JPH0554776B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ophthalmoscopy apparatus, and particularly to an ophthalmoscopy apparatus for observing and photographing a fundus image of an eye to be examined.

[Prior Art] Fundus examination devices for observing and photographing fundus images have been known in the past, but with this type of device, it is not possible to observe or photograph the entire area of the fundus at once. Therefore, it is necessary to set a fixation target, guide the examinee's line of sight, and change the direction of the visual field of the examinee's eye to select the required part of the fundus.

Conventionally, a configuration is known in which a means for guiding the line of sight of the eye to be examined is provided in a main body of a measuring device such as a fundus camera, or in a part of a face support device for a patient to be examined. In particular, when a face support device is provided with a line-of-sight guidance means, a flexible arm or the like is protruded from a part of the support device, and a light-emitting part such as a miniature lamp is provided at the tip of the arm so that the subject can see this. The line of sight was guided by moving the free arm.

[Problems to be Solved by the Invention] However, in the conventional method as described above, the examiner focuses on the fundus while adjusting the delicate relative position of the fundus camera and the eye to be examined, and then moves the hand while maintaining that posture. I had to extend it wide and move the miniature lamp at the end of the flexible arm to guide the line of sight. Therefore, in the conventional method, the examiner has to continue performing delicate and troublesome manual control in an awkward position, which poses a problem in that the examiner is highly fatigued.

In addition, in conventional devices, the distance between the eye-guiding means such as a small lamp and the subject is set to be very small, so if the gaze time is prolonged, the subject may experience physiological pain. It was hot.

In addition, conventional gaze guidance mechanisms have poor reproducibility when it becomes necessary to redirect the gaze to a position once guided, and the same part of the fundus cannot be accurately reproduced at the same coordinates on a recording surface such as film. Ta.

Therefore, images of the observed and photographed fundus are affected by distortion aberration of the optical system of the fundus camera, even of normal parts, and images with different magnifications are obtained even when examining the same coordinates on the fundus. There was a problem. Therefore, when determining the state of a lesion over time, in other words, it is difficult to judge whether a particular area is healing or worsening by arranging the fundus measurement results of a subject over time. It was hot.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the display position of the fundus examination apparatus having an optical system for observing and influencing the fundus image of the eye to be examined is moved. A fixation target that is visible to the subject for guiding the subject's line of sight by control, means for recording display position information of the fixation target, and fixation recorded on the recording means. A configuration is adopted in which a control means is provided for displaying the fixation target at the same position as the target display position.

[Operation] According to the above configuration, the display position of the fixation target is recorded, and when the need for reexamination arises, the fixation target is displayed at the same position as the previous time based on the information in this recording means. By guiding the examinee's line of sight in the same direction, it is possible to observe and photograph the fundus image of the examinee's eye under the same examination conditions.

[Examples] The present invention will be described in detail below based on examples shown in the drawings.

FIG. 1A shows the configuration of an optical system of a fundus camera as a fundus examination apparatus employing the present invention. The fundus camera shown in FIG. 1A is a non-mydriatic type that uses infrared light to observe the eye to be examined and uses visible light to take pictures.

In FIG. 1A, the symbol E indicates the eye to be examined, and the objective lens 1 is placed directly opposite the optical axis of the eye E to be examined. The following optical elements are arranged on the optical axis behind the objective lens 1.

That is, what is indicated by the reference numeral 2 is a mirror with a hole for guiding illumination light from an illumination system, which will be described later, toward the eye E to be examined. A photographic lens consisting of a focus lens 3a and a fixed lens 3b is arranged behind the perforated mirror 2.

A fundus image of the eye E to be examined is formed on a recording surface 4 of a film (or a photoelectric conversion element, etc.) by this photographing system lens. The image to be formed on the recording surface 4 can be observed by an observation optical system consisting of a movable mirror (or half mirror, etc.) 20, a field lens 29, a mirror 21, and an eyepiece 22.

On the other hand, illumination light during observation of the fundus image is generated by the lamp 6 as a light source. Further, illumination light during photographing is generated by a strobe tube 7. These light sources are arranged in series through a condenser lens 30.

The light from the lamp 6, which is composed of a tungsten lamp or the like, is converted into an infrared light beam through a filter R that passes a light beam in the infrared region and blocks light beams in other regions.

The light from any of the above-mentioned light sources is incident on the mirror 23 via the condenser lens 9. The illumination light reflected by the mirror 23 passes through a ring slit 10 for passing the illumination light through the peripheral region of the iris of the eye E, and is introduced into the relay lens 11. The relay lens 11 is directed toward the perforated mirror 2, and as a result, the ring-shaped illumination light is incident on the eye E through the perforated mirror 2 and the objective lens 1.

On the other hand, the light reflected from the fundus is reflected by objective lens 1.
After forming an intermediate image of the fundus, the image passes through the opening of the perforated mirror 2 and is formed by the photographing lens 3 on a field lens 29 provided at a position substantially conjugate with respect to the movable mirror 20.

The infrared light flux from the field lens 29 is reflected by the filter 13 which reflects the light flux in the infrared region and passes the light flux in the visible region.
4, the image is formed on the imaging surface of the TV camera 15,
It is observed on a video monitor (not shown).

On the other hand, the movable mirror 20 and the field lens 29
A fixation target 17 is provided via a relay lens 18 at a position substantially conjugate with the fundus of the eye. This fixation target 17 is visually recognized by the eye to be examined through the optical system during the examination, and guides the eye in a predetermined direction.

The structure of the fixation target 17 and the portion behind the perforated mirror 2 of the main optical system is shown in a perspective view in FIG.

As shown in FIG. 2, the fixation target 17 is a fixation point displayed by a light spot, for example, by illuminating a pinhole 17p from the rear surface. When the fixation target is composed of a single display point in this way, by moving the fixation target 17 in a plane perpendicular to the optical axis of the optical system, the fixation target 17 can be separated from the subject's eye. Since the imaging point of the light flux guided to the fundus of the eye also moves, the line of sight of the eye E to be examined can be guided in a desired direction.

Further, when the fixation target is constituted by a display device including a display element such as a light emitting diode or a liquid crystal as described later, the line of sight can be guided by controlling the display position of the display device.

The position of the fixation target 17 in FIG. 1A is linked to a fixation target display device 17' for imprinting. Second
In the case of the figure, the fixation target display device 17' is constituted by an LED array or the like, and predetermined LED elements on the fixation target display device 17' are turned on depending on the movement position of the fixation target 17.

The fixation target display device 17' for imprinting moves the fixation target 17, selects the imaging region, and then lights the strobe tube 7 and flips up the movable mirror 20 to display the mirror 3f ( Figure 1A
(not shown) is recorded on the recording surface 4' via the recording lens 3c. In the case of FIG. 2, the recording surface 4' is configured to be the same recording surface as the aforementioned recording surface 4 for recording the fundus image.

On the other hand, information regarding the display position of the fixation target 17 recorded on the recording surface 4' is read using the configuration shown in FIG. For this purpose, a configuration as shown in FIG. 1B is provided in the fundus examination apparatus. The structure of this part is shown above the photographing lens 3 in FIG.

In FIG. 1B, reference numeral 41 denotes a lamp for illuminating a recording medium 4' recording the fixation target position during fundus examination. Recording body 4' is a condenser lens 4
2 by a lamp 41, and the recorded image on the recording medium 4' is focused on an area detector 44 by a detection lens 43 (not shown in FIG. 2).

The area detector 44 is, for example, a two-dimensional array.
It is composed of a CCD sensor, etc., and reads information regarding the fixation target display position recorded as the coordinate position of a bright spot on the recording medium 4'.

Therefore, when re-inspecting, load the recording medium 4' on which the previous inspection was carried out into the predetermined position shown in FIG. The image on the recording medium 4' is projected.

By controlling the display position of the fixation target 17 based on the information regarding the fixation target display position recorded by the area detector 44 as the coordinate position of the luminance information on the recording body 4', the display position of the fixation target 17 is controlled. The line of sight of the eye to be examined can be guided in the direction.

As described above, according to this embodiment, the recording surface 4'
The position of the fixation target for imprinting that moves in conjunction with the actual fixation target is recorded at a specific coordinate position,
In addition, when re-examining later, the fixation target position recorded on the recording medium 4' is referred to.
By determining the position 7, it is possible to guide the line of sight of the eye to be examined in the same direction as in the previous examination and to observe and photograph the fundus image under the same conditions. Therefore, unlike conventional configurations, the fixation target is accurately reproduced at the position at the time of the previous examination, eliminating undesirable phenomena such as changes in magnification of the fundus image caused by different aberration conditions of the optical system. be able to.

In the above embodiment, the configuration in which the position information of the fixation target 17 is recorded by optical means is exemplified, but for example, in the embodiment shown in FIG.
Digital information regarding the direction of gaze guidance is formed from the position control signals of The configuration can also be considered.

By the way, when repeating the re-examination of the fundus of the subject's eye, if the macular part of the fundus or the optic nerve head has already been photographed, it may be possible to determine the gaze guidance direction from that position. 3 to 5 show an embodiment in which the display position of the fixation target is determined from the fundus image itself.

FIG. 3 shows a configuration for reading a recording medium 4' on which a fundus image 4a' has already been recorded. In the figures, members designated by numerals 41 to 44 are the same or equivalent to the members having the same symbols shown in FIG. 1B and FIG. 2.

In this embodiment, in order to guide the fundus image 4a' itself recorded on the recording medium 4' to the area detector 44, a condenser lens 42 and an imaging lens 43 are used.
has a corresponding circular shape, and the size of the area detector 44 is set so as to sufficiently cover the image circle of the imaging lens 43.

FIG. 4 illustrates a configuration for controlling the fixation target 17 based on the output of the area detector 44 shown in FIG. 3.

In FIG. 4, reference numeral 50 denotes a control device composed of a microprocessor or the like. The control device 50 includes a ROM 51 that stores programs to be described later.
and is used as a work area for calculations, etc.
RAM52 is connected.

The fixation target 17 is connected to a control device 50 via a fixation target control section 53. The fixation target control section 53 is composed of an interface section such as an input/output port and a drive section suitable for the configuration of the fixation target 17. The drive unit of the fixation target control unit 53 is a drive circuit for a motor that moves the fixation target 17 if the fixation target 17 has a single display point;
If the fixation target 17 is composed of an LED array or the like having a plurality of display points, it is composed of a driver element of the LED array or the like.

FIG. 5 shows the flow of the control program stored in the ROM 51 of FIG.

In FIG. 5, step S1 shows the photographing process at the time of the previous examination.

The recording medium 4' on which the fundus image was recorded in the fundus photographing in step S1 is
It is loaded into a predetermined position of the reading device shown in the figure, and then the lamp 41 is driven to cause the area detector 44 to read the fundus image of the recording body 4'.

Subsequently, in step S3, the control device 50 analyzes the image data input from the area detector 44, and detects the coordinate position of the macular region Y or the optic disc N in the fundus image. Detection of these predetermined areas can be performed by measuring the difference in reflectance (ie, density on the recording medium 4') with other fundus parts. If the specific region cannot be detected from the fundus image on the recording body 4' in step S3, the process moves to step S5 and the process ends with an error.

Since the position of the macular area Y or optic disc N in the fundus is almost the same for any subject, it is possible to determine in which direction the fundus image is taken based on the coordinate position of the above-mentioned specific region in the fundus image. It is possible to know whether the test was performed by guiding the viewpoint of the subject's eye.

Therefore, in step S4, the control device 50 calculates data regarding the gaze guidance direction, that is, the display position of the fixation target 17, from the position of the macular area Y or the optic disc N detected in step S3, using a table calculation or the like. , followed by step S6
Based on the data determined in , the display position of the fixation target 17 is changed via the fixation target control unit 53, and the line of sight of the eye to be examined is guided in the same direction as in the previous examination.

Next, in step S7, an examination such as observation or photographing of the fundus of the eye is performed via an optical system.

According to the above configuration, it is possible to perform a reexamination by reproducing the gaze guidance direction from the position on the recording body of a specific region such as the macular region Y or the optic disc N. Re-inspection can be carried out under the following test conditions. However, in this embodiment, the direction of gaze guidance is calculated backwards from the position of a specific part of the fundus, so it goes without saying that the above embodiment, which directly records the fixation target position, has better reproducibility of gaze guidance. do not have.

In the embodiments shown in FIGS. 3 to 5, if the fundus image is recorded not optically but optically or magnetically in the form of digital data, the digital data itself is analyzed, The direction of the line of sight to be guided may be determined based on the position of a specific site within the fundus.

[Effect] As is clear from the above, according to the present invention, in a fundus examination apparatus having an optical system for observing and photographing a fundus image of an eye to be examined, by controlling the movement of the display position, the line of sight of the examinee can be adjusted. A plurality of fixation targets visible to the subject for guiding direction, means for recording display positions of the fixation targets, and the same position as the fixation target display position recorded in the recording means. Since the system is equipped with a control means for displaying the fixation target, it is possible to obtain almost perfect reproducibility of the gaze guidance position, making it especially suitable for repeated re-examinations. A fundus examination device can be provided.

[Brief explanation of the drawing]

1A, B, and 2 show the first embodiment of the present invention. FIG. 1A is an explanatory diagram showing the configuration of the optical system of the fundus examination device, and FIG. 1B is a recording diagram. FIG. 2 is a perspective view showing the main parts of FIGS. 1A and B in detail, and FIGS. The second embodiment is explained, and FIG. 3 is a perspective view showing the configuration for reading the recorded fixation target display position, and FIG. 4 is a block diagram showing the configuration of the fixation target control device. , FIG. 5 is a flowchart showing the control procedure of the control device of FIG. 4. 1... Objective lens, 1'... Lens barrel, 3... Imprinting lens, 4, 4'... Recording surface (recording body), 6...
... Lamp, 7 ... Strobe tube, 15 ... TV camera, 17, 17' ... Fixation target, 41 ... Lamp,
42... Condenser lens, 43... Imaging lens, 44... Area detector.

Claims (1)

[Claims] 1. In a fundus examination device having an optical system for observing and photographing fundus images of the subject's eye, fixation that is visible to the subject is used to guide the subject's line of sight by controlling the movement of the display position. A target, a means for recording display position information of the fixation target, and a control means for displaying the fixation target at the same position as the fixation target display position recorded in the recording means. Fundus examination device.