WO2014025336A1

WO2014025336A1 - Method and apparatus for making improved surgical incisions in corrective eye surgery

Info

Publication number: WO2014025336A1
Application number: PCT/US2012/049737
Authority: WO
Inventors: Anita Nevyas-Wallace
Original assignee: Anita Nevyas-Wallace
Priority date: 2012-08-06
Filing date: 2012-08-06
Publication date: 2014-02-13

Abstract

A method and apparatus for making improved surgical incisions in corrective eye surgery are provided. It was observed that a uniform elongated AK (or LRI) incision provides a non-uniform corrective effect due to non-uniform post-surgical relaxation of ophthalmic tissue. The method and apparatus leverage this observation to provide for creation of a surgical incision that is structured to be non-uniform along its length in such a manner as to at least partially counteract an expected variation in ophthalmic tissue relaxation to provide overall increased uniformity of corrective effect. An automated laser surgery system includes a laser control system configured to control laser delivery to cause selective ablation of ophthalmic tissue to provide an elongated structured incision that varies along its length in at least one of a depth, a profile, a width, and an angle of attack relative to a surface of the ophthalmic tissue.

Description

METHOD AND APPARATUS FOR MAKING IMPROVED SURGICAL INCISIONS IN CORRECTIVE EYE SURGERY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. Patent Application No. 13/402,389, filed February 22, 2012, which claims the benefit of priority under 35 U.S.C. 119(e) of U.S. Provisional Patent Application No. 61/445,450, filed February 22, 2011 , the entire disclosures of both of which are hereby incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to ophthalmic surgical procedures, and more particularly to a system and method for making improved incisions having novel corrective incision geometries.

DISCUSSION OF RELATED ART

[0003] Limbal relaxing incisions (LRI's) commonly are used to correct small to moderate amounts of astigmatism, particularly in conjunction with cataract surgery. Astigmatic keratotomy (AK) incisions at smaller optical zones have been used for moderate and higher amounts of astigmatism. In either case, an arcuate incision made at the steep meridian of the cornea allows the area of the cornea central to it to flatten and also to elevate, changing both the shape and the curvature of the cornea as the ocular tissue relaxes around the incision site. The coupling effect causes the flat meridian of the cornea to be steepened nearly as much as the steep meridian is flattened. By properly placing such AK (including LRI) relaxing incisions, such steepening and flattening can be used for corrective purposes.

[0004] Figure 1 shows the anatomy of a human eye generally designated by reference numeral 10. The outer surface of the eye 10 is formed by a cornea 12 which terminates at the corneal margin or limbus 14 in the vicinity of an anatomical protuberance on the inner surface of the cornea known as the scleral spur. The ciliary muscle joins the iris. The ciliary muscle is connected by the zonular fibers to the capsule of the crystalline lens. Contraction of the ciliary muscle changes the shape and position of the lens, which results in focusing of the vision of the subject. The iris surrounds the pupil, where light passes through the lens onto the retina (not shown) for transmission of an image to the optic nerve and the brain.

[0005] AK incisions (including LRI's) require precise formation and placement of arcuate incisions, often spanning approximately 30 degrees to 75 degrees of arc, and 3 mm to 6 mm in length. Exemplary AK and LRI incisions are designated by reference numeral 30 in Figure 1.

[0006] A prevalent method of making such arcuate incisions involves the surgeon's manual use of a surgical knife having a diamond blade fixed to protrude between an associated footplate for a predetermined depth of cut. Such incisions are made (or at least are intended to be made) by sweeping the blade in a constant- radius arc while holding the knife/blade at a consistent angular orientation relative to the eye (i.e. using a consistent "angle of attack"). Many such incisions made with this manual approach are shallower at their ends than at their center, for several reasons. First, the intended depth (D) typically is reached only after the diamond blade 20 is advancing through tissue, rather than on its initial insertion, as best shown in Figure 2. Furthermore, if the diamond knife has an angled end face (as is typical), the ends (E) of the incision are necessarily shallower where the blade end itself is angled, even if the blade tip has penetrated to full depth, as best shown in Figure 3. Accordingly, in using such a knife, the incision typically has a geometry in which the depth is substantially uniform, but is greatest toward a central portion along the length of the incision, and lesser towards the leading and trailing ends of the incision, as best shown in Figures 2 and 3.

[0007] Various diamond-bladed (and other) knives are known in the art for use in incisional keratotomy. An improvement to the common knife includes a specially-configured blade having an enhancement portion. The enhancement portion includes a rearward blade edge that is sharpened only distally (for the distal 250 microns) to provide an enhancement cutting edge, so that an unsharpened portion of the rearward blade edge can guide the blade through the incision as the enhancement portion finishes the cut by bringing it to full cut depth. An exemplary knife having such an enhancement portion is commercially-available as a Genesis™ knife, manufactured and/or sold by Accutome, Inc. of Malvern, PA, or the virtually- identical DuoTrak™ knife described in U.S. Patent Nos. 5,222,967 and 5,423,840, the entire disclosures of both of which are hereby incorporated herein by reference.

[0008] The angled edge of such a knife is sharp along its entire length, and is used to make the initial incision. The vertical (opposite) edge of the knife is then used to retrace the incision back to its origin, so that the dull part of the vertical edge guides the knife and avoids cutting a new incision, while the vertical

"enhancement" edge (the sharp distal 250 microns) cuts to bring the incision to full depth. Accordingly, in using such a knife, the incision typically has a constant (uniform) depth (D) along the entire length of the incision, as best shown in Figure 4. [0009] It has been observed that both of the above-described incision geometries (shallow-deep-shallow, and constant depth) create an unevenness of corrective effect along an astigmatic keratotomy incision. This effect was discussed in a 1996 publication by Canrobert Oliveira, who described resulting induced astigmatism at new axes. Radial keratotomy: the combined technique. Assil KK. Int Ophthalmol Clin. 1994 Fall; 34(4):55-77.

[0010] In response to the observed unevenness of effect, Oliveira devised the "Canrobert 'C procedure", in which shorter arcuate incisions are added adjacent to each end of an astigmatic keratotomy incision, peripheral to the main incision. A modification of this was proposed by Freitas and Carvalho in 2008, in which a shorter arcuate incision is added adjacent to each end of an LRI, just central to it. Freitas GD: Limbal Relaxing Incision with Inverse C Procedure. Film, ASCRS 2008. The Canrobert "C" procedure has enjoyed some popularity, and markers with templates for the Canrobert "C" incisions are commercially available.

[0011] However, there are certain difficulties/inadequacies with such procedures, including the need for additional corrective incisions to counteract the unevenness of corrective effect of the initial AK/LRI incision. Such additional incisions create additional opportunities for errors and causes increased trauma to the eye, and associated increased risks associated with infection and healing.

SUMMARY

[0012] The present invention provides a system and method providing an alternative to the "C" procedures, which generally involve making incisions with a uniform cut width, a substantially uniform depth, and substantially uniform angle of attack. Generally, I have observed that a uniform AK (including LRI) incision results in a non-uniform corrective effect. In accordance with the present invention, I leverage this observed relationship to provide a system and method for making a structured AK (including LRI) incision for the purpose of providing a uniform (or at least more consistent) corrective effect. As used herein, "structured" is used to denote a deliberately-made lack of uniformity in at least one of incision profile/width, incision depth, or angle of attack for the purpose of providing a more consistent corrective effect due to a more consistent relaxing of ocular tissue as a result of the configuration of the incision.

[0013] Systems and methods for making structured incisions are provided. An exemplary method for performing ophthalmic laser surgery using an automated laser delivery system comprises providing an automated laser surgery system comprises: a laser delivery system operable to deliver a laser beam for ablating ophthalmic tissue; a user interface configured to receive user input; and a laser control system configured to control delivery of the laser beam in accordance with input received via the user interface. The method further comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision, the structured incision being non-uniform in cross- section along its length in at least one of a depth, a profile, a width, and an angle of attack relative to a surface of the ophthalmic tissue.

[0014] Another exemplary method for performing ophthalmic laser surgery comprises: generating a pulsed laser beam, wherein the duration of each pulse in the beam is less than approximately one picosecond in duration; and directing and focusing the beam onto a plurality of focal spots to ablate ophthalmic tissue, the plurality of focal spots being selected to collectively provide an elongated structured incision in the ophthalmic tissue, the structured incision being non-uniform along its length in at least one of a depth, a profile, a width, and an angle of attack relative to a surface of the ophthalmic tissue.

[0015] An exemplary automated laser surgery system comprises a laser delivery system operable to deliver a laser beam for ablating ophthalmic tissue; a user interface configured to receive user input; and a laser control system operably connected to said laser delivery system and said user interface, said laser control system being configured to control delivery of the laser beam in accordance with input received via said user interface, said laser control system being configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision that varies along its length in at least one of a depth, a profile, a width, and an angle of attack relative to a surface of the ophthalmic tissue. The laser control system may be further configured to control the laser beam to provide variation in the elongated structured incision that at least partially counteracts an expected variation in relaxation of ophthalmic tissue along an incision site to provide increased uniformity of corrective effect to the ophthalmic tissue.

BRIEF DESCRIPTION OF THE FIGURES

An understanding of the following description will be facilitated by reference to the attached drawings, in which:

[0016] Figure 1 is a diagrammatic view of a human eye showing exemplary incisions made in typical incisional keratotomy procedures;

[0017] Figure 2 is a partial cross-sectional view of the eye of Figure 1 , showing a conventional incision having shallower end portions and a deeper central portion due to gradual insertion of the surgical knife; [0018] Figure 3 is a partial cross-sectional view of the eye of Figure 1 , showing a conventional incision having shallower end portions and a deeper central portion due to angled edges of the surgical knife;

[0019] Figure 4 is a partial cross-sectional view of the eye of Figure 1 , showing a conventional incision having a constant depth;

[0020] Figure 5 is a diagrammatic view of the human eye of Figure 1 , showing varied degrees of gaping along the length of the incision;

[0021] Figure 6 is a flow diagram illustrating a manual surgical method in accordance with an exemplary embodiment of the present invention;

[0022] Figure 7A is a diagrammatic view of the human eye of Figure 1 , showing an embodiment of a structured incision in accordance with the present invention;

[0023] Figure 7B is a diagrammatic view of the human eye of Figure 1 , showing alternative embodiments of structured incisions in accordance with the present invention;

[0024] Figure 7C and 7D are cross-sectional views of the human eye of Figure 1 taken along lines 7C-7C and 7D-7D, respectively, of Figure 7B, showing a variable-depth structured incision;

[0025] Figure 7E and 7F are cross-sectional views of the human eye of Figure 1 taken along lines 7E-7E and 7F-7F, respectively, of Figure 7B, showing a variable-angle-of-attack structured incision;

[0026] Figure 8 is a flow diagram illustrating a laser surgery system-based surgical method in accordance with an alternative exemplary embodiment of the present invention; [0027] Figure 9A is a diagrammatic view of the human eye of Figure 1 , showing an alternative embodiment of a structured incision in accordance with the present invention;

[0028] Figure 9B is a diagrammatic view of the human eye of Figure 1 , showing alternative embodiments of structured incisions in accordance with the present invention;

[0029] Figure 9C and 9D are cross-sectional views of the human eye of Figure 1 taken along lines 9C-9C and 9D-9D, respectively, of Figure 9B, showing a variable-width structured incision;

[0030] Figure 9E and 9F are cross-sectional views of the human eye of Figure 1 taken along lines 9E-9E and 9F-9F, respectively, of Figure 9B, showing a variable-profile structured incision;

[0031] Figure 9G is a diagrammatic view of the human eye of Figure 1 , showing an alternative embodiment of structured incisions in accordance with the present invention;

[0032] Figures 9H and 9I are cross-sectional views of the human eye of Figure 1 taken along lines 9H-9H and 9I-9I, respectively, of Figure 9G, showing an alternative structured incision having end portions with a greater uniform width;

[0033] Figure 9J is a cross-sectional view of the human eye of Figure 1 taken along lines 9I-9I of Figure 9G, but showing an alternative structured incision having end portions with a greater width at the tissue surface;

[0034] Figure 9K is a diagrammatic view of the human eye of Figure 1 , showing another alternative embodiment of structured incisions in accordance with the present invention; [0035] Figures 9L and 9M are cross-sectional views of the human eye of Figure 1 taken along lines 9L-9L and 9M-9M, respectively, of Figure 9K, showing an alternative structured incision having end portions having a greater width at the tissue surface and a greater depth of cut;

[0036] Figure 9N is a diagrammatic view of the human eye of Figure 1 , showing yet another alternative embodiment of structured incisions in accordance with the present invention;

[0037] Figures 90 and 9P are cross-sectional views of the human eye of Figure 1 taken along lines 90-90 and 9P-9P, respectively, of Figure 9N, showing an alternative structured incision having a uniform width at the tissue surface but having a wider base at its end portions; and

[0038] Figure 10 is a diagrammatic view of an exemplary automated laser surgery system specially-configured to provide a structured incision in accordance with the present invention.

DETAILED DESCRIPTION

[0039] The present invention relates to a system and method that provide novel incision geometries useful in procedures involving astigmatic keratotomy (AK) incisions or limbal relaxation incisions (LRI).

[0040] I have observed that in astigmatic keratotomy (including AK incisions and LRI incisions - collectively here "AK incision") at any optical zone, the portion of the AK incision that exerts the most relaxing (and thus corrective) effect is the central portion. When an AK incision gapes, the gaping is more prominent at a central portion than at the end portions of the incision, as best shown in Figure 5. Not uncommonly, elevation corneal topography following AKs shows greater elevation and more astigmatic effect toward the central portion of the incision than at the incision's end portions.

[0041] In accordance with the present invention, I have developed a surgical approach that exploits this observation to compensate for and correct the unevenness of effect along an AK incision previously observed by Canrobert Oliveira and others. Accordingly, the present approach is an alternative to the "C" procedures.

[0042] Generally, I have observed that a uniform AK incision results in a non-uniform corrective effect. In accordance with the present invention, I leverage this observed relationship to provide a system and method for making a structured AK (including LRI) incision for the purpose of providing a uniform (or at least more consistent) corrective effect. As used herein, "structured" is used to denote a deliberately-made lack of uniformity in at least one of incision profile/width, incision depth, or angle of attack for the purpose of providing a more consistent corrective effect due to a more consistent relaxing of ocular tissue as a result of the

configuration of the incision. Accordingly, a "structured" incision includes more than mere incidental or unintended variation from uniformity.

[0043] More specifically, the approach of the present invention involves making a structured incision that is designed to cause a greater relaxing effect (due to the configuration of the incision) towards the incision's end portions than at it's central portion. This non-uniformity of relaxing effect resulting from the configuration of the incision is created to counteract the natural tendency of such an incision to have a greater relaxing effect toward the central portion of the incision than at its end portion (believed to be due, at least in part, to the shape of the eye/surgical site, and the material properties of ocular tissue). By inducing a greater relaxing effect toward the end portions that complements or counteracts the naturally-occurring greater relaxing effect toward the central portion, a more consistent relaxing effect along the entire length of the incision, and thus a reduction in higher order aberration, is obtained. Thus, the need for supplemental corrective incisions, as taught by

Canrobert Oliveira and others, is reduced or eliminated.

[0044] Systems and methods for making various structured incisions are provided in accordance with the present invention. In one embodiment, the structured incision is configured to have a shallower central portion and deeper end portions that collectively tend to induce a greater relaxing effect toward the end portions of the incision. In another embodiment, the structured incision is configured to have a varying angle of attack that tends to induce a greater relaxing effect toward the end portions of the incision. In yet another embodiment, the structured incision is configured to have a varying cross-sectional profile area (e.g., width or shape) that tends to induce a greater relaxing effect toward the end portions of the incision. In still other embodiments of the invention, the structured incision includes any combination of more than one of a varying depth, a varying angle of attack and a varying cross-sectional profile along its length to induce a relatively greater relaxing effect toward the end portions of the incision.

[0045] The novel structured incision geometries described herein may be created using both traditional manual surgical techniques and automated surgical techniques. For illustrative purposes, an exemplary manual surgical method is discussed below with reference to Figures 6 and 7A-7F, followed by a discussion of an automated surgical system-based method with reference to Figures 8 and 9A-10.

[0046] Referring now to Figure 6, a flow diagram 100 is shown that illustrates an exemplary manual surgical method in accordance with the present invention. In this exemplary embodiment, the structured incision is configured to have a shallower central portion and deeper end portions that collectively tend to induce a greater relaxing effect toward the end portions of the incision.

[0047] As shown in Figure 6, the exemplary manual method involves use of a conventional surgical knife, such as a Genesis/DuoTrak or other type of diamond-bladed knife. This method first involves obtaining pachymetry of the incision site or sites at which the AK incision(s) is/are to be performed, as shown at step 102. This step may be performed in a conventional manner using an ultrasonic pachymeter, and suitable techniques and equipment for obtaining same are well known in the art. As is typical of this step, such obtaining such pachymetry involves determining a maximum incision depth, e.g., 680 microns.

[0048] Next, the method involves configuring a surgical knife to make a first incision pass having a shallow depth less than the maximum incision depth, as shown at step 104. For example, this step may involve adjusting the micrometer of a conventional surgical knife. By way of example, the shallow depth may be approximately 100 to 150 microns less than the maximum depth. In a preferred embodiment, the shallow depth is approximately 150 microns less than the maximum depth. Maximum incision depth is typically equal to or slightly less than the corneal thickness at the incision site.

[0049] Next, the method involves creation of at least one relaxing incision (e.g., an LRI or an AK incision) in ocular tissue, as shown at step 106. Generally, this step may be performed in a substantially conventional manner, e.g., as to arcuate shape, placement, length, angle of attack, overall surgical technique, etc. By way of example, this step may include using a Genesis/DuoTrak™-style knife to square off both ends of the incision to bring the entire incision to a constant depth. The incision so created has a depth equal to the shallow depth as a result of the configuration of the knife and conventional surgical procedures.

[0050] The surgical knife is then configured to make a deeper incision having the maximum incision depth, as shown at step 108. For example, this step may involve adjusting a micrometer of a surgical knife to provide for a deeper cut.

[0051] Finally, the vertical enhancement edge of the surgical knife is retraced along the end portions of the relaxing incision to increase the depth of the incision's end portions only, as shown at steps 110 and 112. The depth of the end portions is increased to the maximum incision depth, consistent with conventional surgical procedures. By way of example, the deepened portions may be configured to extend for approximately 1 mm of length at each end of the incision.

[0052] Accordingly, a structured incision is provided that has a greater depth at its end portions, and a lesser depth at its central portion (in a deep-shallow- deep configuration), as best shown in Figure 7, consistent with the present invention. Using the structured incision technique described, the profile of the incision might be described as resembling the profile (as viewed from the side) of an arch bridge, in that it is deeper at the ends and shallower in the center. By providing a greater depth at the incision's ends where the relaxing effect naturally tends to be less, and a lesser depth toward the central portion where the relaxing effect naturally tends to be greater, a more uniform relaxing effect is provided along the single incision's entire length.

[0053] It is noted that intraoperative feedback with a qualitative operative keratometer may be helpful to the surgeon. The reflection of its ring allows assessment of the amount and axis of astigmatism. The flat corneal meridian is identified by the long axis of the ellipse. An additional cue can be obtained if an operative keratometer with a ring of LED's is used, in that the reflections of the individual LED's of the ring are spaced further apart at the steep meridian. Identifying the axis of astigmatism on the operating table serves both to reveal torsion on reclining, and serves as a safeguard against a 90 degree axis error.

[0054] In this exemplary embodiment, it is contemplated that the structured incision has a consistent, or substantially-consistent resulting only from any deviation due to the manual and free-hand nature of the incision, angle of attack ( ) in that the angular orientation of the surgical blade relative to the eye (or a vertical reference plane X) along the length of the incision 30, as best shown in Figures 7A, 7B and 7C. As noted from Figures 7B and 7C, the depth Di of the incision 30 at its end portion (Figure 7B) is greater than the depth D₂ of the incision 30 at its central portion (Figure 7C). However, due to the fixed width of the blade, the width/profile of the incision 30 along its length is substantially uniform (i.e.,

absent effects from any resulting relaxation of the eye tissue, as shown in Figures 7C and 7D.

[0055] In another embodiment, the structured incision is configured to have a varying angle of attack (β) that tends to induce a greater relaxing effect toward the end portions of the incision, as best shown in Figures 7B, 7E and 7F. In this exemplary embodiment, the width of the incision is constant, and the depth of both incisions is identical. However, in this embodiment the surgical knife is manually manipulated to vary the tilt of the knife along the length of the incision (relative to a surface of the ophthalmic tissue), and thus to vary the angle of attack of the incision 30. In the exemplary embodiment shown, β₂ is greater than βι . In an alternative embodiment, βι is greater than β₂. In both embodiments, the varying angle of attack (β) that tends to induce a greater relaxing effect toward the end portions of the incision.

[0056] In still other embodiments of the invention, the structured incision includes any combination of more than one of a varying depth, a varying angle of attack and a varying cross-sectional width or shape profile along its length to induce a relatively greater relaxing effect toward the end portions of the incision. It is noted however, that the varying cross-sectional width/profile may not be easily or predictably achieved using a manual method, due to inherent limitations in controlling the knife.

[0057] Referring now to Figure 8, a flow diagram 150 is shown that illustrates an exemplary automated surgical method in accordance with the present invention. As shown in Figure 8, the exemplary manual method involves use a specially-configured automated laser surgery system 200, as shown in Figure 10. The specially-configured automated laser surgery system 200 is substantially similar to existing commercially-available automated laser surgery systems. Examples of such automated laser surgery systems include the LensAR, Victus, LenSX and Catalys™ femtosecond laser surgery systems presently sold by LensAR, Inc. of Winter Park, FL, Bausch &Lomb/Technolas Perfect Vision of Aliso Viejo, CA, LenSX Lasers, Inc., of Fort Worth, TX and OptiMedica Corporation of Santa Clara, CA, respectively. Such existing systems generally include a user interface for receiving user input and imaging, a laser delivery system for creating surgical incisions in ocular tissue of a human patient, and a control system for creating the surgical incisions based upon the user input and consistent with predetermined instructions, logic, parameters, etc.

[0058] As noted above, such existing systems, to the extent that they are adapted to create AK incisions based on user (surgeon) input such as optical zone, arc length, incision depth, are configured to do so in accordance with predetermined instructions, logic and/or parameters resident in the control system. Conventional control systems provide for an incision geometry having a constant/uniform depth, a uniform width/profile, and a uniform angle of attack along the length of the AK incision, consistent with conventional wisdom.

[0059] The present invention further provides a specially-configured automated laser surgery system 200, as shown in Figure 10. In accordance with the present invention, the specially-configured automated laser surgery system 200 resembles conventional laser surgery systems, but includes a modified control system 220 that further accepts user input (via a user interface 210) as to maximum, minimum and/or other incision depth parameters, angle of attack parameters, and incision width/profile parameters, and is further configured to create a structured incision (via the laser delivery system 230) in accordance with such user input and predetermined instructions, logic and/or parameters resident in the control system 220 that provides for a structured incision geometry, consistent with the teachings herein.

[0060] Programming hardware, software, and techniques necessary to implement the control system 220 described herein are well-known in the art, particularly to existing manufacturers of commercially-available automated laser surgery systems, and are beyond the scope of the present invention, and thus are not discussed in detail herein. Generally, the control system may include a microprocessor 222 and a memory 224 operably connected to the microprocessor. The memory 224 may store microprocessor-executable instructions for controlling the laser delivery system to provide the elongated structured incisions described herein.

[0061] The precise configuration of the incision geometry for a particular incision may be based upon explicit user (surgeon) input, may be derived in accordance with predetermined logic from user or other input, or may be otherwise determined, e.g. according to predetermined settings within the control system 220. Any desired structured incision geometry may be used consistent with the present invention, provided that the incision geometry, for example but not limited to depth, angle of attack and cross-sectional width/profile, varies along the length of the incision such that it tends to induce a greater relaxing effect toward the end portions of the incision than at the central portion of the incision. The user interface 210 may provide for any desired additional geometry options.

[0062] The incision geometry created with the laser surgery equipment may have a generally stepped configuration, with discrete portions having distinctly different depths, as shown in Figure 7A, or distinctly different widths, or angles of attack. However, a potential advantage of use of laser surgery equipment is that the depth, angle of attack, and/or width/profile may be substantially continuously variable along the entire length of the incision. An exemplary structured incision having substantially continuously variable depth along its length is shown in Figure 9A.

[0063] Referring now to Figure 9B, alternative exemplary structured incisions are shown. An exemplary structured incision 30 having a substantially continuously variable width is shown in Figures 9C and 9D, where Wi (toward an end portion of the incision 30) is greater than W₂ (toward the central portion of the incision 30). In this example, the angle of attack and depth of the incision are consistent along the incision's length, but it is noted that in other embodiments they may vary. [0064] In Figure 9C and 9D, it is noted that the cross-sectional profile is consistent (rectangular in this example). In Figures 9E and 9F, an exemplary incision 30 having a substantially continuously variable profile is shown. Notably, the cross-sectional area toward an end portion of the incision 30 (Figure 9E) is greater than the cross-sectional area toward the central portion of the incision 30 (Figure 9F). In this example, the angle of attack is consistent along the incision's length, but it is noted that in other embodiments it may vary.

[0065] Figure 9G shows another embodiment in which the incision's cross-sectional profile varies along the length of the incision, such that it is different in the end portions than in a central portion. In some such embodiments, the incision's central portion 35 has a consistent cross-section. In other embodiments, the incision varies within the central portion. In this exemplary embodiment, the incision is significantly wider in its end portions 37 than in its central portion, as shown in Figures 9H and 91. In such an embodiment, the incision may appear at the tissue surface to be outwardly flared toward its end portions, as best shown in Figure 9G.

[0066] In one such embodiment, the width of the incision is uniform along its depth, as shown in Figures 9H and 91. In another such embodiment, the width of the incision at the tissue surface is wider in the end portions 37 than in the central portion 35, as will be appreciated from Figure 9H and 9J. In certain embodiments, the incision is widest at its distal ends.

[0067] In certain embodiments, the incision depth is substantially constant along the length of the incision and the width varies, as will be appreciated from Figures 9H and 91 or 9H and 9J. In other embodiments, the incision depth varies along the length of the incision, such that the incision is both wider at the tissue surface and deeper in its end portions that at its central portion, as will be

appreciated from Figures 9L and 9M. In certain embodiments, the incision is widest and deepest at its distal ends.

[0068] In certain other embodiments, the incision is structured to have a substantially uniform width at the tissue surface (as shown in Figure 9N) but to be wider below the tissue surface at its end portions than in the central portion such that it has a wider base in its end portion, as will be appreciated from Figures 9N-9P. In some such embodiments, the incision depth is uniform along the length of the incision. In other such embodiments, the incision depth is greater toward the end portions than in the central portion. In certain embodiments, the incision is widest and deepest at its distal ends.

[0069] In the exemplary embodiments of Figures 9G-9P, the angle of attack is consistent along the incision's length, but it is noted that in other

embodiments the angle of attack may vary along the length of the incision. Further, in the exemplary embodiments of Figured 9G-9P, the incision is symmetrical relative to a central plane extending along a longitudinal path of the incision, but it is noted that in other embodiments, the incision may be asymmetrical relative to a central plane extending along a longitudinal path of the incision. Further, in the exemplary embodiments of Figured 9G-9P, the incision is symmetrical to a central plane extending along a path transversely to the incision, but it is noted that in other embodiments, the incision may be asymmetrical relative to a central plane extending along a path transversely to the incision.

[0070] The inventive automated laser surgery system 200 may be used in accordance with the flow diagram 150 shown in Figure 8. Referring now to Figure 8, the method first involves obtaining pachymetry of the incision site or sites at which the AK incision(s) is/are to be performed, as shown at step 152. As noted above, with respect to a variable-depth structured incision, this involves determining the maximum incision depth, and may be performed in a conventional manner, which may include, for example, obtaining such pachymetry using the automated laser surgery system 200. By way of example, this may involve various imaging technologies, such as optical coherence tomography, Scheimpflug photography, or confocal microscopy.

[0071] Next, the method involves configuring the automated laser surgery system 200 to make a structured incision. In this example, the structured incision is a variable-depth structured incision having a shallow depth at its central portion and the maximum incision depth at its end portions, as shown at step 154. By way of example, this may involve entering incision optical zone, meridian, length, maximum depth, minimum depth, angle of attack parameters, width parameters, profile parameters and any other variable geometry input via the user interface 210 of the automated laser surgery system 200.

[0072] Finally, the method involves operating the automated laser surgery system 200 to create at least one structured incision in ocular tissue, and the method ends, as shown at steps 156 and 158. For the surgeon, this step may be as simple as selecting a "START PROCEDURE" option via the user interface, but generally this step involves causing the control system 220 of the automated laser surgery system 200 to control the laser delivery system 230 to delivery laser energy to the necessary locations (focal spots) in the patient's ocular tissue to define the desired structured incision consistent with the surgeon's input and any other applicable predetermined instructions, logic and/or parameters resident in the control system [0073] It should be noted that the computer-controlled and/or mechanized aspects of laser surgery equipment are well-suited to provide continuously-variable incision geometry generally unobtainable using manual techniques. Further, such targeted ablation equipment is capable of providing structured incision geometries that cannot be created manually with a surgical blade. For example, the structured incision geometries in accordance with the present invention may be entirely intrastromal. Incisions that do not connect with the surface could be manually spread, or left unspread. Further, such equipment is well-suited to permitting intraoperative modifications to the incision, e.g., to deepen, lengthen or modify curvature of the incision). Further, such ablation equipment, by its very nature, results in the destruction and removal of tissue, and thus is capable of forming structured incisions unlike those typically formed with a conventional surgical blade.

[0074] Advantageously, the present invention is compatible with paired LRI's. Paired LRIs have several advantages over a single, longer LRI. First, they allow shorter incisions. The longer an incision is, the less regular its effect. Second, a single incision flattens only a single hemi-meridian; paired incisions have a more symmetric effect. In treating against-the-rule astigmatism, the temporal cataract incision may serve as the second LRI of the pair, particularly if a Langerman groove (of any geometry) is made. For example, the groove may be structured to have architecture resembling that of the structured incision of the LRI, so that the effect of its ends is augmented with respect to its center.

[0075] Advantages of the structured incision technique over the traditional LRI technique include improved predictability of the astigmatic effect and reduction of induced higher order aberrations. Much of the variability in astigmatic effect of traditional LRI's may be ascribed to variability in the proportion of the incision that is actually at the intended depth. Because with the structured incision technique, the entire incision is fully effective, incisions may be shorter and/or more peripheral for a given astigmatic correction. Shorter incisions and more peripheral incisions induce less aberration, and even less aberration is induced if the effect of the incisions' ends is augmented relative to the effect of an incision's center. This may be accomplished by various means, including those described above, and include making the ends of the incision deeper and/or wider than the center.

[0076] Advantages of the structured incision technique over "C" techniques such as those described by Canrobert Oliveira and by Freitas and Carvalho include the structured incision technique's being easier, faster and safer. It is more readily standardized, yet no template is required. Furthermore, a pair of single incisions is more readily enhanced than a pair of triple arcs.

[0077] In summary, the central portion of a traditional AK incision naturally has greater effect than the end portions, and this effect may induce aberration as well as astigmatism at a new axis. This problem can be prevented by constructing a structured incision designed to induce (absent the natural non-uniform effect) a greater relaxing/corrective effect its end portions than at its central portion, such that non-uniform relaxing due to the structure of the incision combines with the nonuniform natural relaxing of the incision to cause a more consistent relaxing effect along the entire length of the incision.

[0078] By way of further example, the method and system of the present invention may be used as follows with respect to an exemplary 73-year-old man having 1.25 diopters of with-the-rule astigmatism in the right eye, and for which preoperative keratometry measures 44.50/43.25D with the steep meridian at 90 degrees. Superior and inferior limbal relaxing incisions at the 9mm optical zone may be planned. The Lindstrom ARC-T 8-9mm nomogram predicts that for a 73-year-old, two 30 degree incisions at the 8 to 9 mm optical zone would give 0.93 diopters of correction, and two 45° incisions would give 1.86 diopters of correction. Because incisions whose ends are brought to full depth give more effect than typical LRI incisions, the nomogram may be modified. Since the temporal clear corneal cataract incision was predicted to contribute 0.50 diopters of with-the-rule astigmatism, a total of 1.75 diopters correction may be required. A decision may be made to make a 35° superior limbal relaxing incision and a 30° inferior limbal relaxing incision at the 9mm optical zone.

[0079] In this example, it may be considered that the thinnest central pachymetry is 520 microns; the superior incision site's pachymetry is 662 microns and the inferior incision site's is 656. For a manual incision, a Genesis/DuoTrak knife may be set at 555 microns [655 minus 100 microns] initially. For an automated laser surgery system, such a depth of cut may be input via the user interface of the system 200.

[0080] After preparing and draping the patient, but before the cataract procedure has begun, torsion on reclining may be assessed using the operative keratometer or other imaging technology. To avoid induction of artifactual astigmatism, the lid speculum may be held away from the globe while the astigmatic axis is assessed using the keratometer's ring reflection or other technology. In this example, 20 degrees of torsion is revealed by the rotation of the elliptical operative keratometer reflection or other technology. The astigmatic incisions may then be created at the proper meridian at a depth of 505 microns, and then each end of each incision is "squared off' to the full 505 micron depth using the vertical "enhancement" edge of the blade. This edge is then used to deepen the ends of each incision to full incision depth, in this case 655 microns. Alternatively, the laser system 200 may be used to perform such an incision, or any other desired structured incision.

[0081] Postoperatively, keratometry may be measured as 43.87/43.75D with the steep meridian at 90 degrees and manifest refraction is -0.75 sphere.

Elevation corneal topography suggested similar astigmatic effect in the center and at the ends of the incision.

[0082] While there have been described herein the principles of the invention, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention, and that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

What is claimed is:

1. A method for performing ophthalmic laser surgery, the method comprising:

providing an automated laser surgery system comprising:

a laser delivery system operable to deliver a laser beam for ablating ophthalmic tissue;

a user interface configured to receive user input; and

a laser control system configured to control delivery of the laser beam in accordance with input received via the user interface; and

operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a central portion and end portions, the structured incision having a cross-sectional profile that is consistent along the length of the incision in the central portion, and that varies along the length of the incision in the end portions.

2. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a cross- sectional area in the end portions that is equal to its cross-sectional area in the central portion.

3. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a cross- sectional area in the end portions that is greater than its cross-sectional area in the central portion.

4. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central longitudinal plane.

5. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central longitudinal plane.

6. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central transverse plane.

7. The method of claim 1 , wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central transverse plane.

8. A method for performing ophthalmic laser surgery, the method comprising:

providing an automated laser surgery system comprising: a laser delivery system operable to deliver a laser beam for ablating ophthalmic tissue;

a user interface configured to receive user input; and

operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a central portion and end portions, the structured incision having a width at the surface of the tissue in the end portions that is greater than the width at the surface in the central portion.

9. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is greater than the width at the surface in the central portion, and a depth in the end portions that is equal to the depth in the central portion.

10. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is greater than the width at the surface in the central portion, and a depth in the end portions that is greater than the depth in the central portion.

11. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is greater than the width at the surface in the central portion, and a depth in its end portions that is greater than the depth in the central portion, the depth in the end portions increasing with decreasing distance from a nearest end of the elongated incision.

12. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central longitudinal plane.

13. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central longitudinal plane.

14. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central transverse plane.

15. The method of claim 8, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central transverse plane.

16. A method for performing ophthalmic laser surgery, the method comprising:

providing an automated laser surgery system comprising:

a user interface configured to receive user input; and

operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a central portion and end portions, the structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in the end portions that is greater than the base width in the central portion.

17. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in the end portions that is greater than the base width in the central portion, and a depth in the end portions that is greater than the depth in the central portion.

18. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in the end portions that is greater than the base width in the central portion, and a depth in the end portions that is greater than the depth in the central portion, the depth in the end portions increasing with decreasing distance from a nearest end of the elongated incision.

19. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central longitudinal plane.

20. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central longitudinal plane.

21. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is symmetrical relative to a central transverse plane.

22. The method of claim 16, wherein operating the automated laser surgery system comprises operating the automated laser surgery system to selectively ablate ophthalmic tissue to provide an elongated structured incision that is asymmetrical relative to a central transverse plane.

23. A method for performing ophthalmic laser surgery, the method comprising:

generating a pulsed laser beam, wherein the duration of each pulse in the beam is approximately one picosecond in duration; and

directing and focusing the beam onto a plurality of focal spots to ablate ophthalmic tissue, the plurality of focal spots being selected to collectively provide an elongated structured incision in the ophthalmic tissue, the structured incision having a central portion and end portions and that is non-uniform along its length.

24. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a cross-sectional area in its end portions that is greater than its cross-sectional area in its central portion.

25. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is greater than the width at the surface in the central portion.

26. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is greater than the width at the surface in the central portion, and a depth in its end portions that is greater than the depth in the central portion.

27. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in its end portions that is greater than the base width in the central portion.

28. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in its end portions that is greater than the base width in the central portion, and a depth in its end portions that is greater than the depth in the central portion.

29. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is greater than the width at the surface in the central portion, and a depth in its end portions that is greater than the depth in the central portion, the depth in the end portions increasing with decreasing distance from a nearest end of the elongated incision.

30. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is symmetrical relative to a central longitudinal plane.

31. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is asymmetrical relative to a central longitudinal plane.

32. The method of claim 23, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is symmetrical relative to a central transverse plane.

33. The method of claim 22, wherein directing and focusing the beam comprises directing and focusing the beam onto a plurality of focal spots selected to collectively provide an elongated structured incision having a width at the surface of the tissue in its end portions that is asymmetrical relative to a central transverse plane.

34. An automated laser surgery system comprising:

a user interface configured to receive user input; and a laser control system operably connected to said laser delivery system and said user interface, said laser control system being configured to control delivery of the laser beam in accordance with input received via said user interface, said laser control system being configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a central portion and end portions having a substantially- consistent depth along its length, and a varying width profile along its length.

35. The system of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a cross- sectional profile that is consistent along the length of the incision in the central portion, and that varies along the length of the incision in the end portions.

36. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a cross- sectional area in the end portions that is equal to its cross-sectional area in the central portion.

37. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a cross- sectional area in the end portions that is greater than its cross-sectional area in the central portion.

38. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is greater than the width at the surface in the central portion.

39. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue that is substantially uniform along its length, the incision having a base width in its end portions that is greater than the base width in the central portion.

40. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in its end portions that is greater than the width at the surface in the central portion, the width in the end portions increasing with decreasing distance from a nearest end of the elongated incision.

41. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is symmetrical relative to a central longitudinal plane.

42. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is asymmetrical relative to a central longitudinal plane.

43. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is symmetrical relative to a central transverse plane.

44. The method of claim 34, wherein the laser control system is configured to control said laser delivery system to cause the laser beam to selectively ablate ophthalmic tissue to provide an elongated structured incision having a width at the surface of the tissue in the end portions that is asymmetrical relative to a central transverse plane.