Imaging-based guidance system for ophthalmic docking using a location-orientation analysis

An imaging-guided docking system can separate the tilt and location of an imaged ophthalmic target and present them in an intuitive manner for an ophthalmic surgeon. The docking system can include an ophthalmic imaging system to image a portion of an eye of a patient, an image processor to determine a location and an orientation of the imaged portion of the eye, and a guidance system, coupled to the ophthalmic imaging system, to guide an ophthalmic docking based on the determined location and orientation. In some implementations, the imaging system images an internal eye-structure to determine its orientation and a video-imaging system video-images a frontal eye-structure to determine a location of the frontal eye-structure. The determined orientation and location can be displayed for the surgeon. The alignment of ophthalmic procedures can also be assisted with this imaging capability, e.g. the placement and centration of IOLs into the lens capsule.

TECHNICAL FIELD

This patent document relates to systems and techniques for ophthalmic docking. In more detail, this patent document relates to systems and methods for providing an imaging-based guidance system for docking an ophthalmic system to a patient's eye based on a location-orientation analysis.

BACKGROUND

The widespread introduction and acceptance of laser surgical systems in ophthalmic applications ushered in a new era of precision and control. One of the keys to achieving this high level of control is the immobilization of the eye relative to the laser surgical system. In many devices, the immobilization is carried out by affixing a patient interface to an objective of the laser and then docking it to the eye, often by vacuum suction. In other systems, a portion of the patient interface is docked to the eye, another portion to the objective, and then the surgeon gently aligns and locks the two portions together.

One of the factors the precision and utility of these systems depends on is the patient interface being docked to the eye in a central position. Such a central docking or centering can align an optical axis of the objective of the laser system and an optical axis of the eye. Since the laser beam is typically directed and controlled relative to the optical axis of the objective, aligning the optical axis of the eye with the optical axis of the objective by centering the docking can enable controlling the laser beam within the eye with high precision.

Centering the docking with the visible structures of the eye, such as the pupil or limbus is often a challenge, though, for multiple reasons. The patients sometimes move their eyes during docking, even against their own will. Also, even if the patient interface was centered with the eye at the beginning of the docking procedure, the globe of the eye can roll to one side during docking because of the pressure applied by the patient interface after contact has been made with the eye. Further, the shape of the eye structures can be an ellipsoid or irregular to some degree. Also, the limbus and the pupil are often not concentric. In these typical cases the center of the eye is not entirely well-defined: e.g. centering the patient interface with the pupil may not center it relative to the limbus.

An additional layer of complexity arises in systems intended for cataract procedures. The target of the cataract procedures is the lens, having limited visibility because it is an internal structure of the eye and it is essentially transparent. Moreover, the lens is typically not concentric with the visible structures of the eye, including the limbus and the pupil. For all these reasons, centering the patient interface with the limited visibility lens is hard. If the patient interface is centered with the visible limbus instead, this may also result in docking the interface misaligned with the limited-visibility internal lens. In this case, when during the cataract surgery the laser beam is referenced relative to the center of the patient interface aligned and docked with the limbus, the laser beam may be misdirected relative to the center of the lens, the intended target of the cataract surgery.

There can be several reasons for the lens being off-center. In many eyes the lens is anatomically off-center. Moreover, the pressure of the docking may also push and tilt the lens to one side as the lens is held in its place only by soft ciliary muscles.

Some systems compensate the lens being off-center by attempting to align the patient interface with the lens instead of the visible pupil. However, the transparency of the lens makes it difficult for the surgeon to determine the precise location and tilt of the lens and to align the patient interface accordingly.

Some systems employ an imaging system to image the lens to assist the alignment of the patient interface. However, the use of such imaging systems can encounter problems as well.

SUMMARY

A video-imaging system or a video-microscope can be used to assist the alignment of the patient interface and thus the docking. However, a video-microscope is primarily used to image the visible structures of the eye, such as the limbus and the pupil, and may not be able to image and assess the orientation of the lens, an internal and essentially transparent structure of the eye. Using an optical coherence tomography (OCT) system instead of the video-microscope has the advantage that OCT imaging systems can image the lens efficiently. However, the OCT imaging process is typically slow and does not provide the images fast enough to be useful for the docking process.

One way to accelerate the OCT imaging process is to image the target lens only selectively, thus producing images at a faster rate. Examples include scanning OCT systems that image the lens only along one dimensional scanning lines or circles instead of the full two dimensions, transverse to the optical axis. These scanning OCT imaging systems are able to generate images at a faster rate because they capture only limited or selected imaging information. Acquiring only limited imaging information, however, can cause other types of challenges when attempting to center the patient interface with the misaligned lens of the eye, as described next.

The lens can be misaligned with respect to the optical axis of the imaging system and thus the patient interface (PI) in different ways. The optical axis of the lens can be tilted relative to the optical axis of the PI, and the center of the lens can be shifted or displaced from the optical axis of the PI. The surgeon can analyze the OCT image and carry out compensating actions to compensate the lens-shift and the lens-tilt in order to align the patient interface with the lens.

To carry out these two types of compensating actions, the surgeon needs to identify the shift and the tilt separately from the OCT image of the lens. However, the limited imaging information provided by the faster scanning OCT systems typically convolutes information about the tilt and the shift. Therefore, when using a scanning OCT imaging system, the surgeon starts the docking process by attempting to analyze the scanning OCT image mentally to separate the tilt and shift of the lens.

During this separation attempt, the surgeon can determine that the lens is shifted by a certain distance in a certain direction from the PI optical axis and is tilted in a certain direction by a certain degree relative to it.

Once the shift is separated from the tilt, the surgeon can determine a direction and magnitude of a shift-compensating movement of a gantry of the laser system and move the gantry accordingly.

Subsequently, the surgeon can compensate the determined tilt of the lens as well. Since the optical axis in most imaging or laser systems cannot be tilted, the tilt-compensating action may include instructing the patient to rotate the surgical eye, manually rotating the eye ball, or adjusting a fixation light system. Since typically the first centering attempt leads only to an improvement of the alignment or compensation, these steps are often repeated in an iterative manner and in varying order or combinations.

If the surgeon was successful in separating and determining the shift and the tilt, then the result of the (possibly iterative) shift- and tilt-compensating actions is that the PI becomes well-centered with the lens. Therefore, the surgeon can proceed and dock the centered and aligned PI onto the eye.

However, there can be multiple problems with such “unprocessed-images” systems that do not process the images and thus provide no guidance for the surgeon. These problems include that separating the convoluted tilt and shift in the scanning OCT image mentally may not be easy to perform by the surgeon without computational processing and guidance under the intense time pressure of a surgical procedure. This can potentially lead to docking the PI on the eye in a non-centered position. Worse yet, the surgeon may even initiate adjustments that increase the misalignments instead of reducing them and therefore the iterative alignment process may not converge or converge only after several false steps.

A further inefficiency of “two-unprocessed-images” systems is that the OCT image of the lens is typically presented on a dedicated OCT display or screen, separate from the video microscope display. Therefore, in systems where the surgeon uses both an OCT and a video image for the alignment process, the surgeon has to analyze the lens image on the OCT display and the visible eye structures on the separate video display. The images on these two displays are typically from different points of view with different magnification and possibly using different reference conventions. Therefore, separating the shift and the tilt requires a challenging parallel analysis between two quite different images. The need to process and convert the two types of incongruent imaging information back-and-forth can overwhelm the surgeon, possibly undermining the efficiency of the centering and docking process.

To respond to these challenges, this patent document discloses imaging-guided docking systems that separate the tilt and shift and present them in an intuitive manner for the surgeon. In some implementations, an ophthalmic docking system can include an ophthalmic imaging system comprising an image processor, and a guidance system, coupled to the ophthalmic imaging system, wherein the ophthalmic imaging system is configured to image a portion of an eye of a patient, the image processor is configured to determine a location and an orientation of the imaged portion of the eye by analyzing the image, and the guidance system is configured to guide an ophthalmic docking based on the determined location and orientation.

The imaged portion of the eye can be a lens or another structure, feature or landmark of the anterior segment of the eye. The location and orientation can be determined relative to a variety of references, such as an optical axis of the imaging system, an internal reference mirror of the imaging system, an internal surface of an optical element of the surgical system, or an ophthalmic structure or layer of the anterior segment.

In other implementations, an ophthalmic docking system can include an ophthalmic imaging system, comprising an image processor, wherein the ophthalmic imaging system includes an in-depth ophthalmic imaging system configured to image an internal eye-structure of an eye of the patient, and a video-imaging system configured to video-image a frontal eye-structure of the eye, wherein the imaged portion of the eye comprises the internal eye-structure and the frontal eye-structure, and the image processor includes an in-depth image processor configured to determine an orientation of the internal eye-structure from the image of the internal eye-structure, and a video-image processor configured to determine a location of the frontal eye structure based on the image of the frontal eye-structure.

In some implementations, a method of guiding an ophthalmic docking can include imaging a portion of an eye of a patient with an ophthalmic imaging system, determining a location and an orientation of the imaged portion of the eye by analyzing the image with an image processor, and guiding an ophthalmic docking based on the determined location and orientation with a guidance system.

In some implementations, an ophthalmic docking system can include an ophthalmic imaging system, including an image processor, wherein the ophthalmic imaging system is configured to image a portion of an eye of a patient, and the image processor is configured to process the image to recognize an ophthalmic structure of the eye, and to determine a misalignment of the imaged portion of the eye relative to a reference; and a guidance system, coupled to the ophthalmic imaging system, configured to guide an ophthalmic docking based on the determined misalignment.

In some embodiments, an ophthalmic guidance system can include an ophthalmic imaging system, comprising an image processor, wherein the ophthalmic imaging system is configured to image a portion of an eye of a patient, and the image processor is configured to process the image to recognize an ophthalmic structure of the eye, and to determine a position of the imaged portion of the eye relative to a reference; and a guidance system, coupled to the ophthalmic imaging system, configured to guide an ophthalmic ultrasound-based surgical procedure based on the determined position.

DETAILED DESCRIPTION

Implementations and embodiments in this patent document provide an ophthalmic docking system that includes an imaging system, capable of separating and identifying a shift and a tilt of a patient's eye and can present the shift and tilt information in an integrated, congruent manner to avoid overwhelming the surgeon. Such a docking system may be helpful to increase the precision and ease of the docking of a patient interface of an ophthalmic surgical system to the eye, such as a laser cataract surgical system.

FIGS. 1A-Billustrate various misalignments of a patient interface (PI)50and its PI contact lens51relative to an eye1. The well-known structures in the eye1include a cornea2, an iris3, a sclera4, separated from the iris3by the limbus5. An opening of the iris3defines a pupil6. A lens7is an internal structure of the eye1, held in its place by the soft ciliary muscles8.

FIG. 1Aillustrates that, as described above, the lens7can be shifted from an optical axis10of the eye1for a variety of reasons, so that a lens optical axis11of the lens7is shifted from the eye optical axis10by a transverse vector Δ′=(Δ′x,Δ′y) and thus from a PI optical axis52of the PI50by a transverse vector Δ=(Δx, Δy). For simplicity, these transverse displacement or shift vectors will be simply referred to as Δ′ and Δ.

FIG. 1Aillustrates one of the challenges of guiding a docking system by traditional methods. Even if a surgeon aligns and centers the patient interface50with the eye optical axis10as defined by the visible structures of the eye1such as the pupil6, the lens optical axis11of the hard-to-see internal lens7can remain shifted from the PI optical axis52of the patient interface50.

FIG. 1Billustrates another form of misalignment of the lens7and the patient interface50. Even if a center of the lens7lies on the eye optical axis10and even if the eye optical axis10coincides with the PI optical axis52, the lens optical axis11can still remain tilted relative to the PI optical axis52. In general, this tilt can be described by the Euler angles φ=(θ,φ), which will be collectively referred to as the tilt angle φ.

FIG. 1Cillustrates how a misaligned or off-center eye1can appear on a video display65of a video-microscope60. Such video-microscopes60often display a targeting pattern68to guide the surgeon to align or center the PI50with the eye1.

Some “two-unprocessed-images” systems may provide a second image to guide the surgeon docking the PI50: an imaging system70can provide a cross sectional or scanning view of the eye1, shown in a separate imaging display75. The cross-sectional view can show the cornea2and the lens7, separated by an anterior aqueous chamber12. The lens7can be enveloped by an anterior capsular layer14and a posterior capsular layer16. During ophthalmic procedures often muscle relaxants are administered that relax the iris3thus enlarging the pupil6. At least for this reason the expanded pupil6often does not even appear on cross sectional or scanning images.

As described before, when operating such “two-unprocessed-images” systems, the surgeon is expected to analyze the cross sectional image on the display75in combination with the video image of the video display65, mentally separate the tilt and the shift of the lens7and then perform compensating actions, monitoring them on the display65of the video microscope60. However, repeatedly moving back and forth between the two different types of images and translating the image information accordingly without computational processing and guidance can be quite overwhelming and time consuming for the surgeon.

FIG. 2illustrates an imaging-guided ophthalmic docking system100that may facilitate a simplified and more efficient imaging-guided docking. The docking system100can include an ophthalmic imaging system110that may include an image processor120, where the ophthalmic imaging system110can be configured to image a portion of the eye1of a patient19. The imaging can be performed in a variety of ways. For example, an imaging beam can be generated by the imaging system110, then coupled into an optic130of the docking system100through a beam-splitter BS1and directed into the eye1. The returned imaging beam, returned from the eye1, can be redirected or deflected by the same beam-splitter BS1into the imaging system110to form an image of the eye1.

The image processor120can be configured to determine a location and an orientation of the imaged portion of the eye by analyzing the image generated from the returned imaging beam. The location can be expressed in terms of a shift Δ relative to a reference such as the PI optical axis52, and the orientation can be expressed in terms of a tilt φ relative to the PI optical axis52.

The imaged portion can include parts of an internal structure of the eye and parts of its frontal or visible structures. For example,FIG. 1Cillustrates the case when the imaged portion of the eye includes a portion of the cornea2, a portion of the anterior capsular layer14and a portion of the posterior capsular layer16. In other implementations, the imaged portion of the eye can include a lens-capsular layer, a lens target region, the lens7, a hardened nucleus of the lens7, the limbus5, the iris3, the pupil6, a corneal endothelium, a corneal epithelium, or an ophthalmic structure in the anterior segment of the eye1, among others.

The docking system100can also include a guidance system140, coupled to the ophthalmic imaging system110, configured to guide an ophthalmic docking based on the determined location and orientation. The guidance system140can include a video display of a video microscope or a display of the imaging system110. The guidance system140can be configured to guide the ophthalmic docking by displaying images and guidance information for an ophthalmic surgeon.

The docking system100can be part of a larger ophthalmic system that can perform other functions as well. For example, the docking system100can be integrated with a surgical laser101, where a surgical laser beam of the surgical laser101can be coupled into the optic130at a beam splitter BS2to be directed to the eye1. The surgical laser101can perform cataract procedures, such as a fragmentation of the lens7or a lysis of the lens7. It can also perform procedures in the cornea, such as creating limbal relaxing cuts or creating access cuts for an ultrasound phaco-tip. The surgical laser101can also perform LASIK related procedures, including flap-cuts in the cornea2.

The docking system100can be also part of a larger or more complex imaging system, such as a surgical microscope which, however, does not perform a surgical procedure. Instead, it may perform an imaging of a portion of the anterior segment of the eye1. Finally, the docking system100can be part of a variety of diagnostic systems, for example in the form of an alignment system that does not necessarily involve direct physical contact with the eye.

The ophthalmic imaging system110can include a wide variety of imaging systems, such as a time domain optical coherence tomography (OCT) system, a frequency domain OCT system, a spectrometer-based OCT system, an ultrasound-based system, a microscope based system, an electronic imaging system, a digital imaging system, a Purkinje imaging system, a structural illumination system, a slit lamp system, or a Scheimpflug imaging system. The possibly substantial differences between these imaging systems will be discussed below.

The ophthalmic imaging system110can include a scanning imaging system to perform a scan by directing an imaging beam to points of at least one of an arc, a line, a loop, a circle, an ellipse, a star, a line with repeated features, a two dimensional pattern and a two dimensional mesh. The imaging system110can image the imaged portion of the eye in a depth-range at points of the scan.

Implementations of image-guided ophthalmic docking systems which can be advantageously combined with the here-described imaging-guided ophthalmic docking system100have been described in the jointly owned patent document: “Image-Guided Docking for Ophthalmic Surgical Systems” by A. Juhasz and K. Vardin, USPTO patent application Ser. No. 12/815,179, hereby incorporated in its entirety by reference.

FIG. 3Aillustrates an implementation of the imaging system110. The imaging system110can include e.g. a spectrometer based OCT (SB-OCT) system, directing an imaging beam to (x,y) points of a scanning circle or loop112, typically oriented transverse to the PI optical axis52. As the imaging laser beam is returned from a specific (x,y) point of the scanning circle112, it carries imaging information about the ophthalmic structures sharing the same (x,y) transverse coordinates from all depths d within a depth-range between a minimal depth d(min) and a maximal depth d(max)−sometimes called an A-scan. It is noted that time domain OCT systems acquire the A-scan imaging information from different depths sequentially, whereas spectrometer based OCT systems acquire the A-scan imaging information from all depth simultaneously. Here the depth d can be measured from different reference points, including a reference mirror of the SB-OCT system, a reference point internal to the optic130, a distal surface of the PI contact lens51in contact with the cornea2, or even from an ophthalmic structure or landmark inside the eye1. Some ophthalmic imaging systems are capable of collecting and returning imaging information from an imaging range between a minimal depth d(min) that is essentially zero micron, 0μ, measured from the PI contact lens51, capturing corneal imaging information, to a maximal depth of d(max)=5,000μ, 7,000μ, or even 10,000μ, capturing imaging information covering most of the anterior segment of the eye up to the posterior capsular layer16.

The A-scans of the eye taken at subsequent (x,y) points along the scanning circle112can be integrated into a scan-image of the eye, sometimes called a B-scan. A B-scan in essence unfolds the image of the eye from an imaging cylinder113defined by the scanning circle112and the d(min)-d(max) imaging range. This unfolded image can be labeled or indexed by a scanning variable: a length along the scanning circle112or an angular scanning variable α, defined e.g. in radians.

FIG. 3Billustrates an image or B-scan of a fully aligned and centered lens7, unfolded from the imaging cylinder113. Visibly, the scanning beam located the anterior capsular layer (ACL)14at a depth d(ant) along the entire circular scan, thus generating an ACL scan-image114that is a horizontal line at a depth of d=d(ant) of about 3,400μ in this example along the entire 2π radian range of the angular scanning variable α. Analogously, a posterior capsular layer (PCL) scan-image116on the imaging cylinder113is a horizontal line at d=d(post) of about 7,800μ. For simplicity and clarity, the image of the cornea2at a depth close to d=0μ is not shown.

As mentioned above, one of the challenges of the “two-unprocessed-images” systems ofFIG. 1Cis that they provide the surgeon with a video-microscope image and a different-looking cross-sectional or scanning OCT image and prompt the surgeon to quickly analyze these incongruent images to separate and determine the shift and tilt of the lens7. These tasks are quite demanding and can potentially overwhelm the surgeon, especially under the time pressure of the surgery.

Implementations of the imaging-guided docking system100can reduce this problem by the ophthalmic imaging system110not only displaying the image for the surgeon for analysis, but in addition the imaging system110itself performing an image recognition process on the image. The image recognition process may be able to recognize the ACL and PCL within the noisy raw image and generate the corresponding ACL scan-image114and the PCL scan-image116. Once the ACL and PCL scan-images114and116have been generated by the imaging system110, the image processor120can analyze the generated images to computationally separate the shift and the tilt of the lens7, and the guidance system140can display the determined shift and tilt in a manner convenient for the surgeon, thus relieving the surgeon from the hitherto required mental analysis.

The convenient display by the guidance system140can, e.g., integrate the shift and tilt information into the same video-microscope image. In other cases, a second image can be displayed separately but in a manner congruent with the image on the video-microscope, wherein the second image could show the tilt information and the video-microscope image the shift information. The second image can be displayed on the same display as the video image, only in a different region of the display, or on a separate second display.

Performing the image-recognition process by the image processor120can play a useful role as in a raw OCT image the ACL/PCL14/16may appear only as regions of image points reflecting the light somewhat more than their neighboring regions. But the contours of these more reflecting regions are often not defined too clearly, especially if the imaging noise is substantial, or if there is a systematic noise, or there are additional image lines, or if some image lines cross or artifacts are present in the image.

To recognize the capsular layers even in a noisy image and to determine the tilt and shift of the lens, in some implementations the image processor120can be configured to analyze the scan-images of the recognized layers by using a geometric model of the lens7to determine a location and an orientation of the lens7. For example, the image processor120can attempt to fit a sphere, an ellipsoid or elliptical curves to the regions of enhanced reflection, and recognize the reflecting regions as the scan-images of capsular layers if they can be fit sufficiently well with the sphere or ellipsoid of the geometric model. The edges of the regions can be determined, for example, as the points where the gradient of the image intensity exhibits a local maximum. A wide variety of analogous image recognition approaches can be implemented as well. The misalignments and their analysis will be described in the context of the following figures.

FIG. 4Aillustrates a “pure tilt” situation when the center of the lens7is on the PI optical axis52, but the lens optical axis11is tilted relative to the PI optical axis52by a tilt angle φ.

FIG. 4Billustrates that in misaligned situations the scan-images of the capsular layers are often sinusoidal lines as a function of the angular scan variable, angle, or phase α. For example, in the “pure tilt” situation ofFIG. 4Athe ACL scan-image114and PCL scan-image116can be sinusoidal lines that are “in-phase” as a function of the angular scan variable α, as seen from their maxima being aligned along the scan angle α.

FIG. 5Aillustrates a “pure shift” situation, when the lens optical axis11is aligned with the PI optical axis52, but the center of the lens7is shifted from the PI optical axis by a shift Δ.

FIG. 5Billustrates that in this pure shift situation the ACL scan-image114and the PCL scan-image116can still be sinusoidal, but they are “out-of-phase” relative to each other by a phase shift of δ=π radians. This phase shift δ causes the maximum of the ACL scan-image114being aligned with the minimum of the PCL scan-image116. Typically, the phase shift δ can be related to the tilt angle φ by geometric relations.

It is also noted that the image-amplitudes or the minimum and maximum depths of the ACL and PCL scan-images114and116can be related to the tilt angle φ and shift Δ by geometric relations.

FIG. 6illustrates that in a generic situation when the lens7is both shifted and tilted, the ACL/PCL scan-images114/116exhibit a combination of the pure tilt and pure shift images. Correspondingly, the ACL scan-image114and the PCL scan-image116can be separated by a general phase shift δ=αA(min)−αP(min). The phase shift δ is also equal to δ=αA(max)−αP(max) when measured past 2π inFIG. 6. Here, αA(min) refers to the scan angle, or phase, a where the ACL scan-image114has its minimum dA(min) and thus its lowest or deepest depth. The other terms, αP(min), αA(max) and αP(max), are defined analogously in the context of the ACL/PCL scan-images114/116.

More generally, the image processor120can be configured to determine not only the extrema of the ACL/PCL images114/116, but to follow any number of procedures to determine an anterior phase and an anterior amplitude of the scan-image114of the anterior capsular layer and a posterior phase and a posterior amplitude of the scan-image116of the posterior capsular layer, and to determine the location and the orientation of the lens from the anterior phase, the anterior amplitude, the posterior phase and the posterior amplitude.

For example, the image processor120can determine a characteristic anterior phase αA of the ACL scan-image114, such as αA(min) or αA(max), as well as the corresponding characteristic anterior amplitudes or image depths dA, such as the depths dA(min) or dA(max), corresponding to the above anterior phases αA(min) or αA(max). Furthermore, the image processor120can also determine a characteristic phase αP of the PCL scan-image116, such as αP(min) or αP(max), as well as a characteristic image depth dP, such as the corresponding depths dP(min) or dP(max).

With these phases and amplitudes, the image processor120can proceed and determine the unknown components (Δx, Δy) of the shift vector Δ and the unknown Euler angles (θ,φ) of the tilt angle φ from an analysis of various combinations of the above determined phases and depths or amplitudes:
(Δx,Δy,θ,φ)=F1(αA,dA,αP,dP),  (1)

where F1 is a function of its arguments which can be various combinations or pairings of the determined scan angles and depths corresponding to the depth maxima or minima of the ACL/PCL scan images114/116.

As mentioned before, the analysis may involve using a model of the capsular layers. For example, the analysis may assume that the capsular layers14and16can be modeled as portions of a sphere or an ellipsoid, and then proceed to determine the parameters of the sphere or ellipsoid by fitting the ACL/PCL images114/116with the sphere or ellipsoid.

There is a large number of alternative ways to carry out this analysis. Some techniques that can be advantageously implemented for this analysis were already described in the jointly owned patent document: “Imaging Surgical Target Tissue by Nonlinear Scanning” by I. Goldshleger et al., USPTO patent application Ser. No. 12/619,606, hereby incorporated in its entirety by reference.

Examples of alternative analyses include the image processor120determining the anterior maximum depth dA(max) and the anterior minimum depth dA(min) of the ACL scan-image114, and the posterior maximum depth dP(max) and the posterior minimum depth dP(min) of the PCL scan-image116along the scan variable α, and determining the shift and tilt from these extrema:
(Δx,Δy,θ,φ)=F2(dA(min),dA(max),dP(min),dP(max)),  (2)

where F2 is another function of its arguments.

The scan angles and depths can be determined, selected and analyzed according to numerous other criteria. While the corresponding functions Fn(x1, . . . xm) (where m can be 2, 3, 4 or more) and the details of the analysis may proceed differently, the overall scheme of extracting the shift Δ and tilt φ remains the same.

In some implementations, the image processor120can be configured to determine a phase and an amplitude of only one of the capsular layer scan-images, and from those to determine a location or shift and an orientation or tilt of the lens7.

FIGS. 7A-Billustrate that the guidance system140can include a display unit142such as a video-microscope display142. The guidance system140can be coupled to the image processor120so that the display unit142can display a location or shift misalignment indicator based on the determined location of the imaged portion of the eye, and an orientation or tilt misalignment indicator based on the determined orientation of the imaged portion of the eye, both determined by the image processor120processing the SB-OCT image by one of the above methods. The eye1itself can be indicated only very schematically, with only the pupil6and the iris3explicitly shown and the shading suppressed for clarity.

In general, the location misalignment indicator can include an eye location or shift indicator144based on the determined location of the imaged portion of the eye, and a location or shift reference or reference pattern148-s. An operator of the docking system100can reduce the shift misalignment of the imaged portion of the eye by aligning the eye location or shift indicator144with the location reference148-s. In embodiments where the imaged portion of the eye includes the lens7, embodiments of the eye location or shift indicator144can represent a lens location or lens-shift and therefore will be referred to as eye/lens-shift indicator144.

Further, the orientation misalignment indicator can include an eye orientation or tilt indicator146based on the determined orientation of the imaged portion of the eye, and an orientation or tilt reference148-t. The operator of the docking system100can reduce the orientation misalignment or tilt of the imaged portion of the eye by aligning the eye orientation indicator146with the orientation or tilt reference148-t. In embodiments where the imaged portion of the eye includes the lens7, the eye-tilt indicator146can represent a lens-tilt and therefore will be referred to as eye/lens-tilt indicator146.

FIG. 7Aillustrates an embodiment where the shift reference148-sand the tilt reference148-tare integrated into a single target, crosshairs, or reference pattern148on the display unit142. In other implementations, the references148-sand148-tcan be separate, e.g. two target patterns displayed side-by-side, or two reference patterns displayed on separate screens, or in separate areas of the same display.

FIGS. 7A-Billustrate that the eye-shift indicator (or shift indicator)144and the eye-tilt indicator (or tilt indicator)146can be marks or icons on the display unit142, such as the shown X and O marks. The imaging system110can be calibrated in such a way that the eye-shift and the eye-tilt are fully compensated or eliminated when the corresponding shift and tilt indicators144and146are manipulated to the center of the integrated reference pattern148.

FIG. 8Aillustrates that some docking systems100can include a gantry150, controlled by a gantry controller152, capable of moving essentially transverse to the PI optical axis52of the patient interface50and the optic130. The gantry150may be configured to house or engage an objective154of the optic130to which the patient interface50may be affixed. With this design, an operator of the docking system100can operate the gantry150to move or adjust the objective154, the patient interface50and its contact lens51, thereby reducing and eventually eliminating the shift or location misalignment of the eye.

The guidance system140can assist the surgeon in this procedure by displaying the lens-shift indicator mark or icon144on the display unit142. The surgeon can move the gantry150to move the shift indicator144closer to the center or origin of the reference148, in essence using the reference148as crosshairs or a target. The shift indicator144reaching the center of the crosshairs148can signal to the surgeon that the location misalignment or shift Δ of the eye has been eliminated.

Analogously, the guidance system140can display the tilt indicator146on the display unit142to assist the surgeon to reduce and eventually eliminate the orientation misalignment by moving the tilt indicator146to the center of the reference or crosshairs148.

The lens tilt cannot be compensated by tilting the laser system optical axis, as most laser systems or optics do not allow for such tilt. Also, moving the gantry150may not be able to compensate the tilt-misalignment of the lens either. Therefore, in some embodiments of the docking system100, the surgeon may choose to instruct the patient verbally to cause the patient to rotate the imaged eye to reduce its orientation misalignment. The surgeon may monitor the movement of the tilt icon or indicator146when the patient rotates the eye and may give new instructions in light of the patient's actions. Giving instructions in an iterative manner may assist the surgeon to move the tilt icon146into the center of the crosshairs148, reducing and eventually eliminating the tilt misalignment.

FIG. 8Aillustrates that in other implementations of the docking system100the guidance system140may include a fixation light system160, configured so that the surgeon or operator can adjust a fixation light165of the fixation light system160to guide the patient to perform at least one of a rotation or a lateral movement of the eye. The fixation light165can be projected into the non-docking or control eye1c, as shown.

FIG. 8Billustrates that the fixation light165can be also projected into the docking eye1dby an alternate embodiment of the fixation light system160.

The fixation light system160can be advantageously combined with other fixation light systems, described e.g. in the jointly owned patent document “Electronically Controlled Fixation Light for Ophthalmic Imaging Systems”, by T. Juhasz et al., USPTO patent application Ser. No. 12/885,193, hereby incorporated in its entirety by reference.

FIGS. 9A-Cillustrate the steps of a misalignment reduction procedure.FIG. 9Aillustrates the lens optical axis11having both a tilt φ and a shift Δ relative to the PI optical axis52, also referred to as system optical axis28, in a case when the lens7is misaligned even with the eye1itself.

FIG. 9Billustrates the stage of the procedure after the surgeon has caused the rotation of the patient's eye, either by giving a verbal instruction to the patient, by moving the eye1manually, or by adjusting the fixation light165. At this stage the tilt misalignment φ is reduced or optimally eliminated, resulting in the lens optical axis11becoming aligned or parallel with the PI optical axis52, but still having a residual shift misalignment Δ′. The reduction or elimination of the tilt misalignment φ is represented on the video display142by the eye/lens-tilt indicator146having moved to the center of the reference pattern148, whereas the eye/lens-shift indicator144still being off the center of the reference pattern148.

FIG. 9Cillustrates the second stage after the surgeon has moved the gantry150to compensate the residual shift Δ′. At this stage the lens optical axis11and the PI optical axis52(or system optical axis28) can be fully aligned, possibly coinciding entirely. After the residual shift Δ′ is also eliminated, both the eye/lens-tilt indicator146and the eye/lens-shift indicator144are moved to the center of the reference pattern148.

FIG. 10Aillustrates that in some implementations, the docking system100can be configured not only to display the shift and tilt icons/indicators144and146based on the image processor120having processed the SB-OCT image, but also to provide an additional computed docking guidance for the surgeon. The image processor120can not only determine where to display the eye/lens-tilt indicator146and the eye/lens-shift indicator144relative to the reference pattern148, but it may be configured to compute a misalignment reduction response and display it for the operator of the system as well. In particular, the image processor120may compute a location misalignment based on a misalignment of the determined location of the imaged portion of the eye and a location reference of the ophthalmic docking system, and display an embodiment of the location misalignment or shift indicator144that includes a shift correction indicator144based on the computed location misalignment.

In the shown implementation, the shift correction indicator144can be a vector, displayed on the video-monitor142, demonstrating the direction the gantry needs to be moved to reduce the shift misalignment. A magnitude of the vector can indicate the magnitude of the gantry movement. The shift correction indicator vector144can be supplemented by displayed numerical correction suggestions, such as how many millimeters the gantry should be moved and in what precise direction.

FIG. 10Aalso illustrates an analogous tilt correction indicator146being part of the tilt indicator146, computed based on a misalignment of the determined orientation of the imaged portion of the eye, such as the lens optical axis11, and an orientation reference of the ophthalmic docking system, such as system optical axis28or PI optical axis52. The guidance system140can display on the video-monitor or display unit142the orientation misalignment or tilt correction indicator146based on the computed orientation misalignment. The tilt correction indicator146can include a tilt correction vector, whose magnitude and direction, possibly supplemented with numerical values, can indicate how much should the fixation light165of the fixation light system160be moved and in which direction to compensate the tilt.

FIG. 11Ashows another embodiment of the imaging-guided docking system100. In this docking system100, the guidance system140and through it possibly the image processor120can be electronically coupled to a misalignment reduction system177. The misalignment reduction system177may be capable of reducing one or more misalignments of the imaged eye relative to the PI optical axis52or in general to the optic130.

The misalignment reduction system177can include the gantry150with the gantry controller152, or the fixation light source160, or both. In these implementations, the guidance system140may not only compute the shift and tilt correction indicators144and146, as in the implementation ofFIG. 10A, but may send actual control signals through the electronic coupling to at least one of the gantry controller152and the fixation light system160to actually carry out the corresponding misalignment corrections by adjusting the gantry150or the fixation light165, without waiting for an analysis or intervention by the surgeon. In some implementations, the guidance system140may include a misalignment corrector149that performs the computation and the generation of the above control signals based on the image processor120having determined the tilt φ and a shift Δ relative to the PI optical axis52. In other implementations, the image processor120itself can perform these functions.

The gantry controller152, having received the control signal from the guidance system140, can move the gantry150to adjust a position of the objective154to reduce the location misalignment of the imaged portion of the eye. In other examples, the fixation light system160, having received a control signal from the guidance system140can generate or adjust a fixation light165for the eye of the patient to cause or direct a reduction of the orientation misalignment of the imaged portion of the eye. As before, the fixation light system160can project the fixation light165either into the control eye1cor into the docking eye1d.

In such computerized implementations, the shift and tilt misalignments may be reduced or eliminated primarily under the electronic control of the guidance system140. These implementations may relieve the surgeon from the task of actually carrying out some or all of the compensation of the misalignment: the surgeon's duties may be lightened to only supervising the misalignment reduction performed by the computerized docking system100.

FIG. 10Billustrates another implementation of the guidance system140. In this example, at least one of the location misalignment indicator and the orientation misalignment indicator can include an image of a portion of a lens of the eye, indicative of the corresponding misalignment.

In the shown example, the guidance system140can overlay the OCT image of the lens7with the video-image of the eye and the reference pattern148, constituting an integrated shift-tilt indicator147. In some cases, the OCT image can be symbolic only, e.g. a simplified image based on a model form to the actual OCT image. The location and orientation of the overlaid lens image as the shift-tilt indicator147relative to the reference148can be an instructive display of the tilt and shift of the misalignment of the lens7for the surgeon. In some cases, the surgeon may be instructed to center the overlaid lens image147with the center of the reference148to eliminate the shift, and to align the major axes of the ellipsoidal lens image147with those of the reference pattern148to eliminate the tilt.

The OCT image of the lens7, used in the shift-tilt indicator147, can be taken e.g. the following manner. First, a circular OCT scan can be performed, resulting in a sinusoidal OCT image. The angular scan angle corresponding to the maximum and the minimum of the OCT can be identified. Then, a linear scan can be performed across the lens7, between the maximum and minimum angle that is likely to either cross the center of the lens7, or at least pass rather close to it. The result of this linear scan can be quite instructive about the shift and tilt of the lens7. Thus, displaying the OCT image of the lens obtained via the linear scan on the video-microscope display142as the shift-tilt indicator147can assist the surgeon to reduce or eliminate the misalignments efficiently.

A primary function of the docking system100is to assist the docking of the patient interface50onto the eye1. The above described embodiments that generate an image of the imaged portion of the eye before the docking and provide the shift and tilt indicators144and146in conjunction with the target reference pattern148carry out this function well.

The performance of the docking system100can be further improved by implementing an imaging system110that is capable of imaging the imaged portion of the eye not just before the ophthalmic docking but repeatedly during the docking.

Systems that display one or a few updated image during the docking procedure can provide valuable feedback regarding the actions of the surgeon, providing improvement in the precision and performance of the docking system100.

Some embodiments of the imaging system110can offer a further qualitative improvement in this regard. They can provide not only a few updated images during docking, but an essentially live image of the docking procedure. An essentially live feedback can deliver timely information for the surgeon to center the docking with improved precision and to optimize the process in several different ways.

An often used refresh rate of live video images is typically 24 frames/second. Therefore, imaging systems that can provide images at a rate of 20-25 frames/second or higher can provide images that will appear essentially live for the surgeon. Whereas systems with a frame rate or refresh rate of less than 20-25 frames/second may not be perceived as live video imaging, but rather as jerky, jumpy images, possibly even distracting from the docking procedure.

In this respect, embodiments of the present imaging system110can be classified as follows. Time domain OCT, or TD-OCT systems perform an A-scan, i.e. image a range of depths corresponding to a single transverse (x,y) coordinate sequentially. Therefore, TD-OCT A-scans take a long time, and TD-OCT systems can take only several hundred to a few thousand A-scans per second. In some embodiments, their performance can be even slower. To obtain an OCT image with a reasonable resolution may require integrating several hundreds of A-scans taken along a line of (x,y) points into a B scan. Therefore, TD-OCT systems may generate B scans with a refresh rate of 1-10 frames/second, often as little as one or few frames per second. Such images appear jerky for the surgeon and provide a slower-than-live feedback for the docking process. Therefore, TD-OCT systems cannot provide feedback sufficiently fast to validate or discourage the surgeon's misalignment adjustments at the actual speed of the docking.

This slow imaging performance has disadvantages. For example, the ophthalmic docking system100is configured to guide and assist the alignment of the PI50with the eye1before the docking. At this pre-docked stage, the patient19is still capable of moving the eye1. In particular, the patient is breathing, moving the eye up and down. At low imaging speeds, a TD-OCT imaging system cannot keep up with the up-and-down breathing motion of the eye, causing the TD-OCT imaging system to display motional artifacts, such as jumps in the image and discontinuous image lines.

In contrast, Spectrometer-Based, or SB-OCT systems gather image data at an (x,y) point from all depths simultaneously. These images are sometimes still called A-scans, even though no sequential scanning is involved. Because of the parallel or simultaneous nature of gathering the image-data from different depths, SB-OCT systems can take up to 500,000 A-scans per second. Therefore, the same B-scan containing several hundred A-scans as above, can be generated with a refresh rate of higher than 20 frames per second, possibly up to 1,000 frames per second.

It is noted here that actually displaying these images also takes time and can be limited by the electronic performance of the OCT display unit142. The above cited refresh rates characterize the speed of image-acquisition by the imaging system110. The speed of display can be slower, depending on the electronic and data-transfer limiting factors.

The performance of SB-OCT systems can be further accelerated by using dedicated processors and pre-computed scanning patterns stored in dedicated memories to drive the scanning of the imaging beam fast, as described e.g. in the above-referenced US Patent Application “Image-Guided Docking for Ophthalmic Surgical Systems” by A. Juhasz and K. Vardin.

Given that the imaging speeds of the SB-OCT and TD-OCT imaging systems are on opposite sides of the live video-rate of 20-25 frames/second, embodiments of the imaging system110that use SB-OCT imaging systems are capable of providing timely and smooth live feedback information for the surgeon free of motional artifacts, whereas typical TD-OCT imaging systems are not capable of providing smooth live feedback for the surgeon and are prone to display motional artifacts. Systems with live imaging feedback, as discussed above, offer qualitatively improved precision of the docking procedure.

Further, the superior imaging speed allows SB-OCT imaging systems110to create much more complex, sharp and detail-rich images and still provide the images as a live video. Examples include two dimensional images of the lens7or scanning the lens7along several circles to map out the actual shape of the lens7instead of using models and relying on assumptions about the geometry and shape of the lens7.

A final factor, impacting the long term performance of embodiments of the imaging system110is that SB-OCT systems do not have moving parts and thus their reliability and serviceability is quite satisfactory. In contrast, TD-OCT systems have rapidly moving parts, associated with the movement of a reference mirror in a reference arm of the OCT apparatus. Obviously, the presence of moving parts in the TD-OCT systems increases the chance of malfunction and misalignment, thus possibly decreasing their overall performance, demanding more frequent field-service and still facing the possibility of long-term performance degradation.

In sum, TD-OCT systems are not necessarily equivalent to SB-OCT systems, at least for the following reasons. (i) TD-OCT systems do not provide live imaging, or feedback images at refresh rates useful for high precision docking and surgical processes. (ii) TD-OCT systems are prone to display motional artifacts. (iii) TD-OCT systems may also have difficulties providing 2D scanning images or high precision, detail-rich images. (iv) Finally, TD-OCT imaging systems require field services and maintenance much more often than SB-OCT system. Thus, TD-OCT systems and SB-OCT systems are sufficiently different so that for many applications they are not equivalent embodiments of a generic OCT system. Rather, the degree of difference between their performances for the specific application is to be analyzed on a case-by-case basis.

FIG. 11Billustrates that other implementations of the docking system100may acquire some of the misalignment information from a video image created by a video-imaging system180. In these docking systems100, embodiments of the ophthalmic imaging system110can include an OCT or an in-depth imaging system110that can generate an in-depth image of an internal eye-structure of the eye1. The image processor120can include an in-depth image processor120that can determine an orientation of the internal eye-structure from the in-depth image of the internal eye-structure.

In addition, the docking system100and in particular the guidance system140can include the video-imaging system180that can include a video-image processor182and a video-display184that can be analogous to the video microscope display142. The video-imaging system180can be configured to video-image a frontal eye-structure of the eye, and the video-image processor182can be configured to determine a location of the frontal eye-structure from the video-image of the frontal eye-structure. As before, the video-imaging system180can be coupled to the ophthalmic imaging system110and can be configured to display on the video-display184an orientation misalignment indicator using the determined orientation of the internal eye-structure, determined by the image processor120, and a location misalignment indicator using the determined location of the frontal eye-structure, determined by the video-image processor182.

In some implementations, the in-depth image processor120can perform an image recognition process to recognize a portion of the ACL scan-image114and a portion of the PCL scan-image116in the image of the internal eye-structure, which can be the lens7, or its capsular bag or its hardened nucleus.

The in-depth image processor120can determine the orientation or tilt misalignment of the imaged internal eye-structure based on the results of the image recognition process by performing any of the methods described in relation toFIG. 6and subsequently, involving phases and amplitudes of the scan-image.

The video-image processor182can perform a video-image recognition process to recognize an image of the frontal eye-structure in the video-image, and to determine a location of the frontal eye-structure based on the result of the video-image recognition process. The imaged frontal eye-structure can be the pupil6or the limbus5of the eye, for example.

As it has been described in relation toFIGS. 4-6, the analysis by the in-depth image processor120can determine not only the orientation of the lens7, the internal eye-structure, but also its location. Therefore, in some implementations, the docking system100could determine two locations: the location of the imaged internal eye-structure as determined by the in-depth image processor120, and the location of the frontal eye-structure as determined by the video-imaging system180. Since the internal eye structure may not be fully aligned with the eye, these two locations may be different.

Aligning the patient interface50with the location of the imaged internal eye-structure, with the location of the frontal eye-structure, or with an intermediate or averaged location generated using both of these locations may be advantageous for various purposes.

FIGS. 7A-BandFIG. 10Aillustrate that after the image recognition steps were performed by the in-depth imaging system110and the video-imaging system180, the video-display184can display an eye-orientation misalignment indicator related to the determined orientation of the imaged internal eye-structure that includes the eye-orientation indicator146and the orientation reference148. In the embodiment where the imaged internal eye-structure is the lens7, the surgeon can reduce the lens-tilt misalignment by aligning the lens-tilt indicator146with the orientation reference148. As described in relation toFIGS. 7-10, the surgeon can achieve this alignment by instructing the patient19to rotate the docking eye, or by manually rotating the eye1, or by adjusting the fixation light source160, among others.

The video-display184can also display a location misalignment indicator that includes the eye-location indicator144related to the determined location of the video-imaged frontal eye-structure, and the location reference148of the ophthalmic docking system. As before, the operator of the ophthalmic docking system100can reduce a lens location misalignment by aligning the lens location indicator144with the location reference148. As described in relation toFIGS. 7-10, the surgeon can reduce this location misalignment by operating the gantry150.

The docking system100ofFIG. 11Bcan be used in combination with any block or unit of the previously described embodiments ofFIG. 2,FIGS. 8A-BandFIG. 11A. For example, the docking system100can include the fixation light source160, configured to adjust the fixation light165in relation to at least one of the location misalignment indicator and the orientation misalignment indicator.

FIG. 12illustrates that an embodiment of a method300of guiding an ophthalmic docking can include: an imaging310of a portion of the eye1of the patient19with the ophthalmic imaging system110; a determining320of a location and an orientation of the imaged portion of the eye1by analyzing the image with the image processor120; and a guiding330of an ophthalmic docking based on the determined location and orientation with the guidance system140.

The imaging310can include imaging at least one of a lens-capsule, the anterior capsular layer ACL14, the posterior capsular layer PCL16, a lens target region, the lens7, its nucleus, the cornea2, the iris3, the limbus5, the pupil6, a corneal endothelium and a corneal epithelium.

In embodiments where the imaging310includes imaging a portion of the lens7of the eye, the determining320can include performing an image recognition process to recognize an ACL scan-image114of the anterior capsular layer ACL14and to recognize a PCL scan-image116of the posterior capsular layer PCL16in the image.

As described in relation toFIG. 6, once the image recognition has been performed, the determining320can further include determining an anterior phase and an anterior amplitude of the ACL scan-image114and a posterior phase and a posterior amplitude of the PCL scan-image116, and determining the location and the orientation of the lens7from the anterior phase, the anterior amplitude, the posterior phase and the posterior amplitude.

In other embodiments, the determining320can include determining an anterior maximum depth and an anterior minimum depth of the anterior capsular layer and a posterior maximum depth and a posterior minimum depth of the posterior capsular layer along a scanning variable; and determining the location and the orientation of the lens7from the anterior maximum depth, the anterior minimum depth, the posterior maximum depth, and posterior minimum depth.

In yet other embodiments, the determining320can include recognizing an image of a capsular layer portion of the lens in the image; determining a phase and an amplitude of the capsular layer; and determining a location and an orientation of the lens using the determined phase and amplitude.

The guiding330can include displaying a location misalignment indicator based on the determined location of the imaged portion of the eye, and displaying an orientation misalignment indicator based on the determined orientation of the imaged portion of the eye.

The guiding330can also include displaying, as part of the location misalignment indicator, the eye or lens location indicator144based on the determined location of the imaged portion of the eye and the location reference148-sof the ophthalmic docking system, and displaying as part of the orientation misalignment indicator, the eye or lens orientation indicator146based on the determined orientation of the imaged portion of the eye and the orientation reference148-tof the ophthalmic docking system. The orientation reference148-tand the location reference148-scan be the same target or reference pattern148.

The guiding330can also include displaying the location misalignment indicator to assist an operator of the ophthalmic docking system100to operate the gantry150to reduce an eye or lens location misalignment. Further, the guiding330can also include displaying the orientation misalignment indicator146to assist the surgeon to instruct the patient19to rotate the eye, or to manually rotate the eye, or to adjust the fixation light source160to reduce an eye orientation misalignment.

The method300can include performing repeatedly the imaging310, the determining320, and the guiding330. The guiding330may include updating the display of the location misalignment indicator and the orientation misalignment indicator according to the repeated imaging310and determining320during the ophthalmic docking. Such a repeat performance of the guiding method300can provide valuable feedback for the surgeon, improving the precision of the docking process. A further qualitative improvement can be achieved by updating the image or repeating the imaging at a live video refresh rate, such as at 20-25 frames/second or faster. Repeating the method300at such video rates may be able to provide a live video feedback for the surgeon.

FIG. 13illustrates that an alternative method400of guiding an ophthalmic docking can include: an imaging410of an internal eye-structure of an eye of a patient with the in-depth imaging system110; a determining an orientation420of the internal eye-structure from the in-depth image of the internal eye-structure with the image processor120; a video-imaging430of a frontal eye-structure of the eye with the video-imaging system180; a determining of a location440of the frontal eye-structure from the video-image of the frontal eye-structure with the video-image processor182; and a displaying450of an orientation misalignment indicator using the determined orientation of the internal eye-structure and a location misalignment indicator using the determined location of the frontal eye-structure with the guidance system140or the video display unit184.

Another embodiment of the alignment guidance system140can include a system that provides guidance for the precise attachment of the patient interface50onto a distal tip of the ophthalmic docking system100, its optic130or its objective154. The precision of the corneal flaps, created during LASIK procedures, is very sensitive to even the smallest misalignments of the PI optical axis52with the system optical axis28, even of the order of ten microns. Therefore, considerable performance improvements can be achieved by applying the imaging-based guidance system140to image the patient interface50itself before and during the process of attaching it to the distal end of the system100even before any docking process is initiated, and to provide a guidance to the surgeon to adjust the PI50based on the imaged misalignments of the PT50and the objective154.

Yet another application can be to use the guidance system140not to assist a docking procedure, but in conjunction with an ultrasound-based phaco surgical system to guide the precise targeting of the various surgical steps, including the insertion of the phaco-tip by the ophthalmic surgeon.

In yet another implementation, the ophthalmic guidance system140may be coupled to the ophthalmic imaging system110that includes a Spectrometer Based OCT (SB-OCT) imaging system. The imaging system110can be configured to generate a live image of an ophthalmic region modified by a surgical procedure. In some implementations, the image-refresh rate can be 20-25 frames/second or greater.

In the above specification, numerous systems included one or more programmable processors, and numerous method steps included the processors functioning based on a corresponding stored program. In these systems, embodiments exist in which the systems include memory systems, associated with the processors that are capable of storing the corresponding programs, and program means that are stored in the memory systems. For example, the image processor120, the guidance system140, the gantry controller152, the misalignment reduction system177, and the video-image processor182all have embodiments that include a memory or memory systems corresponding to these processors that are capable of storing a program or program means for their processor, possibly on computer-readable media.