DE19950791A1 - Image alignment in ophthalmic refractive surgery systems for refractive treatment of eye involves aligning two images of eye having spatial relationship, for performing refractive treatment - Google Patents

Abstract

Diagnostic measurement of patient's eye (12) is done. An image having an iris image (120) of the patient's eye is obtained. A spatial relationship between the image and the diagnostic measurement is determined. A refractive treatment is developed based on the diagnostic measurement. Another image of patient's eye is aligned to obtain spatial relationship with the previous image for performing refractive treatment. Independent claims are also included for the following: (a) A system for aligning a refractive correction instrument with a patient's eye; (b) Method for providing a course of refractive treatment; (c) Method of aligning a refractive correction instruments with a patient's eye; (d) System for aligning refractive diagnostic and treatment data; (e) Method of aligning refractive tools; (f) Method for eye alignment and characterization; (g) System for alignment and photo refractive treatment of eye; (h) Laser system

Description

Field of the invention

The present invention relates to systems for refrak tive eye surgery and especially the use of Iris detection and localization systems for alignment or comparing refractive diagnostic tools and refractory laser systems with the eye.

Technical background

The field of ophthalmic refractive surgery has grown significantly over the past two decades developed. Task of the ophthalmic refractive surgeon urgie is to refractive or refractive properties of the Au changes to correct various visual defects, e.g. B. Myopia (nearsightedness), hyperopia (farsightedness)  and astigmatism (myopia), as well as other defects. Several attempts have been made to achieve this optical Modify properties, including scratching or Incision of the cornea of the eye to relax of the corneal tissue, or the cornea itself to directly reshape or reshape. An example of the the former procedure is radial keratotomy; Examples the latter are photorefractive keratectos mie ("PRK"), external lamellar keratectomy ("ALK") and laser in situ keratomileusis ("LASIK").

Through the development and further developments or ver refinement of these techniques has resulted in greater precision refractive or refractive error correction. In early treatment types, the precision of the correction was right relatively rough. A correction with a tolerance of e.g. B. plus / minus a diopter of the desired correction for Nearsightedness or myopia would be an excellent result been considered. The types of treatment were increasing further developed or refined, so that a correction more difficult or subtle defects. Nearsightedness (myopia) and farsightedness (hyperopia) can now with high precision using conventional techniques be corrected, and using excimer lasers higher order effects, e.g. B. Asphericity and uneven presbyopia (astigmatism), corrected become. By using topography systems, sight errors determined and regardless of their "evenness" Getting corrected. Such techniques are described in U.S. Patent No. 5891132 entitled "Distributed Excimer Laser Surgery Sy stem ", issued April 6, 1999.

Through various screening and scanning or scanning technologies Such uneven refractive errors can be corrected the unevenness must first be determined  become. With the increasing precision of refractive Opera tion techniques were also refractive diagnostic techniques in the more precise. Except for a variety of topography systems (e.g., System 2000 from EyeSys Technologies, Inc., Hou ston, Texas and the ORBSHOT ™ system from Orbtek, Inc., Salt Lake City, Utah) are the total through numerous systems refractive error by analyzing the entire optical We of the eye, including the front and back of the Cornea, the lens and the distance to the retina, calc net. Some systems use algorithmic techniques, e.g. B. Orbtek's ORBSCAN® system, while other systems Use direct measurements instead of software simulations, e.g. B. the wavefront aberration system or the wavefront sensor disclosed in U.S. Patent No. 5,777,719 to Williams et al. ("Williams") are described.

For example, in the wavefront aberration system Laser beam projected onto the retina of the eye, and that received backscattered or reflected light passes through different refractive sections of the eye. This back sweeping image is segmented and analyzed to produce a required correction and change degree and type for the Determine cornea by means of normal vision (Emmetro pie) or an ideal visual function is obtained.

Description of the invention

Although ophthalmic refractive surgery techniques and ophthalmic refractive diagnostic techniques always pre This precision has become more and more demanding led to accuracy. According to the invention steps in the precision of both operations and of the diagnostic techniques also by using an image of the Iris (or part of the iris or other character  eye characteristic) for alignment or adjustment or alignment purposes during diagnosis and surgery realized. Before the refractive treatment is carried out the operating system will be based on one during the Diagnosis saved or aligned iris image chen.

For example, according to the invention by a horn skin surface topography system or a wavefront sensor system refractive characteristics of the eye recorded, each recorded but also a corresponding picture of the pupil and iris of the eye. Then the data corresponding to the iris image in Connected to data from the diagnostic system. If too additional diagnostic tools can be used, they can also use a pupil and iris camera to get one To provide "standardization point", which serves as a reference point for all data and subsequent treatment is used.

If the refractive treatment is to be carried out, e.g. B. LASIK treatment with an excimer laser another pupil camera takes an image of the iris, and one treatment developed from the diagnostic information normalized to this iris image. Transla tion, rotation, scaling or other transformation include functions. The treatment is then under provided that they are on the desired Points are applied to the cornea.

In addition, the iris image can be an eye tracking system be supplied so that the current target of the excimer laser on a dynamic basis with respect to the iris position can be compared.

The iris system preferably detects characteristic ones Features in the iris and determines translation functions ba based on these characteristics. Generally there are no two Iris equal, so that rotation, translation, scaling  or other transformation functions based on the cha characteristic features can be performed. The Iris system can store various characteristics of the iris, including an image of the iris itself, as well as stripped characteristic features of the iris, features of the pu pill and other parts of the eye, or features related to it can then contribute to reconciling data or that Align operating system before laser treatment or adjust.

As an added benefit, can be linked through iris data stored with the refractive diagnostic analysis a safe mechanism for subsequent treatment to be provided. In particular, if the iris data before the operation not with the one through the operating system recorded real iris image match, the operation un broken or prevented. This can, for example wise surgery of a false eye with specific Data or the use of another patient's data be prevented.

Brief description of the drawings

Fig. 1 is a flowchart showing the acquisition of iris image data and the use of the data for subsequent laser treatment;

Fig. 2A, 2B and 2C are block flow diagrams for illustrating the acquisition of iris data in conjunction with re fraktiven characteristic data, the generation of a treatment basie rend on these data and the use of Behandlungsda th in conjunction with an iris image to perform a La seroperation;

Fig. 3 shows a sectional view of an eye and associated diagnostic tools for determining specific re fractive features of the eye;

Fig. 4 is a diagram illustrating various features of an eye that can be used as characteristic iris data in a system or method according to the invention;

Fig. 5 shows a flowchart provided in the invention for illustrating the use of stored iris data and imaged iris data for converting a desired treatment into a real treatment;

Fig. 6 shows a block diagram of a wave front sensor for use in a system according to the invention;

Figure 7 shows a diagram of an exemplary fixation image for use in the wavefront sensor of Figure 6;

Figs. 8A and 8B show diagrams of the Wellenfrontsen sor of FIG 6 prisms used.

Fig. 8C shows a diagram of a drive system according to the invention for the prisms in Fig. 8B;

FIG. 9A and 9B are diagrams showing typi shear data sent back from the inventive wavefront sensor of Fig. 6;

FIG. 10 shows an image of current or real data that is sent back by the wavefront sensor according to the invention from FIG. 6; and

FIG. 11A and 11B are diagrams showing fuzzy wavefront sensor data, which are sent back from an illustrated example in FIG. 6, wave-front sensor, and the generation of a centroid of the data points of the wavefront sensor.

Embodiments of the invention Using iris data to match the laserbe action

Fig. 1 shows the general flow of a method for use of a system according to the invention. In block 10 , the iris is mapped in connection with the acquisition of refractive data in diagnostic tools. This illustration and the use of the diagnostic tool can be of various types. For example, the tool can be used appropriately before laser treatment in the form of a corneal surface topography system to determine a corneal or refractive profile. Or it can be used immediately before the refractory operation. In any case, the imaged iris or a representation of the iris is held with the data derived by the diagnostic tool.

A treatment is then developed in block 12 based on the data provided by the diagnostic tool. For example, a certain degree of myopia and uneven astigmatism can be treated by this treatment. This treatment can be, for example, a treatment using the algorithms described in PCT / EP95 / 04028 entitled "Excimer Laser System for Correction of Vision with Reduced Thermal Effects", published on April 25, 1996, wherein a A raster algorithm for modifying a corneal profile is provided in conjunction with the distributed system developed in US Patent No. 5891132 entitled "Distributed Excimer Laser System" issued April 6, 1999. However, this treatment is standardized to a stored representation of the iris image. This allows subsequent modifications of the treatment to be normalized to subsequent iris images based on additional diagnostic tool data.

In addition, the treatment itself is preferably targeted to the patient's iris. This takes place in block 14 , where the laser target and the treatment pattern are normalized to the image of an iris of the patient to be treated. This standardization can be a very general standardization, e.g. B. translation of the laser target to a suitable point, or a more complicated normalization, e.g. B. by Rota tion or even a scaling and inclination of the treatment to match the iris image with the laser system.

Then the laser treatment in step 16 is carried out. During the laser treatment, the system can periodically or even continuously compare the iris data with the stored representation of the iris data, ie track the patient's eye.

Figs. 2A, 2B and 2C show the general flow of determining refractive data, normalizing to the iris image, generating a course of treatment and on closing applying the treatment procedure in an OF INVENTION to the invention system. Fig. 2A shows two workstations for determining refractive characteristics of a Hornhautoberflä chentopografiesystems 100 and a wavefront sensor 102 (or aberrometer ™). Both devices generally provide data that represent refractive features of the eye. In addition, a workstation computer or a computing unit 104 is shown, which is used to generate a specific treatment process based on data provided by the diagnostic tool. Although the workstation 104 beitsplatzrechner as a separate Ar for use, for example, in a z. For example, as shown in the distributed system shown in PCT / EP97 / 02821, it and / or its functionality could be integrated into many of the other components of the system shown in Figures 2A, 2B and 2C. For example, a laser system 106 is also shown in FIG. 2C, which receives both the treatment generated by the workstation 104 and corresponding iris data. In the laser system 106, the functionality of the workstation 104 could be integrated, so that an appropriate laser treatment would be produced in nerhalb of the laser system 106 itself.

Starting with Fig. 2A, the Hornhauttopografiesy a patient causes stem 100 topographical data from the eye E. The topography system shown has hardware 108 similar to a Placido disc and a pupil or iris camera 110 . These components are known and various techniques for generating corneal topography data are known. For example, the System 2000 from EyeSys generates corneal topography data, and the ORBSCAN® system from Orbtek not only generates corneal surface topography data, but also an overall topography for the various eye components. The former system is a system based on a Placido disc; the latter system is based on an automatic slit lamp. The topography system 100 may typically generate output data 112 in various formats that are generated using various techniques, e.g. B. in the form of absolute corneal heights at different points, of corneal curvatures at various points, and the like.

In addition to corneal data 112, corneal topography system 100 also captures a corresponding "snapshot" of the visible surface of eye E, thereby providing first iris (and pupil) image data 114 that represents an iris (and pupil) image 120 . Many corneal surface topography systems have a pupil camera that can capture this image. As will be discussed in more detail below, the pupil or iris camera 110 can provide the iris image data in various formats, e.g. B. as a standard image format, or as a reduced format in which different iris or pupil structures or features are identified. These structures or features can have those that are identifiable along the edge of the interface between the pupil and the iris. Iris data 114 may be a combination of an image and identified structures or features of the iris, pupil, its interface, or other eye structures.

The pupil or iris camera 110 can be one of various camera types, e.g. B. a camera working with visible light, an infrared camera or another camera that is suitable for taking the iris image 120 . Preferably, the image is captured at the same time the topography components (hardware similar to a Placido disc) 108 capture the topography data 112 , although an earlier or later time would also be acceptable.

As shown in FIG. 2A, the topography data 112 and the iris image data 114 are preferably related to one another according to a coordinate system, as represented by superimposed images 116 . The relationship between a particular topography 118 and iris image 120 is maintained in the data.

As discussed below, iris image data 114 is suitable for iris image 120 for aligning or aligning an operating tool (here, laser system 106 ). However, data 114 is also useful for normalizing data from various other eye diagnostic tools or devices. In particular, the wavefront sensor 102 also analyzes refractive irregularities or errations in the eye E. Such a wavefront sensor 102 is, for example, similar to the sensor described by Williams; another suitable wavefront sensor is discussed below in connection with FIG. 6. In the wavefront sensor 102 , a pupil camera 122 is preferably focused on the eye E in front of a suitable “telescope” optics 124 . The telescope optics 124 (e.g., a device or optics to adjust the focus or the optical path) is used to change the optical path length and to focus a laser 126 on the retina of the eye E. Te leskopoptik 124 can be used to optical aberrations low order of the eye E, z. B. a defocusing, to determine and compensate. In one embodiment, the wavefront sensor 102 acquires data for determining optical aberrations in the eye E via a lens camera 128 . Various other wavefront sensors or system types can be used to determine refractive ophthalmic waves front aberrations.

As with the corneal surface topography system 100 , the wavefront sensor 102 preferably provides aberration data 130 and iris (and pupil) image data 132 from the pupil camera 122 . An aberration profile 134 - e.g. B. a wavefront sensor light spot profile, from the focus of light spots be determined to determine the wavefront aberrations of the eye, as described by Williams - and get an iris (and pupil) image 136 . Iris image data 132 may be similar to iris image data 114 . The wavefront sensor data 130 and the iris image data 132 are also normalized to one another, as represented by an overlapping reference frame 138 in FIG. 2A. The pupil is preferably dilated when the aberration data 130 and the image data are acquired.

When developing a course of treatment for a refractive surgery, e.g. B. a LASIK treatment, various types of refractive data can be determined and used. This data may be corneal topography data, wavefront sensor data, corneal thickness data or other differential or differential profiles (e.g. using ultrasound) of eye components and other types of refractory data generated by various sources, e.g. B. by slot scanning or optical coherence topography techniques. For example, ultrasound can be used to measure not only the corneal thickness, but also the epithelial and other eye surfaces, the proportion of the current component in a corneal disc obtained by a microkeratome incision (for LASIK), the residual stroma under the corneal disc, and similar parameters . This data is typically provided on a point-by-point basis for the eye E with different resolutions. For example, corneal topography data 112 from corneal topography system 100 will generally have a higher resolution than wavefront sensor data 130 . Similarly, certain types of data relate to an aspect of the eye E, e.g. B. the corneal surface topography data 112 , which map the surface topography of the eye E, while other data may reflect other aspects of the eye E, e.g. B. The total refractive error found in the wavefront sensor data 130 by the wavefront sensor 102 .

In addition, the refractive diagnostic tools could ver have different configurations, for example assign a fixed system, a table system or a handheld system or several in one integrated systems. For professionals it can be seen that the techniques of the invention in one implement a wide variety of physical embodiments are animal.

According to one embodiment of the invention, these data records are normalized to one another for a more precise generation of a refractive treatment. Here, the topography data 112 and their corresponding iris image data 114 are normalized to the wavefront sensor data 130 and their corresponding iris image data 132 . For example, these two data sets (represented by a diagram 140 ) are normalized to one another based on similarities of the iris image 120 and the iris image 136 (represented by an iris image 142 ). As discussed above, this normalization can be obtained by overlapping or overlaying the iris images themselves, or instead by matching characteristic elements of the iris (and pupil) images, as described above in connection with FIG. 4.

In a particular embodiment shown in FIG. 2B, aberration profile 134 is processed (e.g., by Zernike polynomial fitting, as discussed by Williams and herein) to generate wavefront aberration data that is referred to as pupil wavefront aberrations (e.g., contour) - Diagram 160 are shown. The wavefront sensor data 130 and the iris image data 132 ( FIG. 2A) are also normalized to one another, as shown by an overlapping reference frame 162 in FIG. 2B. As discussed above, the pupil is preferably dilated when the aberration data 130 and image data are acquired, and these data sets are normalized to one another for more accurate generation of refractive treatment. The topography data 112 and its corresponding iris image data 114 are normalized to the wavefront sensor data 130 and its iris image data 132 . For example, the normalization of this data is represented by a (superimposed) diagram 164 , which is parallel to the above discussion of FIG. 2A based on similarities of the iris image 120 and the iris image 136 (represented by an iris image 142 ). The topography data 118 may extend over a larger portion of the eye, e.g. B. over most of the cornea or over the entire cornea, while the wavefront aberration diagram (or the wavefront aberration data) 160 can extend over the pupil. It will be apparent to those skilled in the art that a certain correlation between the pupil wave front aberration diagram 160 and the topography 118 , if overlapped like or similar to the diagram 164 , can be discernible, even if no iris image data for the alignment or the adjustment or the normalization be used. To normalize or superimpose the topography and wavefront aberration data (e.g., the topography data 118 and the pupil wavefront aberration diagram 160 ), the changes in the optical path length (e.g. from the wavefront aberration data) or the refractive index (e.g. by averaging refractive indices ) of the eye can be taken into account in a suitable manner in order to correlate this data, as is apparent to experts.

Regardless of whether data is generated according to the method shown in FIG. 2A or in FIG. 2B, a computer program subsequently generates a treatment profile 144 , as shown in FIG. 2C. This can be done, for example, by a stand-alone computer 104 , a computer connected to the Internet or another network, or in a computing system that is part of the laser system 106 , the topography system 100 , the wavefront sensor 102 or other systems. The treatment generated can be one of several treatments. For example, a non-uniform treatment pattern could be performed, as shown in the aforementioned U.S. Patent No. 5,891,132, or various other types of treatment could be performed, e.g. B. a laser treatment with variable light spot size, with a slot scanning or slot scanning technology or with a fixed scanned light spot size. Irrespective of the treatment carried out, the treatment pattern with respect to the data 140 or 164 is generated by various diagnostic tools and can be kept normalized on the stored iris image 142 .

The data from the various diagnostic tools can be used in various ways to generate treatments. For example, only the data 130 from the wavefront sensor 102 could be used to generate a treatment, or instead the data 112 from the corneal surface topography system 100 could be used. Only other alternative types of refractive diagnostic tool data can be used to generate treatments. Advantageous aspects of the data from the different tools could be combined to get better refractive treatments overall. In play, the corneal surface topography system 100 sends surface topography data regardless of the expansion degree back of the pupil, the wavefront sensor 102 may vary but be limited by the degree of expansion of the pupil (that is, the wavefront sensor 102 typically only measures re fraktive effects of optical elements that are located in the optical path) . Therefore, as represented by diagram 164 of FIG. 2B, data 112 from corneal surface topography system 100 could be used over an area larger than the dilated pupil, while data 130 from wavefront sensor 102 could be used for the central portion within the pupil area could become. In the cases, data 130 and data 112 can be matched by a first spatial normalization using their respective iris images 120 and 136 . As another example, the data from different diagnostic tools can be combined to provide an overall model of the optical elements in the eye. For example, the corneal surface topography system 100 could provide surface data, an ultrasound system could provide corneal thickness data, and the wavefront sensor 102 could provide total refractive error data. By "subtracting" the effects of the surface data and the thickness data, optical elements behind the cornea can be modeled using different data sets. By first comparing the data sets based on the respective iris images, higher accuracy can be achieved.

Fig. 3 shows a cross-sectional view of the eye E with a cornea 450, a lens 456 and a retina 458th The cornea 450 has several layers, e.g. B. an Epit hel 452 and a Stroma 454 . These various components, in particular the cornea 450 and the lens 456 , act together and form an overall refractive (optical) power and total refractive properties of the eye E. Several factors can contribute to refractive (e.g. wavefront aberration) errors, e.g. B. irregularities in the cornea 450 or in the lens 456 and the distance (e.g. in the sense of a defocusing aberration) from the cornea 450 and the lens 456 to the retina 458 .

In addition, Fig. 3 shows designations for representing various types of diagnostic tools that are particularly suitable for analyzing refractive and other properties of certain sections of the eye E. These tools can be used to provide different types of data for different sections or components of the eye E. For example, ultrasound techniques 460 can typically determine thicknesses of epithelium 452 and stroma 454 , thereby obtaining the total thickness of cornea 450 . Various types of ultrasound technology can be used, e.g. B. a pachymeter or a technique described by Dan Z. Reinstein, MD in US Patent No. 5,293,871 with the title "System for Ultrasonically Determining Corneal Layer Thickness and Shape" issued March 15, 1994.

A corneal surface topography is typically provided and analyzed by corneal surface topography systems 462 . Topography systems, e.g. The ORBSHOT ™ system from Orbtek and the System 2000 from EyeSys typically have a very high resolution, but are limited to the surface of the epithelium 452 of the cornea 450 .

A combined refractive diagnostic tool 464 , e.g. B. the ORBSCAN® system from Orbtek, typically determines and analyzes different thicknesses and surfaces within the eye. This can include the thickness of the cornea 450 , the surface topography of the cornea 450 , the surface of the lens 456 , the distance from the lens 456 to the cornea 450 and the distance from this front optic of the eye to the retina 458 . Various refractive diagnostic tools typically work together in such tools, e.g. B. A slit lamp as discussed in Richard K. Snook, U.S. Patent Nos. 5,512,965 and 5,512,966, assigned to Orbtek, Inc., Salt Lake City, Utah, and ultrasound or light scattering techniques.

Finally, the wavefront sensor 466 shown in FIG . B. the above-described Wel lenfrontsensor 102 or the Wel lenfrontsensor described by Williams, data about the total refractive aberra tions of the eye are provided, which are shown as aberration waves front profile (data) 468 . The wavefront sensor technologies are empirical in nature and relate to the characterization of the wavefront of external light incident on the eye, which was reflected by the retina 458 , instead of physical parameters of any specific optical component of the eye E.

Referring to FIG. 2C lung 144 is typically a course of treatment based on the generated treatmen, z. For example, a series of shots, a series of slits to be scanned at different aperture sizes, or various other treatments, are provided for a particular type of laser system 106 . The course of treatment represented by a profile 146 is itself spatially related to data representing the iris image. The data 148 could again be an image of the iris itself, a high-contrast black and white representation of the iris, a positional representation of various features of the iris, or various other representations of the iris. In general, the data 148 representing the iris should be suitable for comparing the treatment sequence 146 with the real iris of the eye E if the eye E is to be treated by the laser system 106 .

Laser system 106 is then loaded with the treatment profile, including treatment process 146 and iris data 148 . According to Fig. 2C, the laser system can be any of various laser system types, such. B. a 193-nm excimer laser, and will typically be a laser 150 , a target system 152 (e.g., a series of optical components that are used to direct light from laser 150 to eye E), a pupil camera 154 and have a control system 156 . A lower power target or reference beam (not shown) is typically used in conjunction with the laser 150 . The target beam, e.g. A laser beam, for example, can be monitored by the pupil camera 154 , which is typically an infrared camera, and can be used to align the laser 150 as described in U.S. Patent No. 5,620,436, entitled "Method and Apparatus for Providing Precise Location of Points on the Eye ", issued April 15, 1997 [PCT / EP95 / 01287, published October 19, 1995].

In operation, the pupil camera 154 supplies the control system 156 , which controls the target system 152 , with an image of the iris I (see FIG. 2C) of the eye E. The image of the iris I actually supplied to the excimer laser system 106 is compared with the iris data 148 which are associated with the treatment sequence 146 . The target of the laser head 150 is then set such that the iris data 148 are substantially compared with the image of the iris I provided by the pupil camera 154 . This may include translation, rotation, scaling, or tilt functions, or various other transformation functions. The translation that is applied to iris image data 148 and necessary to match iris I is similarly performed in treatment flow 146 leads so that the final course of treatment, when applied to, corresponds to a course of treatment that is necessary to reduce the optical effects predicted in the generation of the treatment profile 144 .

The data of the treatment process 146 itself can be changed, or instead the target of the laser system 106 or the rotational orientation of the patient can be changed. Regardless of the method, iris data 148 is used to align iris I before treatment 146 is applied.

The techniques or processes described can be found in various types of eye surgery are advantageously used become. (photorefractive keratectomy) procedure can be based on the outer surface of the eye can be applied, or a LASIK Procedure can be performed by first part incised the cornea backwards and then the laserbe action is applied to the underlying part.  

The techniques themselves may also be suitable for others re, non-keratectomy treatments, e.g. B. excimer keratomy, or different thermal methods for refractive Correction. These treatment procedures can be carried out with the Iris des Eye be adjusted exactly, so that the calculated Be action pattern for theoretically optimal positions more precise is produced.

Other advantages result from the use of the iris data in connection with the diagnosis and treatment data. For example, when a patient is in an upright position for diagnostic analysis, the eye position may sometimes be slightly rotated within the eye socket compared to a reclined position of the patient. Although the patient's brain can compensate for such slight twist, in a high-precision correction treatment pattern for higher-order defects, the eye can literally be rotated out of position by the change in the orientation of treatment, thereby treating the eye incorrectly. The effects of such misalignment are for basic treatment procedures, e.g. B. for myopia and hyperopia, typically not essential, and even for minor treatments of astigmatism, but for higher order defects, e.g. B. uneven astigmatism, glare, halo, and the like, the benefits of high-precision treatment can be lost, however, if no precise comparison with the optimal spatial treatment position is obtained and maintained. The techniques of the invention can reduce such alignment or alignment loss. Various techniques can be used with respect to iris adjustment and alignment itself, either using real images of the iris or digital representations of various features of the iris. These techniques have been used in recognition systems based on unique features of an iris, such as. See, for example, US Patent No. 5572596 to Wildes et al., Issued November 5, 1996, entitled "Automated, Non-Invasive Iris Recognition System and Method" assigned to David Sarnoff Research Center, Inc., Princeton, New Jersey, and in U.S. Patent No. 4,641,349 to Flom et al., Issued February 3, 1987, entitled "Iris Recognition System", both of which are incorporated herein by reference. The first of these patents describes scaling, rotation and translati on; the latter of these patents discuss various features that can be used to uniquely match and identify an iris, and also discuss that a control mechanism can be used to adjust the position of the iris with respect to the camera. In one embodiment of the present invention, a similar technique can additionally be used to align laser system 106 . Similarly, Daugman U.S. Patent No. 5,291,560, issued March 1, 1994, entitled "Biometric Personal Identification System, Sed on Iris Analysis" assigned to Iri Scan, Inc., Mount Laurel, New Jersey, also refers to this incorporated herein by reference, which discusses the "optical fingerprint" provided by the iris. The pattern and feature matching or matching techniques of these patents and other known methods are used for matching or alignment purposes rather than for strict identification purposes.

Alternatively or additionally, the camera 154 of the laser system 106 can receive an image of the iris I, which is then displayed on a screen. The iris image data 148 can then be overlaid to enable a doctor, technician, or other medical professional to manually set up or align the laser system 106 or to manually verify the target of the system 106 .

Figure 4 shows the iris I of the eye E in greater detail to illustrate how certain features can be used to adapt the patient's eye E to treatment with his or her previously stored iris (I) image. For example, a set of points 200 that have generally circular features, e.g. B. small collars, define as used as descriptors, as well as grooves 202 or radial grooves 204 . Other useful features are generally described in the aforementioned Flom U.S. Patent No. 4641349, which includes pigment spots, pits, atrophic areas, tumors, and congenital filaments or fibers. Similarly, the pupil to the irisab can be z. B. can be used as a reference point, from which then iris features define the rotational position of the eye. It can e.g. B. depending on the complexity of the treatment to be used fewer or more features ver used. If the treatment is rotationally symmetrical, e.g. B. treatment for pure myopia or hyperopia, a rotational offset has no consequences, so that the center can be localized with respect to the pupil. If the treatment is more complex, however, more detailed features can be used for a more precise adjustment of the eye E before the treatment. Alternatively, artificial features can be impressed on the eye E for determining the position, including the iris area. For example, three laser marks can be created on the eye E if the treatment is to be carried out before the laser marks would heal. Then the diagnostic steps can be carried out and treatment can follow immediately thereafter. In addition to Iris I, other characteristic sections of the visible surface of the eye can be used. In all of these techniques, features of the visible portion of eye E are used to balance the diagnostic system, the treatment being developed, and the actual treatment being applied to eye E.

Fig. 5 shows various settings that can be made based on the signal received by the laser system 106, the real image of the iris I. According to Fig. 2C, the treatment generated 144 is provided as a desired fil Behandlungspro 146 for controlling the laser system 106. The corresponding reference iris image data 148 from the diagnostic tools are used to compare the treatment pattern 146 with the patient's eye E. The iris image 206 is provided by the pupil camera 154 of the laser system 106 and supplied to the control system 156 . The control system 156 compares the image 148 or the descriptors derived from this image with the iris image 206 . Based on the comparison, different scaling functions are applied to the desired treatment 146 . For example, it can be determined based on the total size of the real iris image 206 that the scale of the treatment should be reduced due to different focal lengths of the diagnostic tools 100 or 102 and the laser system 106 . Such scaling 208 is calculated and applied, whereby a scaled treatment 210 is obtained. It can then be determined that the now scaled, desired treatment 210 must undergo both translation and rotation, as represented by a translation and a rotation function 212 . This is applied to the scaled desired treatment 210 , whereby the real treatment 214 is obtained. This data is then used by laser system 106 to carry out the actual treatment.

Alternatively, if the control system 156 has sufficient computing power, each shot (ie laser pulse) can be appropriately rotated and translated or shifted in parallel. This may be desirable if, for example, the eye E has a greater degree of dynamic rotation and movement during the treatment. Then the iris image 206 can be tracked, and the scaling functions 208 and 212 shown in FIG. 5 can be applied dynamically to the shot or each shot sequence in the desired treatment pattern 146 . In this way, the movement of the eye E can be adjusted shot by shot. This technique can be combined with the laser aiming or alignment technique described in PCT / EP95 / 01287 so that the exact placement of each shot or shot sequence with respect to iris image 206 is determined before the shot or shots are performed.

Therefore, in embodiments of the invention, a a variety of diagnostic tools with one Camera or other imaging device the one that is an image of the pupil, iris, or some other characteristic feature of the exterior of the eye and transmits data corresponding to this image. Then when a refractive treatment, e.g. B. an excimer laser treatment in a LASIK system, the stored one is executed Image (or its characteristic components) with the compared real image of the pupil, iris or eye, to align the laser so that the treatment according to the Calculation is carried out precisely.

Patient and eye validation

As an added benefit, when the patient lies and the iris I image ( FIGS. 2C and 4) is captured, the iris matching algorithm can determine not only translation, scaling, rotation and tilt to match the real iris image 206 , but also validate the eye E to be operated. This iris adjustment algorithm therefore serves as a safety mechanism to ensure that a specific laser treatment is actually the appropriate treatment for this patient and not for another patient. Similarly, it serves as a safety mechanism to ensure that the appropriate eye E is operated on, since two irises of a single patient also have different description features. These security mechanisms are particularly suitable in distributed systems in which the diagnostic information is recorded at a first point and the treatment is developed at a second point and then used at a third point. The system can generate a warning if the iris features cannot be matched.

Similar to the alignment or the alignment of the laser system 106 , the validation can be carried out automatically or manually using a visual display on which the iris image data 148 is superimposed on the iris image from the camera 154 .

Wavefront sensor

FIG. 6 shows a block diagram of a wavefront sensor 300 (Aberrometer ™) which is a preferred implementation of the wavefront sensor 102 of FIG. 2A. The wavefront sensor 300 operates similarly to the Williams wavefront sensor, but has certain features that make it particularly suitable for receiving iris data and for focusing the focus of light spots on a sensor used to determine the wavefront aberrations of the eye. Generally, the wavefront sensor 300 focuses light (typically from a laser) on the retina of an eye or scans light across the retina and then analyzes and returns on the return (e.g., scattered back from the retina) through the lens and corneal optics of the eye a lens arrangement imaged and focused by it. Based on optical aberrations in the optical components of the eye, the system develops an overall wavefront aberration analysis based on the returning light. In general, in order to perform the analysis, virtual images are generated on a sensor of the lens camera from the returning light by a lens camera. Each small lens of the lens arrangement scans the returning image wavefront on the lens arrangement and effectively "sees" the laser light spot on the retina of the eye. From this analysis, the wavefront sensor 102 develops a wavefront aberration map to show which corrections of the optical components of the eye are required, through which normal vision (emmetropia) or near normal vision is obtained.

In order to suitably align the patient's eye E, two 660 nm laser diodes 302 shown in FIG. 6 can be aligned at angles to the eye E. When light spots on patient E's eye E from laser diodes 302, by appropriately aligning wavefront sensors 300 (or 102 ), the output beams of laser diodes 302 (or the optical elements for aligning these beams), the patient, or by other factors are united into a single light spot, the eye E is arranged at or approximately at the precise focal distance from the wavefront sensor 300 (or 102 ). Alternatively, the patient's eye E may be appropriately aligned by a doctor, technician, or other medical professional by visually viewing an iris image of eye E to find the correct focal distance from wavefront sensor 300 and reduce the total exposure of eye E. In this case, laser diodes 302 are not required. A light source or eye illumination 304 provides light for a pupil camera 328 described below.

Once the eye E is properly aligned, it receives light from a light source 306 (e.g., a laser diode, such as a 780 nm laser diode) along an optical path to the eye E. Preferably, the laser diode 306 more than an adjustable output power (i.e. it works in two or more power modes), a lower power for the alignment and the initial focusing and at least a higher power for generating a multi-spot or multi-point image in one sensor (e.g. a lens camera) 312 as described below. For example, typical lower and higher powers are 0.5 µW and 30 µW, respectively. These performance values depend on several factors, e.g. B. because of how long the laser diode 306 should be operated at a higher power.

A portion of the beam from laser diode 306 is next reflected by a beam splitter 308 (e.g., with a light transmittance of 80% and a reflectivity of 20%). The reflected beam passes through a polarization beam splitter 310 that improves the signal-to-noise ratio (or signal intensity) of the light scattered back from the retina of the eye, which is ultimately captured by lens camera 312 , as discussed below. The beam splitter 310 polarizes the light received by the laser diode 306 and generally transmits light that is linearly polarized in one direction and reflects light that is not polarized in that direction. The polarized light then passes through a reciprocating or telescoping prism 314 (similar to telescope optics 124 in Fig. 2A), as discussed below in connection with Figs. 8A and 8B, which is used to focus the light by the laser diode 306 to adjust the retina of the eye E, at which point light scattered back from the retina onto the lens arrangement will be correctly or almost correctly focused. The light from the telescoping prism 314 is reflected by a mirror 316 , passes through a beam splitter 318 (e.g., having 20% reflectivity and 80% light transmittance), and then a λ / 4 plate or wave plate 320 . The λ / 4 plate 320 is oriented so that essentially circularly polarized light is generated from the linearly polarized light. The meaning of this will be seen in the discussion below of the light ("returning light") scattered back from eye E to polarizing beam splitter 310 .

After the light has passed through the λ / 4 plate 320 , it is focused on the retina of the eye E. The light is backscattered or reflected by the retina, and the backscattered light spot on the retina then passes through the optical components of the eye, e.g. B. the lens and the cornea. On the way back, the circularly polarized light is retarded by the λ / 4 plate 320 in order to obtain light which is relative to the incoming linearly polarized light which is generated on the first pass through the λ / 4 plate 320 , as discussed above, is vertically linearly polarized. A portion of the perpendicularly polarized light then passes through the beam splitter 318 , is reflected by the mirror 316 , passes back through the prism 314 , and then returns to the polarization beam splitter 310 . At this point, the light is fully or largely polarized perpendicularly so that it is essentially reflected by the polarizing beam splitter 310 and then reflected by a mirror 322 into a lens imaging camera 312 . In order to direct some of the returning light into an alignment camera 323 , as discussed below, the λ / 4 plate 320 can be tilted and / or rotated (e.g., rotated about 5 degrees) in its optimal orientation. . In this implementation, the light received by match camera 320 would be polarized substantially perpendicular to the returning light. Within the scope of the present invention, various methods of supplying the returning light to the alignment camera 323 are also conceivable from tilting and rotating the λ / 4 plate with respect to its optimal orientation, including changes in the optical path and optical components of the wavefront sensor 300 (or 102 ). For example, mirror 322 could instead be a device with controllable light transmittance and reflectivity, e.g. B. a liquid crystal device, and the alignment camera and any Liche optical focusing elements can be positioned so that they let through part of the light transmitted through the controllable device. In such an implementation, beam splitter 308 would be unnecessary and the light received by the controllable device would have substantially the same polarization as the light to be returned or a parallel polarization.

The lens camera 312 is preferably a Ladungsspei cherbaustein (CCD) camera, e.g. B. a TM-9701 camera manufactured by Pulnix with a small lens array 324 , although different cameras and lens array 324 analog, other optical scanning or scanning components could be used (including optical elements separate from a camera) ). The lens arrangement 324 generates virtual images on the light detection element (e.g. CCD arrangement) of the lens camera 312 from the returning light reflected by the mirror 322 . The λ / 4 plate 320 can help reduce the amount of unwanted backscattered or stray light to improve the signal intensity or contrast of the virtual images. The lens assembly 324 focuses portions of the light that initially passed through the optical components of the eye E so that the refractive wavefront aberration effects of the eye E can be determined, similar to what Williams described. In this regard, once the wavefront aberrations and thus the phase error of the eye E have been determined, they can be transformed into a necessary ablation profile in order, with suitable reference to parameters of the eye E (e.g. to the refractive indices of the components of the eye E and / or other parameters) to remove corneal tissue and correct or improve visual defects. Markings on the eye E can be used to support the alignment of the eye E during the acquisition of the wavefront sensor data.

The lens arrangement 324 is preferably an arrangement of approximately 25 × 25 small lenses with an area of 600 μm ² each, e.g. B. Model 0600-40-S, manufactured by Adaptive Optics Associates, Incorporated. The small lenses are smaller than the lenses described in the aforementioned U.S. Patent No. 5,777,719 and used in other systems, which is made possible by the greater light intensity of the light supplied to the lens camera 312 obtained by components of the wavefront sensor 300 to be discussed below becomes. The optical path of the wavefront sensor 300 shown in FIG. 6 may also include lenses 326 (e.g., four lenses) and apertures or openings 327 (to allow changes in beam size) that are typical of the illumination, imaging, and focusing optics and may also represent other possible optical elements that are omitted for clarity. For example, in one embodiment of the invention, the focal length of one or both of the lenses 326 near the telescopic prism 314 can be changed, possibly shortened, to allow for a smaller width of the beam entering the lens assembly 324 . In another embodiment, the diopter measurement range possible by the wavefront sensor 300 (or 102 ) can be changed, for example, by appropriate selection of the lens 326 in front of the laser 306 to adapt to the natural poor sight distribution in the general or in a selected population of patients to obtain. One method to achieve this is to arrange lens 326 (e.g., a 5 diopter lens) in front of laser diode 306 so that the laser beam is no longer parallel. This provides a certain diopter offset that can be used to check the patient's eye through the wavefront sensor 300 (or 102 ). In a non-limiting example, as will be apparent to those skilled in the art, the diopter range can be modified from a symmetrical range from -8 to +8 diopters with a symmetrical structure to an asymmetrical range from -13 to +3 diopters with an asymmetrical structure. This can be achieved without changing the size of the telescopically movable focusing prism 314 (or another alignment device) and / or parameters of the optical elements.

In the illustration, a pupil camera 328 receives z. B. 20% of the light reflected by the beam splitter 318 .

The pupil camera 328 preferably generates the iris image data 132 for the iris image 136 by a control system (not shown) that is the same or similar to the control system 156 discussed above in connection with FIGS. 2A, 2B and 2C. For a comparison, data from the lens camera 312 is processed and provided as aberration data 130 , as shown in FIGS . 2A and 28.

The pupil camera 328 is arranged in the optical path between the eye E and the telescopically movable focusing prism 314 , so that the pupil camera 328 focuses on the pupil and the iris of the eye E regardless of changes in the focal length of the rest of the system for focusing on the retina can. Therefore, the pupil camera 328 can produce a clear image of the surface of the eye E regardless of the depth of the eye E and the corresponding distance from the retina to the iris.

Focus adjustment camera

The wavefront sensor 300 also has the alignment camera 323 , which receives an image of the backscattered light spot on the retina of the eye E from a beam splitter 332 (e.g. with a reflectivity of 50% and a light transmittance of 50%). The alignment camera 323 is arranged in the path of the optical elements that focus light onto the retina of the eye E and is independent of the lens camera 312 . The adjustment camera 323 enables a precise determination of when the light spot striking the retina from the laser diode 306 is in or approximately in focus, and therefore supports the determination of when the light scattered back from the retina is in or approximately in the focus of the lens camera 312 located. The adjustment camera 323 can see the light spot on the retina that is the source of the center of gravity signals (as in Williams) and can be automatically examined when it is in the sharpest focus in order to focus the virtual images as sharply as possible to enable the lens camera 312 . No alignment camera was used in conventional systems. Such systems would only use the lens camera to help focus the light on a retina and the backscattered light on the lens camera. The problem with this method is that the part of the wavefront scanned by a single small lens of a lens assembly from n small lenses immediately detects individual light spots or points on the camera sensor with at most about 1 / n of the total energy (or power) of the returning backscattered light Before one enters the lens camera. As a result, the retina (or the eye) was unnecessarily exposed to high light energy (or power). As will be appreciated by those skilled in the art, the present invention can reduce the total exposure of the retina (or eye) compared to these conventional systems because the light energy (or power) received at the alignment camera 323 is only about the light energy (or -performance) which must be received on a single small lens of the lens arrangement. The alignment camera 323 is used to directly observe the focus of the light from the laser diode 306 on the retina while the laser diode 306 is operating in its lower power mode. The comparison camera 323 therefore supports the sharpest possible focusing of virtual images on the lens camera 312 , while the laser diode 306 is operated in its lower power mode. Thereby, the light transmittance of the polarizing beam splitter 310 and the beam splitter 308 , the reflectivity of the beam splitter 332 and any inclination or rotation of the λ / 4 plate 320 with respect to its optimal orientation can be taken into account to allow a part of the returning light to the matching camera 323 is returned.

As discussed above, the alignment camera 323 is used to ensure that the light spot on the retina is as sharp as possible. That is, the correct settings of the telescope mechanism of prism 314 (or 314 ', as discussed below with reference to Figures 8B and 8C) and the orientation of the patient are checked. Based on these settings and the alignment, a signal can be generated (e.g. from the alignment camera or from a control system, e.g. from the control system 156 in FIG. 2C) to manually check the measurement values of a patient to initiate or start the patient measurement or examination automatically. Such functions also enable an increased light intensity to be supplied to the lens camera 312 only for the duration of the measurements or examination and not during the focusing and adjustment period discussed above.

In the lower power mode, the laser diode 306 is set to a power low enough to prevent damage to the retina of the eye E, e.g. B. to 0.5 µW. The use of the alignment camera 323 in the control system to support the focusing of the laser diode 306 on the retina can be done in several ways. For example, the spot size on the retina can be minimized, or the intensity of the spot on the retina can be maximized by moving the position of the telescoping prism 314 (or 314 'as discussed in connection with FIGS. 8B and 8C ) is set in the optical path of the wavefront sensor 102 (and 300 ) until the light spot is as small as possible. The position of the telescoping prism 314 (or 314 ') defines a "baseline or reference line" of the degree of myopia or hyperopia of diopter correction required to initially correct lower order refractive optical aberration features of the eye E. It is useful to ensure that lasers 302 are aligned at an angle to laser diode 306 that overlaps their respective light spots on the retina (or by other methods, e.g., manual or visual alignment of the retina) Patient's eye) in conjunction with adjusting the position of the telescoping prism 314 (or 314 ') while determining the baseline or reference line level of the myopia or hyperopia error or myopia or hyperopia correction.

Once focus is achieved, laser diode 306 is set to a higher power mode for a very short period of time. For example, a power of 30 µW with a light spot size of 10-20 µm on the retina can be used for a period of 400 ms. Although a higher intensity could damage the retina if it were maintained for a longer period of time (e.g. more than 100 s), such a short pulse is harmless. By the short pulse, however, the intensity of the individual light spots on the sensor of the lens camera 312 is significantly increased, so that by the combination of the multi-power laser diode 306 , the alignment camera 323 , the lens arrangement 342 and the lens camera 312 a higher signal intensity or lens images with a higher Contr are obtained by the lens camera 312 than in other systems. The higher power mode of the laser diode 306 enables the use of individual small lenses with a smaller cross-sectional area in the lens arrangement 324 compared to other systems.

Fixation target

The wavefront sensor 300 (and 102 ) also uses an image that is used as the fixation target 334 , as shown in FIG. 6. The fixation target 334 is illuminated by a light source 336 and enables a patient to fixate and focus his eye on it, while the alignment camera 323 is focused on the retina by the prism 314 . The fixation target 334 is useful when the virtual images from the lens assembly 324 are focused on the sensor of the lens camera 312 by adjusting the telescoping prism 314 . The system advantageously provides an image for the fixation target 334 , with one non-limiting example of a fixation target being the sailboat shown in FIG. 7 on What Water, and not simply a fixation point. The fixation target 334 conveys to the eye E and the patient's brain an image-like or real image or a scene - actually an object or a scene is being viewed by the eye E - which is to be focused on. Focusing the eye E using a real image is typically easier than focusing on a point. The image of the fixation target enables the eye E to finally focus on Un as if the image were far away, whereby the effects of accommodation or rotation of the eye E can be eliminated or reduced when the virtual images are focused or when the waves are sensed front sensor data. That is, the image of the fixation target prevents or helps to some extent prevent the eye from focusing on less than infinity.

The fixation target forces the eye E to rotate its "normal" rotational position, thereby minimizing rotational errors in the diagnostic analysis. Therefore, a rotation reference frame with respect to the eye E can be defined by the fixation target 334 . An asymmetrical picture, e.g. B. the sailboat of Fig. 7, which can be viewed at an infinity focus of the eye E is preferred because it helps that the eye E even with a slight head movement, the normal or a predetermined rotational position bezüg Lich the Fixation target 334 maintained. The fixation target 334 can also be used to determine the rotational position of the eye E in connection with the detection, location and alignment of a. Adjust the iris of the eye E, as discussed above. A similar picture can be used in accordance with the invention in other components, both in diagnosis and in treatment, in order to eliminate or reduce accommodation or rotation errors.

It will be apparent to those skilled in the art from the present description that various components can be used to replace components used in the wavefront sensor 300 (or 102 ) and that various optical configurations are possible to form other embodiments of the invention. For example, the laser diode 306 by a high-intensity, collimated light source or by multiple light sources, e.g. B. a low and a high power light source to be replaced. The alignment camera 323 can be arranged in the path of the mirror 322 , and the lens arrangement 324 of the lens camera 312 can have lenses that are more or less small as desired or according to the design. It will also be apparent to those skilled in the art that all of these components are generally controlled by a control system, e.g. B. a microcomputer can be controlled. A wide variety of other configurations are possible within the scope of the present invention.

Focusing prism

FIG. 8A shows an embodiment of the prism 314 from FIG. 6 as a double prism arrangement with a first prism 350 and a second prism 352 . As represented by a light beam 354 , the first prism 350 successively reflects the beam 354 from two surfaces 356 and 358 so that the beam 360 obtained is parallel or approximately parallel to the direction of the origin of the beam 354 . Beam 360 impinges on second prism 352 , which successively reflects beam 360 from two surfaces 362 and 364 , where a returning beam 366 is obtained. The beam 366 to be returned is successively reflected by the surfaces 358 and 356 , whereby a beam 368 is obtained which runs parallel or approximately parallel to the direction of the origin of the beam 354 . A particularly advantageous aspect of this configuration is that the parallel or non-parallel return path of beam 368 is obtained regardless of the angle at which beam 354 enters prism 314 . This is because surfaces 356 and 358 maintain the vertical deflection angle of the incoming beam 354 and surfaces 362 and 364 maintain the horizontal deflection angle. Although the focusing prism 314 is suitable for feeding the beam from the laser diode 306 to the eye E, it is particularly useful on the way back because the light scattered back by the eye E is not collimated like the beam of the laser diode 306 striking the eye E. Because prism 314 returns the light backscattered by eye E (which is ultimately scanned by lens assembly 324 ) in a vertical path, the probability of error within lens lens ra 312 is reduced.

FIG. 8B shows another telescope-like or telescope optics 314 'which is similar to the telescope optics 124 from FIG. 2A), which can be used according to the invention for the prism 314 in FIG. 6. The optics 314 'has two spaced prisms 370 and 372 . The prisms 370 and 372 form a folded optical system which both the light running from the laser diode 306 towards the eye E and the light running towards the lens arrangement 324 and the lens camera 312 and backscattered from the retina of the eye E is similar to that through Surface reflections reflected six times by prism 314 shown in FIG. 8A. The six reflections are shown schematically in FIG. 8B as light 374 . Although other configurations are possible, in practice lens 372 is fixed in position and the position of 370 is adjusted with respect to lens 372 as shown by arrow 375 in FIG. 8B as a non-limiting type of telescopic movement, in order to maintain an optimal or almost optimal focusing of the light passing through the lens arrangement 372 to the lens camera 312 . The variable distance between prisms 370 and 372 is preferably about 5 mm to about 100 mm, and their dimensions are preferably 40 × 40 mm and 20 × 40 mm, although other distances and dimensions are possible.

The arrangement of the prisms 370 and 372 partially obtains a reflected outgoing beam which is exactly or almost exactly parallel to the incoming beam (ie, either to or from the eye E), even if the prism 370 is inclined during the telescopic movement . This can reduce the cost of a slide or a slide mechanism that can be used to enable automatic computer controlled telescopic movement, e.g. B. the slide 376 shown in Fig. 8C, although an expensive or high-quality slide or a manually operated slide can be used. FIG. 8C shows a view along the line A-A 'if the telescopically movable optics 314 ' in FIG. 8B were arranged on the slide 376 . In Fig. 8C, slider 376 has a track or track 378 on which prism 370 runs, for example, using a suitable clamp or optical component holder, as will be appreciated by those skilled in the art. The slider 376 also includes a stepper motor 380 for moving the position of the prism 370 along the track or rail 378 and an arm 382 to which the prism 370 is mechanically connected by a suitable connector 384 (shown schematically in Fig. 8C), such as is recognizable to experts. When the stepper motor 380 is activated, it moves the position of the connector 384 attached to the prism 370 together with the arm 382 in either direction of the arrow 375 . The direction and degree of movement are determined according to the focusing requirements of the beam incident on the eye E from the laser diode 306 and those of the lens arrangement 324 and the lens camera 312 , which are set by the telescope-like movable optics 314 '. Various other drive mechanisms, prism configurations, or lens systems, including focus-adjusting lens systems, may be used in place of the telescoping optics 314 '(or 314 ) or slider 376 , as will be apparent to those skilled in the art. For example, another alternative optical system for telescoping optics 314 '(or 314 ) could be a lens system with the ability to add or remove lenses, each lens of the system being refractive in terms of a series or other refractive power related to those other lenses may or may not be related. An example of such a lens system is a phoropter or a similar lens system. Such a lens system would allow the patient to see what improvement (e.g. with regard to defocusing and astigmatism) by conventional vision-correcting techniques, e.g. B. conventional glasses or contact lenses, and then see in comparison what improvements can be obtained by correcting other aberrations and higher order aberrations.

Center point calculation for light spot positions of the world lenfrontsensor

FIGS. 9A, 9B, 10, 11A and 11B illustrate another feature of the wavefront sensor 102 (and 300) according to the invention. As shown in connection with FIG. 6, the lens arrangement or matrix 324 of the lens camera 312 typically creates an arrangement or matrix of light spot images (or virtual images) on the sensor of the lens camera 312 . As discussed in the Williams patent, parameters or information related to the centers of these light spots, e.g. B. the two-dimensional displacement of the center points from the ideal positions of these light spots, used in conjunction with a mathematical trans formation, z. B. with an adaptation by Zernike polynomials of different orders to determine the wavefront aberrations associated with the eye E. For example, FIG. 9A shows an arrangement of light spots 400 on the sensor that would typically be a "perfect" eye if the light spots were not offset from their ideal centers. The other hand, Fig. 9B shows an array of light spots 402 which are offset in an area 404, thereby indicating the presence of wavefront aberrations of the eye. The aberrations are determined by analysis of the mathematical transformation, e.g. B. by analysis of the Zerni ke polynomials used to adapt the parameter data. The lines in FIGS. 9A and 9B are only given to show the deviation in the arrangement of light spots 402 and would not appear in the image in the lens camera 312 . A real (inverted or negative) image 406 from a lens camera, e.g. B. from the lens camera 312 , is shown in Fig. 10. Image 406 shows the type and quality of light spots that would typically be observed by lens camera 312 .

As described above, the alignment camera 323 (see FIG. 6) helps to focus the light spot on the retina of the eye E so that each light spot, e.g. B. a light spot 408 on the lens camera 312 is as small as possible. Because such an adjustment is only suitable for low-order effects, each individual light spot obtained will not be an exactly sharp point. As discussed in the Williams patent, adaptive optics can be used in conjunction with the developed image so that an aberration-corrected, sharper "image" of the light spots is obtained. In the wavefront sensor 102 (and 300 ) of FIGS. 2A and 6, however, such an adaptive optics is not used, so that the image 406 of the light spots, e.g. B. the light spot 408 , may be somewhat "smeared" due to the optical aberrations of the eye. Referring to FIGS. 9A and 9B, it is seen that information is used in the wavefront aberration of the eye to determine the total transformation used, which, with an array of light spots, z. B. the arrangement of light spots 400 and 402 , available specific points are related. Therefore, an obvious "smearing" of these light spots, e.g. B. the light spot 408 , are prevented that their centers (z. B. the centers of the ma ximally weighted intensity) can be precisely localized. FIG. 11A and 11B are diagrams showing a centroid method for determining the center of each light spot, z. B. the light spot 408 of FIG. 10.

FIG. 11A shows an arrangement 410 patch "smeared" light such. B. a spot of light 412 . A more detailed profile of the light spot 412 is in F 02412 00070 552 001000280000000200012000285910230100040 0002019950791 00004 02293ig. 11B, which has profile lines 414 that, similar to equipotential lines or contour lines, indicate an increase in intensity generally toward the center of the light spot 412 . The increase in intensity would be found accordingly in the digitized values of the sensor (e.g. CCD) in the lens camera 312 and is visible as darker areas in the light spots of FIG. 10.

Several methods can be used to determine the centers of the various light spots in the embodiments of the invention. According to one method, a weighted intensity "center of gravity" is used in the X and Y directions of a coordinate system, as shown in FIG. 11B, for which the respective centers of gravity for each light spot are given by the following equations:

In these equations, I _i denotes the intensity at a certain point. The intensity can be calculated in several ways, e.g. B. as an intensity threshold, the intensity 0 being assigned to each picture element value that is greater than the threshold value, the intensity 1 and each picture element value that is smaller than the threshold value. Instead, a weighted intensity could be used that simply represents the pixel intensity. The intensity could be non-linearly weighted, picture elements with a higher intensity having a greater than a linear proportional effect, for example by squaring the intensity value I _i . Other non-linear weights could be used. The intensity values I _i can be weighted in various ways in order to calculate the “center points” of the light spots of the wavefront sensor.

Conclusion

The foregoing disclosure and description of the inven are used for presentation and explanation, and within the scope of the present invention may include rich changes in the details of the illustrated device and in the design and operating procedures be taken.

Claims (45)

1. A method for comparing a refractive correction instrument with a patient's eye, the method comprising:
Determining refractive features of the patient's eye;
Generating a first image of an iris of the patient's eye that is used to define a spatial relationship between the iris and the particular refractory features;
Storing a representation of the first image;
Using the determined refractive features, developing a refractive treatment process for the patient's eye that is spatially associated with the stored representation;
Generating a second image of the patient's iris eye in preparation for performing the developed refractive treatment process; and
Align the second iris image and the saved representation to normalize the developed re-active treatment process to the second iris image. 2. The method of claim 1, wherein the matching is the matching same as a laser system of refractive correction the second iris image for the Nor mation essentially with the saved representation balance. 3. The method of claim 1, wherein determining the loading agree refractive features of the patient's eye through a refractive diagnostic tool of the refractive Has correction instrument.   4. The method of claim 1, wherein generating the he most image the generation of the first image by a refractive diagnostic tool of refractive correction instruments. 5. The method of claim 4, wherein generating the two th image the generation of the second image by one Laser system of the refractive correction instrument has. 6. The method of claim 5, wherein the trimming is the trimming same of the laser system to the second iris Image for standardization essentially with the saved to align the presentation. 7. The method of claim 1, wherein determining the loading agree of wavefront aberrations of the pati's eye ducks by a wavefront sensor. 8. The method of claim 1, wherein determining the loading agree with a corneal surface topography of the eye of the patient through a corneal topography analyzer having. 9. The method of claim 1, wherein determining refrak tive features determining the corneal thickness or at whose differential or differential profiles of the eye of the Has patient using ultrasound. 10. The method of claim 1, wherein the matching comprises:
Displaying the stored representation;
Displaying the second image as an overlay on the stored representation; and
manually aligning the refractive correction instrument so that the first and second images overlap. 11. The method of claim 1, wherein the matching further comprises:
Recognizing characteristic features in the first image; and
Matching the characteristic features of the first image with corresponding characteristic features of the second image. 12. The method of claim 1, wherein the determining comprises determining refractive features of the patient's eye through a refractive diagnostic tool of the refractive correction instrument, and further comprising:
Determining additional refractive features of the patient's eye using a second refractive diagnostic tool;
Capturing a third image of the patient's iris that defines a spatial relationship between the patient's iris and the additionally determined refractive features; and
Developing a refractive treatment process based on a normalization of the determined refractive features and the additional determined refractive features from one another from the first and the third image. 13. The method of claim 12, wherein the resolution of the be determined refractive features and the additional be  agreed refractive features differ, and where one resolution is used to the other interpolate. 14. The method of claim 1, wherein the matching comprises:
Aligning a laser system of the refractive correction instrument;
Rotating the refractive treatment process; and
Translate or move the refractive treatment process in parallel. 15. The method of claim 14, wherein aligning the laser system further comprises:
Scaling the refractive treatment process developed. 16. The method of claim 1, wherein the developed right fractive treatment flow serves to be a refractive To use treatment tool that an Excimerla ser has. 17. The method of claim 1, wherein the first image of egg a pupil camera working with visible light will hold. 18. The method of claim 1, wherein the second image of an infrared camera is obtained. 19. The method of claim 1, wherein the stored Dar position is a digital copy of the first image.   20. The method of claim 1, wherein the stored Dar position a digital representation of more characteristic Features of the iris. 21. The method of claim 1, wherein determining the right fractive characteristics determining difference or Differential profiles of components of the eye has. 22. The method of claim 21, wherein determining Difference or differential profiles determining the Differential or differential profiles using of ultrasound. 23. System for comparing a refractive correction instrument with an eye of a patient with:
generate a refractive diagnostic tool that is suitable for generating refractive data for the patient's eye, the refractive diagnostic tool comprising:
a first camera which is suitable for generating a first iris image of the patient's eye, where the refractive diagnostic tool is suitable for providing refractive characteristics and corresponding iris data which are spatially related thereto and which represent the first iris image; and
a laser system which is suitable for applying a re-active treatment sequence to the patient's eye, the laser system comprising:
a second camera capable of producing a second iris image;
a laser suitable for applying the refractory treatment procedure; and
a control system capable of receiving data derived from the refractive characteristics and the iris data to match the iris data with the second iris image before the control system activates the treatment process. 24. The system of claim 23, wherein the control system includes the second camera and the laser. 25. The system of claim 23, wherein the refractive diagnosis tool has a wavefront sensor. 26. The system of claim 23, wherein the refractive diagnosis Tool has a corneal topography analyzer. 27. The system of claim 23, wherein the refractive diagnosis tool is suitable for the corneal thickness or differential or differential profiles using determination of ultrasound. 28. The system of claim 23, wherein the refractive diagnosis tool a hand-held refractive diagnostic tool has stuff. 29. The system of claim 23, wherein the laser system further comprises:
a visual display connected to the second camera and the control system, which is suitable for superimposing the second iris image and the received iris data. 30. The system of claim 23, wherein the control system is there is too suitable, the received iris data with the to compare and compare the second iris image. 31. The system of claim 23, further comprising:
a second refractive diagnostic tool with:
a third camera, which is suitable for generating a third iris image, the second refractive diagnostic tool being connected to the laser system, and being suitable for providing additional refractive data for the patient's eye and additional refractive characteristics and corresponding data to provide spatially related additional iris data representing the third iris image from the third camera. 32. The system of claim 31, further comprising:
a computing system connected to the refractive diagnostic tool, the second refractive diagnostic tool and the laser system, the computing system being suitable for receiving and being suitable for receiving the refractive characteristic data, the additional refractive characteristic data, the received iris data and the additional iris data to standardize the refractive characteristics by comparing the received iris data with the additional iris data to the second refractive characteristics. 33. The system of claim 32, wherein the computing system is suitable for the refractive treatment process Laser system based on the standardized data wrap.   34. The system of claim 33, wherein the laser system comprises the Re system. 35. The system of claim 23, wherein the laser is an excimer has laser. 36. The system of claim 23, further comprising:
a computing system connected to the refractive diagnostic tool and the laser system, which is suitable for receiving the refractive characteristic data and the iris data in order to develop the refractive treatment process, and for generating the refractory treatment process standardized to the iris data. 37. The system of claim 36, wherein the laser system the Re system. 38. A laser system for applying a refractive treatment process to a patient's eye, the laser system receiving the refractive treatment process in conjunction with iris data related thereto that represent an iris image of a patient's eye, the laser system comprising:
a camera capable of capturing the iris image;
a laser suitable for applying the refractory treatment procedure; and
a control system which is suitable for receiving the refractive treatment process and the iris data, and comparing the iris data with the iris image before the control system activates the refractive treatment process. 39. The system of claim 38, further comprising a computing system, which is suitable for the refractive treatment run from refractive characteristics of a refractive Develop diagnostic tool and the refractive Be course of action in a spatial relationship with additional Chen iris data to generate an additional iris picture of an additional camera in the refractive slide represent gnosis tool. 40. The system of claim 39, wherein the control system and the computing system is arranged in the same computer system are. 41. A method for generating a refractive treatment sequence for a patient's eye, the method comprising the steps of:
Determining refractive features of a patient's eye;
Generating an image of a surface of the patient's eye while determining the refractive features;
Developing a refractive treatment flow using the determined refractive features; and
Matching a refractive correction instrument to the patient's eye by matching the captured image of the surface with another image of the patient's eye received by the refractive correction instrument. 42. The method of claim 41, further comprising applying the refractive treatment process.   43. System for comparing a refractive correction instrument with an eye of a patient with:
means for determining refractive features of the patient's eye;
means for forming an image of a surface of the patient's eye while determining the refractive features;
means for developing a refractive treatment flow using the determined re-active features; and
means for comparing a refractive correction instrument with the patient's eye by comparing the generated image of the surface of the patient's eye with another image of the patient's eye received by the refractive correction instrument. 44. The method of claim 43, further comprising a device to apply the refractive treatment process. 45. A method for comparing a refractive correction instrument with an eye of a patient, the method comprising the steps:
Determining refractive features of the patient's eye;
Generating a first image of an iris of the patient's eye that is used to define a spatial relationship between the iris and the particular refractory features;
Storing a representation of the first image;
Generating a second image of an iris of the patient's eye in preparation for performing a refractive treatment procedure; and
Align the second iris image and the stored representation to normalize the refractive treatment process to the second iris image.