JP4233417B2 - Eye refractive power measuring device - Google Patents

Description

  The present invention relates to an eye refractive power measuring device used in an ophthalmic clinic or the like.

In an eye refractive power measuring device that projects a light beam onto the fundus of the subject's eye and receives the reflected light from the fundus of the subject's eye on the light receiving element to obtain eye refractive power, the pupil region illuminated by the reflected light from the fundus is illuminated. An image that can be observed is known (see Patent Document 1 and Patent Document 2).
JP-A-2-302243 JP-A-4-244133

However, in order to observe an appropriate transillumination image, it is necessary to increase the light amount of the light beam projected onto the fundus of the subject's eye compared to when measuring the eye refractive power. On the other hand, if the light amount of the projected light beam is increased during eye refractive power measurement in the same manner as during transillumination, a large amount of reflected light is incident on the light receiving element for measurement and measurement may not be possible. In addition, it is difficult to accurately determine whether the factor affecting the measurement result is due to the opacity of the lens, whether the pupil diameter is too small, the eccentricity of the pupil, or blinking, etc. It was. Also,
The present invention provides an eye refractive power measurement device that can appropriately obtain a transillumination image linked to measurement and that can easily check factors that affect measurement results, in view of the problems of the conventional device. This is a technical issue.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) A light beam projecting unit that projects a light beam onto the fundus of the subject's eye, a light receiving unit that receives a reflected light beam from the fundus, an eye refractive power measuring unit that obtains eye refractive power based on the output of the light receiving unit, and a fundus And an imaging means for imaging an anterior ocular segment image including a pupil region illuminated by the reflected light beam. The imaging means measures the eye refractive power during the eye refractive power measurement by the eye refractive power measurement means. An image recording means for continuously recording an anterior ocular segment image and an image reproduction switch. When an operation signal is output from the image reproduction switch, the image continuously recorded by the image recording means is displayed. characterized in that and an image reproduction means for reproducing every one screen above.
(2) In the eye refractive power measurement device according to (1), the light amount of the projection light beam is temporarily changed to the light amount for transillumination imaging before or after measurement by the eye refractive power measurement means in conjunction with the measurement start signal. And a light amount adjusting unit that adjusts the light amount of the projected light beam so that the output of the light receiving unit becomes a predetermined level set for eye refractive power measurement during measurement by the eye refractive power measuring unit. The image recording means further records a transillumination image picked up by the image pickup means in synchronization with an increase in light quantity by the light quantity adjustment means, and the image reproduction means further comprises a transillumination image reproduction switch. And when the operation signal is output from the transillumination image reproduction switch, the captured transillumination image is reproduced on the display .

  According to the present invention, an appropriate transillumination image linked with measurement can be obtained. In addition, the recorded image of the transillumination image can be confirmed after the measurement is completed, and the factors relating to the measurement error and the reliability of the measurement result can be easily confirmed.

  The best mode for carrying out the invention will be described below with reference to the drawings. FIG. 1 is a schematic external view of an eye refractive power measuring apparatus according to the present invention. 1 is a base, and 2 is a face fixing unit for fixing the face of the eye to be examined. Reference numeral 3 denotes a main body, and 4 denotes a measuring unit in which an optical system, which will be described later, is housed. The main body 3 slides back and forth on the horizontal plane of the base 1 by operation of the joystick 5, and By rotating 5a, the measuring unit 4 moves up and down with respect to the main body 3. A measurement start switch 6 is provided on the top of the joystick 5. Reference numeral 7 denotes a display for displaying an anterior segment image of the eye to be examined and various kinds of information. Reference numeral 8 denotes a switch unit.

  FIG. 2 is a schematic configuration diagram of the optical system. Reference numeral 11 denotes two measurement light sources having wavelengths in the infrared region, which are arranged so as to be rotatable about the optical axis. Reference numeral 12 denotes a condenser lens. Reference numeral 13 denotes a measurement target plate having a measurement index (spot opening) and movable so as to be arranged at a position conjugate with the fundus of the eye E to be examined. 14 is a projection lens, and 15a and 15b are beam splitters. Reference numeral 17 is an objective lens, 31 is a beam splitter, 16 is a mirror, 18 and 19 are relay lenses, 20 is a strip-shaped corneal reflection removing mask arranged at a position conjugate with the cornea of the eye E, and 21 is a target plate 13. The moving lens 22 is an imaging lens. Reference numeral 23 denotes a measurement light-receiving element, and the light-receiving element 23 rotates around the optical axis in synchronization with the measurement light source 11 and the corneal reflection removal mask 20.

  Reference numeral 30 denotes a fixation target presenting optical system. Reference numeral 32 denotes a first relay lens that can move on the optical axis, and the amount of movement is proportional to the spherical refractive power of the eye to be examined. Reference numeral 33 denotes a second relay lens, 34 denotes a fixation target disposed at the focal position of the second relay lens 33, 35 denotes a condenser lens, and 36 denotes an illumination lamp. The first relay lens 32 optically changes the presentation position of the fixation target 34 by moving on the optical axis. At the time of measuring the eye refractive power, the first relay lens 32 is moved to perform adjustment removal of the eye to be examined.

  Reference numeral 40 denotes an index projection optical system that projects an alignment index from the visual axis direction. Reference numeral 41 denotes a point light source that emits infrared light. The light beam emitted from the point light source 41 is reflected by the beam splitter 42, then becomes a parallel light beam by the objective lens 17 via the beam splitter 31, is reflected by the beam splitter 15 a, and is reflected in front of the eye E along the measurement optical axis. Project an indicator from

  Reference numeral 45 denotes an observation optical system. The anterior ocular segment image illuminated by the anterior ocular illumination light source 44 and the alignment index image projected by the index projection optical system 40 are reflected by the beam splitter 15 b and then imaged through the objective lens 46 and the mirror 47. The image is picked up by a CCD camera 48 as an element. The observation optical system 45 can also serve as an alignment index detection optical system that detects an alignment index projected onto the eye E.

  FIG. 3 is a schematic configuration diagram of a control system of the apparatus. The video signal from the CCD camera 48 is input to the image control unit 51 and output to the display 7. The image control unit 51 includes an image memory 51 a for recording (storing) video captured by the CCD camera 48. A system control unit 50 includes a light receiving element 23, a switch unit 8, a measurement light source 11, a motor 56 for driving the measurement light source 11 and the light receiving element 23, a motor 57 for moving the measurement target plate 13 and the lens 21, 1 is connected to a motor 58 that moves the relay lens 32, a potentiometer 60 that detects the movement position of the target plate 13, a drive unit 61 of the measurement light source 11, a memory 62 that stores measurement data, and the like. The system control unit 50 controls these components and calculates the eye refractive power based on detection signals from the light receiving element 23 and the potentiometer 60.

  At the time of measurement, while observing the anterior segment image of the eye to be examined displayed on the display 7, the joystick 5 and the reticle image and the reticle image by the index projection optical system 40 have a predetermined relationship. Alignment is performed by operating the rotary knob 5a. When the alignment is completed, the measurement start switch 6 is pressed to perform measurement. For starting measurement, an optical system that projects an alignment index in the working distance direction is added, and the system control unit 50 determines whether or not the alignment index image detected by the CCD camera 48 is within a predetermined allowable range. It is also possible to employ a configuration in which the system control unit 50 automatically issues a trigger signal for starting measurement.

When the trigger signal of the measurement start switch 6 is input, the system control unit 50 first drives the drive unit 61 to turn on the measurement light source 11, and as shown in FIG. Is temporarily increased to the light amount I ₀ required for the operation. This transillumination image light amount level I ₀ is a light amount increased from the normal light amount I ₁ for eye refractive power measurement. In addition, the image control unit 51 records the image of the anterior segment of the subject's eye captured by the CCD camera 48 in the image memory 51a in conjunction with the trigger signal for starting measurement. The time required to temporarily increase the light amount of the projected light beam to the light amount for viewing image is the time required for imaging at least one screen by the CCD camera 48. The imaging of one screen by the CCD camera 48 and the time for increasing the light amount I ₀ are synchronized.

The measurement light emitted from the measurement light source 11 reaches the fundus of the eye to be examined through the condenser lens 12 to the beam splitter 15b. The reflected light from the fundus is reflected by the beam splitter 15 a, passes through the objective lens 17 and the beam splitter 31, is reflected again by the mirror 16, passes through the relay lenses 18, 19 and the lens 21, and is received by the imaging lens 22. Incident on the element 23. The system control unit 50 reduces the light amount of the projection light beam that has been temporarily increased, and adjusts the light amount so that the signal level output from the light receiving element 23 becomes a predetermined reference level (see FIG. 4). As a result, a light beam with a light amount I ₁ suitable for eye refraction measurement is projected onto the fundus of the eye to be examined, and the influence on measurement due to insufficient light amount or too much light amount is eliminated. In addition, since the luminous flux with an increased amount of light for taking a transillumination image is not projected onto the fundus for a long time, it is possible to prevent a burden on the eye to be examined.

  After the signal level output from the light receiving element 23 reaches a predetermined reference level, the system control unit 50 performs eye refractive power measurement based on the output of the light receiving element 23. First, the system control unit 50 drives the motor 57 based on the output signal from the light receiving element 23 to move the target plate 13 together with the moving lens 21 to a position conjugate with the fundus of the eye E to be examined. Next, after the first relay lens 32 is moved by driving the motor 58 to place the fixation target 34 and the fundus of the eye E in a conjugate position, a further appropriate diopter is used to remove the adjustment of the eye to be examined. The first relay lens 32 is moved so that only fog is applied. In a state where the eye E is clouded, the measurement light source 11, the corneal reflection removal mask 20, and the light receiving element 23 are rotated 180 degrees around the optical axis. During rotation, the target plate 13 and the moving lens 21 are moved by a signal from the light receiving element 23, and the movement amount is detected by the potentiometer 60. The refractive power in each meridian direction is obtained from the amount of movement of the target plate 13. The system control unit 50 obtains measured values of S (spherical refractive power), C (astigmatic power), and A (astigmatic axis angle) of the eye to be examined by performing a predetermined process on the refractive power. The measurement result is stored in the memory 62. If the measurement start switch 6 is kept pressed, measurement is continuously performed in a cloudy state.

  Even during this measurement, the system control unit 50 causes the image memory 51a to continuously record the images of the anterior eye segment imaged by the CCD camera 48. When the measurement is completed, the measurement light source 11 is turned off (or dimmed), and the image recording to the image memory 51a is ended.

When the image reproduction switch provided in the switch unit 8 is operated after the measurement is completed, the image recorded in the image memory 51a is reproduced as a still image on the display 7. FIG. 5 shows a display example when the illumination image is reproduced. Reflected light from the fundus illuminates the lens from behind. If the lens is turbid due to cataracts, the transmittance of the reflected light decreases, and the turbid portion Ca is projected as a dark shadow. On the other hand, the reflected light can pass through the part where the lens is not clouded, and the amount of light flux projected onto the fundus is increased for the transillumination when the transillumination image is captured. Projected. For this reason, it is possible to more clearly grasp a turbid portion that has been overlooked due to poor contrast at the light amount level necessary for eye refraction measurement. Here, also for the amount of light I ₀ required retroillumination observation, similarly to the light amount adjustment at the time of measurement, the bright part of the pupil region Pu in transillumination image captured by the CCD camera 48 (or average luminance) of a predetermined You may adjust so that it may become a luminance level. In this way, a transillumination image can always be observed with the same brightness standard, regardless of the presence or absence of cataracts and the level of reflectance at the fundus.

  In addition, since the image being measured is continuously recorded in the image memory 51a, the state of the anterior segment image being measured can be confirmed. When a frame advance switch provided in the switch unit 8 is pressed, the image reproduced and displayed on the display 7 is switched to the image being measured. The Pu in the pupil region in the anterior segment image being measured is observed with a dark luminance if there is no abnormality in the intermediate translucent body. If it is assumed that the imaging time of one screen by the CCD camera 48 is 30 ms and it takes 0.3 seconds (300 ms) from the start of measurement to the end of measurement, images for 10 screens are recorded in the image memory 62. . A still image of the anterior eye portion reproduced and displayed on the display 7 is reproduced for each screen by the frame advance switch. In addition, by pressing the slow playback switch, the images recorded in the image memory 62 can be continuously played back slowly every predetermined time.

  Here, when the measurement result of the eye refractive power becomes an error, the cause of the measurement error can be easily confirmed by observing the transillumination image at the time of measurement and the image of the anterior segment of the eye during measurement in this way. can do. That is, as shown in FIG. 5, the degree of the influence of the turbidity due to cataract can be confirmed by observing the transillumination image. On the other hand, by observing the image being measured, the pupil diameter, the degree of eccentricity of the pupil, the presence or absence of blinking, misalignment, and the like can be confirmed. Moreover, in the insertion eye of the intraocular lens, the reflection state of the intraocular lens can also be confirmed. FIG. 6 is an example of an image being measured when the intraocular lens is tilted, and the measurement light is reflected on the surface of the intraocular lens, so that the image being measured has a bright luminance in Pu in the pupil region. Ir appears.

  In this way, it is possible to take measures against measurement errors by reproducing the recorded anterior segment image. In addition, since not only the transillumination image but also the anterior segment image being measured can be comprehensively observed, the cause of the measurement error can be easily identified. When measurement errors frequently occur, the burden on the subject can be reduced by taking countermeasures. By explaining the eye state during measurement to the subject and explaining it, it becomes easier to obtain the subject's understanding.

  Note that the confirmation of the recorded anterior ocular segment image is not limited to the case where there is a measurement error, but can also be used to confirm the reliability of the measurement result when the measurement result is obtained. When measurement values vary in continuous measurement, it is also possible to confirm how many times measurement values are reliable.

  In the case of re-measurement, if the cause of measurement error and the decrease in the reliability of the measurement result is due to turbidity, the measurement may be performed with alignment so that the measurement light beam is introduced while avoiding that portion. If the eccentricity of the pupil is a factor, it may be measured by aligning with the center of the pupil.

  The anterior segment image recorded in the image memory 62 is used to measure the pupil diameter and corneal diameter being measured, and the results are displayed on the display 7 or recorded in another recording device together with the transillumination image. It can also be saved. Detection and measurement of the pupil diameter and corneal diameter are performed by the image control unit 51.

  In the above description, the transillumination image is recorded and recorded in conjunction with the start of measurement before the measurement. However, this may be performed after the measurement. In this case, the amount of the projection light beam used for the illumination image observation is increased in accordance with the recording timing. In addition, a light source provided separately from the measurement light source 11 may be used as the projected light beam for obtaining a transillumination image. Further, when photographing a transillumination image, in order to make it easier to confirm the transillumination image, the anterior segment illumination light source 44 is turned off or dimmed in synchronization with an increase in the amount of the projection light beam used for the transillumination image observation. May be.

1 is a schematic external view of an eye refractive power measuring apparatus according to the present invention. It is a schematic block diagram of an optical system. It is a schematic block diagram of the control system of an apparatus. It is a figure explaining adjustment of the light quantity of a projection light beam. It is an example of a display when a transillumination image is reproduced. It is an example of an image under measurement when the intraocular lens is tilted.

Explanation of symbols

6 Measurement start switch 7 Display 8 Switch unit 11 Measurement light source 13 Measurement target plate 23 Light receiving element 45 Observation optical system 48 CCD camera 50 System control unit 51 Image control unit 51a Image memory 60 Potentiometer

Claims (2)

A light beam projecting unit for projecting a light beam onto the fundus of the eye to be examined; a light receiving unit for receiving a reflected light beam from the fundus; an eye refractive power measuring unit for obtaining an eye refractive power based on an output of the light receiving unit; and a reflected light beam from the fundus And an imaging means for imaging an anterior ocular segment image including a pupil region illuminated by the anterior ocular segment imaged by the imaging means during eye refractive power measurement by the ocular refractive power measuring means An image recording means for continuously recording images and an image reproduction switch. When an operation signal is output from the image reproduction switch, the images continuously recorded by the image recording means are displayed on the display. An eye refractive power measuring apparatus comprising: an image reproducing means for reproducing each screen . 2. The eye refractive power measuring apparatus according to claim 1 , wherein the light quantity of the projected light beam is temporarily increased to the light quantity for transillumination imaging before or after measurement by the eye refractive power measuring means in conjunction with a measurement start signal. A light amount adjusting unit that adjusts the light amount of the projected light beam so that the output of the light receiving unit becomes a predetermined level set for measuring the eye refractive power during the measurement by the eye refractive power measuring unit,
The image recording unit further records a transillumination image captured by the imaging unit in synchronization with an increase in the amount of light by the light amount adjusting unit,
The image reproduction means further includes a transillumination image reproduction switch, and when the operation signal is output from the transillumination image reproduction switch, the imaged reproduction image is reproduced on the display. Eye refractive power measurement device.

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