eye by observation laser light seen by using a confocal optical system, detecting the intensity of the reflected light from the predetermined surface of the eye for observation Les laser light an observation image forming means for forming an observation image of the plant Teimen by to,
An observation image display means for displaying on the screen of the display device an observation image was made form the (c) observation image formed hand stage,
(D ) an optical interference system including a second light source that emits low coherent light having an interference length shorter than that of the observation laser light, and an interferometer;
(E) Low coherent light from the second light source is introduced and interfered with the scanning means of the confocal optical system to the portion of the eye to be examined designated on the observation image displayed on the screen of the display device. And measuring means for performing OCT measurement using a meter.
[0008]
That is, in the present invention, a function as a so-called confocal laser scanning microscope is given to the ophthalmologic apparatus so that the fundus surface with good infrared light transmittance can be observed with a non-mydriatic pupil.
[0009]
When realizing the ophthalmologic apparatus of the present invention, a means using a scanning means in the confocal optical system is adopted as a measuring means in order to introduce low coherent light with a short interference length into the measurement position of the eye to be examined. It is desirable to keep it. If such a measuring means is employed, the optical system of the ophthalmologic apparatus can be formed with a small number of optical components. Therefore, an ophthalmologic apparatus that employs the above-described measuring means can obtain an observation image in which the measurement location can be clearly seen without imposing a burden on the subject and can be manufactured at low cost.
[0010]
Furthermore, in the state where the observation image is displayed on the screen of the display device by the point specification means for specifying the point in the screen of the display device and the observation image display means, When the two points are specified, the measurement means measures the portion specified by the specifying means for specifying the portion of the observed image displayed on the line segment connecting the two points. Measurement control means may be added.
[0011]
According to the ophthalmologic apparatus to which these means are added, the measurement site can be easily specified.
When implementing the ophthalmologic apparatus of the present invention, when adding a specifying means or the like, the observation control means forms an observation image and stores the observation image as the measurement control means, and then specifies the measurement means. It is also possible to employ a means for measuring the portion specified by the means, and after the measurement is completed, the observation image forming means forms an observation image and stores the observation image.
[0012]
Also, without providing any specific means, etc., the observation image forming means forms an observation image and stores the observation image, and then the measurement means performs the measurement. The ophthalmologic apparatus of the present invention may be realized by adding measurement control means for forming an image and storing the observation image.
[0013]
If an ophthalmologic apparatus to which such a measurement control unit is added is used, it is possible to easily detect the eye movement during measurement by the measurement unit.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below based on examples.
FIG. 1 shows a configuration of an optical system included in an ophthalmic apparatus according to an embodiment of the present invention, and FIG. 2 shows an overall configuration of the ophthalmic apparatus of the embodiment.
[0015]
As shown in FIG. 1, the optical system of the ophthalmic apparatus according to the embodiment includes a so-called confocal laser scanning microscope in which the ophthalmic apparatus is a semiconductor laser (LD) 1 as a light source and an eye 50 is a measurement object. 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).
[0016]
Furthermore, the position of an optical system in the ophthalmic field can be moved by a super luminescent 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 the mirror 31 and the like (an optical system including elements from the relay lens 21 to the mirror 31; 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 laser light (an optical system from the focusing mirror unit 14 to the objective lens 19; hereinafter referred to as a scanning optical system), which is a part of the observation optical system. ) Is provided in the ophthalmic apparatus so that it can be used via the dichroic mirror (DM) 13. That is, an optical system (hereinafter referred to as a measurement optical system) for causing the ophthalmologic apparatus to function as an apparatus for obtaining a tomographic image of the eye 50 by OCT using the SLD 26 as a light source by the optical interference system, DM 13 and scanning optical system. Is expressed).
[0017]
As schematically shown in FIG. 2, the ophthalmologic apparatus of the embodiment is an apparatus in which various drivers and signal processing circuits, a control device 40 for controlling them in an integrated manner are added to this optical system. It has become.
[0018]
Hereinafter, the operation of the ophthalmologic apparatus of the embodiment and the function (role) of each component of the ophthalmologic apparatus will be specifically described with reference to these drawings.
As is clear from the above description, the ophthalmologic apparatus has low coherent light output from the LD 1 (hereinafter referred to as observation laser light) and low coherent light output from the SLD 26 (hereinafter referred to as measurement low coherent light). To the eye 50 to be examined. However, the ophthalmologic apparatus does not operate in a state where both laser lights are introduced into the eye 50 to be examined, and operates in a state where at least one laser light is not introduced into the eye 50 to be examined.
[0019]
That is, the ophthalmologic apparatus is in a state in which only the observation laser light is introduced into the eye 50, in a state in which only the measurement low coherent light is introduced into the eye 50, and in a state in which both lights are not introduced into the eye 50. Works with either. The ophthalmologic apparatus is a device in which the transition between these states is performed by changing the operating states of the acousto-optic modulator (AOM) 3 and the optical shutter 24 while the respective lights are output to the LD 1 and the SLD 26. It has become.
[0020]
For example, when power is supplied to the ophthalmic apparatus, the control apparatus 40 causes the LD 1 and the SLD 26 to start outputting the respective lights, and the AOM driver for the control signal that causes the AOM 3 to cut the laser light from the LD 1. And the supply of a control signal that causes the optical shutter 24 to cut the low coherent light from the SLD 26 to the optical shutter 24 is started. That is, the control device 40 sets the operation state of the ophthalmologic device in a state where both lights are not introduced into the eye 50 and the galvano mirrors 16 and 18 are not driven (hereinafter referred to as an initial state). And
[0021]
Thereafter, the control device 40 shifts to a state where the signal from the input device 41 (keyboard, mouse) is monitored, and when detecting that a measurement start instruction is given, the control device 40 displays an image of the fundus 51 of the eye 50 to be examined. Then, fundus oculi observation control processing for almost real-time display on the screen of the monitor device 42 is started.
[0022]
At the start of fundus oculi observation control processing, the control device 40 changes the level of the control signal supplied to the AOM driver 33 to output laser light attenuated by the laser light output from the LD 1 to the AOM 3. Let Further, the galvanometer (GM) drivers 35 and 36 are started to drive the galvanometer mirror 16 and the galvanometer mirror 18 (the drive pattern will be described later).
[0023]
As a result of these controls, the observation laser light passes through the lens 2 and the AOM 3 and is then introduced into the photodetector (PD) 5 and the beam shaping optical system 6 by the half mirror 4.
[0024]
The output of the PD 5 is used for feedback control of the AOM 3 by the AOM driver 33 (see FIG. 2) (the AOM driver 33 is set so that the output of the PD 5 becomes a level corresponding to the level of the control signal from the control device 40). In addition, it is a circuit for controlling the AOM 3).
[0025]
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 introduced into the scanning optical system (reflected by the DM 13) has a focusing mirror unit 14, a spherical mirror 15, and a galvano mirror 16 for making the position of the pinhole 11 coincide with the conjugate position of the fundus 51. Then, the light is reflected by the spherical mirror 17 and the galvanometer mirror 18, passes through the objective lens 19, and is introduced into the eye 50 to be examined. The driving pattern of the galvanometer mirrors 16 and 18 described above is set so that a predetermined surface of the eye 50 to be raster-scanned every predetermined time by the observation laser light introduced into the eye 50 to be examined through such a path. Has been.
[0026]
The observation laser light introduced into the eye 50 is diffused and reflected by each part of the eye 50. As a result of the diffusion and reflection, the observation laser light returned in the direction of the objective lens 19 follows the same path as that at the time of incidence, and reaches the perforated mirror 7. Then, 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 provided with a light opaque portion at the center thereof. The avalanche photodiode (APD) 12 passes through a transmissive glass (only the light opacity portion 10 is shown) provided with a light opacity portion 10 at its center, and a pinhole 11 disposed at the fundus conjugate position. To be introduced.
[0027]
The reason why the pinhole 11 and the like are provided between the condenser lens 8 and the APD 12 is to allow only light necessary for forming a fundus image to enter the APD 12. That is, the light reflected by the perforated mirror 7 includes reflected light on the cornea of the eye 50 to be examined, which is reflected light that degrades the fundus image, in addition to the reflected light on the predetermined surface of the fundus 51 of the observation laser. The reflected light from the objective lens 19 and the reflected light other than the predetermined surface of the fundus 51 are included. For this reason, in this ophthalmologic apparatus, the interference filter 9 provided with the light-impermeable portion is provided so that the reflected light from the cornea is not incident on the APD 12. Further, by providing the pinhole 11 so that the reflected light from the objective lens 19 is not incident on the APD 12 by providing the light non-transmissive portion 10, the reflected light from a portion other than the predetermined surface of the fundus 51 is provided on the APD 12. Is prevented from entering as much as possible (so that only reflected light from a predetermined surface of the fundus 51 is incident).
[0028]
The output of the APD 12 is converted into a digital signal at a period corresponding to the scanning period of the galvano mirror 16 after the noise is removed by the observation signal processing circuit 34. The control device 40 displays the fundus image on the monitor device 42 by processing the digital signal in accordance with the scanning period of the galvanometer mirrors 16 and 18.
[0029]
The operator of the ophthalmologic apparatus adjusts the focus by adjusting the position of the focus mirror unit 14 when necessary while viewing the fundus image displayed on the monitor device 42. Then, the operator uses the input device 41 (mouse) to specify the positions of both ends of the portion where tomographic measurement is performed on the fundus image displayed on the monitor device 42, and then instructs execution of OCT measurement.
[0030]
When it is detected that the above designation is performed during execution of the fundus oculi observation control process, the control device 40 sends a control signal supplied to the AOM driver 33 to the observation laser beam spot of the eye 50 to be examined. When the position is on a portion corresponding to a line segment connecting 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 be lowered to a predetermined level.
[0031]
In other words, as schematically shown in FIG. 3, the controller 40 outputs a laser output from the AOM 3 so that an observation image 45 in which the portion 46 where the cross-section measurement is performed can be identified by brightness is displayed on the monitor device 42. Apply intensity modulation to light. FIG. 3 is a diagram showing an example of the display contents of the monitor device 42 when the OCT measurement is completed, and only the observation image 45 is displayed on the monitor device 42 when the measurement section specification is completed.
[0032]
Thereafter, when it is detected that the start of the OCT measurement is instructed, the control device 40 is required to store the fundus image displayed at that time and to continuously display the fundus image on the monitor device 42. Perform proper processing. Further, 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.
[0033]
Next, the control device 40 opens the optical shutter 24 in order to perform OCT measurement. In addition, the portion (the portion designated by the mouse) where the fundus 51 is to be measured by the measurement low coherent light is scanned at the set speed, and the mirror 31 is schematically shown by an arrow in FIG. 1 or FIG. As shown, 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. Note that the setting work of the scanning speed of the measurement low coherent light used during OCT measurement and the operation pattern (movement distance, speed, etc.) of the mirror 31 is performed separately prior to the execution of the OCT measurement.
[0034]
By such control, the optical multiplexer / demultiplexer 27 combines the low-coherent light for measurement whose frequency is shifted by the movement of the mirror 31 and the low-coherent light for measurement diffused and reflected in the eye 50 to the APD 29. Interfering light is incident. The light is converted into an electric signal corresponding to the level by the APD 29, and after the unnecessary wavelength component is removed by the measurement signal processing circuit 38, the light is converted into a digital signal. 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 allowing the inside of the eye 50 to be examined. Find the reflectance of each part. And the point which has the brightness | luminance (or color) according to the calculated | required reflectance in the position corresponding to each part which calculated | required the reflectance in the screen of the monitor apparatus 42 is displayed. As a result, when the OCT measurement is completed, an observation image 46 at the start of the OCT measurement measurement and a tomographic image 47 obtained by the OCT measurement are displayed on the screen of the monitor device 42 as shown in FIG. .
[0035]
Thereafter, the control device 40 obtains and stores the fundus image at that time by closing the shutter 24 and then executing the same control as in the fundus observation control process after the measurement section designation is completed. Next, the control device 40 returns the states of the AOM 3 and the galvanometer mirrors 16 and 18 to the initial state, and accepts various instructions from the operator, that is, the fundus image and tomographic image stored in the control device 40. The process shifts to a state in which a display instruction, which is an instruction to be displayed on the monitor device 42, a print instruction for printing a fundus image or a tomographic image on a printer (not shown), a measurement start instruction, and the like.
[0036]
When the control device 40 is in this state, the operator reviews the measurement result. For example, the operator displays the fundus images before and after the OCT measurement on the monitor device 42 to check whether or not the eyeball has moved during the measurement. When measurement is required, a measurement start instruction is issued.
[0037]
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 this ophthalmologic apparatus is used, the fundus image required for determining the site | part which performs OCT measurement can be obtained, without giving a test subject a burden. In addition, since the position where the cross-sectional measurement is performed on the fundus image can be designated, a desired portion can be easily measured. Furthermore, since it has a function of capturing and storing fundus images before and after OCT measurement, the eye movement during OCT measurement can be easily detected by using this ophthalmologic apparatus.
[0038]
An apparatus equivalent to the ophthalmic apparatus of the embodiment can also be manufactured by providing the observation optical system and the measurement optical system completely separately. However, in this case, since many optical parts are required for manufacturing the apparatus, the optical system for scanning the observation laser light and the coherent light for measurement is the same as in the optical apparatus of the embodiment. It is desirable to configure the ophthalmologic apparatus so that the observation optical system and the measurement optical system are realized.
[0039]
Further, the configuration for performing OCT measurement that can be provided in the present ophthalmic apparatus is not limited to the one shown in the embodiment, and for example, the configuration disclosed in Japanese Patent Application No. 9-73916-8 is implemented. It can also be used instead of the configuration shown in the example.
[0040]
【The invention's effect】
If the ophthalmologic apparatus of the present invention is used, an observation image in which the measurement location is clearly understood can be obtained without imposing a burden on the subject, and various measurements can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an optical system provided in an ophthalmologic apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram schematically showing the configuration of an optical system for explaining the overall configuration and operation of the ophthalmic apparatus according to the embodiment.
FIG. 3 is a diagram illustrating an example of display contents of a monitor device included in the ophthalmic apparatus according to the embodiment.
[Explanation of symbols]
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 Condensing Lens 9 Interference Filter 10 Impervious Portion 11 Pinhole 12, 29 Avalanche Photodiode (APD)
DESCRIPTION OF SYMBOLS 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 51 Eye fundus

Claims (5)

A confocal optical system including a first light source that emits observation laser light, and scanning means for scanning the observation laser light emitted from the first light source;
By scanning the predetermined surface of the eye to be examined with the observation laser light using the confocal optical system and detecting the intensity of the reflected light from the predetermined surface of the eye to be examined by the observation laser light Observation image forming means for forming an observation image of the predetermined surface;
An observation image display means for displaying an observation image formed by the observation image forming means within a screen of a display device;
A second light source that emits low coherent light having a shorter interference length than the observation laser light, and an optical interference system including an interferometer;
Low coherent light from the second light source is introduced into the portion of the eye to be examined designated on the observation image displayed on the screen of the display device using the scanning means of the confocal optical system, and Measuring means for performing OCT measurement using an interferometer;
An ophthalmologic apparatus comprising: A confocal optical system including a first light source that emits observation laser light, and scanning means for scanning the observation laser light emitted from the first light source;
A second light source that emits low coherent light having a shorter interference length than the observation laser light, and an optical interference system including an interferometer;
By scanning the predetermined surface of the eye to be examined with the observation laser light using the confocal optical system and detecting the intensity of the reflected light from the predetermined surface of the eye to be examined by the observation laser light Observation image forming means for forming an observation image of the predetermined surface;
An observation image display means for displaying an observation image formed by the observation image forming means within a screen of a display device;
Point designating means for designating two points on the observation image displayed in the screen of the display device;
A specifying means for specifying a part of the eye to be examined displayed on a line segment connecting the two points specified by the point specifying means;
Measurement that introduces low coherent light from the second light source to the region of the eye to be examined identified by the identifying unit using the scanning unit of the confocal optical system and performs OCT measurement using the interferometer Means,
An ophthalmologic apparatus comprising: Point designating means for designating a point in the screen of the display device;
When the two points in the screen of the display device using a front Symbol point specifying means in a state in which the observation image on a screen of the display device are displayed is designated by the observation image display means, the observation image specifying means for specifying a portion displayed on a line connecting the person said two points,
Measurement control means for causing the OCT measurement of the specific portion in the specific means to said measuring means,
Claim 1 Symbol placement of the ophthalmologic apparatus characterized by obtaining further Bei a. After forming an observation image on the observation image forming unit and storing the observation image, the measurement unit performs measurement, and after the measurement is completed, the observation image forming unit forms an observation image and the observation image is formed. It is obtained prepare for further measurement control means for storing the ophthalmic apparatus according to claim 1 or claim 2 wherein.   The measurement control unit causes the observation image forming unit to form an observation image and stores the observation image, and then causes the measurement unit to measure the portion specified by the specifying unit, and after the measurement is completed, 4. The ophthalmologic apparatus according to claim 3, wherein the observation image forming means forms an observation image and stores the observation image.

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