Source: http://www.google.com/patents/US20070229760?ie=ISO-8859-1&dq=5,966,702
Timestamp: 2014-08-20 15:42:31
Document Index: 563061153

Matched Legal Cases: ['art. 2', 'art 90', 'art 11', 'art 21', 'art 4', 'art 601', 'art 40', 'art 601', 'art 11', 'art 601', 'art 40', 'art 11', 'art 604', 'art 600', 'art 700', 'art 50', 'art 21', 'art 21', 'art 21']

Patent US20070229760 - Ophthalmologic measuring apparatus - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA subject is placed in a more natural state or is encouraged to blink at specified intervals to obtain a measurement result under a fixed condition, and the judgment of the degree of dry eye is facilitated. A measurement part obtains, based on a reflected light flux from a subject eye, optical characteristic...http://www.google.com/patents/US20070229760?utm_source=gb-gplus-sharePatent US20070229760 - Ophthalmologic measuring apparatusAdvanced Patent SearchPublication numberUS20070229760 A1Publication typeApplicationApplication numberUS 11/723,624Publication dateOct 4, 2007Filing dateMar 21, 2007Priority dateMar 30, 2006Also published asUS7677728Publication number11723624, 723624, US 2007/0229760 A1, US 2007/229760 A1, US 20070229760 A1, US 20070229760A1, US 2007229760 A1, US 2007229760A1, US-A1-20070229760, US-A1-2007229760, US2007/0229760A1, US2007/229760A1, US20070229760 A1, US20070229760A1, US2007229760 A1, US2007229760A1InventorsYoko Hirohara, Toshifumi MihashiOriginal AssigneeKabushiki Kaisha TopconExport CitationBiBTeX, EndNote, RefManReferenced by (2), Classifications (4), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetOphthalmologic measuring apparatusUS 20070229760 A1Abstract A subject is placed in a more natural state or is encouraged to blink at specified intervals to obtain a measurement result under a fixed condition, and the judgment of the degree of dry eye is facilitated. A measurement part obtains, based on a reflected light flux from a subject eye, optical characteristic data of a two-dimensional vector form representing the time course of each optical characteristic of the subject eye in an blink interval from a certain blink to a next blink with respect to the first to the nth blink intervals. An analysis part one-dimensionally arranges each of the optical characteristic data with respect to the first to the nth blink intervals measured by the measurement part, and arranges the one-dimensional arrangement of the optical characteristic in a p-th blink interval at a p column to create a two-dimensional array, and performs a principal component analysis processing on the two-dimensional array.
an illuminating optical system including an illuminating light source to illuminate a subject eye; a light receiving optical system including a light receiving part to receive a reflected light flux from the subject eye illuminated with an illumination light flux of the illuminating optical system and to form a received light signal; a measurement part that obtains, based on the received light signal formed by the light receiving part, optical characteristic data of a two-dimensional matrix form to represent a time course of each optical characteristic of the subject eye in a blink interval from a blink to a next blink with respect to a first to an n-th (n is an integer of 2 or more) blink intervals; an analysis part that one-dimensionally arranges each of the optical characteristic data with respect to the first to the n-th blink intervals measured by the measurement part, arranges a one-dimensional array of the optical characteristic in a p-th (1≦p≦n) blink interval at a p-th column to create a two-dimensional matrix, and performs a principal component analysis processing on the two-dimensional matrix; and a display part to display a processing result of the analysis part. 2. The ophthalmologic measuring apparatus according to claim 1, wherein the optical characteristic data includes coefficients of Zernike polynomials.
the analysis part, with respect to principal components obtained by the principal component analysis processing, for each of the principal components of the two-dimensional matrix, converts the one-dimensional array at the p-th column into two-dimensional data to represent the time course of each optical characteristic, and arranges the first to the n-th optical characteristic data, reversely to a manner in which each of the optical characteristic data concerning the first to the n-th blink intervals measured by the measurement part is arranged one-dimensionally, to obtain a two-dimensional space representing a time change of each optical characteristic, and the display part displays a code map based on the obtained two-dimensional space. 5. The ophthalmologic measuring apparatus according to claim 1, wherein the display part displays, as a code map, typical gray codes or color codes of a normal, a light dry eye, an intermediate dry eye, and a serious dry eye, for judgment of a measured case, on a screen, or, the display part displays these gray scale codes or color codes on the screen by a simple operation.
wherein the measurement part measures the optical characteristic of the subject eye varying with elapsed time from an end of the blink of the subject. 7. The ophthalmologic measuring apparatus according to claim 1, further comprising a judgment part to detect a blink of a subject,
wherein when the judgment part detects the blink of the subject, the measurement part measures the optical characteristic of the subject eye varying with elapsed time from an end of the blink of the subject. 8. The ophthalmologic measuring apparatus according to claim 1, wherein
the illuminating optical system illuminates the subject eye with the illumination light flux forming substantially a point light source on an ocular fundus of the subject eye, or with the illumination light flux converging on the center of curvature of a cornea, the light receiving optical system includes plural light receiving parts that receive the reflected light flux from the ocular fundus of the subject eye illuminated with the illumination flux of the illuminating optical system and from a corneal surface, and form a first and a second received light signals, and the measurement part measures a wavefront aberration of the whole subject eye based on the reflected light flux from the ocular fundus, and measures a corneal aberration of the cornea of the subject eye based on the reflected light flux from the corneal surface. 9. The ophthalmologic measuring apparatus according to claim 8, wherein the measurement part simultaneously measures the wavefront aberration of the whole subject eye based on the reflected light flux from the ocular fundus, and the cornea aberration of the cornea of the subject eye based on the reflected light flux from the corneal surface.
the illuminating optical system illuminates the subject eye with the illumination light flux forming substantially a point light source at an ocular fundus of the subject eye, the light receiving optical system receives the reflected light flux from the ocular fundus of the subject eye illuminated with the illumination light flux of the illuminating optical system and forms the received light signal, and the measurement part measures a wavefront aberration of the whole subject eye based on the reflected light flux from the ocular fundus. 11. The ophthalmologic measuring apparatus according to claim 1, wherein
the illuminating optical system illuminates the subject eye with the illumination light flux converging on the center of curvature of a cornea of the subject eye, the light receiving optical system receives the reflected light flux from a corneal surface illuminated with the illumination light flux of the illuminating optical system and forms the received light signal, and the measurement part measures a corneal aberration of the cornea of the subject eye based on the reflected light flux from the corneal surface. 12. The ophthalmologic measuring apparatus according to claim 1, wherein
the illuminating optical system illuminates the subject eye with the illumination light flux to form substantially a point light source on both ocular fundi of a subject and/or with the illumination light flux converging on the centers of curvature of corneas of both eyes of the subject, the light receiving optical system receives the reflected light flux from the ocular fundi of both the eyes of the subject illuminated with the illumination light flux of the illuminating optical system and/or the reflected light flux from corneal surfaces of both the eyes of the subject, and forms a first received light signal and/or a second received light signal, and the measurement part measures a wavefront aberration of the whole subject eye based on the reflected light flux from the ocular fundus, and/or measures a corneal aberration of the cornea of the subject eye based on the reflected light flux from the corneal surface. Description
DETAILED DESCRIPTION OF THE INVENTION 1. Outline (Blink Interval Data) As wavefront aberration measurement in a blink interval from a certain blink to a next blink, the following two methods can be mentioned.
(1) Data in a Blink Interval by a Blink sign First Embodiment In this case, in conformity to a sign signal such as a metronome sound, a subject blinks at, for example, intervals of 10 seconds. At this time, measurement is performed at, for example, intervals of 1 second, and a measurement time is made one minute.
(2) Data in a Natural Blink Interval Second Embodiment In this case, a natural blink of a subject is detected, measurement is performed in a period from a certain blink to a next blink, a change in aberration is extracted with respect to a common time from the blink, and a principal component analysis is performed.
(Ocular Wavefront, Corneal Wavefront, and Combination of Both) As wavefront aberration measurement data which change with the passage of time and on which the principal component analysis is performed, there are conceivable a wavefront aberration (corneal wavefront measurement) generated from the front side of a cornea, which can be measured by a Placido ring type corneal shape measuring apparatus or the like, a wavefront aberration (ocular wavefront measurement) generated from the whole ocular optical system, which can be measured by a Shack-Hartmann wavefront sensor or the like, and both the wavefront aberrations (both-wavefront measurement) of the combination of these two kinds of measurements.
2. Structure of an Optical System FIG. 1 is a structural view of an optical system of an ophthalmologic measurement apparatus.
(Conjugate Relation) The retina of the subject eye 100, the fixed index 92 of the index optical part 90, the first light source part 11, and the first light receiving part 21 are conjugate to each other. Besides, the ocular pupil (iris) of the subject eye 100, the rotary prism 62, the conversion member (Hartmann plate) 22 of the first light receiving optical system, and the diaphragm 12 of the first illuminating optical system 10 at the measurement light incident side are conjugate to each other.
3. Electrical System FIG. 2 is a structural view of an electrical system of the ophthalmologic measuring apparatus.
4. Measurement Flowchart 4-1. Measurement Flowchart First Embodiment FIG. 3 shows a measurement flowchart of a first embodiment.
(1) Corneal Wavefront Measurement Mode In this measurement mode, the measurement part 601 measures the corneal shape and the corneal wavefront aberration by the anterior eye observation part 40 and the like. The details of the measurement processing of the wavefront aberration of the corneal shape, more particularly, the tear film surface shape of the corneal surface will be described later.
(2) Ocular Wavefront Measurement Mode In this measurement mode, the measurement part 601 measures the wavefront aberration of the subject eye by the first light source part 11, the first illuminating optical system 10, the first light receiving optical system 20 and the like.
(3) Both-Wavefront Measurement Mode of the Corneal Wavefront Measurement and the Ocular Aberration Measurement In this measurement mode, the measurement part 601 measures the wavefront aberrations of both the measurement of the corneal shape and the corneal wavefront aberration by the anterior eye observation part 40 and the like and the measurement of the wavefront aberration of the subject eye by the first light source part 11, the first illuminating optical system 10, the first light receiving optical system 20 and the like.
4-2. Measurement Flowchart Second Embodiment FIG. 4 shows a measurement flowchart of a second embodiment.
5. Principal Component Analysis 5-1. Outline The principle component analysis (PCA) is a method in which correlation among many variables is analyzed, and variations in these variables are constructed of the smallest possible variables. By the principal component analysis, the compression of information, and reduction of dimensions can be performed.
5-2. Analysis Example As described before, in the case where the blink interval data by the blink sign is acquired, the measurement is similar to the foregoing, and the subject blinks at intervals of, for example, 10 seconds, the measurement time is 1 minute, and the number of times of measurement of wavefront aberration is once per second. At the measurement, a fixation target is presented to the subject, and adjustment and intervention of an ocular movement are prevented to the utmost. In this example, the analysis uses 25 terms of the secondary-order to sixth-order Zernike polynomials, and 54 points in the time direction for the principal component analysis (image with a blink is removed).
5-3. Processing of the Principal Component Analysis In the well-known principal component analysis to the elapsed time wavefront aberration, there is a case where time dependency of aberration change is not necessarily effectively used. Besides, in the conventional method, there are many outputs to be reviewed, and there is a case where it is inconvenient for a clinical use. In this embodiment, in order to improve these, there is proposed a method in which the arrangement of the coefficients of the Zernike polynomials and the time are processed as a two-dimensional data set as they are.
(Principle Component Analysis) Next, a description will be given to a method in which the principal component analysis is performed by using the matrix Z formed by the above procedure, and its interpretation is performed in the clinical field (incidentally, see, with respect to the principal component analysis, for example, �Haruo Yanai �Multivariate Data Analysis Method� Asakura Shoten�). Here, only minimum expressions necessary for performing the principal component analysis will be indicated.
(1) Corneal Wavefront Measurement Mode In this measurement mode, firstly, corneal wavefront measurement is performed, and corneal wavefront measurement values are obtained. The form of the corneal wavefront measurement values in this example has 25 rows and 54 columns. The measurement values of 25 rows by 54 columns are made input data, the principal component analysis is performed, and the result of the analysis is outputted and displayed.
(2) Ocular Wavefront Measurement Mode In this measurement mode, firstly, ocular wavefront measurement is performed, and ocular wavefront measurement values are obtained. The form of the ocular wavefront measurement values in this example has 25 rows and 54 columns. The measurement values of 25 rows by 54 columns are made input data, the principal component analysis is performed, and the result of the analysis is outputted and displayed.
(3) Both-Wavefront Measurement Mode of the Corneal Wavefront Measurement and the Ocular Wavefront Measurement In this measurement mode, both the corneal wavefront measurement and the ocular wavefront measurement are performed, and the corneal wavefront measurement values and the ocular wavefront measurement values are obtained. In this example, each of the cornea and the wavefront aberration has a form of 25 rows by 54 columns, the measurement values of 25 rows by 54 columns are made input data for each, the principal component analysis is performed, and the result of the analysis is outputted and displayed. Besides, since the Zernike coefficients from both the cornea and the ocular wavefront are used, the number of rows of the matrix is 50, the form has 50 rows and 54 columns, the measurement values of 50 rows by 54 columns are made input data, the principal component analysis is performed, and the result of the analysis can also be outputted and displayed.
(Flowchart) FIG. 8 shows a flowchart of the principal component analysis.
5-4. Code Map FIG. 9 is a view of results of principal components in a normal example. Besides, FIG. 10 is a view of results of principal components in a slight dry eye.
5-5. Dry Eye Index In the automatic diagnosis at step S113, the analysis part 604 calculates a following dry eye index, and the arithmetic part 600 may display the calculation result on the display part 700.
Dry   eye   index 1 = Magnitude   of   first   principle   component   λ 1 ∑ i = 1 6  Magnitude   of   i  -  th   principle   component   λ i The second example is the sum of all principal components (λ1 to λ6) as indicated by a following expression.
Dry   eye   index 2 = ∑ i = 1 6  Magnitude   of   i  -  th   principle   component   λ i It is estimated that as the dry eye index 1 becomes small, or as the dry eye index 2 becomes large, the degree of dry eye is large.
6. Details of Corneal Wavefront Aberration Measurement Hereinafter, with respect to the wavefront aberration of a tear film surface shape of a corneal surface, the details of the measurement processing will be described.
(Anterior Eye Part Image: S401) At step S401, the following anterior eye part image is acquired.
(Image Processing: S403) FIG. 14 shows a flowchart of an image processing of detection of the Placido disk and the pupil edge. This corresponds to the step S403.
(Calculation Method of Corneal Shape: S405) Hereinafter, the step S405 will be described. As an example, a measurement method of the corneal shape will be described along �Rand R H, Howland H C, Applegate R A �Mathematical model of a placido disk karatometer and its implications for recovery of corneal topography�, Optometry and Vision Science 74 (1997) p 926-930�.
x s = 2  ( z s - f ) f x 2 + f y 2 - 1  f x ,    y s = 2  ( z s - f ) f x 2 + f y 2 - 1  f y Where, with respect to Zs, the working distance adjustment part 50 in the drawing can control it or know the accurate distance value. Incidentally, fx denotes a partial differentiation of the function f with respect to x, and fy denotes a partial differentiation with respect to y.
f  ( x , y ) = ∑ j = - i , - i + 2 , , , i - 2 , i 6  c i j  Z i j  ( x r n , y r n ) Where, rn indicates a radius to be analyzed, and is used for normalization.
(Calculation Method of Corneal Wavefront: S407) Hereinafter, the step S407 will be described. Since the corneal shape is obtained, it is well known that the strict corneal wavefront aberrations in the geometry can be obtained from the ray tracing of an aspheric surface known in optical design. Here, as an example, a method of obtaining a corneal wavefront aberrations very simply will be described.
6-2. Ophthalmologic Measurement while a Blink is made a Trigger Next, a description will be given to an ophthalmologic measurement while a blink is made a trigger.
7. Example of Binocular Simultaneous Measurement FIG. 19 and FIG. 20 show an ophthalmologic systems (1) and (2) structural view for a binocular simultaneous measurement.
8. Zernike Analysis and RMS Next, a Zernike analysis will be described. A method of calculating Zernike coefficients ci 2j−l from generally known Zernike polynomials will be described. The Zernike coefficients ci 2j−l are important parameters for grasping the optical characteristics of the subject eye 100 on the basis of, for example, the inclination angle of the light flux obtained by the first light receiving part 21 through the Hartmann plate 22.
W  ( X , Y ) = ∑ i = 0 n  ∑ j = 0 i  c i 2  j - i  Z i 2  j - i  ( X , Y ) Where, (X, Y) are vertical and horizontal coordinates of the Hartmann plate 22.
∂ W  ( X , Y ) ∂ X = Δ   x f ,  ∂ W  ( X , Y ) ∂ Y = Δ   y f Where, the Zernike polynomials Zi 2j−1 is expressed by a following expression.
Z n m = R n m  ( r )  { sin cos }  { m   θ } m > 0   sin m ≦ 0   cos R n m  ( r ) = ∑ S = 0 ( n - m ) / 2  ( - 1 ) S  ( n - S ) ! S !  { 1 2  ( n - m ) - S } !  { 1 2  ( n + m ) - S } !  r m Incidentally, with respect to the Zernike coefficients ci 2j−l, specific values can be obtained by minimizing the square error expressed by a following mathematical expression.
S  ( x ) = ∑ i = 1 data   number  [ { ∂ W  ( X i , Y i ) ∂ X - Δ   x i f } 2 + { ∂ W  ( X i , Y i ) ∂ Y - Δ   Y i f } 2 ] Where, W(X, Y): wavefront aberration, (X, Y): Hartmann plate coordinates, (Δx, Δy): movement distance of the point image received by the first light receiving part 21, and f: distance between the Hartmann plate 22 and the first light receiving part 21.
RMS i 2  j - i = ɛ i 2  j - i 2  ( i + 1 )  c i 2  j - i  ( ɛ i 2  j - i = 2  ( 2  j = i ) , ɛ i 2  j - i = 1  ( 2  j ≠ i ) ) The invention can be widely applied to an ophthalmologic measuring apparatus, a surgical apparatus and the like.
Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8049873Mar 18, 2009Nov 1, 2011Carl Zeiss Meditec AgSurgical microscopy system having an optical coherence tomography facilityUS8459795Mar 16, 2011Jun 11, 2013Carl Zeiss Meditec AgMeasuring system for ophthalmic surgeryClassifications U.S. Classification351/206International ClassificationA61B3/14Cooperative ClassificationA61B3/101European ClassificationA61B3/10DLegal EventsDateCodeEventDescriptionMay 6, 2014FPExpired due to failure to pay maintenance feeEffective date: 20140316Mar 16, 2014LAPSLapse for failure to pay maintenance feesOct 25, 2013REMIMaintenance fee reminder mailedMar 21, 2007ASAssignmentOwner name: KABUSHIKI KAISHA TOPCON, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIROHARA, YOKO;MIHASHI, TOSHIFUMI;REEL/FRAME:019126/0070Effective date: 20070301Owner name: KABUSHIKI KAISHA TOPCON,JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIROHARA, YOKO;MIHASHI, TOSHIFUMI;US-ASSIGNMENT DATABASEUPDATED:20100316;REEL/FRAME:19126/70RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google