JP2013022122A - Method for measuring ophthalmic characteristic and ophthalmic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmic apparatus smoothly performing a series of measurements from a measurement of a shape of the cornea to a measurement of refractive power of the eye even when the vertex of the cornea of a subject's eye and the center of the pupil are decentered.SOLUTION: This ophthalmic apparatus performs steps for: aligning an optical axis of an apparatus body 12 to the vertex P of the cornea C of the subject's eye E; determining that the alignment of the apparatus body 12 to the vertex P of the cornea C has finished and projecting a ring-shaped index for cornea shape measurement, onto the cornea; receiving an image of the ring-shaped index for the cornea shape measurement and calculating the shape of the cornea; scanning each image radially from a central portion of the image of the ring-shaped index for the cornea shape measurement to acquire respective coordinates of the edge Pdx of the pupil Pd of the subject's eye E and estimating the center of the pupil of the subject's eye from the respective coordinates; calculating a deviation of the acquired estimated center PdO' of the pupil from the center portion of the ring-shaped index for the cornea shape measurement; and, when the obtained deviation is a prescribed value or more, driving the apparatus body such that the optical axis of the apparatus matches the estimated center PdO'.

Description

  The present invention relates to an ophthalmic characteristic measurement method and an ophthalmologic apparatus capable of measuring a corneal shape and an eye refractive power.

  2. Description of the Related Art Conventionally, an ophthalmologic apparatus capable of measuring a corneal shape as an eye characteristic and measuring an eye refractive power is known (for example, see Patent Document 1). According to this, the measurement of the corneal shape and the measurement of the eye refractive power can be performed with one instrument.

  Moreover, the technique which illuminates eyes and estimates the center of a pupil is also known (refer patent document 2, patent document 3, patent document 4).

JP 2009-189624 A JP 2003-144388 A Japanese Patent Laid-Open No. 6-142054 JP-A-6-148508

  In an ophthalmic apparatus that performs this type of corneal shape measurement and eye refractive power measurement with a single instrument, for example, as shown in FIG. The main optical axis O1 is aligned, and the shape of the cornea C is measured by projecting the corneal shape measurement ring-shaped index Q1 onto the cornea C as shown in FIG.

  Next, as shown in FIG. 3, the eye refractive power of the eye E is measured by projecting an eye refractive power measuring ring index Q2 onto the fundus oculi Ef. Details of the measurement are described in, for example, Japanese Patent No. 2937373.

However, as shown in FIG. 4, the patient has a person in which the apex P of the cornea C of the eye E and the center PdO of the pupil Pd of the eye E are misaligned.
For this type of patient, as shown in FIG. 4, alignment is performed so that the main optical axis O1 of the apparatus body 1 is aligned with the apex P of the cornea C of the eye E, and a corneal shape measurement ring index Q1 is projected. Then, after measuring the shape of the cornea C, as shown in FIG. 5, when the ring index Q2 for measuring eye refractive power is projected, a part of the ring index Q2 for measuring eye refractive power is obtained. As indicated by the oblique lines, it may be blocked by the iris Eh, and a part of the eye refractive power measurement ring index Q2 may not be projected onto the fundus oculi Ef.
Note that the symbol Pdx indicates the edge of the pupil.

Therefore, in such a case, the examiner unavoidably measures the eye refractive power by manually aligning the main optical axis O1 of the apparatus main body 1 with the center PdO of the pupil Pd.
For this reason, in the case of a patient in which the apex P of the cornea C of the eye E and the pupil center PdO of the pupil Pd are shifted, a series of measurements from the measurement of the corneal shape to the measurement of the eye refractive power should be performed smoothly. There is inconvenience that we cannot do.

  The present invention has been made in view of the above circumstances, and the object of the present invention is that even when the apex P of the cornea C of the eye E and the center PdO of the pupil Pd are eccentric, the cornea An object of the present invention is to provide an ophthalmologic apparatus capable of smoothly performing a series of measurements from measurement of shape to measurement of eye refractive power.

  The ophthalmic apparatus of the present invention includes a step of aligning the optical axis of the apparatus main body with the apex of the cornea of the eye to be examined, and determining that the alignment of the apparatus main body with respect to the apex of the cornea is completed, and projecting a ring-shaped index for measuring the cornea shape onto the cornea A step of receiving an image of a corneal shape measurement ring-shaped index and calculating a corneal shape, and scanning each image in a radial direction from a central portion of the image of the corneal shape measurement ring-shaped index to scan a pupil of the eye to be examined. Obtaining each coordinate of the edge and estimating the center of the pupil of the eye to be examined from each coordinate, calculating the deviation between the obtained estimated center of the pupil and the center portion of the image of the ring-shaped index for corneal shape measurement, The step of driving the apparatus main body is executed so that the optical axis of the apparatus main body coincides with the estimated center when the deviation is not less than a predetermined value.

  According to the present invention, even when the apex of the cornea of the eye to be examined and the pupil center of the pupil are decentered, a series of measurements from the measurement of the corneal shape to the measurement of the eye refractive power can be performed smoothly. .

FIG. 1 is a schematic diagram illustrating an example of alignment of the apparatus main body of the ophthalmologic apparatus with respect to the eye to be examined. FIG. 2 is a diagram showing an anterior segment image of the eye to be examined on which a corneal shape measurement ring-shaped index is projected. FIG. 3 is a diagram illustrating a fundus image of the eye to be examined on which a ring-shaped index for measuring eye refractive power is projected. FIG. 4 is a diagram showing an anterior segment image in which the apparatus main body is aligned with the apex of the cornea of the eye to be examined in which the pupil center of the pupil and the apex of the cornea are decentered and the corneal shape measurement ring index is projected. FIG. 5 is a diagram showing an anterior segment image in which the apparatus main body is aligned with the apex of the cornea of the eye to be examined in which the pupil center and the apex of the cornea are decentered, and a ring-shaped index for measuring eye refractive power is projected. FIG. 6 is a diagram showing an example of the appearance of the ophthalmologic apparatus according to the embodiment of the present invention. FIG. 7 is a view showing an example of a drive mechanism arranged in the base shown in FIG. FIG. 8 is a schematic diagram of the ophthalmologic apparatus shown in FIG. FIG. 9 is a diagram illustrating an example of an optical system of the cornea shape / eye refractive power measurement unit illustrated in FIG. 8. FIG. 10 is a block diagram illustrating an example of the signal processing unit illustrated in FIG. 9. FIG. 11 is a flowchart for explaining the operation of the ophthalmologic apparatus according to the embodiment of the present invention. FIG. 12 is an explanatory diagram showing an example of detection of the edge of the pupil by image scanning in the radial direction with the vertex of the cornea as the origin. FIG. 13 is an explanatory diagram showing an example of the luminance distribution in the radial direction obtained by the image scanning in the radial direction. FIG. 14 is an explanatory diagram showing an example of image processing for obtaining the edge of the pupil.

  FIG. 6 is an external view of an ophthalmologic apparatus according to an embodiment of the present invention. In FIG. 6, reference numeral 10 denotes an ophthalmologic apparatus. The ophthalmic apparatus 10 includes a base 11, a measurement head 12 as an apparatus main body, a liquid crystal display 13 as a monitor unit, a control lever 14, a measurement switch 15, a chin rest 16, and a forehead pad 17. The liquid crystal display 13 is provided on the examiner side, and the chin rest 16 and the forehead pad 17 are provided on the subject (patient) side.

The subject is inspected with the chin placed on the chin rest 16 and the forehead 17 abutting the forehead.
The measuring head 12 is configured to be movable with respect to the base 11 in the vertical direction (Y direction), the front-rear direction (Z direction), and the left-right direction (X direction). The measurement head 12 is driven by a drive mechanism described later.

The liquid crystal display 13 displays an image such as an anterior segment image of the eye to be examined. In addition, inspection results and the like are also displayed. The control lever 14 is used when driving the measuring head 12 manually. In addition, the liquid crystal display 13 may be configured to have a touch panel type and the control lever 14 may not be provided.
The drive mechanism is provided in the base 11. The drive mechanism has a bottom plate 20 as shown in FIG. The bottom plate 20 is fixed to the base 11, and the support portion 21 is provided on the bottom plate 20.

  The support portion 21 has a hollow portion, and a column 22 is disposed in the hollow portion 21. A drive motor (drive unit) 23 is fixed to the bottom plate 20. The drive motor 23 drives the support column 22 in the vertical direction via a drive force transmission mechanism (not shown). A stage 24 is fixed to the column 22. The stage 24 is moved up and down together with the column 22.

  The stage 24 is provided with a pair of longitudinal rails 25. A stage 26 is provided on the front-rear rail 25. The stage 24 is provided with a drive motor (drive unit) 27. The drive motor 27 transmits a driving force to the stage 26 via a driving force transmission mechanism (not shown), whereby the stage 26 is driven in the front-rear direction (Z direction) with respect to the subject.

  The stage 26 is provided with a detection sensor SO for detecting the instrument center position O in the left-right direction of the stage 29 with respect to the base 11. The detection sensor SO is composed of, for example, a photocoupler. The detection sensor SO plays a role of setting the apparatus main body at the initial position.

  A horizontal rail 28 is provided on the stage 26. A stage 29 is provided on the left-right rail 28. The stage 26 is provided with a drive motor (drive unit) 30. The drive motor 30 transmits driving force to the stage 29 via a driving force transmission mechanism (not shown). Thereby, the stage 29 is driven in the left-right direction with respect to the subject.

  As schematically shown in FIG. 8, the measurement head 12 is provided with a corneal shape / eye refractive power measurement unit 12A and an intraocular pressure measurement unit 12B. The corneal shape / eye refractive power measuring unit 12A is used when measuring the shape of the cornea C of the eye E and the eye refractive power (spherical power, astigmatism power, astigmatic axis angle, etc.) of the eye E. The intraocular pressure measurement unit 12B is used when measuring the intraocular pressure of the eye E. The corneal shape / ocular refractive power measurement unit 12A is provided, for example, above the intraocular pressure measurement unit 12B.

(Structure of corneal shape / eye refractive power measuring unit 12A)
The corneal shape / eye refractive power measurement unit 12A includes the optical system shown in FIG. The optical system is compactly arranged in a case (not shown). Note that the configuration of the optical system of the intraocular pressure measurement unit 12B is not directly related to the present invention, and thus the description thereof is omitted.

  In FIG. 9, reference numeral 41 denotes a fixation target projection optical system that projects a visual target onto the fundus oculi Ef to fixate and cloud the eye E, 42 denotes an observation optical system that observes the anterior segment Er of the eye E, 43 is a scale projection optical system for projecting an aiming scale onto a CCD 44 as a two-dimensional solid-state imaging device, and 45 is a pattern light beam as a ring index for eye refractive power measurement for measuring the eye refractive power of the eye E to be examined. A ring-shaped index projection optical system for measuring eye refractive power projected onto the eye, 46 is a light receiving optical system for causing the CCD 44 to receive a ring-shaped index image for measuring eye refractive power reflected from the fundus oculi Ef, and 47 is in a direction perpendicular to the optical axis. An alignment light projection system 49 projects an indicator light for detecting the alignment state toward the eye to be examined, and 49 is a signal processing unit. This optical system has a working distance detection optical system (not shown) for detecting a working distance WO between the eye E and the apparatus main body (measuring head 12).

  The eye refractive power measurement ring index projection optical system 45 and the light receiving optical system 46 together with the observation optical system 42 and a corneal shape measurement ring index projection light source, which will be described later, constitute a corneal shape / eye refractive power measurement optical system. ing.

  The fixation target projection optical system 41 includes a fixation target light source 51, a collimator lens 52, an indicator plate 53, a relay lens 54, a mirror 55, a relay lens 56, a dichroic mirror 57, a dichroic mirror 58, and an objective lens 59.

  The visible light emitted from the fixation target light source 51 is converted into a parallel light beam by the collimator lens 52 and then passes through the indicator plate 53. The index plate 53 is provided with a target for fixing the eye E to be inspected and fogged.

  The target light flux passes through the relay lens 54 and is reflected by the mirror 55, is guided to the dichroic mirror 57 through the relay lens 56, is reflected by the mirror 55, and is guided to the main optical axis O1 of the optical system, and the dichroic mirror. After passing through 58, it is guided to the eye E through the objective lens 59.

  The fixation target light source 51, the collimator lens 52, and the index plate 53 constitute an index unit U10. The index unit U10 fixes the target eye E with a driving motor PM1 to fixate and cloud the eye E. It is possible to move integrally along the optical axis O2 of 41.

  The observation optical system 42 includes an illumination light source (not shown), an objective lens 59, a dichroic mirror 58, a relay lens 62 having a diaphragm 61 ', a mirror 63, a relay lens 64, a dichroic mirror 65, an imaging lens 66, and a two-dimensional solid-state imaging device. As a CCD 44.

  The illumination light beam emitted from the illumination light source illuminates the anterior segment Er of the eye E to be examined. The illumination light beam reflected by the anterior segment Er is reflected by the dichroic mirror 58 through the objective lens 59, passes through the stop 61 ′ of the relay lens 62, is reflected by the mirror 63, and then is relayed by the relay lens 64 and dichroic mirror 65. And is guided to the CCD 44 by the imaging lens 66, and an anterior ocular segment image Er ′ is formed on the imaging surface of the CCD 44.

  The scale projection optical system 43 includes a projection light source 71, a collimator lens 72 having an aiming scale, a relay lens 73, a dichroic mirror 58, a relay lens 62 having a diaphragm 61 ′, a mirror 63, a relay lens 64, a dichroic mirror 65, and an imaging lens. 66 and CCD 44.

  The light beam emitted from the projection light source 71 is converted into a parallel light beam when passing through the collimator lens 72, and is reflected by the mirror 63 through the relay lens 73, the dichroic mirror 58, and the relay lens 62 having a stop 61 '. 64, the image is formed on the CCD 44 by the imaging lens 66 through the dichroic mirror 65.

  The video signal from the CCD 44 is input to the liquid crystal display 13 via the signal processing unit 49, and the anterior segment image Er 'is displayed on the liquid crystal display 13 and alignment marks ALM1 and ALM2 are displayed. Note that the illumination light source and the projection light source 71 are turned off when the refractive power is measured after the alignment is completed.

  An eye refractive power measurement ring-shaped index projection optical system 45 includes an eye refractive power measurement light source 81, a collimator lens 82, a conical prism 83, a ring index plate 84, a relay lens 85, a mirror 86, a relay lens 87, and a perforated prism 88. A dichroic mirror 57, a dichroic mirror 58, and an objective lens 59.

  The eye refractive power measurement light source 81 and the ring indicator plate 84 are optically conjugate, and the ring indicator plate 84 and the fundus oculi Ef of the eye E are disposed at optically conjugate positions. The eye refractive power measurement light source 81, the collimator lens 82, the conical prism 83, and the ring indicator plate 84 constitute an indicator unit U40, and this indicator unit U40 is driven back and forth along the optical axis O3 by the drive motor PM2. The

  The light beam emitted from the eye refractive power measurement light source 81 is converted into a parallel light beam by the collimator lens 82, passes through the conical prism 83, and is guided to the ring index plate 84. The luminous flux passes through the ring-shaped pattern portion formed on the ring index plate 84 to become a pattern luminous flux as a ring-shaped index for measuring eye refractive power.

  After passing through the relay lens 85, this pattern light beam is reflected by the mirror 86, passes through the relay lens 87, is reflected by the reflecting surface of the perforated prism 88, and is guided to the dichroic mirror 57 along the main optical axis Ol. After passing through the dichroic mirrors 57 and 58, an image is formed on the fundus oculi Ef by the objective lens 59.

  The light receiving optical system 46 includes an objective lens 59, dichroic mirrors 58 and 57, a hole 88a of a perforated prism 88, a relay lens 91, a mirror 92, a relay lens 93, a mirror 94, a focusing lens 95, a mirror 96, and a dichroic mirror 65. And an imaging lens 66 and a CCD 44. The focusing lens 95 is movable along the optical axis O4 in conjunction with the index unit U40.

  The pattern reflected light beam guided to the fundus oculi Ef by the ring index projection optical system 45 for measuring eye refractive power and reflected by the fundus oculi Ef is collected by the objective lens 59, passes through the dichroic mirrors 58 and 57, and has holes. The light is guided to the hole 88a of the prism 88 and passes through the hole 88a.

  The pattern reflected light beam that has passed through the hole 88a is transmitted through the relay lens 91, reflected by the mirror 92, transmitted through the relay lens 93, reflected by the mirror 94, transmitted through the focusing lens 95, and transmitted through the mirror 96, dichroic. The light is reflected by the mirror 65 and guided to the CCD 44 by the imaging lens 66. Thereby, an image of the ring-shaped index Q2 for measuring eye refractive power is formed on the CCD 44.

  The alignment light projection system 47 includes an LED 101, a pinhole 102, a collimator lens 103, and a half mirror 104, and automatically projects the apparatus main body on the eye E by projecting an alignment index light beam toward the cornea C of the eye E. Have the function of aligning.

  The alignment index light beam projected as parallel light toward the eye E is reflected by the cornea C of the eye E, and a bright spot image T as an alignment index image is projected on the CCD 44 by the observation optical system 42. When the bright spot image T is positioned within the alignment mark ALM1, it is determined that the alignment is complete.

  In the ring-shaped index projection optical system 45 for measuring eye refractive power, a ring-shaped index for measuring a corneal shape is projected on the front side of the objective lens 59 concentrically with respect to the main optical axis O1 from a finite distance from a corneal shape measuring ring-shaped index. Projection light sources 61A, 61B, and 61C are provided.

These three corneal shape measurement ring-shaped index projection light sources 61A, 61B, 61C are projected onto the cornea C of the eye E to form the corneal shape measurement ring-shaped index Q1.
The light beam forming the corneal shape measurement ring-shaped index Q1 is reflected by the cornea C of the eye E and is imaged on the CCD 44 by the observation optical system 42. The signal processing unit 49 performs signal processing on the output from the CCD 44 to display images 61A ′, 61B ′, 61C ′ (Q1) of the corneal shape measurement ring-shaped index on the liquid crystal display 13.

  As shown in FIG. 10, the signal processing unit 49 includes a control calculation unit 110, an A / D conversion unit 112, a frame memory 113, and a digital / analog conversion unit 114. The control calculation unit 110 includes a CPU and a known minimum value filter processing unit 115. The minimum value filter processing unit 115 has a function of enhancing the contrast of dark pixels in order to detect the edge Pdx of the pupil Pd. A program for executing the flowchart shown in FIG. 11 is incorporated in the CPU.

  The control calculation unit 110 also drives and controls the pulse motors PM1 and PM2 and drives and controls the drive motors 23, 27, and 30. As a result, the apparatus main body (measurement head 12) is driven in the X, Y, and Z directions. In addition, the control calculation unit 110 is connected to a driver (not shown) in order to control lighting of the various light sources 51, 61A to 61C, 71, 81, and the LED 101.

  The control calculation unit 110 executes the measurement of the corneal shape and the measurement of the eye refractive power. Note that the calculation results and the like by the control calculation unit 110 are stored in a RAM (not shown).

Further, the control calculation unit 110 calculates the light receiving position of the bright spot image T received by the CCD 44, and based on the calculation result, the amount of deviation between the main optical axis O1 and the apex P of the cornea C of the eye E to be examined. Δxy, the amount of deviation Δz from the appropriate working distance WO is calculated.
Since the left-right direction instrument center O is known in advance, the position coordinates of the bright spot image T and the main optical axis O1 can be obtained by calculation with the left-right direction instrument center O as the origin.

  In addition, when the deviation amounts Δxy and Δz are equal to or less than the threshold values Δxy0 and Δz0 (when the bright spot image T is positioned on the alignment mark ALM1), the control calculation unit 110 causes the corneal shape measurement ring index projection light source 61A. A drive signal for emitting ~ 61C is output. The threshold values Δxy0 and Δz0 are stored in a RAM (not shown) of the signal processing unit 49. That is, the control calculation unit 110 has a function of automatically aligning the apparatus main body (measurement head 12) with respect to the eye E.

  Further, the control calculation unit 110 outputs a drive signal for causing the eye refractive power measurement light source 81 to emit light when an estimated center PdO ′, which will be described later, of the pupil Pd coincides with a main optical axis O1 of the apparatus main body. That is, the control calculation unit 110 also has a function of automatically aligning the apparatus main body (measurement head 12) with respect to the estimated center PdO ′.

Hereinafter, embodiments of the present invention will be described in detail with reference to the flowchart shown in FIG.
When the power switch is turned on (S1) and an illumination light source (not shown) is turned on, an anterior segment image Er ′ is displayed on the screen of the liquid crystal display 13 as shown in FIG.

  Next, the examiner manually operates the control lever 14 so that the pupil Pd of the eye E is positioned at the alignment mark ALM2 displayed on the screen of the liquid crystal display 13, and moves the apparatus main body back and forth, left and right. Approximate alignment of the device body with respect to eye E is performed (S.2).

  When this rough alignment is completed, the bright spot image T is displayed on the screen of the liquid crystal display 13. Thereafter, alignment detection based on the alignment light projection system 47 and the working distance detection optical system (not shown) is started.

  Thereby, the apparatus main body (measurement head 12) is driven in the X, Y, and Z directions, and automatic alignment adjustment is started. In other words, the apparatus main body (measuring head 12) is driven and controlled in the X, Y, and Z directions so that the shift amounts Δxy and Δz with respect to the eye E are equal to or less than Δxy0 and Δz0, respectively. Thus, when the bright spot image (alignment index image) T is positioned within the alignment mark ALM1, the automatic alignment with respect to the apex of the cornea C of the eye E is completed (S.3, S.4).

When this automatic alignment is completed, the corneal shape measurement ring-shaped index light sources 61A to 61C are turned on, and the corneal shape measurement ring-shaped index light Q1 is projected onto the cornea C (S.5).
The signal processing unit 49 measures the shape of the cornea C based on the images 61A ′ to 61C ′ of the corneal shape measurement ring-shaped index Q1 projected onto the cornea C (S.6). The details of the measurement of the corneal shape C are known and will not be described.

  Next, as shown in FIG. 12, the control calculation unit 110 scans the anterior segment image Er ′ in the radial direction from the central portion of the images 61A ′ to 61C ′ of the corneal shape measurement ring-shaped index Q1. Here, the control calculation unit 110 scans the anterior segment image Er ′ in the radial direction at equal angles in the circumferential direction of the luminescent spot image T with the luminescent spot image T as the central portion.

The control calculation unit 110 acquires the luminance of each pixel existing in the emission direction by setting the pixel existing in the bright spot image T as the origin O ′ (see FIG. 13) by scanning in the emission direction.
For example, the control calculation unit 110 obtains the luminance distribution shown in FIG. 13 by scanning in the radiation direction M.
In FIG. 13, the symbol T ′ is a luminance distribution corresponding to the bright spot image T, the symbol 61A ″ is a luminance distribution corresponding to the image 61A ′ of the corneal shape measuring ring index Q1, and the symbol 61B ″ is The luminance distribution corresponds to the image 61B ′ of the corneal shape measurement ring-shaped index Q1, and the reference numeral 61C ″ represents the luminance distribution corresponding to the image 61C ′ of the corneal shape measurement ring-shaped index Q1.

  Here, the reason why the peak value of the luminance distribution gradually decreases with increasing distance from the origin O ′ is that the amount of light received by the CCD 44 decreases with increasing distance from the apex P of the cornea C.

  In addition, the amount of luminance increases at the edge Pdx of the pupil Pd. The pupil Pd is almost completely dark, whereas the iris Eh exists outside the edge Pdx of the pupil Pd. This is because the amount of reflected light increases.

The control calculation unit 110 performs minimum value filtering on the luminance of each pixel acquired in this way. By this minimum value filter processing, dark portions of the image are darkened and emphasized, and as shown in FIG. 14, a locally high luminance distribution is removed.
Next, the control calculation unit 110 obtains the coordinates M (X, Y) of the edge Pdx of the pupil Pd based on the threshold value Vh.

  The control calculation unit 110 obtains at least three or more coordinates M (X, Y) in the circumferential direction of the bright spot image T to obtain a virtual circle, and determines the center of this virtual circle as the estimated center PdO of the pupil Pd. Get as' (S.7, S.8).

  Next, the control calculation unit 110 calculates the difference between the estimated center PdO ′ and the bright spot image T (the apex P of the cornea C). That is, the difference between the X-direction coordinate position of the estimated center PdO ′ and the X-direction coordinate position of the bright spot image T, and the difference between the Y-direction coordinate position of the estimated center PdO ′ and the Y-direction coordinate position of the bright spot image T are obtained ( S.9).

  Next, when the difference between the estimated center PdO ′ and the bright spot image T is greater than or equal to a predetermined value (S.10), the control calculation unit 110 causes the main optical axis O1 of the apparatus body to coincide with the estimated center PdO ′. The device body is driven (S.11). Next, it is determined whether or not the main optical axis O1 of the apparatus body coincides with the estimated center PdO '(S.12).

  Next, when the difference between the estimated center PdO ′ and the bright spot image T is smaller than a predetermined value, or when the main optical axis O1 of the apparatus body coincides with the estimated center PdO ′, the control calculation unit 110 detects the eye E The unit U40 is driven so that the ring index plate 84 is located at the fundus conjugate position when it is assumed that the eye is a normal eye, and the eye-power measuring ring index projection light source 81 emits light (S.13).

  As a result, the eye refractive power measurement ring index Q2 is projected onto the fundus oculi Ef of the eye E as shown in FIG. 3, and as a result, an image of the eye refractive power measurement ring index Q2 is formed on the CCD 44. The The video signal from the CCD 44 is converted into a digital value by the A / D converter 112 and stored in the frame memory 113. Based on the image data stored in the frame memory 113, the control calculation unit 110 extracts an image of the eye refractive power measurement ring index Q2 by binarization processing.

  As a result, the spherical power, the cylindrical power, and the shaft angle as the eye refractive power are measured by a known method. The configuration of the eye refractive power measurement unit is the same as that disclosed in JP-A-2002-253506, but is not limited to this configuration.

  As described above, the control calculation unit 110 according to the embodiment of the present invention includes the alignment execution processing step for aligning the optical axis of the measurement head (device main body) 12 with the apex P of the cornea C of the eye E, and the cornea C. Corneal shape ring-shaped index projection processing step for judging that the alignment of the apparatus main body with respect to the apex P of the corneal shape is completed and projecting the corneal shape measuring ring-shaped index Q1 on the cornea, and an image of the corneal shape measuring ring-shaped index Q1 The cornea shape calculation processing step for receiving the image and calculating the cornea shape, and scanning the image in the radial direction from the central portion of the image of the ring-shaped index Q1 for measuring the cornea shape to determine the coordinates of the edge Pdx of the pupil Pd of the eye E to be examined And an estimation processing step for estimating the center PdO of the pupil Pd of the eye E from each of the coordinates, and an estimated center PdO ′ of the pupil Pd obtained by this estimation step and the center of the image of the corneal shape measurement ring index Q1 Part And a drive processing step for driving the apparatus main body so that the optical axis of the apparatus main body 12 coincides with the estimated center PdO ′ when the deviation obtained in the deviation calculation step is equal to or greater than a predetermined value. And execute.

  Next, when the optical axis of the apparatus main body 12 after the drive processing of the apparatus main body 12 coincides with the estimated center PdO ′, the control calculation unit 110 displays the eye refractive power measurement ring index Q2 on the fundus oculi Ef of the eye E to be examined. By performing the projection, an eye refractive power calculation processing step for measuring the eye refractive power is executed.

 The central part of the image of the corneal shape measurement ring index Q1 is preferably the bright spot image T formed at the apex P of the cornea C, but the central part is determined from the shape of the image of the corneal shape measurement ring index Q1. Alternatively, the coordinates of the edge Pdx of the pupil Pd may be obtained by scanning the image in the radial direction with the central portion as the origin.

  According to this embodiment, the center of the pupil Pd is estimated during execution of the corneal shape calculation process, and the apparatus main body 12 is automatically driven toward the estimated center of the pupil Pd. Even if a series of measurements from the measurement of the corneal shape to the measurement of eye refractive power is performed on a patient whose apex P of the cornea C and the center PdO of the pupil Pd are eccentric, the measurement can be performed smoothly. it can.

12 ... Measuring head (device main body)
C ... Cornea
P ... apex
Pd ... Pupil
PdO '... Estimated center
Pdx ... the edge of the pupil

Claims (5)

An alignment execution processing step for aligning the optical axis of the apparatus main body with the apex of the cornea of the eye to be examined; and
A corneal shape ring-shaped index projection processing step of determining that alignment of the apparatus main body with respect to the corneal apex is completed and projecting a corneal shape measurement ring-shaped index on the cornea;
A corneal shape calculation processing step of receiving an image of the ring-shaped index for measuring the corneal shape and calculating a corneal shape;
Scanning each image in the radial direction from the central part of the image of the ring-shaped index for corneal shape measurement to obtain the coordinates of the edge of the pupil of the eye to be examined, and estimating the center of the pupil of the eye to be examined from the coordinates An estimation process step;
A deviation calculation processing step for calculating a deviation between the estimated center of the pupil obtained by the estimation step and the central portion of the image of the corneal shape measurement ring index;
An eye characteristic comprising: a drive processing step of driving the apparatus main body so that the optical axis of the apparatus main body coincides with the estimated center when the deviation obtained by the deviation calculating step is equal to or greater than a predetermined value. Measuring method.   When the optical axis of the apparatus main body after the driving process of the apparatus main body coincides with the estimated center, the eye refractive power is measured by projecting a ring-shaped index for measuring eye refractive power onto the fundus of the eye to be examined. A method for measuring eye characteristics, comprising: an eye refractive power calculation processing step.   The method for measuring ocular characteristics according to claim 2, wherein a central portion of the corneal shape measuring ring-shaped index is a bright spot image formed at the apex of the cornea.   An ophthalmologic apparatus comprising a processing circuit in which a processing program capable of executing the processing steps according to any one of claims 1 to 3 is incorporated.   The ophthalmologic apparatus according to claim 4, wherein the processing program includes a minimum value filter that emphasizes a dark portion of an image in order to detect an edge of the pupil.