Patent Publication Number: US-9427145-B2

Title: Ophthalmologic measurement apparatus, method and program of controlling the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an ophthalmologic measurement apparatus or the like for measuring an eye to be inspected. 
     2. Description of the Related Art 
     As for an ophthalmologic measurement apparatus for measuring an eye to be inspected, two types are known: a stationary type; and a hand-held type. 
     An ophthalmologic measurement apparatus of the stationary type includes a stand for putting a main part of the apparatus on an installation surface, a base configured to be slidable on the stand in back-and-forth and right-and-left directions, a measurement unit connected to the base and including various kinds of optical systems and an imaging system, a jaw receiving stand/forehead support for positioning a jaw or a forehead of a person to be inspected, and the like. In the stationary-type ophthalmologic measurement apparatus, the base is slid to the right or left mainly to switch an eye to be inspected of a person between his/her right and left eyes. Thus in the stationary-type ophthalmologic measurement apparatus, it is possible to recognize which one of right and left eyes is to be inspected by detecting whether the measurement unit is located on the right or left side with respect to the center of the stand. 
     On the other hand, the hand-held type ophthalmologic measurement apparatus has neither a stand nor a base, and thus it may be difficult to recognize which one of right and left eyes is to be inspected in the same manner as the stationary-type ophthalmologic measurement apparatus. To handle the above situation, Japanese Patent Laid-Open NO. 7-246188 discloses ophthalmologic equipment configured to have a shielding plate movable between a position where to shield a right eye a position where to shield a left eye, and also have a switch disposed in the inside of the main part of the equipment to allow it to recognize which one of right and left eyes is to be inspected. 
     On the other hand, Japanese Patent Laid-Open No. 8-256984 discloses an eye examination apparatus having a function of detecting whether an eye of interest is a right or left eye. This eye examination apparatus has two illumination units that provide illumination light from both sides of an eye examination unit, and a photosensor unit disposed between the two illumination units and configured to sense two light rays that are originally emitted from the two illumination units and reflected from a face of a person to be inspected. The photosensor unit detects a light intensity for each reflected light ray and determines, based on the detected light intensity of each reflected light ray, whether the eye to be inspected is a right or left eye. 
     In conventional ophthalmologic measurement apparatuses, including those disclosed in Japanese Patent Laid-Open Nos. 7-246188 and 8-256984 described above, although it is possible to recognize which one of right and left eyes is to be inspected, an eyepiece part (a so-called eyecup) has the same shape regardless of whether a right or left eye is to be inspected, and thus it is difficult to achieve a good contact between the eyepiece part and a face of a person to be inspected. More specifically, a positional relationship between a part from an inner eye corner to a nose and a part from an outer eye corner to an ear is opposite between right and left eyes. In general, the length between an eye (inner corner) and a nose is shorter than the length between an eye (outer corner) and an ear. Besides, there is a difference in an angle of a face with respect to a straight-ahead eye direction. Therefore, for example, when an eyepiece part has a shape that allows the eyepiece part to be in good contact with an area around left eye, if it is tried to directly put this eyepiece part into contact with an area around right eye, a fitting error in size and/or angle may occur. 
     SUMMARY OF THE INVENTION 
     In view of the above, the present invention provides a technique that allows it to put an eyepiece part into a good contact with an area around an eye of a person to be inspected regardless of whether it is a right or left eye. 
     Disclosed herein is an ophthalmologic measurement apparatus including a measurement unit configured to acquire an image of an eye to be inspected, a main unit in which the measurement unit is placed and which includes a holding part for holding the main unit with a hand, an eyepiece part having a shape asymmetric about a measurement optical axis of the measurement unit and capable of being in contact with an area around an eye to be inspected, a position detection unit configured to detect a position of the eyepiece part, an acquisition unit configured to acquire eye distinguishing information indicating whether the eye to be inspected is a right eye or a left eye, and a display control unit configured to control a display unit to display an image of the eye to be inspected such that the image of the eye to be inspected is rotated in a clockwise or counterclockwise direction based on the eye distinguishing information and a resultant image is displayed. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating in a brief manner a structure of an ophthalmologic measurement apparatus according to an embodiment. 
         FIG. 2  is a perspective view illustrating an external appearance of an ophthalmologic measurement apparatus according to an embodiment. 
         FIGS. 3A and 3B  are diagrams illustrating an example of a manner in which an ophthalmologic measurement apparatus is used according to an embodiment. 
         FIGS. 4A to 4   c  are diagrams illustrating a manner in which an eyepiece part turns. 
         FIGS. 5A to 5C  are diagrams illustrating a manner in which an eyepiece part slides. 
         FIG. 6  is a flow chart illustrating a process associated with an ophthalmologic measurement apparatus according to a first embodiment. 
         FIGS. 7A and 7B  are diagrams illustrating a manner in which a measurement is performed on a person to be inspected in supine position using an ophthalmologic measurement apparatus according to an embodiment. 
         FIG. 8  is a flow chart illustrating a process associated with an ophthalmologic measurement apparatus according to a second embodiment. 
         FIGS. 9A to 9D  are diagrams illustrating a manner in which a measurement is performed on a person to be inspected from a side of the person to be inspected. 
         FIG. 10  is a table describing relationships among a position of an eyepiece part, information input by an operator to distinguish between right and left eyes, and a rotation angle of an image. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments are described below with reference to drawings. 
     First Embodiment 
       FIG. 1  is a diagram illustrating in a brief manner a structure of an ophthalmologic measurement apparatus  100  according to a first embodiment. 
     The ophthalmologic measurement apparatus  100  includes an eyepiece part  11 , a measurement unit  12 , a control unit  13 , a display unit  14 , and the like. 
     The eyepiece part  11  is a so-called eyecup that is to be put into contact with a face of a person to be inspected to maintain a constant distance between the measurement unit  12  and an eye E to be inspected. The eyepiece part  11  may be formed with a material having a certain degree of elasticity. The elasticity ensures that the eyepiece part  11  is put into contact with a face of a person to be inspected such that the ophthalmologic measurement apparatus  100  are easily held in a proper position and angle. Besides, the elasticity allows a reduction in pain a person to be inspected may feel when the eyepiece part  11  is put into contact with his/her face. The eyepiece part  11  may be formed with a transparent material or may have a gap. In this case, an operator is allowed to put the eyepiece part  11  into contact with a face of a person to be inspected while visually watching an eye to be inspected, which suppresses or prevents a position error between the ophthalmologic measurement apparatus  100  and the eye to be examined. The eyepiece part  11  may be formed with a material opaque to light. In this case, it is possible to prevent an eye to be inspected from being exposed to external light. 
     The measurement unit  12  includes an infrared light emitting diode (LED) light source  201 , a while LED light source  202 , a capacitor C, an illumination optical path O 1 , a measurement optical axis O 2 , a ring slit  205 , an illumination relay lens  207 , an illumination relay lens  209 , a split unit  208 , and a mirror  210  with a hole. The measurement unit  12  includes an objective lens  211 , a focus lens  213 , an image sensor  217 , an anterior eye observation lens  220 , an eyepiece part position sensor  221 , an attitude sensor  222 , and the like. 
     The infrared LED light source  201  is a light source for use in observing, in infrared light, an eye fundus of a person to be inspected. The while LED light source  202  is a light source for use in observing, in visible light, an eye fundus of a person to be inspected. The infrared LED light source  201  and the while LED light source  202  are capable of being moved by a driving unit M 4  into a position in the illumination optical path O 1 . 
     The ring slit  205  is a mask for converting illumination light from the infrared LED light source  201  or the white LED light source  202  into a ring shape. The ring illumination light is focused on an eye E to be inspected via the illumination relay lens  207  and the illumination relay lens  209 . 
     The capacitor C supplies electric power to the while LED light source  202 . The amount of charge stored in the capacitor C varies depending on an image capture mode. Each time the image capture mode is changed, the capacitor C is charged and discharged properly. The charging and discharging are controlled by the control unit  13 . 
     The split unit  208  includes a light source for use in projecting a focus target, a moving mechanism configured such that when an eye is observed, the moving mechanism enters the illumination optical path O 1  and moves in either direction denoted by an up-and-down arrow to move the focus target along the optical axis, and a moving-off mechanism that moves the focus target off the illumination optical path O 1  when an image is captured. The split driving motor M 1  drives the split unit  208  so as to adjust the focal position of the focus target, and the split position sensor S 1  detects a position at which the split unit  208  stops. The driving unit M 5  moves the split unit  208  in either direction represented by an up-and-down arrow in  FIG. 1 , and the position sensor S 6  and the position sensor S 7  detect the position of the split unit  208  in the above-described situation. 
     The mirror with hole  210  is a total reflection mirror having a hole formed at the center thereof. The mirror with hole  210  reflects the ring illumination light from a not-hole part thereof and transmits image light via the hole at the center of the mirror with hole  210 . The ring illumination light reflected by the mirror with hole  210  is focused via the objective lens  211  onto the eye to be inspected E thereby illuminating the eye to be inspected E. Light reflected from the eye to be inspected E is focused at the center of the mirror with hole  210  via the objective lens  211 . The measurement optical axis O 2  is an optical axis extending from the eye E to be inspected to the image sensor  217 . 
     When the anterior eye observation lens  220  is inserted in the measurement optical axis O 2 , it becomes possible to observe an anterior eye. On the other hand, in a state in which the anterior eye observation lens  220  is off the measurement optical axis O 2 , it becomes possible to observe an eye fundus. The operation of moving the anterior eye observation lens  220  in or off the measurement optical axis O 2  is performed by an anterior eye observation lens driving motor M 3  and an anterior eye observation lens position sensor S 4  under the control of the control unit  13 . 
     The focus lens  213  is a lens for adjusting a focus of an image light ray passing through the hole at the center of the mirror with hole  210 . The focus lens  213  moves in either direction represented by a right-and-left arrow in  FIG. 1 . The focus lens driving motor M 2  drives the focus lens  213  according to a pulse supplied from the control unit  13 . A focus lens position sensor S 2  detects the position of the focus lens  213 . 
     The image sensor  217  converts image light into an electric signal. The resultant electric signal is converted to digital data by the control unit  13 . In an infrared observation mode, an observation image is displayed on the display unit  14 . In an image capture mode, a captured image is stored in the memory  132  or a not-illustrated storage medium. The digital data may be transmitted via a communication unit/medium. 
     The eyepiece part position sensor  221  is disposed on a part where the eyepiece part  11  is connected to the measurement unit  12  so as to detect a position (the rotation angle or the slide position) of the eyepiece part  11  with reference to a main unit  20  (described later) in which the measurement unit  12  is disposed. The eyepiece part position sensor  221  is an example of a position sensor unit. 
     The attitude sensor  222  is a three-axis attitude sensor realized by a combination of a gyroscope sensor for measuring a three-axis angular velocity and an acceleration sensor for measuring a three-axis acceleration. The attitude sensor  222  detects the attitude of the ophthalmologic measurement apparatus  100  and more particularly the direction of the measurement optical axis O 2  with respect to the vertical axis in the gravitational direction. The attitude sensor  222  is an example of an attitude detection unit. 
     The control unit  13  controls various operations including driving operations of the driving units M 1  to M 5  operations of the sensors S 1  to S 7 , a control operation based on inputting given via the user interface, an operation of processing image data, an operation of displaying a captured image on the display unit  14 , and the like. The control unit  13  receives information associated with the position of the eyepiece part  11  detected by the eyepiece part position sensor  221 , and information associated with the attitude of the ophthalmologic measurement apparatus  100  detected by the attitude sensor  222 . 
     The control unit  13  includes a CPU  131  and a memory  132 . The CPU  131  executes a program stored, for example, in the memory  132  to perform various the driving control operations, the detection control operations, the data processing operation, the data input/output operation, the display control operation, and the like. 
     As for the display unit  14 , for example, a liquid crystal display may be used. The display unit  14  displays an image of an eye to be inspected under the control of the control unit  13  or displays an image of an eye examined and stored in the memory  132 . Note that the display unit  14  is also capable of displaying data about a name, an age, gender, information indicating whether the eye is a right or left eye, and the like such that the information/data is superimposed on the image of the eye to be inspected or separately from the image of the eye. The display unit  14  may be configured such that a touch panel is formed on a display surface in an integral manner thereby providing a user interface that allows an operator to perform an operation or to input a command or data. The display unit  14  may be provided either integrally with the measurement unit  12  or the like or separately from the measurement unit  12  or the like. 
       FIG. 2  is a perspective view illustrating an external appearance of the ophthalmologic measurement apparatus  100  according to the present embodiment. 
     As illustrating in  FIG. 2 , the ophthalmologic measurement apparatus  100  includes, in its external structure, the eyepiece part  11 , the main unit  20  in which the measurement unit  12  and the control unit  13  are disposed, and the display unit  14 . In  FIG. 2 , O 2  denotes a measurement optical axis (hereinafter also referred to simply as an optical axis O 2 ), and A denotes a center vertical axis (hereinafter also referred to as a vertical axis A) of the main unit  20  of the ophthalmologic measurement apparatus  100 . 
     The eyepiece part  11  is disposed on an end on one side, as seen along the optical axis O 2 , of the main unit  20 . The eyepiece part  11  is used to put the ophthalmologic measurement apparatus  100  into contact with an eye area of a face, and more particularly, an area around an eye E to be inspected. The eyepiece part  11  is connected to the main unit  20  via a connection part  111  having a substantially cylindrical shape. In the present embodiment, the eyepiece part  11  has a substantially oval or elliptical shape whose long axis extends in a horizontal direction as seen in  FIG. 2  (a direction perpendicular to the optical axis O 2  and also to the vertical axis A) and is asymmetric about the optical axis O 2  in the horizontal direction. 
     Herein, let Cl denote an end part, on one side as seen in the longitudinal direction, of the eyepiece part  11  and let Cs denote an end part on the other side, then a relation in magnitude between a distance L 1  from the optical axis O 2  to the end part Cl and a distance L 2  from the optical axis O 2  to the end part Cs is as follows: distance L 1 &gt;distance L 2 . A relation in magnitude between a distance D 1  from the main unit  20  to the end part Cl along the optical axis O 2  and a distance D 2  from the main unit  20  to the end part Cs along the optical axis O 2  is as follows: distance D 1 &gt;distance D 2 . 
     When the eyepiece part  11  is in the state illustrated in  FIG. 2 , it is possible to put the eyepiece part  11  into a good contact with a right eye of a person to be inspected. However, if it is tried to put the eyepiece part  11  into contact with a left eye of the person to be inspected while maintaining the state illustrated in  FIG. 2 , there may occur a problem that it is difficult to adjust the optical axis O 2  with respect to a direction of the line of sight of the person to be inspected. In the present embodiment, to handle the above situation, an operator is allowed to select the position of the eyepiece part  11  depending on the eye to be examined is a right or left eye so as to achieve a good contact with an area around the eye. That is, the eyepiece part  11  is configured so as to be rotatable or horizontally slidable with reference to the main unit  20  such that, for example, distance L 1 &lt;distance L 2  and distance D 1 &lt;distance D 2 . Referring to  FIGS. 3A and 3B ,  FIGS. 4A to 4C , and  FIGS. 5A to 5C , a description is given below as to a manner in which the eyepiece part  11  is rotated or slid. 
     The main unit  20  is formed in the shape of a substantially rectangular parallelepiped with its longest axis extending in a direction perpendicular to the optical axis O 2 . The main unit  20  includes a holding unit  21  that allows an operator to hold the ophthalmologic measurement apparatus  100  with his/her hand. The holding unit  21  is formed along an axis line of the main unit  20 . 
     The display unit  14  is disposed on an end, on the other side as seen in the direction of the optical axis O 2 , of the main unit  20 . The display unit  14  is formed in the shape of a substantially rectangular flat plate. The display unit  14  is disposed at a location so as to be intersected with the optical axis O 2 . 
     In  FIG. 2 , the ophthalmologic measurement apparatus  100  is in a position in which the display unit  14  of the main unit  20  is located on an upper side U of the ophthalmologic measurement apparatus  100  while the holding unit  21  of the main unit  20  is located on a lower side L of the ophthalmologic measurement apparatus  100 . 
     The eyepiece part position sensor  221  is disposed at a location, not seen from the outside, that allows it to detect the position of the eyepiece part  11  and more specifically, for example, at a location where the eyepiece part  11  is connected with the main unit  20 . The attitude sensor  222  is disposed at a location, not seen from the outside, inside the main unit  20 . 
       FIGS. 3A and 3B  are diagrams illustrating an example of a manner in which the ophthalmologic measurement apparatus  100  is used.  FIG. 3A  illustrates a state in which the eyepiece part  11  is in contact with an area around a right eye (Er), and  FIG. 3B  illustrates a state in which the eyepiece part  11  is in contact with an area around a left eye (El). An operator is allowed to change the state of the eyepiece part  11  between a state in which the eyepiece part  11  is allowed to be in contact with an area around a right eye as illustrated in  FIG. 3A  and a state in which the eyepiece part  11  is allowed to be in contact with an area around a left eye as illustrated in  FIG. 3B . 
     First, a structure that allows the eyepiece part  11  to turn with respect to the main unit  20  is described referring to  FIGS. 4A to 4C  illustrating the eyepiece part  11  seen from the side of a person to be inspected. 
     In  FIG. 4A , the eyepiece part  11  is in a position that allows it to be contact with an area around a right eye. In this state, distance L 1 &gt;distance L 2 . In  FIG. 4B , the eyepiece part  11  is in the middle of an operation in which the eyepiece part  11  is turned about the optical axis O 2  in a direction denoted by an arrow. In  FIG. 4C , the eyepiece part  11  has been turned to a position that allows it to be in contact with an area around a left eye. In this state, distance L 1 &lt;distance L 2 . 
     The structure that allows it to turn the eyepiece part  11  about the optical axis O 2  makes it possible to put the eyepiece part  11  in a good contact with an eye regardless of whether it is a right or left eye although the eyepiece part  11  has a shape asymmetric about the optical axis O 2 . This makes it possible to maintain the apparatus on a face of a person to be inspected in a stable manner, and it is possible to achieve good blocking of light. 
     Next, a structure that allows the eyepiece part  11  to slide with respect to the main unit  20  (and more specifically, with respect to the connection part  111 ) is described below referring to  FIGS. 5A to 5C . In each of  FIGS. 5A to 5C , a view seen from the side of a person to be inspected and a view seen from the top side of the ophthalmologic measurement apparatus  100  are shown side by side. 
     In  FIG. 5A , the eyepiece part  11  is in a position in which it is allowed to be in a good contract with an area around a right eye. In this state distance L 1 &gt;distance L 2 . In  FIG. 5B , the eyepiece part  11  is in a state in which the eyepiece part  11  is being slid in a direction (horizontal direction) perpendicular to the optical axis O 2  and also to the vertical axis A as denoted by arrows. In  FIG. 5C , the eyepiece part  11  has been slid to a position that allows it to be in a good contact with an area around a left eye. In this state, distance L 1 &lt;distance L 2 . As illustrated in  FIG. 5A  to  FIG. 5C , to make it possible for the eyepiece part  11  to be slidable, the eyepiece part  11  has a long hole  112  along a direction in which the eyepiece part  11  is to be slid. By forming the eyepiece part  11  to be slidable in the horizontal direction as described above, it becomes possible to put the eyepiece part  11  in contact with either a right eye or a left eye in a good manner regardless of whether it is a right or left eye although the eyepiece part  11  has a shape asymmetric about the optical axis O 2 . This makes it possible to maintain the apparatus on a face of a person to be inspected in a stable manner. 
     The eyepiece part position sensor  221  detects the position of the eyepiece part  11 , and more specifically, the rotational angle or the slide position thereof. Thus, the control unit  13  is capable of making a determination, based on the information about the position detected by the eyepiece part position sensor  221 , as to whether the eyepiece part  11  is in the position that allows it to be in contact with an area around a right eye ( FIG. 4A ,  FIG. 5A ) or in the position that allows it to be in contact with an area around a left eye ( FIG. 4C ,  FIG. 5C ). That is, the control unit  13  is capable of determining whether a captured image of an eye E to be inspected is of a right eye or a left eye. 
       FIG. 6  is a flow chart illustrating a process perform by the control unit  13  when the ophthalmologic measurement apparatus  100  measures an eye E to be inspected according to the present embodiment. The process illustrated in this flow chart is realized by the CPU  131  in the control unit  13  by executing a program stored in the memory  132  or a storage medium. 
     In step S 601 , when an operator turns on the power of the ophthalmologic measurement apparatus  100 , the control unit  13  takes an image of an eye E to be inspected via the measurement unit  12 . Note that in the state immediately after the power of the ophthalmologic measurement apparatus  100  is turned on and the eyepiece part  11  is put into contact with an area around the eye E to be inspected, the anterior eye observation lens  220  is inserted in the optical axis O 2 . 
     In step S 602 , the control unit  13  determines whether a measurement start command is issued by an operator. 
     In step S 603 , the control unit  13  analyzes an anterior eye portion observation image. 
     In step S 604 , the control unit  13  determines whether an image of a pupil of the eye E to be inspected is located substantially at the center of the captured image. In a case where the image of the pupil of the eye E to be inspected is located substantially at the center of the captured image, the processing flow proceeds to step S 605 . However, in a case where the image of the pupil of the eye E to be inspected is not located substantially at the center of the captured image, the processing flow returns to step S 603 . 
     In step S 605 , the control unit  13  moves the anterior eye observation lens  220  off the optical axis O 2 . 
     In step S 606 , the control unit  13  projects a focus target. 
     In step S 607 , the control unit  13  moves the focus target and the focus lens  213 . 
     In step S 608 , the control unit  13  determines whether an in-focus state is achieved or not. In a case where the in-focus state is achieved, the processing flow proceeds to step S 609 , but otherwise the processing flow returns to step S 607 . 
     In step S 609 , the control unit  13  moves the focus target off the illumination optical path O 1 . In step S 610 , the control unit  13  turns on the infrared LED light source  201  or the while LED light source  202  to emit light therefrom. 
     In step S 611 , the control unit  13  stores a still image of an eye E to be inspected as image data in the memory  132  or a storage medium. 
     In step S 612 , the control unit  13  receives information about the position of the eyepiece part  11  detected by the eyepiece part position sensor  221 . 
     In step S 613 , the control unit  13  stores the information about the position of the eyepiece part  11  in relation to the image data stored in the memory  132  or the storage medium, and ends the measurement. 
     By storing the information about the position of the eyepiece part  11  and the image data in relation to each other as described above, it becomes possible for the control unit  13  to display on the display unit  14  image data together with information indicating the position of the eyepiece part  11 . More specifically, the control unit  13  makes a determination based on the information about the position of the eyepiece part  11  as to whether the image data is of a right eye or a left eye, and displays on the display unit  14  the image data and the information indicating whether the image is of the right eye or the left eye. This makes it possible for an operator to recognize whether the stored image data is of the right eye or the left eye. 
     Second Embodiment 
     Next, in a second embodiment, a description is given for a case where a measurement is performed on an eye E of a person to be inspected in supine position. 
       FIGS. 7A and 7B  are diagrams illustrating a manner in which the ophthalmologic measurement apparatus  100  is used for a person to be inspected in supine position. 
     In  FIG. 7A , an operator is handling the ophthalmologic measurement apparatus  100  such that the ophthalmologic measurement apparatus  100  is put in a position in which the holding unit  21  faces towards the abdomen of a person to be inspected in supine position and the eyepiece part  11  is in contact with a face of the person to be inspected. In this state, the position of the eyepiece part  11  with respect to the main unit  20  is similar to that for the case where the measurement is performed for a person to be inspected in a sitting position or a standing position. Thus the control unit  13  is capable of determining whether an eye E to be inspected is a right eye or a left eye in a similar manner to the first embodiment described above. 
     On the other hand, in  FIG. 7B , an operator is handling the ophthalmologic measurement apparatus  100  such that the ophthalmologic measurement apparatus  100  is in a position in which the holding unit  21  faces towards a side of a person to be inspected in supine position and the eyepiece part  11  is in contact with a face of the person to be inspected. In this case, the position of the eyepiece part  11  with reference to the main unit  20  is different by about 90° in rotational position from that for the case where the measurement is performed for a person to be inspected in a sitting position or a standing position. The rotational position of the eyepiece part  11  is opposite depending on whether the eyepiece part  11  is put into contact with a person to be inspected from the right-hand side or left-hand side, and thus the rotational position of the eyepiece part  11  with reference to the main unit  20  does not indicate whether the eye E to be inspected is a right eye or a left eye. 
     Thus, in the present embodiment, in a case where the eyepiece part  11  is in a position in which its longitudinal direction is substantially parallel to the vertical axis A ( FIG. 7B ), the control unit  13  prompts an operator to input information indicating whether a right eye or a left eye is to be inspected. Furthermore, the control unit  13  displays an image of the eye E to be inspected and the like on the display unit  14  such that the image is rotated in a clockwise direction or a counterclockwise direction. 
       FIG. 8  is a flow chart illustrating a process performed by the control unit  13  when an eye E to be inspected is measured by the ophthalmologic measurement apparatus  100  according to the present embodiment. The process illustrated in this flow chart is performed by the CPU  131  of the control unit  13  by executing a program stored in the memory  132  or another storage medium. 
     In step S 801 , when an operator turns on the power of the ophthalmologic measurement apparatus  100 , the control unit  13  takes an image of an eye E to be inspected via the measurement unit  12 . 
     In step S 802 , the control unit  13  determines whether a measurement start command (an image capture start command) is issued by an operator. In a case where the measurement start command is issued, the processing flow proceeds to step S 803 . 
     In step S 803 , the control unit  13  performs a process similar to the process from step S 603  to step S 611  in  FIG. 6 . That is, the control unit  13  performs an automatic alignment process, an automatic focusing process, and an automatic shooting process, and stores a still image of the eye E to be inspected as image data in the memory  132  or a storage medium. 
     In step S 804 , the control unit  13  receives information about the position of the eyepiece part  11  detected by the eyepiece part position sensor  221 . 
     In step S 805 , based on the information about the position of the eyepiece part  11 , the control unit  13  determines the direction in which the eyepiece part  11  is in. More specifically, the control unit  13  determines whether the longitudinal direction of the eyepiece part  11  is substantially parallel to or perpendicular to the vertical axis A of the main unit  20 . In a case where the direction of the eyepiece part  11  is substantially parallel to the vertical axis A, the processing flow proceeds to step S 806 . However, in a case where the direction of the eyepiece part  11  is substantially perpendicular to the vertical axis A, the processing flow proceeds to step S 814 . In step S 814 , a process is performed in a similar manner to the process in step S 613  according to the first embodiment, and the measurement is ended. 
     On the other hand, in step S 806 , the control unit  13  prompts an operator to input information indicating whether the measurement is performed for a right eye or a left eye. More specifically, the control unit  13  displays a message such as “Input information indicating which one of right and left eyes is to be inspected” on the display unit  14  thereby prompting the operator to perform inputting to indicate whether the eye is a right eye or a left eye. 
     In step S 807 , the control unit  13  waits for the operator to perform inputting via a user interface to indicate whether the eye is a right eye or a left eye. For example, the operator operates a touch panel of the display unit  14  to perform inputting to indicate that the eye is a right eye or a left eye. Thus the CPC  131  acquires via the touch panel eye distinguishing information indicating that the eye is a right eye or a left eye. In a case where inputting is performed, the processing flow proceeds to step S 808 . 
     In step S 808 , the control unit  13  stores the input information indicating whether the eye is a right or left eye in relation to the image data stored in the memory  132  or the storage medium. 
     In step S 809 , the control unit  13  determines whether the input information indicates a right eye or a left eye. In a case where a right eye is indicated, the processing flow proceeds to step S 810 . However, in a case where a left eye is indicated, the processing flow proceeds to step S 811 . 
     In step S 810 , the control unit  13  determines, based on the detection made by the eyepiece part position sensor  221 , whether the position of the end part Cl in the longitudinal direction of the eyepiece part  11  with reference to the main unit  20  is at the upper or lower side of the ophthalmologic measurement apparatus  100 . Note that the end part Cl of the eyepiece part  11  being at the upper side refers to a state in which the end part Cl of the eyepiece part  11  is located at the side of the display unit  14 , while the end part Cl of the eyepiece part  11  being the lower side refers to a state in which the end part Cl of the eyepiece part  11  is located at the side of the holding unit  21  of the main unit  20 . In a case where the position is lower side, the processing flow proceeds to step S 812 , while in a case where the position is the upper side, the processing flow proceeds to step S 813 . 
     Also in step S 811 , the control unit  13  determines, based on the detection made by the eyepiece part position sensor  221 , whether the position of the end part Cl in the longitudinal direction of the eyepiece part  11  with reference to the main unit  20  is at the upper or lower side of the ophthalmologic measurement apparatus  100 . In a case where the position is on the upper side, the processing flow proceeds to step S 812 , while in a case where the position is on the lower side, the processing flow proceeds to step S 813 . 
     In step S 812 , the control unit  13  (display control unit) rotates the image of the eye E to be inspected by 90° in the clockwise direction and displays the resultant image on the display unit  14 . 
     On the other hand, in step S 813 , the control unit  13  (display control unit) rotates the image of the eye E to be inspected by 90° in the counterclockwise direction and displays the resultant image on the display unit  14 . 
     Note that in the process of observing the eye E to be inspected, the control unit  13  may directly display the image of the eye E to be inspected on the display unit  14  without rotating the image. For example, in the observation mode (in the moving image observation mode), the control unit  13  may directly display the image of the eye E to be inspected on the display unit  14  without rotating the image, but in the image capturing mode, the control unit  13  may display the still image of the eye E to be inspected on the display unit  14  such that the image is rotated in a proper direction. 
       FIGS. 9A to 9D  illustrate a manner in which an operator performs a measurement from a side of a person to be inspected ( FIG. 7B ). 
     In  FIGS. 9A and 9B , the measurement is performed from the right-hand side of the person to be inspected in supine position. More specifically, in  FIG. 9A , the position of the end part Cl in the longitudinal direction of the eyepiece part  11  is at the lower side of the ophthalmologic measurement apparatus  100 , and the operator inputs information to indicate that a right eye is to be inspected. Thus, the control unit  13  rotates the image of eye E to be inspected by 90° in the clockwise direction and displays the resultant image on the display unit  14 . On the other hand, in  FIG. 9B , the position of the end part Cl in the longitudinal direction of the eyepiece part  11  is at the upper side of the ophthalmologic measurement apparatus  100 , and the operator inputs information to indicate that a left eye is to be inspected. Thus, the control unit  13  rotates the image of eye E to be inspected by 90° in the clockwise direction and displays the resultant image on the display unit  14 . 
     In  FIGS. 9C and 9D , the measurement is performed from the left-hand side of the person to be inspected in supine position. More specifically, in  FIG. 9C , the position of the end part Cl in the longitudinal direction of the eyepiece part  11  is at the lower side of the ophthalmologic measurement apparatus  100 , and the operator inputs information to indicate that a left eye is to be inspected. Thus, the control unit  13  rotates the image of eye E to be inspected by 90° in the counterclockwise direction and displays the resultant image on the display unit  14 . On the other hand, in  FIG. 9D , the position of the end part Cl in the longitudinal direction of the eyepiece part  11  is at the upper side of the ophthalmologic measurement apparatus  100 , and the operator inputs information to indicate that a right eye is to be inspected. Thus, the control unit  13  rotates the image of eye E to be inspected by 90° in the counterclockwise direction and displays the resultant image on the display unit  14 . 
       FIG. 10  is a table illustrating correspondence among parameters in  FIGS. 9A to 9D  in terms of the position of the end part Cl in the longitudinal direction of the eyepiece part  11 , the information input by the operator as to whether the eye to be inspected is a right or left eye, and the rotation of the image displayed on the display unit  14 . Note that the correspondence table such as that illustrated in  FIG. 10  is stored in the memory  132  or a storage medium such that the control unit  13  is allowed to refer to this correspondence table to determine the rotational direction of the image of the eye E to be inspected. 
     By displaying the rotated image on the display unit  14 , it becomes possible to present the image of the eye to be inspected such that the image is in a normal position as seen from the operator even in the case where the person to be inspected in supine position is measured from a side of the person to be inspected. 
     Note that in the case where the control unit  13  detects via the eyepiece part position sensor  221  that the position of the end part Cl in the longitudinal direction of the eyepiece part  11  is on the upper or lower side of the ophthalmologic measurement apparatus  100 , the control unit  13  may store information indicating that the image data is for a person to be inspected in supine position. 
     The control unit  13  is capable of detecting, via the attitude sensor  222 , the attitude of the ophthalmologic measurement apparatus  100 . That is, when the control unit  13  detects, via the attitude sensor  222 , that the vertical axis A of the main unit  20  is substantially perpendicular to the vertical axis in the gravitational direction, or the optical axis O 2  is substantially parallel to the vertical axis in the gravitational direction, the control unit  13  determines that the measurement is performed for a person to be inspected in supine position. Thus, by detecting the attitude of the ophthalmologic measurement apparatus  100  using the attitude sensor  222 , the control unit  13  is capable of storing the image data in relation to information indicating that the image is that taken for a person to be inspected in supine position. Note that even in the case where the ophthalmologic measurement apparatus  100  is in the position in which the holding unit  21  faces toward the abdomen of the person to be inspected in supine position, it may be allowed to store information indicating that the image is taken for the person to be inspected in supine position. 
     By storing image data together with information indicating that the image data is that taken for a person to be inspected in supine position as described above, it becomes possible for the control unit  13  to display on the display unit  14  image data together with information indicating that the image data is that taken for a person to be inspected in supine position. This makes it possible for an operator to recognize that the stored image data is that taken for the person to be inspected in supine position. 
     According to the present embodiment, as described above, the eyepiece part  11  is configured so as to be allowed to be in contact with an area around of either a right eye or a left eye of an eye E to be inspected selected by an operator in a manner that a good contact is achieved regardless of whether the eye is a right eye or a left eye. This makes it possible to maintain the apparatus on a face of a person to be inspected in a stable manner. 
     Furthermore, it is possible to easily change the position of the eyepiece part  11  simply by rotating or sliding the eyepiece part  11  with reference to the main unit  20  so as to provide the optimum position depending on whether the eye E to be inspected is a right eye or a left eye. 
     The memory  132  or the storage medium stores the image of the eye E to be inspected captured by the measurement unit  12  and the position of the eyepiece part  11  detected by the eyepiece part position sensor  221  such that they are related to each other. Thus, when the stored image of the eye E to be inspected is reproduced, the information about the position of the eyepiece part  11  allows an operator to recognize whether the reproduced image is of a right eye or a left eye. 
     Furthermore, the display unit  14  displays information based on the position of the eyepiece part  11  detected by the eyepiece part position sensor  221  to indicate whether the image of the eye E to be inspected is of a right eye or a left eye. This makes it possible for an operator to recognize whether the image displayed on the display unit  14  is of a right eye or a left eye. 
     Furthermore, there is provided a user interface that allows an operator to input information based on the position of the eyepiece part  11  detected by the eyepiece part position sensor  221  to indicate whether the eye E to be inspected is a right eye or a left eye. Thus even in the case where an image of an eye E of a person to be inspected in supine position is taken from a side of the person to be inspected, inputting of information by an operator to indicate whether the eye E to be inspected is a right eye or a left eye makes it possible to store the image of the eye E to be inspected captured by the measurement unit  12  in relation to the information indicating whether the image is of a right eye or a left eye. 
     Furthermore, an image of an eye E to be inspected is rotated in a clockwise or counterclockwise direction based on the position of the eyepiece part  11  detected by the eyepiece part position sensor  221  and the information input via the user interface, and the resultant image is displayed. Thus even in the case where an image of an eye E of a person to be inspected in supine position is taken from a side of the person to be inspected, it is possible to display the image of the eye E to be inspected such that the image is in a normal position as seen by the operator. 
     Furthermore, based on the attitude of the ophthalmologic measurement apparatus  100  detected by the attitude sensor  222 , an image of an eye E to be inspected taken by the measurement unit  12  is stored in relation to information indicating that the image is taken for a person to be inspected in supine position. This makes it possible for an operator to recognize that the stored image of the eye E to be inspected is that taken for the person to be inspected in supine position. 
     The present invention has been described above with various embodiments. However, the invention is not limited to those embodiments, but various modifications or combinations of embodiments are possible without departing from the scope of the invention. 
     For example, in the embodiments described above, the eyepiece part  11  is connected to the main unit  20  via the connection part  111 . Alternatively, the eyepiece part  11  may be directly connected to the main unit  20 . 
     Instead of employing the structure that allows the eyepiece part  11  to rotate with respect to the main unit  20 , a structure may be configured such that the eyepiece part  11  is allowed to rotate with respect to the connection part  111  or such that the eyepiece part  11  and the connection part  111  are formed in an integral fashion so as to be capable of rotating with respect to the main unit  20 . 
     Other Embodiments 
     Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2014-116999, filed Jun. 5, 2014, which is hereby incorporated by reference herein in its entirety.