Source: https://patents.google.com/patent/EP1430829B1/en
Timestamp: 2020-01-28 11:53:30
Document Index: 770014107

Matched Legal Cases: ['art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'art 4', 'Application No. 02405272']

EP1430829B1 - Ophthalmic device and measuring method - Google Patents
EP1430829B1
EP1430829B1 EP02406102A EP02406102A EP1430829B1 EP 1430829 B1 EP1430829 B1 EP 1430829B1 EP 02406102 A EP02406102 A EP 02406102A EP 02406102 A EP02406102 A EP 02406102A EP 1430829 B1 EP1430829 B1 EP 1430829B1
EP1430829A1 (en
2009-10-21 First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=32338235&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP1430829(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
230000003287 optical Effects 0 claims 13
The present invention relates to an ophthalmological apparatus and an ophthalmological measuring method. More particularly, the invention relates to an ophthalmologic device and an ophthalmological measuring method in which a beam is projected through a cross-sectional part of an eye by a light projector, in particular through a cross-sectional part of the cornea, in which a cross-sectional image is taken by means of first image capturing means arranged in a Scheimpflug arrangement relative to the beam is detected and stored from at least a portion of the cross-section illuminated by the light projector from a first position outside the beam and in which by means of second image acquisition means a view image of the eye is detected and stored associated with the acquired cross-sectional image.
In the prior art, opthalmological devices and ophthalmic measuring methods are known, in which by means of a light projector, a beam is projected through a cross-sectional part of an eye, in particular through a cross-sectional part of the cornea. Typically, the beam is projected in the form of a light gap. In the patent US 5404884 For example, a method and apparatus for examining corneal tissue of a patient are described. According to US 5404884 For example, a substantially planar laser beam with a slit-shaped profile is projected through a cross-sectional part of the cornea. By detecting at least part of the light scattered in the cornea, that is to say of at least part of the light gap, is determined according to US 5404884 obtained a cross-sectional image of the cornea. From several such cross-sectional images of the cornea can according to US 5404884 Corneal opacities, corneal thickness and corneal topography can be determined extensively for the entire cornea. Since the eyes can move relative to the examination device, the examination of the according to the eye US 5404884 lead to inaccuracies, because these relative movements are not detected and taken into account. In the article BR Masters et al. , "Transformation of a Set of Slices", "Rotated on a Common Axis to a Set of Z Slices: Application to Three-Dimensional Visualization of the In Vivo Human Lens," Computerized Medical Imaging and Graphics, Vol. 3, pages 145-151, 1997 Moreover, it is explicitly stated that extensive examination of the eye, based on the combination of several cross-sectional images, may result in measurement artifacts due to the difficulty of mutual alignment of the individual cross-sectional images.
In the patent US 4711541 describes an opthalmological device which has a slit lamp for projecting a light gap on the lens of an eye. The device according to US 4711541 also includes a photo-camera arranged with respect to the plane of the light gap according to Scheimpflug conditions to sharply image the entire cross-sectional part of the eye lens illuminated by the light slit. The device according to US 4711541 has a stereomicroscope to allow the user to view the eye. By means of optical elements of the device, the supervision for imaging the camera can be supplied. However, it is ensured by means of polarizing filters that not reflected on the surface of the eye lens light gap, but only visible in the supervision backlighting of the eye, which results from the reflection of the light gap on the fundus and the scattering by the eye lens, the photo camera for imaging becomes. By means of a movable mirror, the light section in the eye lens and the supervision of the eye with the backlight can be displayed side by side on the same photograph. Since the device according to US 4711541 only a single image examination is possible, no coherent examination of the entire eye can be performed.
In the patent US 5341180 An opthalmological imaging device is described, which projects a light gap onto an eye by means of a slit lamp. The image pickup device comprises a CCD camera (Charged Coupled Device) which is arranged to the plane of the light gap according Scheimpflug conditions to sharply map the entire cross-sectional part of the eye, which is illuminated by the light slit. The device according to US 5341180 comprises a second CCD camera, which grants the user a view of the eye to be examined and serves to align the device or the eye with the aid of light marks projected onto the eye. The device according to US 5341180 has polarizing filters to prevent the light gap from being visible in the top view of the second CCD camera. In order to enable precise alignments, the patient to be examined must focus his eyes on fixation marks with each shot, which in a study of the entire eye of the patient can be perceived as laborious and is also time consuming.
In EP 0933060 An opthalmological apparatus is described which comprises a slit lamp for projecting a light slit onto an eye, a CCD camera for detecting a cross-sectional image, and a CCD camera for detecting a view image of the eye. In the device according to EP 0933060 For example, the view image and the cross-sectional image are stored in various frame memories connected to an image changer. To EP 0933060 either the view image or the cross-sectional image is displayed on a display. The view images become after EP 0933060 taken to align the device and the device is switched after alignment by means of a dedicated switch in a special mode in which the cross-sectional image is taken.
Another opthalmological device adapted to receive a cross-sectional image of a light slit projected onto an eye is disclosed in the patent US 5,208,708 described. Also after US 5,208,708 For example, a view image is used to align the device and the cross-sectional image is taken after alignment is complete.
It is an object of the present invention to propose a new ophthalmological apparatus and a new ophthalmological measuring method, which do not have the disadvantages of the prior art and in particular allow a coherent examination of the entire eye, in particular the determination of topography and measurements of structures of the anterior chamber of the eye, for example the corneal topography and thickness, taking into account relative movements of the eye to the device.
The opthalmological device comprises a first light projector for projecting a beam through a cross-sectional part of an eye, in particular through a cross-sectional part of the cornea of the eye, first image acquisition means for acquiring and storing a cross-sectional image of at least one sub-region of the first A light projector illuminated cross-sectional part, from a first position outside the beam, which are arranged in Scheimpflug arrangement to the beam, and second image acquisition means for detecting a view image of the eye and for storing the detected view image associated with the acquired cross-sectional image.
The above-mentioned objects are achieved by the invention in particular in that the second image acquisition means of this opthalmological device are adapted to capture and store the view image such that the view image comprises an image of the cross-sectional part illuminated by the first light projector, and that said opthalmological device comprises processing means for positioning the stored cross-sectional image relative to the eye based on the associated stored view image. The acquisition and storage of the cross-sectional image and the associated view image with the illuminated cross-sectional portion allows the determination of the position of the cross-sectional image and the illuminated cross-sectional part detected therein relative to the eye based on the associated view image, which in turn allows a coherent examination of the entire eye with multiple cross-sectional images in which relative movements of the eye can be taken into account on the basis of the specific positions of the relevant cross-sectional images. As reference points for the position determination, natural features of the eye, such as limbus, iris or pupil, can be used, which are shown in the view image. Since the relative position is also automatically determined for each cross-sectional image, the entire eye can be examined coherently by joining several cross-sectional images according to their assigned position into a three-dimensional image of the eye. A coherent examination of the entire eye is made possible in which relative movements of the eye to the device are taken into account, without the patient to be examined having to focus his eyes on fixation marks with each shot in order to avoid measurement errors. For example, corneal thickness, corneal topography, and / or corneal opacities may be included for the whole of a plurality of cross-sectional images that are assembled according to their particular location Cornea of the eye to be determined. The processing means are preferably arranged for positioning a plurality of stored cross-sectional images relative to each other on the basis of their respective associated stored image images.
In one embodiment, the processing means are arranged for determining the thickness of the cross-sectional part of the eye illuminated by the first light projector on the basis of the stored view image. Since the beam projected by the first light projector has a finite thickness and may be divergent, the thickness of the illuminated cross-sectional portion in the cross-sectional image detected outside the beam appears larger or smaller depending on the thickness of the beam. The determination of the thickness of the cross-sectional part of the eye illuminated by the first light projector has the advantage that the influence of the finite thickness of the beam in the thickness measurement of illuminated cross-sectional parts of the eye, for example in the corneal thickness measurement, can be taken into account and the thickness measurement can be corrected accordingly higher measurement accuracy leads. For the determination of the thickness of the illuminated by the first light projector cross-sectional part respectively of the beam proves a plan view, ie a view image, in which the second image sensing means are arranged so that their optical axis is substantially parallel to the optical axis or the visual axis of the eye or coincides with the optical axis or the visual axis of the eye, as particularly advantageous because particularly precisely and simply when the optical axis of the second image acquisition means coincides with the beam passing through the cross-sectional part of the beam.
The preferred arrangement of the second image acquisition means and the first light projector, in which the optical axis of the second image acquisition means coincides with the beam passing through the cross section part advantageously also allows a particularly simple and accurate position determination of the imaged illuminated cross-sectional part, in particular if the eye through the second image capture means is detected as a supervisory image.
In a preferred embodiment, the first and the second image acquisition means are arranged so that their optical axes lie in a common plane. With this arrangement, the cross-sectional images captured by first image capturing means and the associated image images captured by second image capturing means can be geometrically more easily related than is possible with alternative arrangements, facilitating the relative positioning of multiple cross-sectional images with one another and the joining of these cross-sectional images.
Preferably, the first and second image capture means comprise a common imager and the first image capture means comprise beam redirecting optical elements, wherein the beam redirecting optical elements are arranged to redirect light beams to the common imager to produce the cross-sectional image. In an alternative embodiment, the first and second image capture means comprise a common image converter and the second image capture means comprise beam redirecting optical elements, wherein the beam redirecting optical elements are arranged to redirect light rays to the common image converter to produce the view image. Both of these embodiments have the advantage that they have only one image converter and thus can be made more cost effective and compact, as an alternative embodiment with two separate image converter. The first-mentioned preferred of these two embodiments also has the advantage that the first image acquisition means can be provided in a simple and compact way with other beam deflecting optical elements, so that light beams can be deflected to produce multiple cross-sectional images from different positions to the common image converter.
The first image acquisition means are preferably arranged to acquire and store a second cross-sectional image of the sub-region of the cross-section part illuminated by the first light projector from a second position outside the radiation bundle, simultaneously with the acquisition of the first cross-sectional image, the first position and the first cross-sectional image second position on different sides of a plane lying in the beam and detect the illuminated cross-section part, for example, under a same large observation angle. The advantage of capturing images of the illuminated cross-sectional part from several positions is that several measured values can be determined and from this averaging more accurate measurement results can be determined. In the averaging, for example, deviations in determining a first distance between eye structures in the first cross-sectional image and a second distance between eye structures in the second cross-sectional image cancel each other out. Thus, when the opthalmological device is applied so that the beam is projected substantially perpendicular to the light projecting (corneal) surface of the eye, for example, slight tilting of the beam with respect to the normal to the light projector facing surface of the cornea does not affect determination of corneal thickness. Even if the device is applied so that the beam is projected substantially along the optical axis of the eye, slight tilting and eccentricity of the beam, that is shifts from the apex of the eye, do not affect the determination of corneal thickness. The same applies to small deviations of the observation angle from the first position from the observation angle from the second position. The advantage of detecting two cross-sectional images from different positions at the same observation angles is therefore that small inaccuracies in the application, adjustment and / or calibration of the opthalmological device have no major deviations on the measurement results. If the opthalmological device is applied, for example, in meridian sections, a calibration in the meridian section is sufficient in order to be able to measure accurately even with slight eccentricities and tilting. The opthalmological device thus enables easier application and execution while maintaining the accuracy of the measurement results.
In the embodiment in which the first image acquisition means comprise an image converter and further beam-deflecting optical elements, preferably first of the beam-deflecting optical elements are in the case of the second position of the beam deflecting optical elements are arranged at the second position, that light beams are deflected to the image converter for generating the second cross-sectional image. This results in a particularly compact and inexpensive design.
In one embodiment variant, the opthalmological device comprises one or more additional second light projectors for projecting light marks on the eye, and the second image capturing means are synchronized with the first light projector and with the second light projectors such that when capturing and storing the view image of the eye, the image of the cross section part illuminated by the first light projector and an image of the light marks projected by the second light projectors are also recorded and stored. The projected and co-detected light marks serve as artificial reference marks that can be used to determine the relative position of the opthalmological device to the eye and thus to determine the position of the cross-sectional image and the illuminated cross-section, respectively.
In one embodiment, the opthalmological device comprises a screen body with a visible pattern, which screen body is arranged so that the visible pattern is in an application of the device on an eye-facing side of the screen body and that the beam is freely projected through the cross-sectional part of the eye and that the cross-sectional image and the view image are freely detectable by the first and second image capturing means, respectively. Since the visible pattern, such as a placid pattern, is reflected by the eye, it can be captured with the view image and used as an artificial reference pattern to determine the relative position of the opthalmological device to the eye and thus position the cross-sectional image or illuminated cross-section, respectively.
In one embodiment variant, the opthalmological device comprises drive means for rotating the first light projector and the first and the second image capture means essentially around a normal to the surface of the eye facing the first light projector or for moving it substantially perpendicular to this normal. These drive means enable automated contiguous examination of the entire eye based on multiple cross-sectional images.
Preferably, the first light projector is such that it projects the beam in the form of a light gap. Although other forms of the beam are useful, such as punctiform, a beam in the form of a light gap is particularly suitable for the coherent examination of the entire eye based on multiple light sections of the eye.
Preferably, the second image acquisition means are arranged so that their optical axis coincides with the optical axis of the eye or is substantially parallel to the optical axis of the eye. As a result, the eye can be detected as a supervisory image, which is advantageous both for determining the position of the illuminated cross-sectional part and for determining the thickness of the illuminated cross-sectional part, as has already been explained above. In combination with the preferred arrangement of the second image acquisition means and the first light projector, in which the optical axis of the second image acquisition means coincides with the beam passing through the cross section part, there results an arrangement in which the first light projector projects the radiation beam so that the radiation beam the optical axis of the eye coincides or that the beam is parallel to the optical axis of the eye.
FIG. 1a FIG. 12 is a block diagram schematically illustrating an ophthalmological apparatus including a light projector, an image acquisition apparatus for acquiring a cross-sectional image of an eye, an image capturing apparatus for acquiring a view image of the eye, and an additional light source.
Figure 1c shows a view image of an eye with a lit cross-sectional part.
FIG. 2a 10 is a block diagram schematically illustrating an ophthalmological apparatus including a light projector, an image capturing apparatus for acquiring a cross-sectional image of an eye, an image capturing apparatus for acquiring a view image of the eye, and a perforated screen body.
FIG. 2b shows a view of the eye-facing side of an umbrella body with openings and a visible pattern.
FIG. 3 shows a sectional view of an illuminated cross-sectional part of an eye, in which the beam path of the incident and reflected beam is schematically illustrated.
FIG. 4 FIG. 12 is a block diagram schematically illustrating a side view of an ophthalmological apparatus having a light projector and an image sensing device aligned along the optical axis of the eye for acquiring a view image of an eye. FIG.
FIG. 5 Fig. 12 is a block diagram schematically showing an ophthalmological apparatus having a light projector and an image capturing apparatus for acquiring a view image of an eye illustrated in which the optical axis of the image capture device coincides with the beam passing through the cross-sectional part.
FIG. 6 10 is a block diagram schematically illustrating an ophthalmological apparatus having a light projector and image acquisition means for acquiring a cross-sectional image and a view image of an eye in which light rays for generating the view image and light rays for generating the cross-sectional image are supplied to a common image converter by means of beam deflecting optical means.
FIG. 7 10 is a block diagram schematically illustrating another embodiment of an ophthalmological apparatus having a light projector and image acquisition means for acquiring a cross-sectional image and a view image of an eye in which light rays for generating the view image and light rays for generating the cross-sectional image are supplied to a common image converter by beam deflecting optical means ,
FIG. 9 12 is a block diagram schematically illustrating an ophthalmological apparatus having a light projector and image acquisition means for acquiring two cross-sectional images and a view image of an eye in which light rays for generating the view image and light rays for generating a first cross-sectional image from a first position and light rays for producing a second cross-sectional image be supplied from a second position by means of beam deflecting optical means a common image converter.
FIG. 10 shows a combined image with a first cross-sectional image of an illuminated cross-sectional part of an eye of a first position, a view image of the eye with the illuminated cross-sectional part and a second cross-sectional image of the illuminated cross-sectional part from a second position.
In the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 Reference numeral 1 denotes an opthalmological device, and in the following description, referring to these figures, various embodiments of the opthalmological device 1 will be explained. Otherwise, in the figures corresponding, identical components are denoted by the same reference numerals.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 illustrated embodiments of the opthalmological device 1 include a light projector 11 for projecting a beam 2 through a cross-sectional part of an eye 3, in particular through a cross-sectional part of the cornea 30 of the eye 3. The beam 2 is preferably projected in the form of a light gap. The light projector 11 includes, for example, a slit lamp or a laser whose light is shaped into a fan by beam-shaping optics.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 Illustrated embodiments of the opthalmological device 1 comprise image acquisition means for acquiring and storing a cross-sectional image 30A of at least a sub-area of the illuminated by the light projector 11 cross-section part 4, which are arranged in Scheimpflug arrangement to the beam 2.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 illustrated embodiments of the opthalmological device 1 also comprise further image acquisition means for detecting a view image 3A of the eye 3, which comprises an image of the illuminated cross-sectional part 4A, and to Storage of the acquired view image 3A and the image of the illuminated cross-sectional part 4A contained therein associated with the acquired cross-sectional image 30A.
As in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 Depending on the embodiment of the opthalmological device 1, the image acquisition means comprise image acquisition devices 12A, 12B, for example CCD cameras (Charged Coupled Device) or CMOS cameras (Complementary Metal-Oxide-Silicon), image converters 120, for example CCD chips or CMOS chips, beam deflecting optical elements 121A, 121B, 121E, for example mirrors, beam deflecting optical elements 121C, 121D, for example beam splitting optical elements such as semitransparent mirrors, and / or imaging optical elements 122A, 122B, 122C, for example lenses.
For visualization of natural eye features, such as limbus 33, iris 34 or pupil 35, and / or for the projection of artificial light marks 36 include in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 one or more additional light sources 16. In particular, for the visualization of natural eye features, for example, one or more infrared light emitting diodes can be used. The natural and / or artificial reference features are included in the view image 3A of the eye 3.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 Illustrated embodiments of the opthalmological device 1 comprise processing means 13 with functional modules for processing acquired view images 3A and cross-sectional images 30A. The processing means 13 comprise at least one processor, data and program memory. The functional modules are preferably implemented as programmed software modules which are stored in the program memory and executed on the processor. The person skilled in the art will understand that the functional modules can also be implemented partly or completely by hardware.
The functional modules of the processing means 13 comprise a programmed positioning module which determines the position of a stored cross-sectional image 30A relative to the eye 3. The relative positioning is performed on the basis of the view images 3A associated with the cross-sectional images 30A, respectively. The position of a cross-sectional image 30A is determined by determining the position of the eye 3 relative to the opthalmological device 1. The relative position of the opthalmological device 1 to the eye 3 based on the image of the illuminated cross-sectional part 4A, the natural features of the eye 3 and / or the imaged artificial reference features, such as the imaged light marks 36 determined. The position of a cross-sectional image 30A or the associated image of the illuminated cross-sectional part 4A can be defined with reference to the natural features of the eye 3 included in the respective view image 3A.
The functional modules of the processing means 13 also comprise a programmed composition module which positions a plurality of captured and stored cross-sectional images 30A relative to each other. Knowing the geometric arrangement of the opthalmological device 1, the composition module combines the acquired and stored cross-sectional images 30A according to their relative position to the eye 3 and to a three-dimensional image of the eye 3, in particular to form a three-dimensional image of anterior chamber structures of the eye 3, in particular the cornea 30th
The functional and sequence control of the opthalmological device 1 can be effected by the processing means 13 and / or by further electronic control modules, not shown.
The electrical supply of the opthalmological device 1 is effected by an internal or by means of a cable connected external energy source.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 illustrated embodiments of the opthalmological device 1 include a Display 14, on which certain measured values and / or application aids are displayed.
The in the FIGS. 1a . 2a . 4, 5 . 6, 7 and 9 illustrated embodiments of the opthalmological device 1 comprise drive means 15 for rotating the light projector 11 and the image detecting means, substantially to a normal to the light projector 11 facing surface of the eye 3 or for moving these components substantially perpendicular to this normal. Like in the FIG. 9 is schematically shown, the light projector 11 and the image sensing means 120, 121 A, 121 B, 121 C, 122 A, 122 B, 122 C are mounted for this purpose on a movable support device 10, which is driven by the drive means 15. The additional light source (s) 16 may be mounted and moved along the carrier device 10, or may be attached to the opthalmological device 1 so as not to be coupled to the drive means 15. The drive means 15 preferably comprise a rotation driver, for example an electric motor, which rotates the carrier device 10 about the optical axis Z of the eye. The rotation of the light projector 11 and the image acquisition means 120, 121A, 121B, 121C, 122A, 122B, 122C about the optical axis Z measures the entire eye, in particular the entire cornea 30. In this configuration, due to the high symmetry, the lowest measurement uncertainties can be achieved.
Like in the FIG. 1a For example, image capture device 12A for acquiring and storing cross-sectional images 30A includes imaging optical elements 122A and imager 120 arranged in Scheimpflug configuration for projected beam 2. In the FIG. 1b For example, a cross-sectional image 30A of the illuminated cross-sectional part 4 of the eye 3 captured by the image capture device 12A is shown. Other structures of the eye 3, such as iris or lens, are for simplicity in the FIG. 1b not shown. In particular, a cross-sectional image of the anterior corneal surface 31A and a cross-sectional image of the posterior corneal surface 32A are visible in the cross-sectional image 30A. In the Embodiment according to FIG. 1a is the optical axis of the separate image sensing device 12B for detecting the view image 3A of the eye 3 outside the beam 2. The in the Figure 1c However, view image 3A of the eye 3 corresponds to a view image which is captured by an image capture device 12B as a plan view, the image capture device 12B is arranged so that its optical axis substantially parallel to the optical axis Z of the eye 3 or the visual axis of the eye. 3 runs or coincides with the optical axis Z or the visual axis of the eye 3, which is for example in the FIGS. 4 and 5 is shown. In the view image 3A, in particular, an image of the illuminated cross-sectional part 4A with the finite thickness d, the projected light marks 36 and the limbus 33, iris 34 and pupil 35 of the eye 3 are visible. Light marks are, for example, highlights of light-emitting diodes or projected dots. Projection locations are, for example, the sclera 37 or the cornea 30. The acquired cross-sectional image 30A and the acquired view image 3A are fed to the processing means 13 and stored there associated with each other in the data memory. The light projector 11 and the image acquisition means 12A, 12B are moved by the drive means 15 into further receiving positions and further cross-sectional images 30A and view images 3A are recorded and stored in association with each other.
In the FIG. 2a an embodiment of the opthalmological device 1 is shown, which comprises a perforated screen body 17. The apertures 171, 172, 173 of the screen body 17 are each arranged so that the beam paths to the image acquisition means 12A, 12B and the light projector 11 can pass through the screen body 17 unhindered. On the side of the screen body 17 facing the eye 3 there is a visible pattern 17 ', a so-called placid pattern, for example with circular rings 174, which is mirrored through the surface of the eye 3, as known, for example, from keratometers. On the screen body 17, light sources can also be attached to the eye 3, for example light projectors 16 for the projection of light marks 36. A view of the side of the screen body 17 facing the eye 3 with apertures 171, 172, 173 and the visible pattern 17 'is shown in FIG FIG. 2b shown. The reflection of the visible Pattern 17 'on the ocular surface is imaged by image capture device 12B in view image 3A and may be used in positioning the cross-sectional images 30A as an artificial reference pattern for determining the relative position of opthalmological device 1 to eye 3. The screen body 17 is preferably connected to the drive means 15 so as to be moved with the light projector 11 and the image acquisition means. In an alternative embodiment, the screen body 17 may also be attached to the opthalmological device 1 in such a way that it is not coupled to the drive means 15, the openings 171, 172, 173 being adapted accordingly. It should be noted at this point that the screen body 17 can also be arranged so that the image capture means 12A, 12B and / or the light projector 11 come to lie between the screen body 17 and the eye 3, the image acquisition means 12A, 12B and / or or the light projector 11, for example, mounted on the eye 3 facing side of the screen body 17.
The FIG. 3 shows a sectional view of an illuminated cross-sectional part 4 of the eye 3, in particular the cornea 30. In the FIG. 3 reference numeral 31 denotes the anterior corneal surface and reference numeral 32 denotes the posterior corneal surface. The cornea 30 is illuminated by the beam 2 in the cross-sectional part 4. Like in the FIG. 3 is shown, the beam 2 has a finite thickness d. The reflected light beams 21, 22 make the thickness D of the illuminated cross-section part 4 in a cross-sectional image 30A appear thicker than it actually is, due to the finite thickness d of the beam. Since the geometrical arrangement of light projector 11 and image acquisition means is known, the influence of the finite thickness d of the radiation beam 2 on the cross-sectional image 30A or on measured values determined from the cross-sectional image 30A can be corrected with knowledge of the value of the finite thickness d. The finite thickness d of the beam 2 can be determined particularly accurately when the view image 3A is captured by the image capture means in the top view.
In the embodiment of the opthalmological device 1 according to the FIG. 4 For example, the image sensing device 12B is arranged to detect a view image 3A corresponding to a top view of the eye 3. The optical axis of the image acquisition device 12B can be aligned during the application along the optical axis Z of the eye 3. Like the side view in the FIG. 4 4, the beam 2, which is shown in this view as a light plane (or light fan), is laterally projected onto the eye 3 from outside the optical axis of the image capture device 12B in this embodiment.
In the FIG. 5 a further embodiment of the opthalmological device 1 is shown, which allows a view image 3A with a top view of the eye 3. In the embodiment according to FIG. 5 For example, the beam 2 of the light projector 11 passing through the cross-sectional part 4 and the optical axis of the image capturing device 12B for capturing the view image 3A coincide. This is achieved, for example, by arranging the image capture device 12B and the light projector 11 so that their optical axes lie in a common plane, whereby the beam 2 of the light projector 11 is directed onto the optical axis of the image capture device 12B by the beam deflecting optical element 121C becomes. The coincidence of the beam bundle 2 passing through the cross-sectional part 4 and the optical axis of the image capturing device 12B enables a particularly accurate and simple determination of the finite thickness d of the radiation beam 2 and the position of the cross-sectional images 30A from the view image 3A.
In the FIG. 6 A further embodiment of the opthalmological device 1 is shown which permits a view image 3A with a view of the eye 3 and in which the beam 2 passing through the cross-sectional part 4 and the optical axis of the image acquisition means for detecting the view image 3A coincide. The embodiment according to the FIG. 6 However, it has the advantage over that of FIG. 5 that both the cross-sectional image 30A and the view image 3A by means of a single common image converter 120th be recorded. The embodiment according to FIG. 6 arises as a further development of the embodiment according to FIG. 1a in which the light beams for generating the view image 3A are supplied to the image converter 120 from the top view by means of the beam deflecting optical element 121D arranged in the optical axis of the light projector 11 by the imaging optical elements 122C and by the beam deflecting optical element 121E.
In the FIG. 7 A further embodiment of the opthalmological device 1 is shown which permits a view image 3A with a view of the eye 3 and in which the beam 2 passing through the cross-sectional part 4 and the optical axis of the image acquisition means for detecting the view image 3A coincide. The embodiment according to the FIG. 7 However, it has the advantage over that of FIG. 5 in that both the cross-sectional image 30A and the view image 3A are detected by means of a single common image converter 120. Compared to the embodiment according to the FIG. 6 It also has the advantage that it is easier and more compact executable. The embodiment according to FIG. 7 arises as a further development of the embodiment according to FIG. 5 in which the light beams for generating the cross-sectional image 30A are supplied to the image converter 120 by means of the imaging optical elements 122A arranged with the image converter 120 in Scheimpflug arrangement to the beam 2 passing through the cross-sectional part 4 and by means of the beam-deflecting optical element 121A. The in the FIG. 5 The image capture device 12B shown corresponds to the combination of the image converter 120 and the imaging optical elements 122C of FIG FIG. 7 ,
In the FIG. 8 FIG. 3 illustrates the combined cross-sectional image 30A and the image 3A of the image converted by the imager 120 of the embodiments according to FIGS FIGS. 6 and 7 is detected. The combined image can be like in the FIG. 8 can be generated shown by the cross-sectional image 30A and the view image 3A separately detected side by side. The cross-sectional image 30A and the view image 3A can be obtained with the aid of color filters, for example, color cameras are known, and a plurality of light sources with different colors, but also partially or completely superimposed detected. Image separation is then performed by the processing means 13 on the basis of the colors. It is also possible to use optical or electrical shutters (so-called shutters) and to rapidly acquire the cross-sectional image 30A and the view image 3A as separate images, so that relative movements between the eye 3 and the opthalmological device 1 have no noticeable influence. With the use of cameras or imagers with fields and pulsed light sources, the cross-sectional image 30A and the view image 3A can be sequentially synchronized detected as two fields.
In the FIG. 9 A further embodiment of the opthalmological device 1 is shown which permits a view image 3A with a view of the eye 3 and in which the beam 2 passing through the cross-sectional part 4 and the optical axis of the image acquisition means for detecting the view image 3A coincide. The embodiment according to FIG. 9 arises as a further development of the embodiment according to FIG. 7 wherein the opthalmological device 1 is provided with further imaging optical elements 122B and a further beam-deflecting optical element 121B to additionally detect a second cross-sectional image 30B. The imaging optical elements 122A and the beam-deflecting optical element 121A directing the light beams for detecting the cross-sectional image 30A from a first position under the observation angle α A for detecting the image converter 120. The additional imaging optical elements 122B and the additional beam-deflecting optical element 121B direct the Light beams for detecting the cross-sectional image 30B from a second position below the observation angle α B for detection also to the imager 120. Preferably, the two positions are located on different sides of the beam 2 and the amounts of the observation angles α A and α B are preferably equal. Compared to the embodiment according to the FIG. 7 has the embodiment according to the FIG. 9 the advantage that measurement results, which are determined from measured values on the cross-sectional image 30A in the opthalmological device 1 according to the FIG. 9 out of two Measurements of two cross-sectional images 30A and 30B acquired from different positions can be more accurately determined by averaging. For example, the corneal thickness D can be more accurately determined by averaging the measurements D A and D B , as in the unpublished at the time of filing European Patent Application No. 02405272 has been described.
In the FIG. 10 FIG. 3 illustrates the combined cross-sectional image 30A, view image 3A, and cross-sectional image 30B taken by the imager 120 of the embodiments of FIGS FIG. 9 is detected. The combined image can be like in the FIG. 10 can be generated by separately detecting the cross-sectional image 30A, the view image 3A, and the cross-sectional image 30B side by side. However, the combined image can also be captured and displayed differently, as related to FIG. 8 already mentioned. In addition, the person skilled in the art can make other image arrangements and, for example, display the two cross-sectional images 30A, 30B directly next to one another above the view image 3A.
The functional modules of the processing means 13 also comprise programmed evaluation modules, for example measuring modules which determine eye structures in the acquired and stored cross-sectional images 30A, 30B, in particular images of the cornea with the anterior corneal surface 31A, 31B and the posterior corneal surface 32A, 32B, and determine distances or thicknesses therefrom, in particular the measured values D A and D B of the distances between the front corneal surface 31 A, 31 B and the rear corneal surface 32 A, 32 B for determining the corneal thickness D.
Finally, it should be noted that the opthalmological device 1 is preferably designed as a compact measurement sample, wherein additional processing means for the comprehensive detection of the entire eye 3 in an external processing unit, for example in a personal computer, executed, the data exchange via a contact or contactless communication connection takes place. Certain measurement results, such as the local corneal thickness D or topography, may be displayed on the display 14 or on an external processing unit display.
Ophthalmologic device (1), comprising:
- a first light projector (11) for projection of a beam of rays (2) through a cross-sectional portion (4) of an eye (3), in particular through a cross-sectional portion (4) of the cornea of the eye (3),
- first image-capturing means for capturing a cross-sectional image (30A) of at least one sub-area of the cross-sectional portion (4), illuminated by the first light projector (11), from a first position outside the beam of rays (2), which means are disposed in Scheimpflug configuration with respect to the beam of rays (2), and
- second image-capturing means for capturing a view image (3A) of the eye (3), in such a way that the view image (3A) comprises an image (4A) of the cross-sectional portion (4) illuminated by the first light projector (11),
- processing means (13) for storing the captured cross-sectional image (30A) and the captured view image (3A) assigned to each other in a data store, and determining the position of the stored cross-sectional image (30A) relative to the eye on the basis of the stored assigned view image (3A).
Device (1) according to claim 1, wherein the processing means (13) are designed to position the stored cross-sectional image (30A) relative to the previously stored cross-sectional images of the eye (3) on the basis of the stored assigned view image (3A).
Device (1) according to one of claims 1 or 2, wherein the processing means (13) are set up to determine the thickness (d) of the cross-sectional portion (4), illuminated by the first light projector, of the eye (3) on the basis of the stored view image (3A).
Device (1) according to one of claims 1 to 3, wherein the second image-capturing means and the first light projector (11) are disposed such that the optic axis of the second image-capturing means coincides with the beam of rays (2) running through the cross-sectional portion (4).
Device (1) according to one of claims 1 to 4, wherein the first and the second image-capturing means are disposed such that their optic axes are situated in a common plane.
Device (1) according to one of claims 1 to 5, wherein the first and the second image-capturing means comprise a common image converter (120), and the first image-capturing means comprise ray-redirecting optical elements (121A), the ray-redirecting optical elements (121A) being disposed such that, for generation of the cross-sectional image (30A), light beams are redirected to the common image converter (120).
Device (1) according to one of claims 1 to 5, wherein the first and second image-capturing means comprise a common image converter (120), and the second image-capturing means comprise ray-redirecting optical elements (121 E), the ray-redirecting optical elements (121 E) being disposed such that light beams are redirected to the common image converter (120) for generation of the view image (3A).
Device (1) according to one of claims 1 to 7, wherein the first image-capturing means are set up to capture and store a second cross-sectional image (30B) of the sub-area of the cross-sectional portion (4) illuminated by the first light projector (11), from a second position outside the beam of rays (2) simultaneously with the capturing of the first cross-sectional image (30A), the first position and the second position lying on different sides of a plane situated in the beam of rays (2).
Device (1) according to claim 8, wherein the first image-capturing means comprise an image converter (120), and the first image-capturing means comprise ray-redirecting optical elements (121A, 121 B), the first of the ray-redirecting optical elements (121A) being disposed at the first position in such a way that light beams are redirected to the image converter (120) for generation of a first cross-sectional image (30A), and second of the ray-redirecting optical elements (121 B) being disposed at the second position in such a way that light beams are redirected to the image converter (120) for generation of the second cross-sectional image (30B).
Device (1) according to one of claims 1 to 9, wherein it comprises one or more additional second light projectors (16) for projection of light markers (36) on the eye (3), and the second image-capturing means are synchronized with the first light projector (11) and with the second light projectors (16) in such a way that, during the capturing and storing of the view image (3A) of the eye (3), the image of the cross-sectional portion (4) illuminated by the first light projector (11) and an image of the light markers (36) projected by the second light projectors (16) are co-captured and co-stored.
Device (1) according to one of claims 1 to 10, wherein it comprises a screen element (17) with a visible pattern (17'), which screen element (17) is disposed such that the visible pattern (17') is situated on a side of the screen element (17) turned toward the eye (3) during application of the device, and the screen element (17) being disposed such that the beam of rays (2) is able to be projected unimpeded through the cross-sectional portion (4) of the eye (3), and such that the cross-sectional image (30A) and the view image (3A) are able to be captured unimpeded by the first, respectively second, image-capturing means.
Device (1) according to one of claims 1 to 11, wherein it comprises drive means (15) to rotate the first light projector (11) and the first and the second image-capturing means substantially about a normal to the surface of the eye (3) turned toward the first light projector (11) or to shift them substantially perpendicular to this normal.
Device (1) according to one of claims 1 to 12, wherein the first light projector (11) is designed such that it projects the beam of rays (2) in the form of a light slit.
Ophthalmologic measuring method, comprising:
- projecting a beam of rays (2) through a cross-sectional portion (4) of an eye (3), in particular through a cross-sectional portion (4) of the cornea of the eye (3), by means of a first light projector (11),
- capturing a cross-sectional image (30A) of at least one sub-area of the cross-sectional portion (4), illuminated by the first light projector (11), from a first position outside the beam of rays (2), by means of first image-capturing means which are disposed in Scheimpflug configuration with respect to the beam of rays (2),
- capturing a view image (3A) of the eye (3) by means of second image-capturing means, in such a way that the view image (3A) comprises an image (4A) of the cross-sectional portion (4) illuminated by the first light projector (11),
- storing the captured cross-sectional image (30A) and the captured view image (3A) assigned to each other in a data store, and
- determining the position of the stored cross-sectional image (30A) relative to the eye (3) on the basis of the stored assigned view image (3A).
Method according to claim 14, wherein the stored cross-sectional image (30A) is positioned relative to the previously stored cross-sectional images of the eye (3) on the basis of the stored assigned view image (3A).
Method according to one of claims 14 or 15, wherein the thickness (d) of the cross-sectional portion (4) of the eye (3) illuminated by the first light projector (11) is determined on the basis of the stored view image (3A).
Method according to one of claims 14 to 16, wherein the second image-capturing means and the first light projector (11) are disposed such that the optic axis of the second image-capturing means coincides with the beam of rays (2) running through the cross-sectional portion (4).
Method according to one of claims 14 to 17, wherein the first image-capturing means and the second image-capturing means are disposed such that their optic axes lie in a common plane.
Method according to one of claims 14 to 18, wherein the first image-capturing means are provided with ray-redirecting optical elements (121A), the ray-redirecting optical elements (121A) being disposed such that for generation of the cross-sectional image (30A) light beams are redirected to an image converter (120) used jointly with the second image-capturing means.
Method according to one of claims 14 to 18, wherein the second image-capturing means are provided with ray-redirecting optical elements (121 E), the ray-redirecting optical elements (121 E) being disposed such that for generation of the view image (3A) light beams are redirected to an image converter (120) used jointly with the first image-capturing means.
Method according to one of claims 14 to 20, wherein simultaneously with the capturing of the first cross-sectional image (30A) a second cross-sectional image (30B) is captured of the sub-area of the cross-sectional portion (4), illuminated by the first light projector (11), by means of the first image-capturing means from a second position outside the beam of rays (2) and is stored, the first position and the second position being established on different sides of a plane situated in the beam of rays (2).
Method according to claim 21, wherein first ray-redirecting optical elements (121A) of the first image-capturing means are disposed at the first position in such a way that for generating the first cross-sectional image (30A) they redirect light beams to an image converter (120) of the first image-capturing means, and second ray-redirecting optical elements (121 B) of the first image-capturing means are disposed at the second position in such a way that for generating the second cross-sectional image (30B) they redirect light beams to the image converter (120) of the first image-capturing means.
Method according to one of claims 14 to 22, wherein light markers (36) are projected on the eye (3) by means of one or more additional second light projectors (16), and the second image-capturing means are synchronized with the first light projector (11) and with the second light projectors (16) in such a way that during the capturing and storing of the view image (3A) of the eye (3), the image of the cross-sectional portion (4) illuminated by the first light projector (11) and an image of the light markers (36) projected by the second light projectors (16) are co-captured and co-stored.
Method according to one of claims 14 to 23, wherein a screen element (17) provided with a visible pattern (17') is disposed such that the visible pattern (17') is turned toward the eye (3), and the beam of rays (2) is projected unimpeded through the cross-sectional portion (4) of the eye (3), and the cross-sectional image (30A) and the view image (3A) are captured by the first, respectively second, image-capturing means in an unimpeded way.
Method according to one of claims 14 to 24, wherein the first light projector (11) and the first and the second image-capturing means are rotated substantially about a normal to the surface of the eye (3) turned toward the first light projector (11) or are shifted substantially perpendicular to this normal.
Method according to one of claims 14 to 25, wherein the first light projector (11) projects the beam of rays (2) in the form of a light slit.
Method according to one of claims 14 to 26, wherein the second image-capturing means are disposed such that their optic axis coincides with the optic axis (Z) of the eye (3) or runs substantially parallel to the optic axis (Z) of the eye (3).
Method according to one of claims 14 to 26, wherein the second image-capturing means are disposed such that their optic axis coincides with the line of vision of the eye (3) or runs substantially parallel to the line of vision of the eye (3).
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