JP2014045950A - Fundus device and ophthalmological lighting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of an obstacle on a measuring beam.SOLUTION: A fundus device includes scanning means for scanning of a measuring beam to irradiate the fundus of a subject eye, and incident position change means that changes an incident position of the measuring beam subjected to scanning by the scanning means upon the subject eye so as to avoid an obstacle that prevents the incidence of the measuring beam upon the subject eye.

Description

  The present case relates to a fundus apparatus and a fundus illumination method.

  In recent years, ophthalmologic images typified by fundus images have been used for medical treatment for observing the progress of diseases. For this reason, various devices are used as ophthalmic devices for capturing ophthalmic images. For example, as an optical device for capturing a fundus image, there are a fundus camera, an optical coherence tomography (hereinafter referred to as OCT) device, a scanning laser ophthalmoscope (hereinafter referred to as SLO), and the like.

  Patent Document 1 discloses an OCT apparatus equipped with a fundus camera. Appropriateness of the alignment state, focus state, etc. of the eye to be examined and the apparatus is determined by the fundus camera.

JP2010-181172

  Needless to say, in OCT measurement, alignment and focus between the apparatus and the eye to be examined are important. However, even after alignment or focus adjustment, the captured tomographic image may be degraded. One reason for this is that the measurement light is prevented from entering the fundus by obstacles such as eyelids and eyelashes.

  The purpose of this case is to reduce the influence of obstacles on measuring light.

  In addition, the present invention is not limited to the above-described object, and other effects of the present invention can be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the invention which will be described later. It can be positioned as one of

  In order to achieve the above object, the ophthalmologic apparatus includes a scanning unit that scans measurement light that irradiates the fundus of the eye to be examined, and a scanning unit that avoids an obstacle that prevents the measurement light from entering the eye to be examined. Incident position changing means for changing the incident position of the scanned measurement light on the eye to be examined.

  The ophthalmologic apparatus further includes a scanning mirror that scans the measurement light that irradiates the fundus of the eye to be examined, and an incident position changing mirror that changes the incident position of the measurement light on the scanning mirror.

  Further, the ophthalmologic illumination method includes a scanning step of scanning measurement light that irradiates the fundus of the eye to be examined, and a measurement scanned in the scanning step so as to avoid an obstacle that prevents the measurement light from entering the eye to be examined. And an incident position changing step of changing the incident position of light on the eye to be examined.

  According to the present case, it is possible to reduce the influence of the obstacle on the measurement light.

It is a figure explaining the structural example of the OCT apparatus in Example 1. FIG. 3 is a flowchart for explaining an example of signal processing in the first embodiment. (A), (b) is a figure explaining an example of control of the measurement light in Example 1. FIG. (A), (b), (c), (d) is a figure explaining an example of the signal processing in Example 1. FIG. 10 is a flowchart for explaining an example of signal processing in the second embodiment. It is a figure explaining the structural example of the OCT apparatus in Example 3. FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the disclosed technology is not limited to the following examples, and various modifications can be made without departing from the spirit of the present embodiment.

Example 1
In this embodiment, an OCT apparatus to which the present invention is applied will be described.

(Optical system)
FIG. 1 shows an example of a schematic configuration of an OCT apparatus (ophthalmic apparatus) using a Michelson interference system. In FIG. 1, the vertical direction of the eye 108 is defined as the Y-axis direction, the direction opposite to the depth direction of the eye to be examined is defined as the Z-axis direction, and the depth direction on the paper is defined as the X-axis direction.

  First, light emitted from the light source 101 is collimated by the fiber collimator 102 and separated into measurement light and reference light by the half mirror 103. That is, the light source 101 corresponds to an example of a light source that emits measurement light. The light source 101 is, for example, an SLD (Super Luminescent Diode) which is a low coherent light source. Here, as an example, the light emitted from the SLD has a center wavelength of 840 nm and a wavelength width of 50 nm. Of course, other wavelengths may be selected depending on the measurement site to be observed. The type of the light source only needs to emit low-coherent light, and ASE (Amplified Spontaneous Emission) or the like can also be used.

  Here, the measurement light will be described. The measurement light is scanned by the XY scanner 105 via the incident position control mechanism 104. That is, the XY scanner 105 corresponds to an example of a scanning unit that scans the measurement light. The incident position control mechanism 104 is a mechanism for adjusting the incident position of the beam with respect to the pupil of the eye 108 to be examined, and is provided so as to be movable in the direction of the arrow. The incident position control mechanism 104 includes a mirror, for example. That is, the incident position control mechanism 104 corresponds to an example of an incident position changing unit and an incident position changing mirror. For example, the position of the incident position control mechanism 104 and the incident position with respect to the pupil of the eye 108 to be examined are associated in advance and recorded in a storage device such as a memory (not shown). The incident position with respect to the position of the incident position control mechanism 104 is determined based on optical arrangement information indicating the optical arrangement of the OCT apparatus. The position of the incident control mechanism 104 and the incident position of the measurement light on the eye 108 are associated in advance and are recorded in a storage device such as a memory (not shown). Alternatively, the movement amount of the incident control mechanism 104 and the movement amount of the measurement light in the y-axis direction are associated with each other and recorded in a storage device such as a memory (not shown). The computer 115 refers to any of these correspondences and moves the incident control mechanism 104 so as to avoid an obstacle.

  Between the XY scanner 105 and the eye 108 to be examined, a lens 106 and an objective lens 107 are disposed for irradiating the fundus 118 with measurement light. Here, for the sake of simplicity, the XY scanner 105 is described as a single mirror, but in actuality, two mirrors of an X scan mirror and a Y scan mirror are arranged close to each other. As a result, the XY scanner 105 can perform a raster scan of the fundus 118 in a direction perpendicular to the optical axis. That is, the XY scanner 105 corresponds to an example of a scanning unit that scans measurement light that irradiates the fundus of the eye to be examined and a scanning mirror that scans measurement light that irradiates the fundus of the eye to be examined.

  Then, the measurement light incident on the eye 108 is reflected or scattered by the fundus 118 and returned as return light. The return light returns to the objective lens 107, follows the same path (via the XY scanner 105 and the incident position control mechanism 104), and enters the half mirror 103 again. Then, the return light transmitted through the half mirror 103 enters the spectroscope 112. The spectroscope 112 includes a sensor (not shown). That is, the sensor included in the spectroscope 112 corresponds to an example of a sensor that receives reflected light from the fundus of the scanned measurement light.

  Next, reference light will be described. The reference light divided by the half mirror 103 passes through the dispersion compensation glass 113 and changes its direction by the mirror of the optical path length varying mechanism 114. The dispersion compensation glass 113 is for compensating for the dispersion of the eye 108 and the measurement optical system. The optical path length of the reference optical system is adjusted by the optical path length variable mechanism 114, and a tomographic image can be obtained at a desired depth of the eye 108 to be examined. The reference light reflected by the mirror passes through the dispersion compensation glass 113 again and reaches the spectroscope 112 via the half mirror 103. The spectroscope 112 performs spectroscopic measurement of the combined light obtained by combining the return light and the reference light, and outputs the result to the computer 115 as data.

  Here, imaging of the anterior segment will be described. A ring-shaped light source (not shown) outside the objective lens is used as illumination light for imaging the anterior segment. The illumination light reflected by the cornea 116 is deflected by the dichroic mirror 109 through the objective lens 107, and is imaged by the anterior eye imaging device 111 for imaging the anterior eye through the imaging lens 110.

  The computer 115 controls the incident position control mechanism 104, the scanner 105, the spectroscope 112, and the like. Then, the computer 115 creates an OCT image or the like from the obtained data, and analyzes and displays the image. Of course, the computer 115 has a keyboard, a mouse, etc., and also supports external input. (Signal processing)

  Next, an example of signal processing will be described using the flowchart shown in FIG. Note that the following steps are performed by the operation of each component under the control of the computer 115.

  In step S1, measurement is started. In this state, the OCT apparatus is activated and the eye 108 to be examined is placed at the measurement position. Naturally, in the case of wide angle of view measurement, mydriasis is preliminarily made with a mydriatic agent or the like. The examiner selects a measurement mode by the OCT apparatus and roughly adjusts the height of the OCT apparatus with respect to the eye 108 to be examined. The measurement mode includes, for example, a scanning range, a scanning pattern, and the number of measurements. The scanning range is, for example, a 6 mm square range including the macula, a 10 mm square range including the macula and the nipple, and a 12 mm square range for wide angle of view measurement. The scanning pattern includes, for example, a line scan for obtaining a B scan, an asterisk scan that repeats a line scan in a radial manner, a circle scan that draws a locus of a certain radius, and a 2D scan for obtaining 3D data. Here, for example, it is assumed that a 2D scan mode in which 500 lines are acquired in the x direction and 500 lines is acquired in the y direction is selected as a 3D image of a 12 mm square is captured by the retina.

  In step S2, the anterior segment is imaged. The imaging of the anterior segment will be described with reference to FIG. FIG. 3A is a diagram schematically showing the anterior segment of the eye 108 to be examined. An image of the anterior segment can be acquired by the anterior segment imaging device 111. Here, it is assumed that the image is, for example, 600 × 800 pixels in length and width and an 8-bit image is obtained. For example, using the center of the pupil 120 as the center of the xy coordinates, the computer 115 acquires the positional relationship between the pupil 120, the iris 121, the white eye 122, the eyelid 119, and the eyelash 117. In other words, the computer 115 acquires position information indicating the positions of the pupil 120, the iris 121, the white eye 122, the eyelid 119, and the eyelash 117. In addition, the computer 115 can acquire the sizes of the pupil 120, the iris 121, the white eye 122, the eyelid 119, and the eyelash 117 by acquiring the position information. That is, the anterior segment imaging device 111 corresponds to an example of an imaging unit that captures an anterior segment image of an eye to be examined including an obstacle. Furthermore, the computer 115 functions as an example of an acquisition unit that acquires position information of an obstacle on the anterior segment from the captured anterior segment image. Note that the diameter of the pupil 120 is a dilated pupil, for example, a diameter of 5 mm or more. In that case, if the spot diameter of the measurement light at the pupil 120 is 1 mm, the incident position control mechanism 104 can adjust the incident position of the measurement light by ± 2 mm or more. Moreover, the diameter of the pupil 20 when not having a mydriasis or having a miosis is, for example, 3 to 4 mm and 2 mm, respectively. That is, the incident position control mechanism 104 (incident position changing unit) changes the incident position of the scanned measurement light on the subject's eye based on the size of the pupil of the subject's eye and the diameter of the illumination light.

  The computer 115 constructs, for example, a cross-sectional view of the eye 108 shown in FIG. 3B using the measured positional relationship between the pupil 120, the iris 121, the white eye 122, the eyelid 119, and the eyelash 117. For the sake of simplicity, FIG. 3B shows only one cross-sectional view in the x direction (horizontal direction of the eye to be examined). For example, the computer 115 configures a plurality of cross-sectional views in the x direction. . In the case of the human eye, since there is no great difference in shape depending on the person, for example, the lens 124 has a diameter of 10 mm and a width of 4 mm, the distance between the pupil 120 and the cornea 116, and the distance between the pupil and the retina is 3 mm and 17 mm, respectively. Can be In addition, these numerical values are illustrations, and are not limited to these numerical values.

  Therefore, when constructing the cross-sectional view of the eye 108 shown in FIG. 3B, the modeled data and the positional relationship of each element such as the pupil 120 obtained from the anterior eye image are selectively used. It is good as well. That is, the cross-sectional view may be configured using only modeled data, or the cross-sectional view may be configured using only data obtained from the anterior segment image.

  Here, in FIG. 3B, typical trajectories of measurement light by a normal OCT apparatus, that is, an OCT apparatus that does not include the incident position control mechanism 104 are shown in FIGS. Note that the y-axis is defined in the vertical direction and the z-axis is defined in the eye axis direction with the center of the pupil as the origin. The upward direction in the vertical direction is the positive direction of the y axis, and the corneal direction is the positive direction of the z axis. Here, the pupil 120 of the eye 108 to be examined is designed to be the rotational center of scanning of the measurement light. When the measurement light is tilted toward the upper eyelid as in the locus (1), the negative region of the y axis can be measured. In this case, it is easy to prevent the measurement light from entering the eye by upper eyelashes or the like. Conversely, when the measurement light is tilted toward the lower eyelid as in the locus (3), the positive region of the y axis can be measured. In this case, incidence of measurement light on the eye to be examined is likely to be hindered by lower eyelashes or the like.

  By the way, in a general anterior segment imaging device, the eyelashes may not enter the depth of focus when the pupil is focused. In such a case, the computer 115 obtains the positional relationship of each element such as the pupil 120 and the size of each element from the image excluding the eyelashes in FIG. Then, the computer 115 constructs a cross-sectional view as shown in FIG. 3B by selectively using the modeled data, the positional relationship of each element such as the pupil 120 and the size of each element. Note that elements that could not be photographed, such as eyelashes, are reflected in the sectional view by the computer 115 using, for example, statistical data acquired in advance.

  Moreover, when constructing a cross-sectional view as shown in FIG. 3B, values measured in advance by another apparatus may be used. Further, for example, by imaging the eye to be examined by changing the focal position and the horizontal position of the anterior ocular segment imaging device 111 so that obstacles such as eyelashes and eyelids can be reliably imaged, FIG. You may acquire the three-dimensional data which consist of (b).

  In addition, if data obtained by photographing the eye to be examined from at least one of the horizontal direction and the vertical direction is used, the exact length of the eyelashes can be grasped, and the cross-sectional view shown in FIG. Is possible.

  In step S3, the computer 115 creates a measurement profile. Here, the measurement profile is information indicating how to perform measurement, and includes information indicating how to control the incident position control mechanism 104 and the XY scanner 105, for example. First, the computer 115 determines whether the measurement light is obstructed by an obstacle. The obstacle is, for example, an obstacle that prevents measurement light such as eyelids, eyelashes, iris, and turbidity from entering the eye.

  For example, when measuring 12 mm square with the retina, the scanning range 123 of the measurement light at the cornea 116 is about 2.3 mm square. This increases with distance from the eyelids, eyelashes and pupils. Here, the computer 115 determines whether the three-dimensional data of the anterior segment obtained in step S2 and the trajectory of the measurement light overlap. The trajectory of the measurement light is known at the time of designing the apparatus. Since the computer 115 knows the coordinates of each element of the cross-sectional view obtained in the step S2 and the coordinates of the miracle of the measurement light, for example, by comparing these coordinates, the trajectory of the measurement light is an obstacle such as eyelashes. It can be determined whether or not it overlaps. That is, the computer 115 functions as an example of a determination unit that determines whether or not the measurement light is prevented from entering the eye based on the position information of the obstacle acquired by the acquisition unit. If the trajectory of the measurement light does not overlap the obstacle, for example, normal measurement with the rotation center set to the pupil is set to the control profile.

  On the other hand, when the trajectory of the measurement light overlaps with an obstacle, a measurement profile is created so that the influence of the obstacle is reduced (preferably minimized). In other words, the computer 115 creates a measurement profile so that the measurement light avoids an obstacle.

  First, for example, when the retina is measured in a 12 mm square, the maximum incident angle to the pupil 120 of the measurement light [see (1) in FIG. 3B] when measuring one end of the 12 mm square in the y-axis direction Is about 22 degrees. At this angle, the computer 115 parallels the incident position of the normal measurement light along the y-axis so that the influence of the obstacle (for example, the upper eyelashes 117) on the measurement light is reduced (preferably minimized). The incident position of the moved measurement light is set [see (1) ′ in FIG. 4 (a)]. In other words, the incident position control mechanism 104 (incident position changing means) changes the incident position in parallel in the vertical direction of the eye to be examined so as to avoid an obstacle. Specifically, the incident position control mechanism 104 changes the incident position of the scanned measurement light on the eye when it is determined by the determination means that the measurement light is not incident on the eye. Note that the imaging range does not change substantially due to the optical property that parallel light forms an image at the same or substantially the same position. Therefore, in the incident position control mechanism 104, the fundus imaging range when the incident position is not changed by the incident position changing unit is substantially equal to the fundus imaging range when the incident position is changed by the incident position changing unit. The incident position of the measurement light scanned so as to enter the eye to be examined is changed.

  Further, the measurement light when measuring the other end portion in the y-axis direction of 12 mm square incident from the lower eyelash side, that is, the measurement light [(3) in FIG. 3A] having the lowest incident angle to the pupil. An example of processing will be described. For example, even if the measurement light having the lowest incident angle is not obstructed by the eyelashes, the computer 115 sets the incident position of the normal measurement light to the pupil 120 to the same amount as the amount of movement of the measurement light having the maximum incident angle and vice versa. An incident position translated in the direction along the y-axis is set [see (3) ′ in FIG. 4A].

  Then, for example, the computer 115 creates a profile for controlling the incident position so as to linearly change between the set incident positions of the measurement light. In the normal measurement, the pupil 120 is the rotation center of the scanning of the measurement light. By creating the profile in this way, the area other than the pupil 120 is the rotation center of the measurement light. For example, in the example shown in FIG. 4A, the cornea 123 is the center of rotation. That is, the center of rotation changes by changing the incident position.

  Note that it is not necessary to move the incident position of the measuring light having the maximum incident angle and the incident position of the measuring light having the lowest incident angle by the same amount along the y-axis. For example, the measurement light incident position with the maximum incident angle and the measurement light incident position with the minimum incident angle may be moved by an amount that reduces the influence of obstacles such as eyelashes. The amount of movement of the position may be different.

Furthermore, in the above, when creating a profile for controlling the incident position so as to change linearly between the incident position of the measuring light having the maximum incident angle after the incident position is changed and the incident position of the measuring light having the lowest incident angle Although described, it is not limited to this. For example, when the measurement light is not hindered by eyelashes or the like, the normal measurement light incident position does not have to be changed. That is, when the measurement light is blocked by eyelashes or the like, the incident position of the measurement light is changed, but when the measurement light is not blocked by eyelashes or the like, the incident position of the measurement light may not be changed.
Naturally, the measurement profile may be set so that the diameter of the pupil is moved to the maximum. Here, although the upper and lower incident positions are set, the upper and lower incident positions may be equidistant from the center or different in distance. In short, an optimal position may be set for each. In addition, when moving the incident position of the measurement light, it is desirable to consider the beam diameter of the measurement light and the size of the pupil as described above.

  The incident position control mechanism 104 moves in the optical axis direction of the measurement light incident on itself based on the profile set in this manner, thereby changing the incident position of the measurement light to the XY scanner 105, and as a result, XY The incident position of the measurement light scanned by the scanner 105 on the eye to be examined is changed. That is, the incident position control mechanism 104 includes an incident position changing unit that changes the incident position of the measurement light scanned by the scanning unit on the subject's eye so as to avoid an obstacle that prevents the measurement light from entering the subject's eye. It corresponds to an example. Further, the incident position control mechanism 104 is constituted by a mirror, for example. Therefore, the incident position control mechanism 104 corresponds to an example of an incident position changing mirror that changes the incident position of the measurement light on the scanning mirror.

  In step S4, pre-imaging adjustment is performed. In this step, the working distance between the eye 108 and the objective lens 107, the focus, the optical path length variable mechanism, and the like are adjusted to adjust the OCT image to a desired image.

  In step S5, the computer 115 determines whether the imaging switch has been pressed. If the imaging switch is pressed, the process proceeds to step S6. If not, the process returns to step S2.

  In step S6, OCT measurement is performed. For example, in 3D measurement, when the fast scan scans the measurement light from a low position on the y-axis toward a high position, the incident position of the measurement light at the pupil 120 for measurement while being controlled by the incident position control mechanism 104 Reciprocates as shown by the arrows in FIG. The measurement light trajectory (1) 'is incident on the pupil at a low position on the y-axis, and measures the low position on the y-axis of the retina. At this time, the measurement light is bent by the incident position control mechanism 104 on the side close to the half mirror 103 and enters the XY scanner 105. The trajectory (3) 'of the measurement light is incident on the pupil at a high position on the y axis, and measures the high position on the y axis of the retina. At this time, the measurement light is bent on the side far from the half mirror 103 by the incident position control mechanism 104 and enters the XY scanner 105. The incident angle to the pupil is not different from the case where the same measurement as in the normal measurement [FIG. 3B] is performed. When the measurement light changes from (1) 'to (3)', the XY scanner 105 scans the measurement light incident on itself in the Y direction. That is, step S6 corresponds to an example of a scanning step of scanning measurement light that irradiates the fundus of the eye to be examined. Further, the step S6 corresponds to an example of an incident position changing step for changing the incident position of the measurement light scanned in the scanning process on the eye so as to avoid an obstacle that prevents the measurement light from entering the eye. . Thus, in this apparatus, the incident position of the measurement light is changed using the incident position changing mechanism 104 while scanning the XY scanner 105.

  FIGS. 4B to 4E show measurement profiles before and after the i-th frame. FIG. 4B shows the incident position with respect to the pupil when the y-axis is the Fast scan, and FIG. 4C shows the incident angle with respect to the pupil in that case. Control each sawtooth wave shape. FIG. 4D shows the incident position of the measurement light with respect to the pupil when the x-axis is the Fast scan, and FIG. 4E shows the incident angle in that case. Each is controlled in steps.

  With the measurement profile shown in FIGS. 4B to 4E, one-dimensional array data (for example, 1024 pixels) is acquired from the spectroscope 112 for each measurement point in a state where the measurement light is scanned, and the computer 115 sequentially Sent. Then, one continuous line (for example, 500 points) for each frame is stored in units of two-dimensional array data. The data size is, for example, 1024 × 500 × 12 bits. The computer 115 obtains a tomographic image (B-Scan image) by performing fixed noise removal, wavelength wave number conversion, Fourier transform, and the like from the measured two-dimensional array data.

  In step S7, the computer 115 determines whether all images have been obtained. If necessary 500 frames have been shot, the process proceeds to step S8. If not completed, the process returns to step S6.

  The process ends in step S8. Here, the eye 108 is removed from the apparatus, and the apparatus is returned to the initial position.

  As a result, it is possible to reduce the influence of the obstacle such as the eyelids or eyelashes on the measurement light when the OCT image is captured. Specifically, dimming of measurement light due to obstacles such as eyelids and eyelashes can be reduced. In particular, in the wide field angle measurement, there is a high possibility that the measurement light is affected by an obstacle, and such control is effective. On the other hand, even in the case of a narrow angle of view, the measurement light is effective when there is a possibility of being affected by an obstacle.

  Further, since the incident position on the eye to be examined is moved in parallel, even when the incident position is changed, it is possible to obtain an image in a range substantially similar to the case where the incident position is not changed.

  Although the incident position is controlled by the incident position control mechanism 104 here, this control may be realized by a mechanism that changes the relative height of the eye 108 and the apparatus.

  Further, the measurement light can be moved in the pupil by changing the working distance between the eye and the apparatus. However, this is not preferable because the focal position and the like are shifted, but such adjustment may be possible depending on circumstances.

  Further, when the incident position control mechanism 104 is moved, the optical path length of the measurement light may slightly change. In order to correct this, the amount of movement of the incident position control mechanism 104 and the amount of change in the optical path length of the measurement light may be obtained in advance and corrected by controlling the optical path length variable mechanism 114.

(Example 2)
Although the apparatus configuration is the same as that of the first embodiment, an example in which the incident position of the measurement light is sequentially corrected using the result of the anterior segment imaging will be described. An example of signal processing will be described with reference to the flowchart shown in FIG. Note that the following steps are performed by the operation of each component under the control of the computer 115.

  In step C1, measurement is started. In this state, the OCT apparatus is activated and the eye 108 to be examined is placed at the measurement position. When the C1 step is completed, the above-described S2 step and S3 step are performed. And it moves to C2 process.

  In step C2, pre-imaging adjustment of the anterior segment and tomographic image is performed. First, the anterior segment is imaged by the anterior segment imaging device 111 in the same manner as in step S2. Then, the image obtained by the anterior eye imaging device 111 is recorded as a template in a memory (not shown) in the computer 115. Further, similarly to step S3 described in the first embodiment, the computer 115 creates a control profile so that the influence of the obstacle on the measurement light is reduced. Then, adjustment before imaging of the anterior segment and tomographic image is performed. In the adjustment of the tomographic image, the positions of the focus, the coherence gate, and the like are adjusted. When the preparation for imaging is completed, it waits for the imaging switch to be pressed.

  In step C3, the computer 115 determines whether the imaging switch is pressed. If the button is pressed, the anterior segment imaging proceeds to step A1, and the tomographic imaging proceeds to step B1.

  First, an imaging loop of the anterior segment (A1 step-A3 step and C4 step) will be described. Assume that the imaging of the anterior segment is, for example, 25 msec per frame.

  In step A1, the anterior segment is imaged. For example, an image of 600 × 800 pixels is acquired by the anterior eye imaging device 111.

  In step A2, the computer 115 evaluates the anterior segment. Specifically, the template recorded in the C2 process and the image acquired in the A1 process are compared. In this comparison, a place where the acquired image matches the template is searched. Since this method is performed by general pattern matching or the like, details are omitted.

  In step A3, the computer 115 calculates a movement amount. The amount of movement of the template can be calculated from the pattern matching position and the initial position. Note that the case where there is no matching place may occur, for example, when the anterior segment moves greatly or when the eyelid is closed. In such a case, the movement amount is set to a value obtained last time, for example. The calculated movement amount is transferred to the signal processing unit of the OCT, and the process proceeds to step C4.

  Next, a tomographic imaging loop (B1 process-B3 process and C4 process) will be described. Assume that imaging by the OCT imaging unit is, for example, 25 msec per frame.

  In step B1, under the control of the computer 115, the incident position control mechanism 104 corrects the incident position of the measurement light. Correction of the incident position of the measurement light is performed by referring to the calculation result of the movement amount from step A3. The incident position is corrected every frame, for example. In addition, when the process of the imaging loop of the anterior eye part is stagnant, the movement amount is not sent to the signal processing part of the OCT. In this case, the computer 115 may correct the incident position using the movement amount sent last time.

  For example, when the eye to be examined moves upward, the incident position of the measurement light is moved upward by moving the incident position control mechanism 104 to the 103 side. The moving amount of the eye to be examined and the moving direction and moving amount of the incident position control mechanism 104 are associated in advance and recorded in a storage device such as a memory (not shown). Therefore, the incident position control mechanism 104 moves using the information recorded in this storage device.

  In step B2, the XY scanner 105 is moved. For example, when the x-axis is a slow scan and the y-axis is a fast scan, the measurement light is moved stepwise in the direction of the x-axis.

  In step B3, line data is acquired by a line sensor (not shown) provided in the spectroscope 112. More specifically, line data is acquired while performing y-axis scanning. At the time of scanning, an OCT image can be obtained while avoiding an obstacle by changing the incident position of the measurement light according to the profile in the same manner as in step S6 described above.

  In step C4, the computer 115 determines whether acquisition of a desired number of OCT images has been completed. If the desired number has not been acquired, fundus image capturing returns to A1. On the other hand, the tomographic imaging returns to B1. On the other hand, if it is determined that acquisition of the desired number of OCT images has been completed, the process proceeds to step C5.

  In step C5, the process ends.

  As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained, and the incident position of the measurement light can be controlled (corrected) while analyzing the movement of the anterior segment in substantially real time. Therefore, imaging failures can be reduced. This is particularly effective when the eye to be examined moves.

(Example 3)
In this embodiment, an OCT apparatus having an SLO apparatus will be described with reference to the drawings. The SLO device and the OCT device share a part of the optical system, and each can correct the incident position of the measurement light with respect to the pupil.

(Configuration of optical system)
FIG. 6 shows a configuration in which the OCT apparatus using the photocoupler 301 and the SLO apparatus share the objective lens. Since the OCT apparatus has substantially the same configuration as that of the first embodiment except that the photocoupler 301 and the fiber collimators 302 and 303 are used, description thereof will be omitted.

  Next, the optical system configuration of the SLO imaging unit that acquires the fundus image will be described. As the laser light source 304, a semiconductor laser or an SLD light source can be used. It is sufficient that this wavelength can be separated from the wavelength of the low-coherent light source 101 for OCT by the dichroic mirror 310. In general, a near-infrared wavelength region of 700 nm to 1000 nm, which is good as the image quality of the fundus image, is used. In this embodiment, for example, a semiconductor laser having a wavelength of 760 nm capable of wavelength separation is used.

  First, a laser beam (SLO beam) emitted from the laser light source 304 is emitted as parallel light from the fiber collimator 306 via the fiber 305 and guided to the incident position adjusting mechanism 308 and the SLO scanner 309. The dichroic mirror 310 is configured to transmit the OCT beam and reflect the SLO beam. Similar to the OCT imaging unit, the scanner of the SLO imaging unit uses a galvano scanner. The SLO beam that has entered the eye 108 is irradiated on the fundus of the eye 108. Here, the incident position control mechanism 308 changes the incident position of the SLO beam to the SLO scanner 309 and is a member having substantially the same function as the above-described incident position control mechanism 104, and thus detailed description thereof is omitted. . The SLO scanner 309 scans the SLO beam in the X direction and the Y direction, and is a member having substantially the same function as that of the XY scanner 105 described above, so detailed description thereof is omitted. That is, the SLO scanner 309 corresponds to an example of a scanning unit that scans measurement light that irradiates the fundus of the eye to be examined and a scanning mirror that scans measurement light that irradiates the fundus of the eye to be examined. The incident position control mechanism 308 corresponds to an example of an incident position changing unit and an incident position changing mirror.

  This SLO beam is reflected or scattered by the fundus of the eye 108 to be examined, follows the same optical path, and returns to the perforated mirror 307. The position of the perforated mirror 307 is conjugate with the pupil position of the eye 108 to be examined, and the light passing through the periphery of the pupil out of the light backscattered by the beam irradiated to the fundus is caused by the perforated mirror 307. The light is reflected and imaged on the light detection element 312 by the lens 311. The light detection element 312 is, for example, an APD (avalanche photodiode). The computer 115 generates a planar image of the fundus based on the intensity information from the light detection element 312. In this embodiment, the SLO is used in which the fundus image is obtained by irradiating and scanning the fundus with a beam having a predetermined spot diameter.

  The computer 115 not only controls and acquires data such as the OCT scanner, the optical path length variable mechanism 114, the spectroscope 112, the SLO scanner 309, and the light detection element 412, but also performs signal processing, data extraction and storage, and the like. . Note that each of the OCT apparatus and the SLO apparatus may be a single apparatus.

(Signal processing)
In the signal processing in this embodiment, the signal processing in Embodiment 1 may be performed by each of the SLO device and the OCT device. That is, the main difference is the next step.

  In step S3, the computer 115 creates a measurement profile. At this time, a profile for OCT imaging and a profile for SLO imaging are created. The imaging range may be different between SLO and OCT, so a profile suitable for each is created. The same profile may be used.

  In step S6, SLO imaging and OCT imaging are performed based on the respective profiles.

  In step S <b> 7, the computer 115 determines whether a desired measurement has been completed in the OCT imaging.

  As a result, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and interference by eyelids or eyelashes can be reduced at the time of imaging both the SLO image and the OCT image.

  The present embodiment is an OCT apparatus with an SLO apparatus, but naturally, this configuration can be applied even when the SLO apparatus and the OCT apparatus are a single unit.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 101 Light source 102 Fiber collimator 103 Half mirror 104 Incident position control apparatus 105 XY scanner 106 Lens 107 Objective lens 108 Eye to be examined 109 Dichroic mirror 110 Imaging lens 111 Anterior eye imaging device 112 Spectroscope 113 Compensation glass 114 Optical path length variable mechanism 115 Computer 116 Cornea 117 Eyelash 118 Fundus 119 Eyelid 120 Pupil 121 Iris 122 White Eye 123 Scanning Range 124 Quartz Lens 301 Photocoupler 302 Fiber Collimator 303 Fiber Collimator 304 Laser Light Source 305 Fiber 306 Fiber Collimator 307 Hole Perforated Mirror 310 Die Position Adjustment Mechanism 309 S Mirror 311 Lens 312 Photodetecting element

Claims (11)

Scanning means for scanning measurement light for irradiating the fundus of the eye to be examined;
An incident position changing means for changing an incident position of the measurement light scanned by the scanning means on the eye so as to avoid an obstacle that prevents the measurement light from entering the eye to be examined;
An ophthalmic apparatus characterized by having   The incident position changing means includes an imaging range of the fundus when the incident position is not changed by the incident position changing means and an imaging range of the fundus when the incident position is changed by the incident position changing means. The ophthalmologic apparatus according to claim 1, wherein an incident position of the scanned measurement light on the eye to be examined is changed so as to be substantially equal.   The ophthalmic apparatus according to claim 2, wherein the incident position changing unit changes the incident position in parallel in a vertical direction of the eye to be examined.   The ophthalmologic apparatus according to claim 1, wherein the incident position changing unit changes an incident position of the measurement light on the scanning unit.   The incident position changing means changes the incident position of the scanned measurement light on the subject's eye based on the size of the pupil of the subject's eye and the diameter of the illumination light. The ophthalmologic apparatus of any one. Imaging means for imaging an anterior segment image of the eye to be examined including the obstacle;
Obtaining means for obtaining position information of the obstacle on the anterior eye part from the imaged anterior eye part image;
Determination means for determining whether the measurement light is prevented from entering the eye to be examined based on the position information of the obstacle acquired by the acquisition means;
When it is determined that the measurement light is prevented from entering the eye to be examined by the determination means, the incident position changing means changes the incident position of the scanned measurement light to the eye to be examined. The ophthalmologic apparatus of any one of Claims 1-5.   The ophthalmic apparatus according to claim 1, wherein the obstacle is at least one of eyelashes, eyelids, iris of the subject eye, and turbidity appearing in the subject eye. A scanning mirror that scans measurement light that irradiates the fundus of the eye to be examined; and
An ophthalmologic apparatus comprising: an incident position changing mirror that changes an incident position of the measurement light on the scanning mirror.   The ophthalmologic apparatus according to claim 8, wherein the incident position changing mirror is provided so as to be movable in an optical axis direction of the measurement light incident on the mirror. A light source for emitting the measurement light;
A sensor for receiving reflected light from the fundus of the scanned measurement light,
The ophthalmologic apparatus according to claim 8 or 9, wherein the reflected light is received by the sensor via the scanning mirror and the incident position changing mirror. A scanning step of scanning measurement light that irradiates the fundus of the eye to be examined; and
An incident position changing step of changing the incident position of the measurement light scanned in the scanning step to the subject eye so as to avoid an obstacle that prevents the measurement light from entering the eye to be examined;
An ophthalmic lighting method characterized by comprising:

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