JP6700876B2 - Ophthalmologic apparatus, control method thereof, and program - Google Patents

Description

  The present invention relates to an ophthalmologic apparatus that scans the eye fundus of the eye to be inspected with a fixation light for fixing the eye to be inspected, a control method therefor, and a program for causing a computer to execute the control method.

  2. Description of the Related Art Conventionally, in an optical coherence tomography (optical coherence tomography, hereinafter referred to as "OCT") device, a fixation light from a fixation lamp is two-dimensionally scanned on a fundus of an eye to be examined by a scanning means. A technique for visually recognizing an optotype is known (for example, see Patent Document 1). Here, various members such as a galvano scanner, a polygon scanner, or a resonance scanner are used as the scanning means. For example, in a polygon scanner that scans light by rotating a polyhedral mirror at a constant speed, the scanning speed is constant because the mirror is driven to rotate at a constant speed.

JP, 2014-188187, A

  However, in a galvano scanner or a resonance scanner that scans light by reciprocally driving a mirror, since the scanning speed is accelerated or decelerated each time the mirror is reciprocally driven, a fixation target visually recognized by the subject is displayed. There is a problem that distortion and uneven brightness may occur.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a mechanism for reducing the distortion and uneven brightness of the fixation target visually recognized by the subject.

The ophthalmologic apparatus of the present invention scans the fixation light on the fundus of the eye to be inspected by reciprocally driving the fixation light generating means to generate fixation light which is light for fixing the eye to be inspected. a scanning means, a detection means for detecting information indicating the scanning position of the scanning for both definitive forward and return to the reciprocating drive of said scanning means, based on the information indicating the scanning position is irradiated onto the subject's eye Fixation light control means for controlling the fixation light.
Another aspect of the ophthalmologic apparatus of the present invention is a fixation light generating unit that generates fixation light that is light for fixing the eye to be inspected, and reciprocally drives the fixation light to generate the eye fixation of the eye to be examined. A scanning means for scanning above, and a light detection sensor arranged at a position where the light scanned by the scanning means can be irradiated, for detecting information indicating the scanning position of the scanning based on the reciprocating drive of the scanning means. And a fixation light control means for controlling the fixation light with which the eye to be inspected is irradiated based on the information indicating the scanning position.
Also, the other aspect of the ophthalmologic apparatus of the present invention, the said fixation light and fixation light generating means for generating a fixation light is a light for fixing an eye, by reciprocating the A scanning unit that scans on the fundus of the optometry and an estimating unit that estimates the sine wave motion associated with the reciprocating drive of the scanning unit and calculates information indicating the scanning position of the scan based on the estimated sine wave motion. And a fixation light control means for controlling the fixation light applied to the eye to be inspected based on the information indicating the scanning position.
Further, the present invention includes a control method of the above-mentioned ophthalmologic apparatus and a program for causing a computer to execute the control method.

  According to the present invention, it is possible to reduce distortion and unevenness in brightness that occur in the fixation target visually recognized by the subject.

It is a figure which shows an example of schematic structure of the ophthalmologic apparatus which concerns on embodiment of this invention. FIG. 3 is a diagram showing an embodiment of the present invention and showing an example of an internal configuration of a control unit shown in FIG. 1. FIG. 3 illustrates an embodiment of the present invention, and is a diagram illustrating an example of a scanning range on the fundus of the eye and an arrangement position of the correction PD by the resonance scanner and the galvano scanner shown in FIG. .. FIG. 3 illustrates an embodiment of the present invention, and is a diagram illustrating an example of a timing chart of each component illustrated in FIG. 2 and a fixation target based on fixation light. It is a figure showing a comparative example which does not apply an embodiment of the present invention, and showing an example of a timing chart of each component of an ophthalmologic apparatus, and a fixation target based on fixation light. It is a figure showing a comparative example which does not apply an embodiment of the present invention, and showing an example of a timing chart of each component of an ophthalmologic apparatus, and a fixation target based on fixation light. FIG. 3 illustrates an embodiment of the present invention, and is a diagram illustrating an example of a timing chart of each component illustrated in FIG. 2, an example of the amount of fixation light from a fixation target based on fixation light, and a fixation lamp. It is a figure which shows the comparative example which does not apply embodiment of this invention, and shows an example of the light amount of the fixation light from the timing chart of each component of an ophthalmologic apparatus, the fixation target based on fixation light, and a fixation lamp.

  Hereinafter, modes (embodiments) for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of a schematic configuration of an ophthalmologic apparatus 100 according to an embodiment of the present invention. Here, as the ophthalmologic apparatus 100 according to the present embodiment, an example in which an ophthalmologic apparatus having the function of an SLO device that images the fundus Er of the eye E to be examined is applied will be described. The present invention is not limited, and can be applied to a general ophthalmologic apparatus that scans the eye E such as an OCT apparatus or an AO-SLO apparatus.

  As shown in FIG. 1, the ophthalmologic apparatus 100 according to the present embodiment is configured to include an optical system 110 and an information processing unit 120.

<Structure of the optical system 110>
As shown in FIG. 1, the optical system 110 includes a fixation lamp 101, an SLO light source 102, a dichroic mirror 103, mirrors 104, lenses 105 and 106, a galvano scanner 107, a resonance scanner 108, a lens 109, a mirror 111, and a dichroic mirror 112. An objective lens 113, a correction PD (photodiode) 114, an APD (Avalanche Photodiode) 115, lenses 116 and 117, and a CCD 118 for fundus observation.

  The fixation lamp 101 is a fixation light generation unit that generates fixation light that is light for fixing the eye E to be inspected. The SLO light source 102 is an observation light generation unit that generates observation light for fundus observation (including fundus imaging) having a center value near 780 nm. The dichroic mirror 103 reflects the observation light from the SLO light source 102 and transmits the fixation light from the fixation lamp 101.

  The light output from the fixation lamp 101 or the SLO light source 102 forms an image once near the resonance scanner 108 and the galvano scanner 107 via the dichroic mirror 103, the mirror 104, and the lenses 105 and 106, and the eye to be inspected. An image is formed again near the fundus Er of E. The information processing section 120 drives the lens 106 by a motor (not shown) so that the second imaging position matches the fundus of the eye E to be examined.

  The resonance scanner 108 is reciprocally driven so that the fixation light output from the fixation lamp 101 and the observation light output from the SLO light source 102 are moved in the X direction (main scanning direction) on the fundus of the eye E (on the fundus Er). Scanning means for scanning in the direction). In addition, the galvano scanner 107 is reciprocally driven so that the fixation light output from the fixation lamp 101 and the observation light output from the SLO light source 102 are moved in the Y direction (on the fundus Er) of the eye E to be inspected. This is a scanning means for scanning in the sub-scanning direction). At this time, by interlocking with the resonance scanner 108 and scanning the galvano scanner 107 in the Y direction, the fundus of the subject eye E (on the fundus Er) can be two-dimensionally scanned.

  An objective lens 113 is installed so as to face the eye E to be inspected, and the reflected light from the fundus Er is provided on the optical axis of the objective lens 113 by the anterior segment observation system optical path L1 and the fixation lamp and SLO optical system optical path L2. It is branched for each wavelength band.

  The optical path L1 is an optical axis that causes the reflected light from the fundus Er to be received by the CCD 118 for fundus observation via the lenses 116 and 117. The CCD 118 is a sensor having a sensitivity near the wavelength of the anterior eye observation illumination light, specifically, near 970 nm.

  The optical path L2 is an optical axis that allows the fixation light from the fixation lamp 101 and the observation light from the SLO light source 102 to enter the fundus Er, and the reflected light from the fundus Er to enter the SLO optical system. The reflected light from the fundus Er that is reflected in the direction of the optical path L2 by the dichroic mirror 112 is reflected by the mirror 104 and guided to the APD 115. Then, the APD 115 detects the incident reflected light. The APD 115 is a sensor for fundus imaging that has a sensitivity near 780 nm. Note that the specific numerical values of the wavelengths in this specification are examples, and other numerical values may be used.

  Further, the correction PD 114 is a light detection sensor for detecting the scanning state of the above-mentioned scanning unit (specifically, the resonance scanner 108 in the present embodiment) for lighting correction of the fixation lamp 101.

<Structure of Information Processing Unit 120>
The information processing unit 120 is configured by, for example, a PC (personal computer), and includes a control unit 121 and a storage unit 122 as illustrated in FIG. 1.

  The control unit 121 includes a processing device such as a CPU, for example, and controls the operation of the ophthalmologic apparatus 100 by controlling each component of the ophthalmologic apparatus 100 in accordance with various information of programs stored in the storage unit 122. Control it comprehensively. For example, the control unit 121 controls driving of the fixation lamp 101, the SLO light source 102, the lens 106, the resonance scanner 108, the galvano scanner 107, and the like.

  The storage unit 122 stores programs and various information necessary for the control unit 121 to perform processing, and also stores various information obtained as a result of the processing of the control unit 121.

  Hereinafter, the lighting control of the fixation lamp 101 for reducing the distortion and brightness unevenness that occur in the fixation target will be described.

  First, the control unit 121 detects the scanning state based on the reciprocating drive of the above-described scanning unit (specifically, the resonance scanner 108 in this embodiment) based on the output signal from the correction PD 114. Then, the control unit 121 controls the fixation light applied to the eye E based on the detected scanning state. At this time, specifically, for example, the control unit 121 controls the light emission period and the light amount of the fixation light output from the fixation lamp 101 based on the detected scanning state.

  Here, an example is shown in which the control unit 121 detects the scanning state once for each of the forward scan and the backward scan for each frame, and controls the fixation light for each frame. It is known that the scanning characteristics of the resonant scanner 108 change due to environmental changes. Therefore, when the environmental change is large and the change in the scanning characteristic is rapid, the control unit 121 may detect the scanning state for each frame or a plurality of times in one frame to control the fixation light. Further, when the fluctuation of the scanning characteristics is gentle, the control unit 121 may reduce the frequency of controlling the fixation light. In addition, the control unit 121 may sequentially change the control frequency of the fixation light according to the detected temporal change amount of the scanning state.

  FIG. 2 shows an embodiment of the present invention and is a diagram showing an example of an internal configuration of the control unit 121 shown in FIG. In FIG. 2, the same components as those shown in FIG. 1 are designated by the same reference numerals.

  The control unit 121 executes the program stored in the storage unit 122 to execute the scanning state estimation unit 210, the control timing signal generation unit 220, the fixation lamp control unit 230, the SLO imaging control unit 240, and the SLO image signal acquisition unit. 250 and the SLO image output unit 260.

  Note that the control unit 121 may include one CPU or a plurality of CPUs. Moreover, the storage unit 122 may be one or plural. That is, when at least one processing device (CPU) and at least one storage device (ROM or RAM, etc.) are connected, and at least one processing device executes a program stored in at least one storage device, The control unit 121 functions as each of the above-mentioned components.

<Detection of scanning state>
First, a method for detecting the scanning state of the scanning unit by the correction PD 114 and the scanning state estimation unit 210 will be described. Specifically, in the present embodiment, the correction PD 114 and the scanning state estimating unit 210 constitute a detecting unit that detects, as the scanning state, information indicating the scanning position of the main scanning based on the reciprocating drive of the resonant scanner 108. Here, in the present embodiment, the correction PD 114 and the detection unit of the scanning state estimation unit 210 detect the information on the scanning position by the resonance scanner 108 as the information indicating the above-described scanning position. Is not limited to this form. For example, a mode in which the detection unit of the correction PD 114 and the scanning state estimation unit 210 detects the information of the angle with respect to the reference position of the resonance scanner 108 as the information indicating the scanning position described above is also applicable to the present invention.

  FIG. 3 shows an embodiment of the present invention, and the scanning range on the fundus of the eye and the arrangement position of the correction PD 114 by the resonance scanner 108 and the galvano scanner 107 shown in FIG. It is a figure which shows an example.

  FIG. 3A shows an example of arrangement positions of the fundus scanning range 310 and the correction PD 114 by the resonance scanner 108 and the galvano scanner 107 shown in FIG. In the ocular fundus scanning range 310, the X direction (main scanning direction) is the scanning direction of the resonant scanner 108, and the Y direction (sub scanning direction) is the scanning direction of the galvano scanner 107.

  Further, as shown in FIG. 3A, one correction PD 114 is arranged outside the fundus scanning region 310 where the resonance scanner 108 and the galvano scanner 107 scan the fundus Er of the eye E to be examined. Further, the arrangement position of the correction PD 114 in the X direction is a position distant from both ends of the on-fundus scanning range 310 where the scanning speed is slow in order to reduce detection variations. Further, when the correction PD 114 cannot be arranged outside the Y-direction scanning range in the on-fundus scanning range 310, it may be arranged outside the X-direction scanning range in the on-fundus scanning range 310. ..

  Further, FIG. 3A shows a scanning locus 320 for scanning the correction PD 114 in order to detect the scanning state together with the scanning range 310 on the fundus oculi. For example, after performing two-dimensional scanning on the fundus Er, the galvano scanner 107 is driven to bring the fixation light from the fixation lamp 101 out of the Y-direction scanning range on the fundus Er. Scan on. Thus, the correction PD 114 is arranged at a position where it can be scanned by the scanning means.

  FIG. 3B shows an example of the scanning position of the resonance scanner 108 and the light reception signal of the correction PD 114. Specifically, in the upper diagram of FIG. 3B, the horizontal axis is the time, and the waveform 330 is the waveform when the correction PD 114 is scanned and shows the scanning position of the resonance scanner 108. The scanning position p of the resonance scanner 108 corresponds to, for example, y in the equation (1) described below, which indicates the angle of the resonance scanner 108. Further, in the lower diagram of FIG. 3B, the horizontal axis represents time, and the signal 340 represents the light reception signal of the correction PD 114.

  When the scanning position of the resonance scanner 108 reaches the position of the correction PD 114, the correction PD 114 receives the fixation light from the fixation lamp 101, and the correction PD signal 340 having a level corresponding to the received light amount is output.

  In the lower diagram of FIG. 3B, the time of the center of gravity of the waveform of the corrected PD signal 340 is set as the detection time. When the resonance scanner 108 reciprocates once, the correction PD 114 detects the fixation light from the fixation lamp 101 once in each of the forward path and the return path. At this time, the forward detection time is t1, the backward detection time is t2, and the scanning position of the resonant scanner 108 when scanning the correction PD 114 is p. The scanning position p is a constant determined when adjusting the ophthalmologic apparatus 100.

  Here, as described above, the time of the center of gravity of the waveform of the corrected PD signal 340 is set as the detection time, but the center of the pulse width generated by binarizing the analog signal of the corrected PD signal 340 with a certain threshold value. May be the detection time. At that time, when the binarization of the analog signal of the corrected PD signal 340 has hysteresis, the center calculation may be performed according to the degree. Since the shape of the waveform of the above-mentioned corrected PD signal 340 and the width of the above-mentioned pulse change depending on the position of the lens 106 for SLO focusing, it is like the center of gravity or the center of the pulse width of the above-mentioned waveform of the corrected PD signal 340. It is necessary to set a detection time that does not depend on the position of the SLO focusing lens 106.

  Further, here, the scanning state is detected by performing one reciprocating scan on the correction PD 114, but when the detection is not stable due to external noise or the like, the scanning locus 320 may be scanned a plurality of times. In this case, the detected average value of multiple times is set as the detection time. At this time, values that are significantly deviated may be excluded and the average value may be calculated. Further, the number of scans on the scan locus 320 may be sequentially changed according to the variation in the detection time.

  Next, the correction information calculated by the scanning state estimation unit 210 based on the detection time will be described. Since the resonance scanner 108 makes a sine wave motion, the angle y of the resonance scanner 108 at the time t can be approximated by the following equation (1).

  In Expression (1), A is the amplitude (that is, the maximum swing angle of the resonant scanner 108), ω is the angular frequency, and α is the initial phase. The resonance scanner 108 outputs a synchronization signal every cycle. This synchronization signal is input from the resonance scanner 108 to the scanning state estimation unit 210. The scanning state estimation unit 210 calculates the period T of the resonant scanner 108 by measuring the period of the synchronization signal, and calculates the angular frequency ω (=2π/T).

  The scanning state estimation unit 210 substitutes (t1, p) and (t2, p) into (t, y) of the equation (1) to solve two equations, and thus A and α of the equation (1) are obtained. To calculate. That is, the scanning state estimation unit 210 can estimate the scanning position of the resonant scanner 108 by using the information t1 and t2 of the two times detected by the correction PD 114. Note that p is a known value determined by the arrangement of the correction PD 114, for example.

  The number of timings at which the fixation lamp 101 can perform light emission control is n, and the scanning positions of the resonance scanner 108 on the fundus Er that can be emitted by the fixation lamp 101 are Y1 to Yn. In order to cause the fixation lamp 101 to emit light on the fundus Er at equal scanning distances, the fixation lamp 101 may emit light at the coordinates obtained by the following equation (2).

In the equation (2), i is a light emission control timing number and is an integer in the range of 1 to n. Therefore, the scanning state estimation unit 210 substitutes Y1, Y2, Y3,..., Yn into the inverse function of the equation (1) to determine the times T1, T2,..., Tn at which the fixation lamp 101 can emit light. obtain. The scanning state estimation unit 210 stores the times T1, T2,..., Tn in the storage unit 122 as times for correction. The times T1, T2,..., Tn correspond to an example of the above-described correction information calculated by the scanning state estimation unit 210. Further, the times T1, T2,..., Tn are simply times for equal scanning distance intervals.

<Light emission control of fixation lamp 101>
In the present embodiment, the light emission control of the fixation lamp 101 is performed on both the forward and backward paths of the reciprocating drive of the resonant scanner 108. In this case, the correction PD 114 and the detection unit of the scanning state estimation unit 210 detect the information indicating the scanning position for both the forward path and the backward path in the reciprocating drive of the resonant scanner 108. Since the driving directions of the forward path and the backward path are only opposite to each other, the processing of the forward path will be described below as a representative.

  FIG. 4 shows an embodiment of the present invention, and is a diagram showing an example of a timing chart of each component shown in FIG. 2 and a fixation target based on fixation light. Specifically, FIG. 4 illustrates an example of controlling the light emission period of the fixation light from the fixation lamp 101.

  FIG. 4A shows an example of a timing chart of each component shown in FIG. In FIG. 4A, the horizontal axis represents time, the waveform 401 represents the scanning position of the resonance scanner 108 on the fundus Er, the signal 402 represents the synchronization signal of the resonance scanner 108, and the signal 403 represents the control timing counter signal. Signals 404-1 and 404-2 indicate fixation lamp control signals.

  The control timing signal generation unit 220 detects the synchronization signal 402 output from the resonance scanner 108 once in one cycle, and counts up a time counter (not shown) by a fixed reference clock for control. Then, when the control timing signal generation unit 220 detects that the counting time has reached the times T1, T2,..., Tn for correction stored in the storage unit 122, the control timing counter signal is sequentially output. 403 is incremented to 1, 2,..., N. This counter is counted up at unequal time intervals (T1, T2,..., Tn), and the counter value means the scanning position at that time. Therefore, by controlling the light emission of the fixation lamp 101 using this counter value, the fixation target (fixation target pattern) can be displayed at a desired position.

  Here, the position and pattern of the fixation target are initially set, or set by the user at the time of shooting. The control unit 121 calculates the light emission period of the fixation lamp 101 according to the setting. The fixation lamp control unit 230 turns on the fixation lamp control signal 404 during the calculated light emission period. In FIG. 4, the fixation lamp control unit 230 turns on the fixation lamp control signal 404-1 during the period 411 in which the control timing counter signal 403 is a to a+c, and the control timing counter signal 403 is b to b+c. The fixation lamp control signal 404-2 is turned on for the period 412 of.

  The fixation lamp control unit 230 controls the fixation light emitted to the eye E based on the information indicating the scanning position detected by the detection unit of the correction PD 114 and the scanning state estimation unit 210. Is. Specifically, in the present embodiment, the fixation lamp control unit 230 causes the fixation lamp 101 to generate a fixation based on the information indicating the scanning position detected by the detection unit of the correction PD 114 and the scanning state estimation unit 210. Control the light.

  In FIG. 4A, by making the periods 411 and 412 different from each other, the distance between the scanning range 421 scanned by the resonant scanner 108 during the period 411 and the scanning range 422 scanned by the resonant scanner 108 during the period 412 becomes The same or almost the same.

  FIG. 4B shows a scanning locus 430 on the fundus oculi, and a scan 431 of the resonance scanner 108 shown in FIG. 4A on the scanning locus 430 on the fundus oculi and the fixation lamp ON (light emission). The timing of light emission/non-light emission of fixation light on the fundus Er when the fixation target pattern “x” indicated by 432 is turned on is shown.

  In FIG. 4B, the lighting range of the fixation lamp 101 in the scanning range 421 and the scanning range 422 is the same or substantially the same. Thus, in the case of the example shown in FIG. 4, the fixation lamp control unit 230 sets the scanning position of the resonance scanner 108 as shown in the fixation lamp control signals 404-1 and 404-2 of FIG. By controlling the light emission period of the fixation light generated from the fixation lamp 101 based on the information shown, the subject is presented with a fixation target pattern with reduced distortion as shown in FIG. 4B. be able to. Further, in the waveform 401 relating to the scanning position of the resonant scanner 108 in FIG. 4A, the scanning speed of the resonant scanner 108 at the end portion is slower than that at the central portion. Then, as shown by the fixation light control signals 404-1 and 404-2 in FIG. 4A, the fixation lamp control unit 230 causes the waveform 401 to be detected at the scanning position of the resonant scanner 108 near the end of the waveform 401. The light emitting period of the fixation light is controlled to be longer than the scanning position of the resonance scanner 108 near the center of the. That is, in the example shown in FIG. 4A, the fixation lamp control unit 230 performs control such that the light emission period of the fixation light is extended as the scanning speed of the resonant scanner 108 becomes slower.

  Similarly, in the case of the return path, since the scanning position of the resonance scanner 108 can be estimated, the forward scanning timing and the return scanning timing by the resonance scanner 108 can be accurately known, and the scanning range for the forward scanning and the scanning for the backward scanning. The scanning range can be matched. Therefore, even when the fixation lamp 101 is turned back and forth, the subject can observe the fixation target pattern in which the deviation between the forward and return paths is reduced.

  Here, in order to describe the effect of the present embodiment in the case shown in FIG. 4, a comparative example thereof will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a diagram showing a comparative example to which the embodiment of the present invention is not applied and showing an example of a timing chart of each component of the ophthalmologic apparatus and a fixation target based on fixation light. 5 is different from FIG. 4 in that the light emission period of the fixation light is not changed in the fixation lamp control signal of FIG. Then, in FIG. 5, a case where the fixation target pattern is distorted will be described.

  First, consider the case where the fixation target pattern “x” is turned on. In FIG. 5A, the horizontal axis is time, the waveform 501 shows the scanning position of the resonant scanner 108 when a certain main scan is performed, the signal 502 shows the synchronization signal of the resonant scanner 108, and the signal 503 shows. A control timing counter signal is shown, and a signal 504 is a fixation lamp control signal.

  In the comparative example shown in FIG. 5, the information indicating the scanning position of the resonance scanner 108 shown in FIG. 5A is not detected, and the correction times T1, T2,... Consider a case where Tn is not used for the fixation lamp light emission timing. At this time, the control timing signal generation unit 220 detects the synchronization signal 502 output from the resonance scanner 108 once in one cycle, and counts up a time counter (not shown) with a fixed reference clock for control. Then, in this case, the control timing signal generation unit 220 counts up the control timing counter signal 503 each time a fixed control reference time elapses. This counter is counted up at equal time intervals, and the count value means the scanning time at that time.

  The fixation lamp control unit according to the comparative example turns on the fixation lamp control signal 504 in two periods, that is, a period 511 in which the control timing counter signal 503 is n to n+1 and a period 512 in m to m+l. In FIG. 5A, the period 511 and the period 512 have the same or substantially the same length. However, since the resonance scanner 108 is driven in a sinusoidal waveform as shown by the waveform 501, the distance between the scanning range 521 scanned by the resonance scanner 108 in the period 511 and the scanning range 522 scanned by the resonance scanner 108 in the period 512. Will be different. Specifically, in the waveform 501 related to the scanning position of the resonance scanner 108 in FIG. 5A, the scanning speed of the resonance scanner 108 is slower at the end portion than in the central portion, so scanning near the end portion is performed. The range 521 is narrower than the scanning range 522 near the center thereof.

  FIG. 5B shows the scanning locus 530 on the fundus oculi, and the scanning 531 of the resonance scanner 108 shown in FIG. 5A on the scanning locus 530 on the fundus oculi and the fixation lamp ON (light emission). The timing of light emission/non-light emission of the fixation light on the fundus Er when the fixation target pattern “x” indicated by 532 is turned on is shown. As shown in FIG. 5B, since the scanning range 521 is narrower than the scanning range 522, the fixation lamp 101 moves closer to both ends of the scanning with respect to the central part of the scanning by the resonant scanner 108. The lighting range becomes narrow. As a result, the subject visually recognizes the distorted fixation target pattern as shown in FIG.

  On the other hand, in the present embodiment, as shown in FIG. 4, the control timing counter signals 403 at non-equal intervals are generated based on the information indicating the scanning position of the resonance scanner 108, and fixation is performed based on the control timing counter signal 403. The fixation lamp control signals 404-1 and 404-2 for turning on the lamp 101 are generated. Therefore, instead of the distorted fixation target pattern as shown in FIG. 5B, the distortion can be reduced as shown in FIG. 4B and the fixation target pattern can be presented to the subject.

  FIG. 6 is a diagram showing a comparative example to which the embodiment of the present invention is not applied and showing an example of a timing chart of each component of the ophthalmologic apparatus and a fixation target based on fixation light. 6 also differs from FIG. 4 in that the light emission period of the fixation light is not changed in the fixation lamp control signal of FIG. Then, in FIG. 6, a case where the fixation target pattern is distorted, and particularly, the fixation target pattern is displaced will be described.

  First, consider a case where the fixation target pattern “■” is turned on by reciprocating scanning. In FIG. 6A, the horizontal axis represents time, the waveform 601 represents the scanning position of the resonant scanner 108 when a certain main scan is performed, the signal 602 represents the synchronization signal of the resonant scanner 108, and the signal 603 represents A control timing counter signal is shown, and a signal 604 is a fixation lamp control signal.

  The fixation lamp control unit according to the comparative example turns on the fixation lamp control signal 604 in two periods, i.e., a period 611 of i to i+h and a period 612 of k to k+h of the control timing counter signal 603. In FIG. 6A, the period 611 and the period 612 have the same or substantially the same length. However, if the information indicating the scanning position of the resonance scanner 108 shown in FIG. 6A is not detected and the forward scan timing and the backward scan timing are not accurately known, as shown in FIG. A gap occurs between the scanning range 621 scanned by the resonant scanner 108 in the period 611 and the scanning range 622 scanned by the resonant scanner 108 in the period 612. As a result, the subject visually recognizes the fixation target pattern having unevenness as shown in FIG. 6B.

  6A. Note that FIG. 6B shows the forward scanning locus 630-1 on the fundus oculi, the backward scanning locus 630-2 on the fundus oculi, and the scanning locus 630 on the fundus oculi of FIG. The forward scanning 631-1 and the backward scanning 631-2 of the resonance scanner 108 shown in FIG. 7 and the fixation on the fundus Er when the fixation target pattern “■” indicated by the fixation lamp ON (light emission) 632 is turned on. The timing of light emission/non-light emission is shown. As shown in FIG. 6B, the scanning range 621 and the scanning range 622 are deviated from the X direction (main scanning direction). For this reason, as described above, the subject visually recognizes the fixation target pattern having the unevenness as shown in FIG. 6B.

  On the other hand, in the present embodiment, since the fixation lamp control signal for turning on the fixation lamp 101 is generated based on the information indicating the scanning position of the resonance scanner 108, it is shown in FIG. It is possible to present the fixation target pattern in which the displacement is reduced, to the subject, instead of the fixation target pattern in which the displacement is uneven.

  FIG. 7 shows the embodiment of the present invention, and is a diagram showing an example of the timing chart of each component shown in FIG. 2, an example of the amount of fixation light from the fixation target based on the fixation light, and the fixation lamp 101. .. Specifically, FIG. 7 shows an example of controlling the light amount of the fixation light from the fixation lamp 101. That is, the fixation lamp control unit 230 controls the light amount of the fixation light based on the information indicating the scanning position of the resonance scanner 108.

  Here, it is assumed that the light emission timing of the fixation lamp 101 is controlled and the fixation target pattern “x” is turned on.

  FIG. 7A shows an example of a timing chart of each component shown in FIG. In FIG. 7A, the horizontal axis represents time, the waveform 701 represents the scanning position of the resonant scanner 108 on the fundus Er, the signal 702 represents the synchronous signal of the resonant scanner 108, and the signal 703 represents the control timing counter signal. Signal 704 represents the fixation light control signal.

  Similar to FIG. 4, the distance between the scanning range 721 and the scanning range 722 is the same or substantially the same, but the light emitting period 711 and the light emitting period 712 are different. The fixation lamp control unit 230 pulse-drives the fixation lamp control signal 704 in accordance with the times T1, T2,..., Tn read from the storage unit 122 in order to change the light amount per unit time. The time Tn stored in the storage unit 122 is commonly used for the light emission period control of the fixation light and the light amount control.

  Specifically, in the waveform 701 relating to the scanning position of the resonance scanner 108 in FIG. 7A, the scanning speed of the resonance scanner 108 at the end portion is slower than that at the center portion, and the emission period of the fixation light is long. Become. Therefore, the fixation lamp control unit 230 performs control to reduce the high duty ratio in the pulse of the fixation lamp control signal 704 as the scanning speed of the resonance scanner 108 becomes slower.

  For example, since the light emission period 711 is longer than the light emission period 712, control is performed to reduce the high duty ratio in the pulse of the fixation lamp control signal 704 with respect to the light emission period 712. Here, when the interval between pulses is long, the fixation target pattern may appear to be separated for each pulse. Therefore, it is necessary to reduce the pulse interval and emit the fixation light so that each pulse cannot be seen separately. That is, it is desirable that these pulse intervals are so short that the subject cannot perceive them.

  Similar to FIG. 4B, FIG. 7B shows the scanning locus 730 on the fundus oculi, and the scanning locus 730 of the resonance scanner 108 shown in FIG. And the timing of light emission/non-light emission of the fixation light on the fundus Er when the fixation target pattern “x” indicated by the fixation lamp ON (light emission) 732 is turned on.

  In FIG. 7C, the horizontal axis is the scanning position, and the waveforms 740-1 and 740-2 show the light amount of the fixation light from the fixation lamp 101. By pulse-driving the fixation light control signal 704, the maximum value of the light amount of the fixation light in the scanning range 721 and the maximum value of the light amount of the fixation light in the scanning range 722 are close to each other (approximately the same value). Can be That is, the fixation lamp control unit 230 controls so that the integrated light amount of the fixation light becomes equal regardless of the scanning position of the resonance scanner 108. This makes it possible to present a fixation target pattern with reduced unevenness in brightness.

  In addition to the pulse drive, a circuit for changing the drive current of the fixation lamp 101 may be added to change the drive current during scanning to change the light amount of the fixation light. Further, a filter having a variable transmittance may be arranged on the optical path of the fixation lamp 101 to change the light amount of the fixation light applied to the fundus Er during scanning.

  Further, in the example shown in FIG. 7, the fixation lamp 101 is turned on only for one of the reciprocal driving of the resonance scanner 108. However, in order to increase the light amount, the fixation lamp 101 is turned on by the reciprocating scanning. Good.

  Here, in order to describe the effect of the present embodiment in the case shown in FIG. 7, a comparative example thereof will be described with reference to FIG.

  FIG. 8 shows a comparative example to which the embodiment of the present invention is not applied, and shows an example of the timing chart of each component of the ophthalmologic apparatus, the fixation target based on the fixation light, and the light amount of the fixation light from the fixation lamp 101. FIG. This FIG. 8 differs from FIG. 7 in that the fixation lamp control signal of FIG. 8A is not a pulse and the pulse is not controlled. Then, in FIG. 8, a case where unevenness in brightness occurs in the fixation target pattern will be described.

  First, consider the case where the fixation target pattern “x” is turned on. In FIG. 8A, the horizontal axis represents time, the waveform 801 represents the scanning position of the resonance scanner 108 on the fundus Er, the signal 802 represents the synchronization signal of the resonance scanner 108, and the signal 803 represents the control timing counter signal. Signal 804 represents the fixation light control signal.

  Then, in the comparative example shown in FIG. 8, a case is considered in which the light amount of the fixation light per unit time is not changed without detecting the information indicating the scanning position of the resonance scanner 108 shown in FIG. 8A.

  FIG. 8B shows a scanning locus 830 on the fundus oculi, and a scan 831 of the resonance scanner 108 shown in FIG. 8A on the scanning locus 830 on the fundus oculi and the fixation lamp ON (light emission). 8B shows the timing of light emission/non-light emission of the fixation light on the fundus Er when the fixation target pattern “x” indicated by 832 is turned on.

  In FIG. 8C, the horizontal axis represents the scanning position, signals 840-1 and 840-2 represent fixation lamp control signals, and waveforms 841-1 and 841-2 indicate fixation light from the fixation lamp 101. It shows the amount of light. In the scanning range 821 and the scanning range 822, the fixation light 101 emits the same amount of fixation light per unit time, but the lighting period 811 and the lighting period 812 are different. Therefore, the maximum value of the amount of fixation light in the scanning range 821 indicated by the waveform 841-1 is different from the maximum value of the amount of fixation light in the scanning range 822 indicated by the waveform 841-2.

  The shade of the fixation target pattern in FIG. 8B indicates the brightness, and the darker the shade is, the brighter it is. Since the fixation target pattern becomes brighter as it approaches the vicinity of both ends of the scan with respect to the vicinity of the center of the scan by the resonance scanner 108, the subject has a fixed brightness pattern as shown in FIG. The target pattern is observed.

  On the other hand, in the present embodiment, the light amount of the fixation light emitted from the fixation lamp 101 is controlled based on the information indicating the scanning position of the resonance scanner 108, so that the brightness as shown in FIG. It is possible to present the fixation target pattern with reduced brightness unevenness to the subject instead of the fixation target pattern having unevenness.

  Note that, in the present invention, the control unit 121 can adopt a mode of performing either one of the above-mentioned fixation light emission period control and light amount control, or a mode of performing both controls. ..

  As shown in FIG. 1, since the resonance scanner 108 is shared by the optical system related to the fixation lamp 101 and the SLO optical system, the correction of the resonance scanner 108 is also performed when an SLO image is captured. Specifically, the above-mentioned correction information is used for the timing of reading the signal from the APD 115 of the SLO image signal acquisition unit 250. In this case, the correction of the imaging of the SLO image is also performed using the correction information used for the fixation lamp lighting correction. On the contrary, when the SLO image is captured, the scanning state estimation unit 210 can obtain the correction information by scanning the correction PD 114 with the light from the SLO light source 102, similarly to the above. Then, the fixation lamp lighting correction may be performed using the correction information obtained based on the light from the SLO light source 102. As a result, it is not necessary to separately perform detection and correction calculation, and correction of the fixation lamp 101 and SLO imaging can be performed collectively.

  Further, the control unit 121 may consider the delay time in the circuit or the like. For example, in capturing an SLO image, a delay time occurs due to the response characteristic of the APD 115 and the circuit characteristic until the signal is captured. On the other hand, when the fixation lamp 101 is turned on, a delay time occurs due to circuit characteristics until a current is applied to the fixation lamp 101 and responsiveness until the fixation lamp 101 emits light. That is, the delay time that occurs differs between the capturing of the SLO image and the lighting of the fixation lamp 101. That is, there is a difference in these delay times. For example, the control unit 121 shifts the timing of reading the signal from the APD 115 of the SLO image signal acquisition unit 250 by the delay time related to the SLO image, and sets the times T1, T2,..., Tn obtained for the fixation lamp 101. Shift by the delay time relating to the fixation lamp 101. Note that the delay time regarding the SLO image and the delay time regarding the fixation lamp 101 described above are values determined by circuit design and the like, and may be stored in the storage unit 122 in advance. For example, the control unit 121 may shift the times T1, T2,..., Tn by the delay time relating to the fixation lamp 101, or may be a period during which the fixation lamp 101 is turned on (for example, 411 and 412 in FIG. 4). May be shifted by the delay time relating to the fixation lamp 101. Further, the storage unit 122 may store the delay time regarding the SLO image and the difference between the delay time regarding the SLO image and the delay time regarding the fixation lamp 101, without storing the delay time regarding the fixation lamp 101. In this case, the control unit 121 shifts only the time T1, T2,..., Tn or the period during which the fixation lamp 101 is turned on, based on the delay time regarding the SLO image and the difference. The storage unit 122 may store the delay time regarding the fixation lamp 101 and the difference between the delay time regarding the SLO image and the delay time regarding the fixation lamp 101, without storing the delay time regarding the SLO image. In this case, the control unit 121 shifts the signal reading timing from the APD 115 of the SLO image signal acquisition unit 250 based on the delay time regarding the fixation lamp 101 and the difference.

That is, the fixation lamp lighting correction may be performed by adding a time offset in consideration of the difference in delay time described above to the correction information used to correct the SLO image capturing described above. Take the form.
Specifically, the SLO image signal acquisition unit (that acquires an image based on the return light obtained by irradiating the fundus of the eye E with the observation light generated by the SLO light source 102 through the above-described scanning unit ( Image acquisition means) 250, and an SLO imaging control section (image acquisition timing control means) that controls the image acquisition timing at which the SLO image signal acquisition section 250 acquires an image based on the above-described information indicating the scanning position of the scanning means. The start point timing of the light emission period described above takes a form in which the offset time is taken into consideration with respect to the image acquisition timing.

  Further, in the present embodiment, the fixation lamp 101 is used as the light source for scanning the correction PD 114, but the SLO light source 102 may be used instead of the fixation lamp 101. That is, in the present invention, the correction PD 114 can be applied with a mode of detecting the fixation light generated by the fixation lamp 101 or the observation light generated by the SLO light source 102.

  In addition to the fixation lamp 101 and the SLO light source 102, a dedicated light source for scanning the correction PD 114 may be used. Further, in the present embodiment, one correction PD 114 is arranged as a sensor for scanning detection, and the correction is performed based on the time when the correction PD 114 receives light. However, one or more correction PDs 114 may be arranged. . Further, as the sensor, a one-dimensional sensor such as a line sensor, a CCD, a PSD or a two-dimensional sensor may be used.

  Further, the chart for scanning correction may be arranged outside the fundus scanning angle of view, and the correction may be performed by using the formula (1) based on the signal intensity data of the SLO imaged image. In this case, the above-mentioned detection means is a chart-like structure arranged outside the scanning range where the above-mentioned scanning means scans the fundus Er, and a light detection sensor for detecting the light reflected by the chart-like structure. And will be equipped with.

  Further, a speed sensor or a position sensor may be attached inside the resonance scanner 108 to detect the scanning state. Further, in the present embodiment, an example in which the resonant scanner 108 is used in the main scanning direction has been shown, but a galvano scanner, an acousto-optical deflector (MEMS) or a micro electro mechanical system (MEMS) scanner that causes acceleration/deceleration is mainly used. Even when it is used in the scanning direction, it can be applied to the present invention.

  As described above, according to the present embodiment, it is possible to reduce the distortion and the unevenness in brightness that occur in the fixation target visually recognized by the subject.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. It can also be realized by the processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
The program and a computer-readable storage medium storing the program are included in the present invention.

  It should be noted that the above-described embodiments of the present invention are merely examples of embodying the present invention, and the technical scope of the present invention should not be limitedly interpreted by these. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

101 fixation lamp, 108 resonance scanner, 114 correction PD, 115 APD, 121 control unit, 122 storage unit, 210 scanning state estimation unit, 220 control timing signal generation unit, 230 fixation light control unit, 240 SLO imaging control unit, 250 SLO image signal acquisition unit, 260 SLO image output unit

Claims (24)

A fixation light generating means for generating fixation light which is light for fixing the eye to be inspected,
Scanning means for scanning the fixation light on the fundus of the eye by reciprocating,
Detection means for detecting the information indicating the scanning position of the scanning for both definitive forward path and the backward path to the reciprocating drive of said scanning means,
An ophthalmologic apparatus comprising: a fixation light control unit that controls the fixation light applied to the eye to be inspected based on the information indicating the scanning position.   The ophthalmologic apparatus according to claim 1, wherein the detection unit detects information on the scanning position by the scanning unit as information indicating the scanning position.   The ophthalmologic apparatus according to claim 1, wherein the detection unit detects, as the information indicating the scanning position, information on an angle of the scanning unit with respect to a reference position.   The ophthalmologic apparatus according to claim 1, wherein the fixation light control unit controls the fixation light generated from the fixation light generation unit. The ophthalmologic apparatus according to any one of claims 1 to 4 , wherein the detection unit includes a light detection sensor arranged at a position where the light scanned by the scanning unit can be emitted. A fixation light generating means for generating fixation light which is light for fixing the eye to be inspected,
Scanning means for scanning the fixation light on the fundus of the eye to be examined by reciprocating,
Detecting means for detecting information indicating a scanning position of the scanning based on the reciprocating drive of the scanning means, the detecting means having a light detection sensor arranged at a position where light scanned by the scanning means can be irradiated ;
Based on the information indicating the scanning position, fixation light control means for controlling the fixation light applied to the eye to be inspected,
Ophthalmology device further comprising a.   The ophthalmologic apparatus according to claim 6, wherein the light detection sensor is arranged outside a scanning range in which the scanning unit scans the fundus. It said detecting means comprises said scanning means chart-like structure arranged outside of the scanning range of scanning the fundus,
The optical detection sensor, ophthalmologic apparatus according to any one of claims 5 to 7, characterized and Turkey to detect light reflected by the chart-like structure. 9. The ophthalmologic apparatus according to claim 5 , wherein the light detection sensor detects the fixation light or the observation light generated by the observation light generation unit. The detection unit includes the light detection sensor and an estimation unit that estimates a sinusoidal motion associated with the reciprocating drive of the scanning unit, and detects information indicating the scanning position based on the estimated sinusoidal motion. The ophthalmologic apparatus according to claim 5 , wherein the ophthalmologic apparatus comprises: A fixation light generating means for generating fixation light which is light for fixing the eye to be inspected,
Scanning means for scanning the fixation light on the fundus of the eye to be examined by reciprocating,
Estimating means for estimating a sine wave motion associated with the reciprocating drive of the scanning means, and calculating information indicating a scanning position of the scan based on the estimated sine wave motion;
An ophthalmologic apparatus comprising: a fixation light control unit that controls the fixation light applied to the eye to be inspected based on the information indicating the scanning position. Further comprising a light detection sensor arranged at a position where the light scanned by the scanning means can be irradiated,
The estimating means may calculate the information indicating the scanning position based on the time at which the light detection sensor detects light by using a function of the information indicating the scanning position and the time in the sine wave motion. The ophthalmic device according to claim 10 or 11, characterized.   13. The ophthalmologic apparatus according to claim 1, wherein the fixation light control unit controls the light emission period of the fixation light based on the information indicating the scanning position.   The ophthalmologic apparatus according to claim 13, wherein the fixation light control unit performs control such that the light emission period becomes longer as the scanning speed of the scanning unit becomes slower. An image acquisition unit that acquires an image based on the return light obtained by irradiating the observation light generated by the observation light generation unit onto the fundus of the eye to be examined through the scanning unit,
An image acquisition timing control means for controlling an image acquisition timing at which the image acquisition means acquires the image based on the information indicating the scanning position,
The ophthalmologic apparatus according to claim 13 or 14, wherein the start point timing of the light emission period is a timing in which an offset time is taken into consideration with respect to the image acquisition timing.   The ophthalmology according to claim 15, wherein the timing considering the offset time is a timing considering a difference between a delay time related to the image by the image acquisition unit and a delay time related to the fixation light generating unit. apparatus.   17. The fixation light control means controls the light emission period of the fixation light according to the setting of the position and pattern of the fixation target based on the fixation light. The ophthalmic device according to Item 1.   13. The ophthalmologic apparatus according to claim 1, wherein the fixation light control unit controls the light amount of the fixation light based on the information indicating the scanning position.   The ophthalmologic apparatus according to claim 18, wherein the fixation light control unit controls the integrated light quantity of the fixation light to be equal regardless of the scanning position.   20. The ophthalmologic apparatus according to claim 18, wherein the fixation light control unit performs control such that the high duty ratio in the pulse of the fixation light becomes smaller as the scanning speed of the scanning unit becomes slower.   21. The ophthalmologic apparatus according to claim 1, wherein the scanning unit is a resonance scanner. An ophthalmologic apparatus including a fixation light generating unit that generates fixation light that is light for fixing the eye to be inspected, and a scanning unit that reciprocally drives the scanning light to scan the eye fundus of the eye to be inspected. Control method of
A detecting step of detecting an information indicating the scanning position of the scanning for both definitive forward path and the backward path to the reciprocating drive of said scanning means,
And a fixation light control step of controlling the fixation light with which the eye to be inspected is irradiated based on the information indicating the scanning position. An ophthalmologic apparatus including a fixation light generating unit that generates fixation light that is light for fixing the eye to be inspected, and a scanning unit that reciprocally drives the scanning light to scan the eye fundus of the eye to be inspected. Control method of
An estimating step of estimating a sine wave motion related to the reciprocating drive of the scanning means, and calculating information indicating a scan position of the scan based on the estimated sine wave motion;
And a fixation light control step of controlling the fixation light with which the eye to be inspected is irradiated based on the information indicating the scanning position.   A program for causing a computer to execute each step in the method for controlling an ophthalmologic apparatus according to claim 22 or 23.