Patent Publication Number: US-2021161654-A1

Title: Method and Apparatus for Creating Ocular Surgical and Relaxing Incisions

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/906,944, filed Mar. 13, 2007, and which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to ophthalmic surgical procedures and systems. 
     BACKGROUND OF THE INVENTION 
     Cataract extraction is one of the most commonly performed surgical procedures in the world with estimated 2.5 million cases performed annually in the United States and 9.1 million cases worldwide in 2000. This was expected to increase to approximately 13.3 million estimated global cases in 2006. This market is composed of various segments including intraocular lenses for implantation, viscoelastic polymers to facilitate surgical maneuvers, disposable instrumentation including ultrasonic phacoemulsification tips, tubing, and various knives and forceps. Modern cataract surgery is typically performed using a technique termed phacoemulsification in which an ultrasonic tip with an associated water stream for cooling purposes is used to sculpt the relatively hard nucleus of the lens after performance of an opening in the anterior lens capsule termed anterior capsulotomy or more recently capsulorhexis. Following these steps as well as removal of residual softer lens cortex by aspiration methods without fragmentation, a synthetic foldable intraocular lens (IOLs) is inserted into the eye through a small incision. 
     Many cataract patients are astigmatic. Astigmatism can occur when the cornea has a different curvature one direction than the other. IOLs are not presently used to correct beyond 5D of astigmatism, even though many patients have more severe aberrations. Correcting it further often involves making the corneal shape more spherical, or at least more radially symmetrical. There have been numerous approaches, including Corneaplasty, Astigmatic Keratotomy (AK), Corneal Relaxing Incisions (CRI), and Limbal Relaxing Incisions (LRI). All are done using manual, mechanical incisions. Presently, astigmatism cannot easily or predictably be corrected fully using standard techniques and approaches. About one third of those who have surgery to correct the irregularity find that their eyes regress to a considerable degree and only a small improvement is noted. Another third of the patients find that the astigmatism has been significantly reduced but not fully corrected. The remaining third have the most encouraging results with most or all of the desired correction achieved. 
     What is needed are ophthalmic methods, techniques and apparatus to advance the standard of care of corneal shaping that may be associated with invasive cataract and other ophthalmic pathologies. 
     SUMMARY OF THE INVENTION 
     Rapid and precise opening formation in the cornea and/or limbus are possible using a scanning system that implements patterned laser cutting. The patterned laser cutting improves accuracy and precision, while decreasing procedure time. 
     A scanning system for treating target tissue in a patient&#39;s eye includes a light source for generating a light beam, a scanner for deflecting the light beam to form first and second treatment patterns of the light beam under the control of a controller, and a delivery system for delivering the first treatment pattern to the target tissue to form a cataract incision therein that provides access to an eye chamber of the patient&#39;s eye. The delivery system is also for delivering the second treatment pattern to the target tissue to form a relaxation incision along or near limbus tissue or along corneal tissue anterior to the limbus tissue of the patient&#39;s eye to reduce astigmatism thereof. 
     A method of treating target tissue in a patient&#39;s eye includes generating a light beam, deflecting the light beam using a scanner to form first and second treatment patterns, delivering the first treatment pattern to the target tissue to form an incision that provides access to an eye chamber of the patient&#39;s eye, and delivering the second treatment pattern to the target tissue to form a relaxation incision along or near limbus tissue or along corneal tissue anterior to the limbus tissue of the patient&#39;s eye to reduce astigmatism thereof. 
     Other objects and features of the present invention will become apparent by a review of the specification, claims and appended figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of the optical beam scanning system. 
         FIG. 2  is an optical diagram showing an alternative beam combining scheme. 
         FIG. 3  is a schematic diagram of the optical beam scanning system with an alternative OCT configuration. 
         FIG. 4  is a schematic diagram of the optical beam scanning system with another alternative OCT combining scheme. 
         FIG. 5A  is a top view of a patient&#39;s eye showing a cataract incision. 
         FIG. 5B  is a side cross sectional view of a patient&#39;s eye showing the cataract incision. 
         FIG. 6  is a schematic diagram of the optical beam scanning system with a profilometer subsystem. 
         FIG. 7  is a top view of a patient&#39;s eye showing corneal relaxing incisions. 
         FIG. 8  is a side cross sectional view of a patient&#39;s eye showing an incision with a specialized geometry. 
         FIG. 9  is a side cross sectional view of a contact lens in proximity to a patient&#39;s eye. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The techniques and systems disclosed herein provide many advantages over the current standard of care. Specifically, rapid and precise openings in the cornea and/or limbus are formed using 3-dimensional patterned laser cutting. The accuracy and precision of the incisions are improved over traditional methods, while the duration of the procedure and the risk associated with creating incisions are both reduced. The present invention can utilize anatomical and optical characterization and feedback to perform astigmatic keratotomy such as limbal and corneal relaxing incisions in conjunction with the creation of surgical incision that provides the surgeon access to the anterior chamber of an eye. The surgical incision may be made completely, or partially, depending upon the clinical situation. A wavefront sensor, interferometer, surface profiler, or other such device may be used to yield prescriptions for correcting the astigmatism or other visual aberrations. Likewise, these same devices may be used to verify the surgical correction of the patterned scanning system, even adjusting it during the treatment procedure to produce the desired outcome. Furthermore, the present invention may be used in multiple sessions to coordinate the healing of the astigmatic correction, and drive the corrective treatment over the course of the wound healing process. The present invention also provides for the image guided alignment of the incision. 
     There are surgical approaches provided by the present invention that enable the formation of very small and geometrically precise opening(s) and incision(s) in precise locations in and around the cornea and limbus. The incisions enable greater precision or modifications to conventional ophthalmic procedures as well as enable new procedures. The incision is not limited only to circular shapes but may be any shape that is conducive to healing or follow on procedures. These incisions might be placed such that they are able to seal spontaneously; or with autologous or synthetic tissue glue, photochemical bonding agent, or other such method. Furthermore, the present invention provides for the automated generation of incision patterns for optimal effect. 
     Another procedure enabled by the techniques described herein provides for the controlled formation of an incision or pattern of incisions. Conventional techniques are confined to areas accessible from outside the eye using mechanical cutting instruments and thus can only create incisions from anterior to posterior segments of tissue. In contrast, the controllable, patterned laser techniques described herein may be used to create an incision in virtually any position and in virtually any shape. Matching incisions may be made in both the anterior and posterior sections. The present invention is uniquely suited to perform such matching incisions. 
     Furthermore, these incisions may be tailored to complement an asymmetric IOL that is being inserted as part of the procedure or has been previously inserted. The present invention enables the measurement of the IOL placement and subsequent automated calculation and generation of these complimentary corneal or limbus incisions. The controllable, patterned laser techniques described herein have available and/or utilize precise lens measurement and other dimensional information that allows the incision or opening formation while minimizing impact on surrounding tissue. 
     The present invention can be implemented by a system that projects or scans an optical beam into a patient&#39;s eye  68 , such as system  2  shown in  FIG. 1  which includes an ultrafast (UF) light source  4  (e.g. a femtosecond laser). Using this system, a beam may be scanned in a patient&#39;s eye in three dimensions: X, Y, Z. In this embodiment, the UF wavelength can vary between 1010 nm to 1100 nm and the pulse width can vary from 100 fs to 10000 fs. The pulse repetition frequency can also vary from 10 kHz to 250 kHz. Safety limits with regard to unintended damage to non-targeted tissue bound the upper limit with regard to repetition rate and pulse energy; while threshold energy, time to complete the procedure and stability bound the lower limit for pulse energy and repetition rate. The peak power of the focused spot in the eye  68  and specifically within the crystalline lens  69  and anterior capsule of the eye is sufficient to produce optical breakdown and initiate a plasma-mediated ablation process. Near-infrared wavelengths are preferred because linear optical absorption and scattering in biological tissue is reduced across that spectral range. As an example, laser  4  may be a repetitively pulsed 1035 nm device that produces 500 fs pulses at a repetition rate of 100 kHz and an individual pulse energy in the ten microjoule range. 
     The laser  4  is controlled by control electronics  300 , via an input and output device  302 , to create optical beam  6 . Control electronics  300  may be a computer, microcontroller, etc. In this example, the entire system is controlled by the controller  300 , and data moved through input/output device IO  302 . A graphical user interface GUI  304  may be used to set system operating parameters, process user input (UI)  306  on the GUI  304 , and display gathered information such as images of ocular structures. 
     The generated UF light beam  6  proceeds towards the patient eye  68  passing through half-wave plate,  8 , and linear polarizer,  10 . The polarization state of the beam can be adjusted so that the desired amount of light passes through half-wave plate  8  and linear polarizer  10 , which together act as a variable attenuator for the UF beam  6 . Additionally, the orientation of linear polarizer  10  determines the incident polarization state incident upon beamcombiner  34 , thereby optimizing beamcombiner throughput. 
     The UF beam proceeds through a shutter  12 , aperture  14 , and a pickoff device  16 . The system controlled shutter  12  ensures on/off control of the laser for procedural and safety reasons. The aperture sets an outer useful diameter for the laser beam and the pickoff monitors the output of the useful beam. The pickoff device  16  includes of a partially reflecting mirror  20  and a detector  18 . Pulse energy, average power, or a combination may be measured using detector  18 . The information can be used for feedback to the half-wave plate  8  for attenuation and to verify whether the shutter  12  is open or closed. In addition, the shutter  12  may have position sensors to provide a redundant state detection. 
     The beam passes through a beam conditioning stage  22 , in which beam parameters such as beam diameter, divergence, circularity, and astigmatism can be modified. In this illustrative example, the beam conditioning stage  22  includes a 2 element beam expanding telescope comprised of spherical optics  24  and  26  in order to achieve the intended beam size and collimation. Although not illustrated here, an anamorphic or other optical system can be used to achieve the desired beam parameters. The factors used to determine these beam parameters include the output beam parameters of the laser, the overall magnification of the system, and the desired numerical aperture (NA) at the treatment location. In addition, the optical system  22  can be used to image aperture  14  to a desired location (e.g. the center location between the 2-axis scanning device  50  described below). In this way, the amount of light that makes it through the aperture  14  is assured to make it through the scanning system. Pickoff device  16  is then a reliable measure of the usable light. 
     After exiting conditioning stage  22 , beam  6  reflects off of fold mirrors  28 ,  30 , &amp;  32 . These mirrors can be adjustable for alignment purposes. The beam  6  is then incident upon beam combiner  34 . Beamcombiner  34  reflects the UF beam  6  (and transmits both the OCT  114  and aim  202  beams described below). For efficient beamcombiner operation, the angle of incidence is preferably kept below 45 degrees and the polarization where possible of the beams is fixed. For the UF beam  6 , the orientation of linear polarizer  10  provides fixed polarization. 
     Following the beam combiner  34 , the beam  6  continues onto the z-adjust or Z scan device  40 . In this illustrative example the z-adjust includes a Galilean telescope with two lens groups  42  and  44  (each lens group includes one or more lenses). Lens group  42  moves along the z-axis about the collimation position of the telescope. In this way, the focus position of the spot in the patient&#39;s eye  68  moves along the z-axis as indicated. In general there is a fixed linear relationship between the motion of lens  42  and the motion of the focus. In this case, the z-adjust telescope has an approximate 2× beam expansion ratio and a 1:1 relationship of the movement of lens  42  to the movement of the focus. Alternatively, lens group  44  could be moved along the z-axis to actuate the z-adjust, and scan. The z-adjust is the z-scan device for treatment in the eye  68 . It can be controlled automatically and dynamically by the system and selected to be independent or to interplay with the X-Y scan device described next. Mirrors  36  and  38  can be used for aligning the optical axis with the axis of z-adjust device  40 . 
     After passing through the z-adjust device  40 , the beam  6  is directed to the x-y scan device by mirrors  46  &amp;  48 . Mirrors  46  &amp;  48  can be adjustable for alignment purposes. X-Y scanning is achieved by the scanning device  50  preferably using two mirrors  52  &amp;  54  under the control of control electronics  300 , which rotate in orthogonal directions using motors, galvanometers, or any other well known optic moving device. Mirrors  52  &amp;  54  are located near the telecentric position of the objective lens  58  and contact lens  66  combination described below. Tilting these mirrors  52 / 54  causes them to deflect beam  6 , causing lateral displacements in the plane of UF focus located in the patient&#39;s eye  68 . Objective lens  58  may be a complex multi-element lens element, as shown, and represented by lenses  60 ,  62 , and  64 . The complexity of the lens  58  will be dictated by the scan field size, the focused spot size, the available working distance on both the proximal and distal sides of objective  58 , as well as the amount of aberration control. An f-theta lens  58  of focal length 60 mm generating a spot size of 10 μm, over a field of 10 mm, with an input beam size of 15 mm diameter is an example. Alternatively, X-Y scanning by scanner  50  may be achieved by using one or more moveable optical elements (e.g. lenses, gratings) which also may be controlled by control electronics  300 , via input and output device  302 . 
     The aiming and treatment scan patterns can be automatically generated by the scanner  50  under the control of controller  300 . Such patterns may be comprised of a single spot of light, multiple spots of light, a continuous pattern of light, multiple continuous patterns of light, and/or any combination of these. In addition, the aiming pattern (using aim beam  202  described below) need not be identical to the treatment pattern (using light beam  6 ), but preferably at least defines its boundaries in order to assure that the treatment light is delivered only within the desired target area for patient safety. This may be done, for example, by having the aiming pattern provide an outline of the intended treatment pattern. This way the spatial extent of the treatment pattern may be made known to the user, if not the exact locations of the individual spots themselves, and the scanning thus optimized for speed, efficiency and accuracy. The aiming pattern may also be made to be perceived as blinking in order to further enhance its visibility to the user. 
     An optional contact lens  66 , which can be any suitable ophthalmic lens, can be used to help further focus the optical beam  6  into the patient&#39;s eye  68  while helping to stabilize eye position. The positioning and character of optical beam  6  and/or the scan pattern the beam  6  forms on the eye  68  may be further controlled by use of an input device such as a joystick, or any other appropriate user input device (e.g. GUI  304 ) to position the patient and/or the optical system. 
     The UF laser  4  and controller  300  can be set to target the surfaces of the targeted structures in the eye  68  and ensure that the beam  6  will be focused where appropriate and not unintentionally damage non-targeted tissue. Imaging modalities and techniques described herein, such as for example, Optical Coherence Tomography (OCT), Purkinje imaging, Scheimpflug imaging, or ultrasound may be used to determine the location and measure the thickness of the lens and lens capsule to provide greater precision to the laser focusing methods, including 2D and 3D patterning. Laser focusing may also be accomplished using one or more methods including direct observation of an aiming beam, Optical Coherence Tomography (OCT), Purkinje imaging, Scheimpflug imaging, ultrasound, or other known ophthalmic or medical imaging modalities and/or combinations thereof. In the embodiment of  FIG. 1 , an OCT device  100  is described, although other modalities are within the scope of the present invention. An OCT scan of the eye will provide information about the axial location of the anterior and posterior lens capsule, the boundaries of the cataract nucleus, as well as the depth of the anterior chamber. This information is then be loaded into the control electronics  300 , and used to program and control the subsequent laser-assisted surgical procedure. The information may also be used to determine a wide variety of parameters related to the procedure such as, for example, the upper and lower axial limits of the focal planes used for cutting the lens capsule and segmentation of the lens cortex and nucleus, and the thickness of the lens capsule among others. 
     The OCT device  100  in  FIG. 1  includes a broadband or a swept light source  102  that is split by a fiber coupler  104  into a reference arm  106  and a sample arm  110 . The reference arm  106  includes a module  108  containing a reference reflection along with suitable dispersion and path length compensation. The sample arm  110  of the OCT device  100  has an output connector  112  that serves as an interface to the rest of the UF laser system. The return signals from both the reference and sample arms  106 ,  110  are then directed by coupler  104  to a detection device  128 , which employs either time domain, frequency or single point detection techniques. In  FIG. 1 , a frequency domain technique is used with an OCT wavelength of 920 nm and bandwidth of 100 nm. 
     Exiting connector  112 , the OCT beam  114  is collimated using lens  116 . The size of the collimated beam  114  is determined by the focal length of lens  116 . The size of the beam  114  is dictated by the desired NA at the focus in the eye and the magnification of the beam train leading to the eye  68 . Generally, OCT beam  114  does not require as high an NA as the UF beam  6  in the focal plane and therefore the OCT beam  114  is smaller in diameter than the UF beam  6  at the beamcombiner  34  location. Following collimating lens  116  is aperture  118  which further modifies the resultant NA of the OCT beam  114  at the eye. The diameter of aperture  118  is chosen to optimize OCT light incident on the target tissue and the strength of the return signal. Polarization control element  120 , which may be active or dynamic, is used to compensate for polarization state changes which may be induced by individual differences in corneal birefringence, for example. Mirrors  122  &amp;  124  are then used to direct the OCT beam  114  towards beamcombiners  126  &amp;  34 . Mirrors  122  &amp;  124  may be adjustable for alignment purposes and in particular for overlaying of OCT beam  114  to UF beam  6  subsequent to beamcombiner  34 . Similarly, beamcombiner  126  is used to combine the OCT beam  114  with the aim beam  202  described below. 
     Once combined with the UF beam  6  subsequent to beamcombiner  34 , OCT beam  114  follows the same path as UF beam  6  through the rest of the system. In this way, OCT beam  114  is indicative of the location of UF beam  6 . OCT beam  114  passes through the z-scan  40  and x-y scan  50  devices then the objective lens  58 , contact lens  66  and on into the eye  68 . Reflections and scatter off of structures within the eye provide return beams that retrace back through the optical system, into connector  112 , through coupler  104 , and to OCT detector  128 . These return back reflections provide the OCT signals that are in turn interpreted by the system as to the location in X, Y Z of UF beam  6  focal location. 
     OCT device  100  works on the principle of measuring differences in optical path length between its reference and sample arms. Therefore, passing the OCT through z-adjust  40  does not extend the z-range of OCT system  100  because the optical path length does not change as a function of movement of  42 . OCT system  100  has an inherent z-range that is related to the detection scheme, and in the case of frequency domain detection it is specifically related to the spectrometer and the location of the reference arm  106 . In the case of OCT system  100  used in  FIG. 1 , the z-range is approximately 1-2 mm in an aqueous environment. Extending this range to at least 4 mm involves the adjustment of the path length of the reference arm within OCT system  100 . Passing the OCT beam  114  in the sample arm through the z-scan of z-adjust  40  allows for optimization of the OCT signal strength. This is accomplished by focusing the OCT beam  114  onto the targeted structure while accommodating the extended optical path length by commensurately increasing the path within the reference arm  106  of OCT system  100 . 
     Because of the fundamental differences in the OCT measurement with respect to the UF focus device due to influences such as immersion index, refraction, and aberration, both chromatic and monochromatic, care must be taken in analyzing the OCT signal with respect to the UF beam focal location. A calibration or registration procedure as a function of X, Y Z should be conducted in order to match the OCT signal information to the UF focus location and also to the relate to absolute dimensional quantities. 
     Observation of an aim beam may also be used to assist the user to directing the UF laser focus. Additionally, an aim beam visible to the unaided eye in lieu of the infrared OCT and UF beams can be helpful with alignment provided the aim beam accurately represents the infrared beam parameters. An aim subsystem  200  is employed in the configuration shown in  FIG. 1 . The aim beam  202  is generated by a an aim beam light source  201 , such as a helium-neon laser operating at a wavelength of 633 nm. Alternatively a laser diode in the 630-650 nm range could be used. The advantage of using the helium neon 633 nm beam is its long coherence length, which would enable the use of the aim path as a laser unequal path interferometer (LUPI) to measure the optical quality of the beam train, for example. 
     Once the aim beam light source generates aim beam  202 , the aim beam  202  is collimated using lens  204 . The size of the collimated beam is determined by the focal length of lens  204 . The size of the aim beam  202  is dictated by the desired NA at the focus in the eye and the magnification of the beam train leading to the eye  68 . Generally, aim beam  202  should have close to the same NA as UF beam  6  in the focal plane and therefore aim beam  202  is of similar diameter to the UF beam at the beamcombiner  34  location. Because the aim beam is meant to stand-in for the UF beam  6  during system alignment to the target tissue of the eye, much of the aim path mimics the UF path as described previously. The aim beam  202  proceeds through a half-wave plate  206  and linear polarizer  208 . The polarization state of the aim beam  202  can be adjusted so that the desired amount of light passes through polarizer  208 . Elements  206  &amp;  208  therefore act as a variable attenuator for the aim beam  202 . Additionally, the orientation of polarizer  208  determines the incident polarization state incident upon beamcombiners  126  and  34 , thereby fixing the polarization state and allowing for optimization of the beamcombiners&#39; throughput. Of course, if a semiconductor laser is used as aim beam light source  200 , the drive current can be varied to adjust the optical power. 
     The aim beam  202  proceeds through a shutter  210  and aperture  212 . The system controlled shutter  210  provides on/off control of the aim beam  202 . The aperture  212  sets an outer useful diameter for the aim beam  202  and can be adjusted appropriately. A calibration procedure measuring the output of the aim beam  202  at the eye can be used to set the attenuation of aim beam  202  via control of polarizer  206 . 
     The aim beam  202  next passes through a beam conditioning device  214 . Beam parameters such as beam diameter, divergence, circularity, and astigmatism can be modified using one or more well known beaming conditioning optical elements. In the case of an aim beam  202  emerging from an optical fiber, the beam conditioning device  214  can simply include a beam expanding telescope with two optical elements  216  and  218  in order to achieve the intended beam size and collimation. The final factors used to determine the aim beam parameters such as degree of collimation are dictated by what is necessary to match the UF beam  6  and aim beam  202  at the location of the eye  68 . Chromatic differences can be taken into account by appropriate adjustments of beam conditioning device  214 . In addition, the optical system  214  is used to image aperture  212  to a desired location such as a conjugate location of aperture  14 . 
     The aim beam  202  next reflects off of fold mirrors  222  &amp;  220 , which are preferably adjustable for alignment registration to UF beam  6  subsequent to beam combiner  34 . The aim beam  202  is then incident upon beam combiner  126  where the aim beam  202  is combined with OCT beam  114 . Beamcombiner  126  reflects the aim beam  202  and transmits the OCT beam  114 , which allows for efficient operation of the beamcombining functions at both wavelength ranges. Alternatively, the transmit and reflect functions of beamcombiner  126  can be reversed and the configuration inverted. Subsequent to beamcombiner  126 , aim beam  202  along with OCT beam  114  is combined with UF beam  6  by beamcombiner  34 . 
     A device for imaging the target tissue on or within the eye  68  is shown schematically in  FIG. 1  as imaging system  71 . Imaging system includes a camera  74  and an illumination light source  86  for creating an image of the target tissue. The imaging system  71  gathers images which may be used by the system controller  300  for providing pattern centering about or within a predefined structure. The illumination light source  86  for the viewing is generally broadband and incoherent. For example, light source  86  can include multiple LEDs as shown. The wavelength of the viewing light source  86  is preferably in the range of 700 nm to 750 nm, but can be anything which is accommodated by the beamcombiner  56 , which combines the viewing light with the beam path for UF beam  6  and aim beam  202  (beamcombiner  56  reflects the viewing wavelengths while transmitting the OCT and UF wavelengths). The beamcombiner  56  may partially transmit the aim wavelength so that the aim beam  202  can be visible to the viewing camera  74 . Optional polarization element  84  in front of light source  86  can be a linear polarizer, a quarter wave plate, a half-wave plate or any combination, and is used to optimize signal. A false color image as generated by the near infrared wavelength is acceptable. 
     The illumination light from light source  86  is directed down towards the eye using the same objective lens  58  and contact lens  66  as the UF and aim beam  6 ,  202 . The light reflected and scattered off of various structures in the eye  68  are collected by the same lenses  58  &amp;  66  and directed back towards beamcombiner  56 . There, the return light is directed back into the viewing path via beam combiner and mirror  82 , and on to camera  74 . Camera  74  can be, for example but not limited to, any silicon based detector array of the appropriately sized format. Video lens  76  forms an image onto the camera&#39;s detector array while optical elements  80  &amp;  78  provide polarization control and wavelength filtering respectively. Aperture or iris  81  provides control of imaging NA and therefore depth of focus and depth of field. A small aperture provides the advantage of large depth of field which aids in the patient docking procedure. Alternatively, the illumination and camera paths can be switched. Furthermore, aim light source  200  can be made to emit in the infrared which would not directly visible, but could be captured and displayed using imaging system  71 . 
     Coarse adjust registration is usually needed so that when the contact lens  66  comes into contact with the cornea, the targeted structures are in the capture range of the X, Y scan of the system. Therefore a docking procedure is preferred, which preferably takes in account patient motion as the system approaches the contact condition (i.e. contact between the patient&#39;s eye  68  and the contact lens  66 . The viewing system  71  is configured so that the depth of focus is large enough such that the patient&#39;s eye  68  and other salient features may be seen before the contact lens  66  makes contact with eye  68 . 
     Preferably, a motion control system  70  is integrated into the overall control system  2 , and may move the patient, the system  2  or elements thereof, or both, to achieve accurate and reliable contact between contact lens  66  and eye  68 . Furthermore, a vacuum suction subsystem and flange may be incorporated into system  2 , and used to stabilize eye  68 . The alignment of eye  68  to system  2  via contact lens  66  may be accomplished while monitoring the output of imaging system  71 , and performed manually or automatically by analyzing the images produced by imaging system  71  electronically by means of control electronics  300  via IO  302 . Force and/or pressure sensor feedback may also be used to discern contact, as well as to initiate the vacuum subsystem. 
     An alternative beamcombining configuration is shown in the alternate embodiment of  FIG. 2 . For example, the passive beamcombiner  34  in  FIG. 1  can be replaced with an active combiner  140  in  FIG. 2 . The active beamcombiner  34  can be a moving or dynamically controlled element such as a galvanometric scanning mirror, as shown. Active combiner  140  changes it angular orientation in order to direct either the UF beam  6  or the combined aim and OCT beams  202 , 114  towards the scanner  50  and eventually eye  68  one at a time. The advantage of the active combining technique is that it avoids the difficulty of combining beams with similar wavelength ranges or polarization states using a passive beam combiner. This ability is traded off against the ability to have simultaneous beams in time and potentially less accuracy and precision due to positional tolerances of active beam combiner  140 . 
     Another alternate embodiment is shown in  FIG. 3  which is similar to that of  FIG. 1  but utilizes an alternate approach to OCT  100 . In  FIG. 3 , OCT  101  is the same as OCT  100  in  FIG. 1 , except that the reference arm  106  has been replaced by reference arm  132 . This free-space OCT reference arm  132  is realized by including beamsplitter  130  after lens  116 . The reference beam  132  then proceeds through polarization controlling element  134  and then onto the reference return module  136 . The reference return module  136  contains the appropriate dispersion and path length adjusting and compensating elements and generates an appropriate reference signal for interference with the sample signal. The sample arm of OCT  101  now originates subsequent to beamsplitter  130 . The potential advantages of this free space configuration include separate polarization control and maintenance of the reference and sample arms. The fiber based beam splitter  104  of OCT  101  can also be replaced by a fiber based circulator. Alternately, both OCT detector  128  and beamsplitter  130  might be moved together as opposed to reference arm  136 . 
       FIG. 4  shows another alternative embodiment for combining OCT beam  114  and UF beam  6 . In  FIG. 4 , OCT  156  (which can include either of the configurations of OCT  100  or  101 ) is configured such that its OCT beam  154  is coupled to UF beam  6  after the z-scan  40  using beamcombiner  152 . In this way, OCT beam  154  avoids using the z-adjust. This allows the OCT  156  to possibly be folded into the beam more easily and shortening the path length for more stable operation. This OCT configuration is at the expense of an optimized signal return strength as discussed with respect to  FIG. 1 . There are many possibilities for the configuration of the OCT interferometer, including time and frequency domain approaches, single and dual beam methods, swept source, etc, as described in U.S. Pat. Nos. 5,748,898; 5,748,352; 5,459,570; 6,111,645; and 6,053,613 (which are incorporated herein by reference.) 
     The present invention provides for creating the incision to allow access for the lens removal instrumentation, typically referred to as the “cataract incision.” This is shown as cataract incision  402  on the patient&#39;s eye  68  illustrated in  FIGS. 5A &amp; 5B . In these figures cataract incision  402  is made to eye  68  to provide access to crystalline lens  412  through cornea  406  while pupil  404  is dilated. The incision  402  is shown in cornea  406 , but could be alternately placed in limbus  408  or sclera  410 . The incision may be made with adjustable arcuate dimensions (both radius and extent), radial orientation and depth. A complete cut may not be desirable in all situations, such as in an unsterile field where opening the eye to the environment poses further risks of endophthalmitis, for example. In this case, the present invention may provide a cataract incision that only partially penetrates cornea  406 , limbus  408  and/or sclera  410 . The resident imaging apparati in system  2  may also provide input for planning the incision. For example, imaging system  71  and/or OCT  100  could identify the limbal boundary, and guide the incision to follow it along at a predetermined depth. Furthermore, surgeons often have difficulty in starting the incision at the correct location relative to limbus  410  when employing cold steel techniques, as well as keeping the knife straight to avoid incisions that ultimately penetrate both cornea  406  and sclera  410 . Such angled incisions prove more likely to have torn edges and significantly higher risks of endophthalmitis. 
     The present invention may make use of the integrated OCT system  100  to discern limbus  408  and sclera  410  relative to cornea  406  by virtue of the large optical scattering differences between them. These can be directly imaged using OCT device  100 , and the location of the transition (limbus  408 ) from clear (cornea  406 ) to scattering (sclera  410 ) can be determined and used by CPU  300  of system  2  to guide the placement of the laser-created incisions. The scanner position values corresponding to this transition define the location of limbus  408 . Thus, once registered to each other, OCT  100  can guide the position of beam  6  relative to limbus  408 . This same imaging approach may be used to discern the thickness of the tissue, as well. Thus, the depth of the incisions and their disposition within the tissue may be precisely defined. With that in mind, the choice of wavelength for OCT device  100  preferably accounts for the requirement of scleral measurement. Wavelengths in the range of 800-1400 nm are especially suited for this, as they are less scattered in tissue (and penetrate to depths of ˜1 mm) while not suffering from linear optical absorption by water or other tissue constituents that would otherwise diminish their performance. 
     Standard cataract incisions typically require ˜30° of limbal angle as seen from directly above the eye. Such incisions have been shown to induce from 0-1.0D of astigmatism, on average. Thus, achieving postoperative emmetropia can be made more difficult. To address astigmatism, the present invention may also produce Astigmatic Kerototomy (AK) incisions. Such incisions are routinely used to correct astigmatism by relaxing an asymmetrically shaped cornea along its steep axis. Similar to the cataract incision, such relaxing incisions (RIs) must be accurately placed along or nearby the limbus and are known as Limbal Relaxing Incisions (LRIs). Relaxing incisions, however, are only partially penetrating incisions. They should leave at least 200 μm of tissue thickness in order to maintain its ongoing structural integrity. Similarly, Corneal Relaxing Incisions (CRIs) are incisions that are placed anterior to the limbus in the clear corneal tissue to serve the same clinical purpose of astigmatic correction. In addition to the specific clinical details, the circumferential orientation and angular extent are also influenced by the cataract incision. Thus, with the present invention, the RIs may be planned and executed in conjunction with the cataract incision to achieve a better visual correction than otherwise possible. To optimize the entire treatment, the cataract incision should not be placed at or near the steep axis of the cornea. If it is, only one RI is traditionally recommended. There are a variety of nomograms based upon empirical observations that are currently used by clinicians to prescribe the placement and extent of RIs. These include, but are not limited to, the Donnenfeld, Gills, Nichamin, and Koch nomograms. 
       FIG. 6  illustrates system  2  as shown in  FIG. 1 , but with a sub-system to characterize the astigmatism of the patient&#39;s cornea. Specifically, a profilometer  415  distal to X-Y scanner  50  is included to allow for a continuous unobstructed view of the cornea of patient&#39;s eye  68 . Profilometer  415  and its sensor  417  are added to system  2  via beamcombiner  419  and are connected as shown in  FIG. 6  to the system controller  300  through input/output bus  302 . As compared to the configuration described in  FIG. 1 , in this embodiment, contact lens  66  or its disposition relative to cornea  406  of eye  68  may have to be modified, or compensated for, to suit the profilometer&#39;s mode of operation. This is because profilometer  415  requires the cornea to be in its natural state, not forced into contact with a surface and possibly conforming to its shape, to accurately measure cornea  406  and provide data to system  2  for calculation and registration via input/output bus  302  and control electronics  300 . Alternately, contact lens  66  may be removed from contact with the eye, and the diagnostic and therapeutic portions of system  2  made to traverse gap  421  to eye  68  as shown in  FIG. 9 . The change in relationship between eye  68  and system  2  made by removing contact lens  66  must then be accounted for in ranging and registration of beams  6 ,  114 , and  202 . The use of OCT  100  to discern the location and shape of cornea  406  is especially useful in this regard, as the reflection from cornea  406  will provide a very strong signal making registration straight forward. 
     In this embodiment, profilometer  415  may be used to prescribe an astigmatic keratotomy to correct the shape of a patient&#39;s cornea to diminish its astigmatism. The profilometer  415  may be a placido system, triangulation system, laser displacement sensor, interferometer, or other such device, which measures the corneal topography also known as the surface profile or the surface sag (i.e. sagitta) of the cornea as a function of the transverse dimension to some defined axis. This axis is typically the visual axis of the eye but can also be the optical axis of the cornea. Alternately, profilometer  415  may be replaced by a wavefront sensor to more fully optically characterize the patient&#39;s eye. A wavefront sensing system measures the aberration of the eye&#39;s optical system. A common technique for accomplishing this task is a Shack-Hartmann wavefront sensor, which measures the shape of the wavefronts of light (surfaces of constant phase) that exit the eye&#39;s pupil. If the eye were a perfect optical system, these wavefronts would be perfectly flat. Since the eye is not perfect, the wavefronts are not flat and have irregular curved shapes. A Shack-Hartmann sensor divides up the incoming beam and its overall wavefront into sub-beams, dividing up the wavefront into separate facets, each focused by a microlens onto a subarray of detection pixels. Depending upon where the focal spot from each facet strikes its subarray of pixels, it is then possible to determine the local wavefront inclination (or tilt). Subsequent analysis of all facets together leads to determination of the overall wavefront form. These deviations from the perfectly overall flat wavefront are indicative of the localized corrections that can be made in the corneal surface. The measurements of the wavefront sensor may be used by controller  300  to automatically prescribe an astigmatic keratotomy via predictive algorithms resident in the system, as mentioned above. 
       FIG. 7  shows a possible configuration of such an astigmatic keratotomy. In this example, eye  68  is shown and a set of relaxing incisions RI  420  are made at locations within the area of the cornea  406 . Likewise, as is known in the art, such relaxing incisions may be made in the limbus  408 , or sclera  410 . Astigmatism is present when the cornea is not spherical; that is, it is steeper in one meridian than other (orthogonal) meridian. Determining the nature of the corneal shape is important, whether the astigmatism is “with-the-rule,” “against-the-rule,” or oblique. In “with-the-rule” astigmatism, the vertical meridian is steeper than the horizontal meridian; in “against-the-rule” astigmatism, the horizontal meridian is steeper than the vertical meridian. Limbal relaxing incisions (LRIs) are a modification of astigmatic keratotomy (AK), a procedure to treat astigmatism. LRIs are placed on the far peripheral aspect of the cornea (the limbus), resulting in a more rounded cornea. Astigmatism is reduced, and uncorrected vision is improved. LRIs can correct astigmatism up to 8 diopters (D); however, the use of LRIs is presently routinely reserved for corrections of 0.5-4 D of astigmatism. Although LRIs are a weaker corrective procedure compared to corneal relaxing incisions (CRIs), LRIs produce less postoperative glare and less patient discomfort. In addition, these incisions heal faster. Unlike CRIs, making the incision at the limbus preserves the perfect optical qualities of the cornea. LRIs are also a more forgiving procedure, and surgeons often get excellent results, even with early cases. 
     The desired length, number, and depth of relaxing incisions  420  can be determined using nomograms. A starting point nomogram can titrate surgery by length and number of LRIs. However, the length and placement can vary based on topography and other factors. The goal is to reduce cylindrical optical power and to absolutely avoid overcorrecting with-the-rule astigmatism, because against-the-rule astigmatism should be minimized. Relaxing incisions formed in the sclera, limbus, or cornea are generally used for cases of with-the-rule astigmatism and low against-the-rule astigmatism. When using the relaxing incision in conjunction with against-the-rule astigmatism, the LRI can be moved slightly into the cornea, or, alternatively, the LRI could be placed opposite another relaxing incision in the sclera, limbus or cornea. For patients who have with-the-rule astigmatism or oblique astigmatism, the relaxing incision is made temporally, and the LRIs are placed at the steep axis. The placement of the LRI should be customized to the topography of the cornea. In cases of asymmetric astigmatism, the LRI in the steepest axis can be elongated slightly and then shortened the same amount in the flatter of the 2 steep axes. Paired LRIs do not have to be made in the same meridian. Patients with low (&lt;1.5 D) against-the-rule astigmatism receive only a single LRI in the steep meridian, placed opposite to the cataract incision. However, if astigmatism is greater than 1.5 D, a pair of LRIs should be used. In against-the-rule astigmatism cases, one pair of LRIs may be incorporated into the cataract incision. The length of the LRI is not affected by the presence of the cataract incision. This is difficult to perform precisely with present methods. In low with-the-rule astigmatism cases, a single 6-mm LRI (0.6 mm in depth) is made at 90°. The LRI can be independent of the cataract incision in with-the-rule astigmatism cases (if the cataract incision is temporal and the LRI is superior). 
     Furthermore, unlike traditional cold steel surgical approaches to creating incisions that must start at the outside and cut inwards, using a light source for making these incisions allows for RI  420  to be made from the inside out and thus better preserve the structural integrity of the tissue and limit the risk of tearing and infection. Moreover, the cataract incision  402  and the relaxation incision(s)  420  can be made automatically using the imaging and scanning features of system  2 . A pair of treatment patterns can be generated that forms incisions  402  and  420 , thus providing more accurate control over the absolute and relative positioning of these incisions. The pair of treatment patterns can be applied sequentially, or simultaneously (i.e. the pair of treatment patterns can be combined into a single treatment pattern that forms both types of incisions). For proper alignment of the treatment beam pattern, an aiming beam and/or pattern from system  2  can be first projected onto the target tissue with visible light indicating where the treatment pattern(s) will be projected. This allows the surgeon to adjust and confirm the size, location and shape of the treatment pattern(s) before their actual application. Thereafter, the two or three dimensional treatment pattern(s) can be rapidly applied to the target tissue using the scanning capabilities of system  2 . 
     Specialized scan patterns for creating alternate geometries for cataract incisions  402  that are not achievable using conventional techniques are also possible. An example is illustrated in  FIG. 8 . A cross-sectional view of an alternate geometry for cataract incision  402  is shown to have a bevel feature  430 . Bevel feature  430  may be useful for wound healing, sealing, or locking. Such 3-dimensional cataract incisions  402  can be achieved accurately and quickly utilizing the 3-dimensional scanning ability of system  2 . Although a beveled incision is shown, many such geometries are enabled using the present invention, and within its scope. As before, the incision  402  is shown in cornea  406 , but could be alternately placed in limbus  408  or sclera  410 . 
     For large fields as when incisions are made in the outer most regions such as the limbus or sclera, a specialized contact lens can be used. This contact lens could be in the form of a gonioscopic mirror or lens. The lens does not need to be diametrically symmetric. Just one portion of the lens can be extended to reach the outer regions of the eye such as the limbus  408  and sclera  410 . Any targeted location can be reached by the proper rotation of the specialized lens. 
     It is to be understood that the present invention is not limited to the embodiment(s) described above and illustrated herein, but encompasses any and all variations falling within the scope of the appended claims. For example, references to the present invention herein are not intended to limit the scope of any claim or claim term, but instead merely make reference to one or more features that may be covered by one or more of the claims. All the optical elements downstream of scanner  50  shown in  FIGS. 1, 3 and 4  form a delivery system of optical elements for delivering the beam  6 ,  114  and  202  to the target tissue. Conceivably, depending on the desired features of the system, some or even most of the depicted optical elements could be omitted in a delivery system that still reliably delivers the scanned beams to the target tissue.