Patent Description:
The present disclosure relates to ophthalmic surgical instruments, and more particularly, to ophthalmic surgical instruments and methods that facilitate the fragmentation and removal of a lens from a lens capsule.

Cataract surgery and other surgical procedures that treat lenticular tissue, such as, for example, the intraocular lens, are performed by making a small incision in the edge of the cornea, which provides access to the anterior chamber and to the anterior surface of the lens capsule. Afterward, a generally circular incision called a capsulorhexis is made through the anterior surface of the lens capsule to provide surgical access to the lens. An ophthalmic surgical instrument may be inserted through the capsulorhexis and used to fragment the cataractous lens to facilitate its removal from the lens capsule. However, during segmentation by the surgical instrument, the distal portion of the lens may be caused to shift undesirably in an upward (i.e., anterior) direction. Such movement may cause trauma to delicate adjacent eye structures such as the lens zonule, lens capsule or, corneal endothelium.

Accordingly, a continuing need exists in the surgical arts for improved tools and methods for safely fragmenting and removing a cataractous lens. <CIT> and <CIT> disclose lens removal devices of the prior art.

Claims <NUM> and <NUM> define the invention and dependent claims disclose embodiments. No surgical methods are claimed per se, In accordance with an aspect of the present disclosure, an ophthalmic surgical instrument for severing a lens of an eye is provided and includes an elongated shaft and a wire extending along the elongated shaft. The elongated shaft includes a distal end portion defining a first opening and a second opening. The first and second openings are spaced from one another along a longitudinal axis defined by the elongated shaft. The wire includes a cutting segment extending through the first and second openings. The cutting segment is configured to move between a contracted configuration, and a dilated configuration, in which the cutting segment assumes a diameter approximating a diameter and shape of a lens of an eye. The cutting segment is configured to sever the lens upon moving toward the contracted configuration.

In aspects, the distal end portion of the elongated shaft may have a cutting surface that extends longitudinally between the first and second openings. The cutting segment and the cutting surface may be configured to cooperate to apply a cutting force on the lens of the eye upon the cutting segment moving toward the contracted configuration.

In aspects, the cutting segment may have a section configured to engage the cutting surface when the cutting segment is in the contracted configuration.

In aspects, the cutting segment may have a curvature along a majority of a length thereof.

In aspects, the section of the cutting segment may be linear.

In aspects, the section of the cutting segment may protrude inwardly toward the cutting surface of the elongated shaft when the cutting segment is in the contracted configuration.

In aspects, the elongated shaft may have a distal tip and the first opening may be spaced proximally of the distal tip.

In aspects, the second opening may be spaced proximally of the distal tip and distally of the first opening.

In aspects, the second opening may be defined in the distal tip and may be spaced distally of the first opening.

In aspects, the elongated shaft may have a closed distal tip.

In aspects, the cutting segment may have a looped configuration.

In aspects, the distal end portion of the elongated shaft may define a third opening disposed between the first and second openings. The third opening may be configured to receive a cutting section of the cutting segment when the cutting segment is in the contracted configuration.

In aspects, the wire may have a first end portion fixed relative to the elongated shaft, and a second end portion configured to translate relative to the elongated shaft to transition the cutting segment between the dilated and contracted configurations.

In aspects, the first opening may be a proximal opening and the second opening may be a distal opening. The first end portion of the wire may extend through the proximal opening and the second end portion of the wire may extend through the distal opening.

In accordance with another aspect of the disclosure, an ophthalmic surgical instrument for severing a lens of an eye is provided and includes a housing and a snare opearbly coupled to the housing. The housing includes a handle body and a hollow, elongated shaft extending distally of the handle body. The elongated shaft has a bottom surface configured to be oriented toward a human eye. The bottom surface defines a proximal opening, and a distal opening spaced distally from the proximal opening. The snare is operably coupled to the housing and includes a looped segment configured to move through the proximal and distal openings between a contracted configuration and a dilated configuration. In the dilated configuration, the looped segment may assume a diameter approximating a diameter and shape of a lens of the human eye. The looped segment is configured to sever the lens upon moving toward the contracted configuration.

In aspects, the bottom surface of the elongated shaft may have a cutting surface that extends longitudinally between the proximal and distal openings. The looped segment and the cutting surface may be configured to cooperate to apply a cutting force on the lens of the human eye as the looped segment moves toward the contracted configuration.

In aspects, the looped segment may have a cutting section configured to engage the cutting surface when the looped segment is in the contracted configuration.

In aspects, the cutting section of the looped segment may be linear.

In aspects, the cutting section of the looped segment may protrude inwardly toward the cutting surface of the elongated shaft when the looped segment is in the contracted configuration.

In aspects, the bottom surface of the elongated shaft may define an intermediate opening disposed between the proximal and distal openings. The intermediate opening may be configured to receive the cutting section of the looped segment when the looped segment is in the contracted configuration.

In aspects, a majority of the looped segment may be disposed proximally of a distal end of the elongated shaft.

As used herein, the term "about" means that the numerical value is approximate and small variations would not significantly affect the practice of the disclosed embodiments. Where a numerical limitation is used, unless indicated otherwise by the context, "about" means the numerical value can vary by ±<NUM>% and remain within the scope of the disclosed embodiments.

Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein:.

Embodiments of the presently disclosed ophthalmic surgical instruments are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein and as is traditional, the term "distal" will refer to that portion of the ophthalmic surgical instrument which is further from the user (i.e., closer to the eye) while the term "proximal" will refer to that portion of the ophthalmic surgical instrument which is closer to the user (i.e., further from the eye).

The present disclosure provides embodiments of an ophthalmic surgical instrument used to fragment cataractous lenticular tissue prior to its removal from a lens capsule. The ophthalmic surgical instrument includes a handle portion and a snare for enclosing and severing the lenticular tissue. The ophthalmic surgical instrument is constructed so that a distally-extending shaft thereof acts as the stabilization element. In aspects, the shaft defines a pair of first and second openings through which the snare extends. A surface is defined between the first and second openings and acts as a cutting surface against which the snare cuts the lenticular tissue. These and other features and advantages of the various embodiments of the disclosed ophthalmic surgical instruments will be described below.

With reference to FIGS. 1A-3C, an exemplary embodiment of an ophthalmic surgical instrument is illustrated and is generally designated <NUM>. The ophthalmic surgical instrument <NUM> generally includes a housing <NUM>, a snare <NUM> for severing lenticular tissue, and a pair of stabilization elements, such as, for example, elongated arms <NUM>, <NUM> that selectively expand from a closed or collapsed configuration (<FIG>, <FIG>, <FIG>) to an open or expanded configuration (<FIG>, <FIG>, <FIG>).

The housing <NUM> of the ophthalmic surgical instrument <NUM> has a handle body <NUM> and first and second levers 116a, 116b slidably coupled to the handle body <NUM>. The handle body <NUM> may be ergonomic and have an elongated configuration. In embodiments, the handle body <NUM> may assume any suitable shape, such as, for example, rounded, planar, rectangular, or the like. The handle body <NUM> has a tapered distal end portion <NUM> dimensioned to assist in positioning the ophthalmic surgical instrument <NUM> adjacent eye structure. The levers 116a, 116b may be configured as sliders, buttons, triggers, or the like. In embodiments, the housing <NUM> may include a cannulated member, such as, for example, a hollow shaft (not shown), extending distally from the distal end portion <NUM> of the handle body <NUM> to facilitate entry of the ophthalmic surgical instrument <NUM> through a standard corneal incision.

The snare <NUM> of the ophthalmic surgical instrument <NUM> is operably coupled to the first lever 116a of the housing <NUM> and includes a first end portion 112a and a second end portion 112b (<FIG>). The first end portion 112a of the snare <NUM> is movable relative to the housing <NUM>, while the second end portion 112b of the snare <NUM> is fixed relative to the housing <NUM>. In particular, the first end portion 112a of the snare <NUM> is coupled to the first lever 116a of the housing via a first actuator rod <NUM>, such that movement of the first lever 116a moves the first end portion 112a of the snare <NUM>, and the second end portion 112b of the snare <NUM> is fixed to an inner tubular structure <NUM> (<FIG>) formed in the distal end portion <NUM> of the handle body <NUM>. It is contemplated that the second end portion 112b of the snare <NUM> may be fixed to the inner tubular structure <NUM> of the handle body <NUM> by crimping, welding, adhesives, mechanical interlocks, or any other suitable structure or method.

With reference to <FIG>, the snare <NUM> has a looped segment <NUM> disposed at least partially outside of the housing <NUM>. The looped segment <NUM> of the snare <NUM> is transitionable, via an actuation of the first lever 116a, between an insertion or contracted configuration, as shown in <FIG>, <FIG>, and <FIG>, and a deployed or dilated configuration, as shown in <FIG>, <FIG>, and <FIG>. For example, a proximal retraction of the first lever 116a moves the first end portion 112a of the snare <NUM> proximally away from the second end portion 112b of the snare <NUM>, thereby reducing the diameter of the looped segment <NUM>. In contrast, a distal advancement of the first lever 116a moves the first end portion 112a of the snare <NUM> distally toward the second end portion 112b of the snare <NUM>, thereby increasing the diameter of the looped segment <NUM> of the snare <NUM>. The looped segment <NUM> has a predefined shape dimensioned to closely encircle a lens when the looped segment <NUM> is in the dilated configuration.

In embodiments, at least the looped segment <NUM> of the snare <NUM> may be a metal or polymer wire, tether, strap, belt, or the like, with any suitable cross-section configuration configured to sever lenticular tissue during contraction of the looped segment <NUM> about the lenticular tissue.

For an exemplary description of further features of the snare <NUM> and the mechanism of its operation, reference may be made to <CIT>.

With continued reference to <FIG> and <FIG>, the stabilization elements or arms <NUM>, <NUM> of the ophthalmic surgical instrument <NUM> are disposed on opposite sides of a longitudinal axis "X" defined by the snare <NUM>. The arms <NUM>, <NUM> are configured to move from the closed configuration (<FIG>, <FIG>, <FIG>) to the open configuration (<FIG>, <FIG>, <FIG>) to maintain lenticular tissue in its current location, typically but not always within its lens capsule, as will be described. In embodiments, the arms <NUM>, <NUM> may be configured to move independently of one another. The arms <NUM>, <NUM> are illustrated as being linear, but it is contemplated that the arms <NUM>, <NUM> may assume any suitable shape, such as, for example, wing-shaped, disc-shaped, plate-like, or polygonal.

The arms <NUM>, <NUM> may be resiliently-biased toward the open configuration by a biasing member, such as, for example, a coil spring <NUM>, disposed therebetween. As such, upon moving the arms <NUM>, <NUM> distally out of the handle body <NUM> or the hollow shaft (not shown) of the housing <NUM>, the arms <NUM>, <NUM> automatically expand outwardly relative to one another. The arms <NUM>, <NUM> each have a proximal end portion 120a, 122a pivotably coupled to a hub <NUM>, and a distal end portion 120b, 122b. In other embodiments, instead of being pivotable, the arms <NUM>, <NUM> may be configured to shift laterally outward from the collapsed configuration to the expanded configuration.

The hub <NUM> couples the arms <NUM>, <NUM> to the second lever 116b of the housing <NUM>. In particular, the housing <NUM> has a second actuator rod <NUM> interconnecting the hub <NUM> and the second lever 116b. Upon sliding the second lever 116b relative to the handle body <NUM>, the second actuator rod <NUM> transfers the sliding motion to the hub <NUM> to axially move the arms <NUM>, <NUM> along the longitudinal axis "X" of the snare <NUM> relative to the handle body <NUM> between a proximal position and a distal position. In the proximal position, the arms <NUM>, <NUM> are concealed within the inner tubular structure <NUM> of the handle body <NUM> or the hollow shaft when the hollow shaft is used. With the arms <NUM>, <NUM> disposed within the housing <NUM>, the inner tubular structure <NUM> of the handle body <NUM> (or the hollow shaft when used) maintains the arms <NUM>, <NUM> in the collapsed configuration, in which the arms <NUM>, <NUM> are parallel with one another and the longitudinal axis "X" of the snare <NUM>, therefore assuming a reduced profile. Upon moving the arms <NUM>, <NUM> toward the distal position, the arms <NUM>, <NUM> move distally out of the housing <NUM> (the handle body <NUM> and/or the hollow shaft when used) allowing the outwardly-oriented bias of the biasing member <NUM> to transition the arms <NUM>, <NUM> toward the expanded configuration. In embodiments, rather than automatically moving toward the expanded configuration upon exiting the housing <NUM>, the arms <NUM>, <NUM> may be expanded manually via a drive mechanism (not shown).

As shown in <FIG> and <FIG>, in the expanded configuration, the arms <NUM>, <NUM> flare outwardly from opposite sides of the snare <NUM> to define an angle α between the arms <NUM>, <NUM>. In embodiments, the angle α may be between about <NUM> degrees and about <NUM> degrees. In embodiments, the angle α may be between about <NUM> degrees and about <NUM> degrees.

The arms <NUM>, <NUM> together define and reside in a horizontal plane, and the expanded looped segment <NUM> of the snare <NUM> defines and resides in a vertical plane that is aligned with the longitudinal axis "X" of the snare <NUM>. The arms <NUM>, <NUM> remain the horizontal plane throughout their movement between the collapsed and expanded configurations. The arms <NUM>, <NUM> are parallel with the longitudinal axis "X" of the snare <NUM> while the horizontal plane of the arms <NUM>, <NUM> is perpendicular relative to the vertical plane of the looped segment <NUM> of the snare <NUM>.

In embodiments, the arms <NUM>, <NUM> may be axially movable in a direction perpendicular to the horizontal plane of the looped segment <NUM> to adjust a vertical position of the arms <NUM>, <NUM> relative to the housing <NUM> as well as lenticular tissue. For example, the housing <NUM> may further include a third lever (not shown) coupled to the hub <NUM> for moving the arms <NUM>, <NUM> vertically relative to the housing <NUM>.

As best shown in <FIG>, each of the arms <NUM>, <NUM> has a posterior tissue-contacting surface <NUM>. The posterior tissue-contacting surface <NUM> of the arms <NUM>, <NUM> may define an arcuate recess <NUM> therein dimensioned to conform to an anterior surface of a lens of an eye. As such, upon deploying the arms <NUM>, <NUM> over a lens, the posterior tissue-contacting surface <NUM> of each of the arms <NUM>, <NUM> cups the anterior surface of the lens, thereby providing increased surface contact between the arms <NUM>, <NUM> and the lens. It is contemplated that the posterior tissue-contacting surface <NUM> may have a coating or liner of pliable material, such as an elastomer to help protect vulnerable structures in the eye.

In operation, a small incision in the edge of a cornea is made to provide access to an anterior chamber and an anterior surface of a cataractous lens of a patient's eye "E" (<FIG>). A capsulorhexis is made through the anterior surface of a lens capsule of the patient's eye "E," thereby providing surgical access to the cataractous lens "L. " With the arms <NUM>, <NUM> of the ophthalmic surgical instrument <NUM> disposed in the proximal position within the housing <NUM>, and the snare <NUM> in the insertion configuration, as shown in <FIG> and <FIG>, the hollow shaft of the housing <NUM> is inserted through the corneal incision and the capsulorhexis to position the looped segment <NUM> of the snare <NUM> adjacent the anterior surface of the lens "L. " Once in position, the first lever 116a is advanced to move the first end portion 112a of the snare <NUM> distally, thereby transitioning the looped segment <NUM> from the insertion configuration to the deployed configuration, as shown in <FIG>. With the looped segment <NUM> in the deployed configuration, the snare <NUM> is rotated about its longitudinal axis "X" (e.g., via rotation of the entire ophthalmic surgical instrument <NUM> or via a rotation mechanism (not shown) coupled to the snare <NUM>) to rotate the looped segment <NUM> circumferentially about the lens to encircle the lens and position the looped segment <NUM> so that the vertical plane defined by the looped segment <NUM> bisects the lens.

With the looped segment <NUM> of the snare <NUM> in the selected position noted above, the second lever 116b of the housing <NUM> may be advanced to move the arms <NUM>, <NUM> from the proximal position to the distal position. As noted above, as the arms <NUM>, <NUM> move to the distal position, the arms <NUM>, <NUM> automatically transition from the closed configuration to the open configuration, as shown in <FIG> and <FIG>. More specifically, the arms <NUM>, <NUM> move distally along the anterior surface of the lens "L" while also expanding relative to one another and the longitudinal axis "X" of the snare <NUM> to position the posterior tissue-contacting surface <NUM> (<FIG>) of each of the arms <NUM>, <NUM> over lateral side portions of the anterior surface of the lens "L.

With the arms <NUM>, <NUM> overlaying and in contact with the anterior surface of the lens "L," the first lever 116a may then be retracted to transition the looped segment <NUM> from the dilated configuration to the contracted configuration, dividing the lens "L" into two hemispherical sections. During constriction of the looped segment <NUM> about the lens "L," the looped segment <NUM> may exert a proximally-oriented and/or anteriorly oriented force on a distal pole "P" of the lens "L. " However, since the arms <NUM>, <NUM> are in position over the lens "L," the arms <NUM>, <NUM> resist and/or prevent the distal pole "P" of the lens "L" from shifting proximally out of the lens capsule notwithstanding the proximally-oriented force exerted thereon by the snare <NUM>.

After one or more fragmentations of the lens "L" by the ophthalmic surgical instrument <NUM>, the fragmented sections of the cataractous lens "L" may then be removed from the eye "E" using any suitable mechanism, such as, for example, an ultrasonic aspirator.

In some embodiments, the snare <NUM> and/or the arms <NUM>, <NUM> may be mechanically powered through an electric motor, a pneumatic power source, a hydraulic power source, magnets, or the like. It is also contemplated that the ophthalmic surgical instrument <NUM> may be incorporated into a robotic surgical system.

With reference to <FIG>, another embodiment of an ophthalmic surgical instrument <NUM> is illustrated, similar to the ophthalmic surgical instrument <NUM> described above. Due to the similarities between the ophthalmic surgical instrument <NUM> of the present embodiment and the ophthalmic surgical instrument <NUM> described above, only those elements of the ophthalmic surgical instrument <NUM> deemed necessary to elucidate the differences from ophthalmic surgical instrument <NUM> described above will be described in detail.

The ophthalmic surgical instrument <NUM> generally includes a housing <NUM> and a snare <NUM> for severing lenticular tissue. The housing <NUM> of the ophthalmic surgical instrument <NUM> has a handle body <NUM> and a cannulated body, such as, for example, a hollow shaft <NUM> extending distally from the handle body <NUM>. The hollow shaft <NUM> is dimensioned for passage through a corneal incision and has a proximal end 226a integrally formed with or attached to the handle body <NUM>.

The snare <NUM> of the ophthalmic surgical instrument <NUM> includes a first end portion 212a and a second end portion 212b. The first end portion 212a of the snare <NUM> is movable relative to and within the hollow shaft <NUM> of the housing <NUM> via an actuation mechanism (not shown), while the second end portion 212b of the snare <NUM> is fixed relative to the housing <NUM>. It is contemplated that the first end portion 212a of the snare <NUM> may be axially movable within the hollow shaft <NUM> via any suitable actuation mechanism, such as, for example, manual actuation or any suitable motorized actuation mechanism. The second end portion 212b of the snare <NUM> may be fixed to an inner surface of the hollow shaft <NUM> by crimping, welding, adhesives, mechanical interlocks, or any other suitable structure or method.

The snare <NUM> has a looped segment <NUM> disposed protruding out of a distal end 226b of the hollow shaft <NUM>. The looped segment <NUM> of the snare <NUM> is transitionable, via axial movement of the first end portion 212a of the snare <NUM>, between an insertion or contracted configuration, as shown in <FIG>, and a deployed or dilated configuration, as shown in <FIG>. For example, a proximal retraction of a lever (not shown) of the housing <NUM> moves the first end portion 212a of the snare <NUM> proximally away from the second end portion 212b of the snare <NUM>, thereby reducing the diameter of the looped segment <NUM>. In contrast, a distal advancement of the lever moves the first end portion 212a of the snare <NUM> distally toward the second end portion 212b of the snare <NUM>, thereby increasing the diameter of the looped segment <NUM> of the snare <NUM>. The looped segment <NUM> has a predefined shape dimensioned to closely encircle a lens when the looped segment <NUM> is in the dilated configuration.

The looped segment <NUM> of the snare <NUM> differs from the looped segment <NUM> of the snare <NUM> of the ophthalmic surgical instrument <NUM> of <FIG> in that a majority of the looped segment <NUM> overlaps with the housing <NUM> (e.g., the hollow shaft <NUM>) rather than a majority of the looped segment <NUM> being disposed distally of the housing <NUM>. The looped segment <NUM> has a proximal section 228a having a predefined curvature, and a distal section 228b having a predefined curvature. The distal section 228b of the looped segment <NUM> is disposed distally of the distal end <NUM> of the hollow shaft <NUM>, and the proximal section 228a of the looped segment <NUM> is disposed below the hollow shaft <NUM> and proximally of the distal end 226b of the hollow shaft <NUM>.

The looped segment <NUM> further includes a pre-bent section 228c extending from the second end portion 212b of the snare <NUM>. The pre-bent section 228c is disposed distally and outside of the housing <NUM> and has a smaller radius of curvature relative to the proximal and distal sections 228a, 228b of the looped segment <NUM> to position the proximal section 228a of the looped segment <NUM> proximally of and underneath the distal end <NUM> of the hollow shaft <NUM> of the housing <NUM>. The proximal section 228a, the distal section 228b, and the pre-bent section 228c of the looped segment <NUM> may be fabricated from the same material or different materials. For example, the pre-bent section 228c may be fabricated from a less flexible material than the proximal and distal sections 228a, 228b of the looped segment <NUM> to ensure that a majority of the looped segment <NUM> overlaps with the hollow shaft <NUM> throughout the transition of the looped segment <NUM> between the contracted and dilated configurations.

The looped segment <NUM> defines a length "L" parallel with a central longitudinal axis "A" defined by the hollow shaft <NUM>. The proximal section 228a of the looped segment <NUM> has a length "L1," which is approximately ½ or more of the overall length "L" of the looped segment <NUM>, and the distal section 228b of the looped segment <NUM> has a length "L2," which is less than ½ of the overall length of the looped segment <NUM>. In embodiments, the length "L1" of the proximal section 228a of the looped segment <NUM> is approximately ¾ of the overall length "L" of the looped segment <NUM>, and the distal section 228b of the looped segment <NUM> has a length "L2," which is approximately ¼ of the overall length "L" of the looped segment <NUM>. In this way, during use of the ophthalmic surgical instrument <NUM>, a majority of the looped segment <NUM> overlaps with the housing <NUM> (e.g., the hollow shaft <NUM>), such that the housing <NUM> is configured to rest on lenticular tissue during its fragmentation to prevent upward movement thereof during constriction of the looped segment <NUM>.

The looped segment <NUM> is fabricated from shape memory materials, such as, for example, a nickel-titanium alloy to allow the looped segment <NUM> to move to its predefined, dilated configuration. Other shape memory materials, such as shape memory plastics are also contemplated. In other embodiments, the looped segment <NUM> may be fabricated from any suitable biocompatible material including, but not limited to, stainless steel, titanium, silicone, polyimide, polyether block amide, nylon, polycarbonate, or combinations thereof.

In operation, a small incision in the edge of a cornea is made to provide access to an anterior chamber and an anterior surface of a cataractous lens of a patient's eye. A capsulorhexis is made through the anterior surface of a lens capsule of the patient's eye providing surgical access to the cataractous lens. With the snare <NUM> of the ophthalmic surgical instrument <NUM> in the insertion configuration, as shown in <FIG>, the hollow shaft <NUM> of the housing <NUM> is inserted through the corneal incision and the capsulorhexis to position a distal end portion of the hollow shaft <NUM> in an overlapping arrangement with the anterior surface of the lens, and position the looped segment <NUM> of the snare <NUM> adjacent the anterior surface of the lens.

Once the looped segment <NUM> is in the appropriate position, the first end portion 212a of the snare <NUM> is advanced distally, thereby transitioning the looped segment <NUM> from the insertion configuration to the deployed configuration, as shown in <FIG>. With the looped segment <NUM> in the deployed configuration, the snare <NUM> is rotated about its longitudinal axis "A" (e.g., via rotation of the entire ophthalmic surgical instrument <NUM> or via a rotation mechanism (not shown)) to rotate the looped segment <NUM> circumferentially about the lens to encircle the lens and position the looped segment <NUM> relative to the lens so that the plane defined by the looped segment <NUM> bisects the lens. Upon rotating the snare <NUM> to the selected position, the distal end portion of the hollow shaft <NUM> overlaps with the anterior surface of the lens and a majority of the looped segment <NUM> of the snare <NUM>.

With the looped segment <NUM> of the snare <NUM> disposed about the lens, and the distal end portion of the hollow shaft <NUM> overlaying and in contact with the anterior surface of the lens, the looped segment <NUM> is transitioned from the dilated configuration to the contracted configuration, dividing the lens into two hemispherical sections. During constriction of the looped segment <NUM> about the lens, the looped segment <NUM> may exert a proximally-oriented and/or anteriorly-oriented force on a distal pole of the lens. However, since the distal end portion of the hollow shaft <NUM> is in position over the lens, the hollow shaft <NUM> resists and/or prevents elevation and/or tilting of the distal pole of the lens notwithstanding the proximally-oriented force exerted thereon by the closing snare <NUM>.

After one or more fragmentations of the lens by the ophthalmic surgical instrument <NUM>, the fragmented sections of the cataractous lens may then be removed from the eye using any suitable mechanism, such as, for example, an ultrasonic aspirator.

The ophthalmic surgical instrument <NUM> generally includes a housing <NUM> and a snare <NUM> operably coupled to the housing <NUM> for severing lenticular tissue. The housing <NUM> of the ophthalmic surgical instrument <NUM> has a handle body <NUM> and a cannulated body, such as, for example, a hollow shaft <NUM> extending distally from the handle body <NUM>. The hollow shaft <NUM> is dimensioned for passage through a corneal incision and has a proximal end 326a integrally formed with or attached to the handle body <NUM>, and a closed distal end 326b. In embodiments, the distal end 326b of the hollow shaft <NUM> may be open. The hollow shaft <NUM> defines a central longitudinal axis "B" and defines a lateral opening <NUM> in a lateral side surface <NUM> thereof. The lateral opening <NUM> is laterally offset from the central longitudinal axis "B" and defines an axis "C" therethrough that is perpendicular to the central longitudinal axis "A" of the hollow shaft <NUM>. The lateral opening <NUM> may be any suitable shape, such as, for example, circular, elongated, square, or the like.

The snare <NUM> of the ophthalmic surgical instrument <NUM> includes a first end portion 312a and a second end portion 312b. The first end portion 312a of the snare <NUM> is movable relative to and within the hollow shaft <NUM> of the housing <NUM> via an actuation mechanism (not shown), similar to the actuation mechanism described above, while the second end portion 312b of the snare <NUM> is fixed relative to the housing <NUM>. The second end portion 312b of the snare <NUM> may be fixed to an inner surface of the hollow shaft <NUM> by crimping, welding, adhesives, mechanical interlocks, or any other suitable structure or method. In other embodiments, both the first and second end portions 312a, 312b may be axially movable.

The snare <NUM> has a looped segment <NUM> protruding out of the lateral opening <NUM> in the lateral side <NUM> of the hollow shaft <NUM>. The looped segment <NUM> of the snare <NUM> is transitionable, via axial movement of the first end portion 312a of the snare <NUM>, between an insertion or contracted configuration, as shown in <FIG>, and a deployed or dilated configuration, as shown in <FIG>. For example, a proximal retraction of a lever (not shown) of the housing <NUM> moves the first end portion 312a of the snare <NUM> proximally away from the second end portion 312b of the snare <NUM>, thereby reducing the diameter of the looped segment <NUM>. In contrast, a distal advancement of the lever moves the first end portion 312a of the snare <NUM> distally toward the second end portion 312b of the snare <NUM>, thereby increasing the diameter of the looped segment <NUM> of the snare <NUM>. The looped segment <NUM> has a predefined shape dimensioned to closely encircle a lens when the looped segment <NUM> is in the dilated configuration. In embodiments, both the first and second end portions 312a, 312b of the snare <NUM> may be movable to contract or dilate the looped segment <NUM>.

The looped segment <NUM> defines a length "L" parallel with a central longitudinal axis "B" defined by the hollow shaft <NUM>. A majority of the length "L" of the looped segment <NUM> is in side-by-side, parallel relation with the lateral side <NUM> of the hollow shaft <NUM>. Further, a majority of the looped segment <NUM> (i.e., at least half) is disposed proximally of the distal end 326b of the hollow shaft <NUM>. In this way, during use of the ophthalmic surgical instrument <NUM>, the hollow shaft <NUM> hangs over a majority of the looped segment <NUM>, such that the hollow shaft <NUM> sits on a lens during lens fragmentation to prevent upward movement of the lens as the looped segment <NUM> is constricted thereabout.

The looped segment <NUM> includes a proximal section 328a disposed proximally of the lateral opening <NUM>, and a distal section 328b disposed distally of the lateral opening <NUM>. Both the proximal and distal sections 328a, 328b of the looped segment <NUM> are disposed proximally of the distal end 326b of the hollow shaft <NUM> when the looped segment <NUM> is in the contracted configuration, as shown in <FIG>. When the looped segment <NUM> is in the dilated configuration, the proximal section 328a of the looped segment <NUM> is disposed proximally of the distal end 326b of the hollow shaft <NUM>, whereas a majority, e.g., at least about half, of the distal segment 328b is disposed proximally of the distal end 326b of the hollow shaft <NUM>. As such, a majority of the looped segment <NUM> is disposed alongside the lateral side <NUM> of the hollow shaft <NUM> throughout the transition of the looped segment <NUM> between the contracted and dilated configurations.

In operation, a small incision in the edge of a cornea is made to provide access to an anterior chamber and an anterior surface of a cataractous lens of a patient's eye. A capsulorhexis is made through the anterior surface of a lens capsule of the patient's eye providing surgical access to the cataractous lens. With the snare <NUM> of the ophthalmic surgical instrument <NUM> in the contracted configuration, as shown in <FIG>, the hollow shaft <NUM> of the housing <NUM> is inserted through the corneal incision and the capsulorhexis to position a distal end portion of the hollow shaft <NUM> in an overlapping arrangement with the anterior surface of the lens, and position the looped segment <NUM> of the snare <NUM> adjacent the anterior surface of the lens.

Once the looped segment <NUM> is in the appropriate position, the first end portion 312a of the snare <NUM> is advanced distally, thereby transitioning the looped segment <NUM> from the contracted configuration to the dilated configuration, as shown in <FIG>. With the looped segment <NUM> in the deployed configuration, the snare <NUM> is rotated about its longitudinal axis "B" (e.g., via rotation of the entire ophthalmic surgical instrument <NUM> or via a rotation mechanism (not shown)) to rotate the looped segment <NUM> circumferentially about the lens to encircle the lens and position the looped segment <NUM> relative to the lens so that the plane defined by the looped segment <NUM> bisects the lens. Upon rotating the snare <NUM> to the selected position, the axis "C" defined through the lateral opening <NUM> in the hollow shaft <NUM> extends perpendicularly through a center of the eye, whereby the hollow shaft <NUM> overlaps with the anterior surface of the lens and a majority of the looped segment <NUM> of the snare <NUM>.

With the looped segment <NUM> of the snare <NUM> disposed about the lens, and the hollow shaft <NUM> overlaying and in contact with the anterior surface of the lens, the looped segment <NUM> is transitioned from the dilated configuration to the contracted configuration, dividing the lens into two hemispherical sections. During contraction of the looped segment <NUM> about the lens, the looped segment <NUM> may exert a proximally-oriented force on a distal pole of the lens. However, since the hollow shaft <NUM> is in position over the lens, the hollow shaft <NUM> resists and/or prevents elevation and/or tilting of the distal pole of the lens notwithstanding the proximally-oriented force exerted thereon by the closing snare <NUM>.

The ophthalmic surgical instrument <NUM> generally includes a housing (not explicitly shown), an elongated shaft <NUM> extending distally from the housing, and a snare <NUM> for severing lenticular tissue. The elongated shaft <NUM> is dimensioned for passage through a corneal incision "E" and has a proximal portion <NUM> and a distal end portion 426b formed with or otherwise coupled to the proximal portion <NUM>. The proximal portion <NUM> may include a proximal end portion 426a integrally formed with or attached to the handle housing and an intermediate portion 426c. In aspects, the elongated shaft <NUM> may be devoid of any intermediate portion, such that the distal end portion 426b bends directly from the proximal end portion 426a. In embodiments, the distal tip of the elongated shaft <NUM> may be open or closed.

The proximal end portion 426a of the elongated shaft <NUM> may have a linear configuration and define a central longitudinal axis "X1," and the distal end portion 426b may also be linear and define a central longitudinal axis "X2," that is offset from and parallel with the central longitudinal axis "X1" of the proximal end portion 426a. The distal end portion 426b is angled relative to the proximal portion <NUM> so that upon entry of the distal end portion 426b into a corneal incision "E," the distal end portion 426b will be positioned flush with the anterior surface "AS" of the lens "L" rather than at an angle, which would otherwise occur if the distal end portion 426b were coaxial with the proximal portion <NUM>. In aspects, the distal end portion 426b or the proximal end portion 426a may assume any suitable configuration. For example, the distal end portion 426b may be curved along its length (e.g., to match a curvature of a lens).

The intermediate portion 426c of the elongated shaft <NUM> extends between the proximal and distal end portions 426a, 426b, and is angled relative to the proximal and distal end portions 426a, 426b. The intermediate portion 426c may extend between a bent proximal segment <NUM> of the elongated shaft <NUM> and a bent distal segment <NUM> of the elongated shaft <NUM>. The intermediate portion 426c may have a length of about <NUM> between opposite ends "E" and "F" thereof. The intermediate portion 426c has a linear configuration and defines a third central longitudinal axis "X3" that is non-parallel relative to the first and second central longitudinal axes "X1," "X2. " In aspects, the central longitudinal axis "X2" of the intermediate portion 426c may be an obtuse angle (e.g., from about <NUM> degrees to about <NUM> degrees), an acute angle (e.g., from <NUM> degrees to about <NUM> degrees), or a right angle (e.g., about <NUM> degrees) relative to the first and second central longitudinal axes "X1," "X2.

In aspects, instead of the intermediate portion 426c being linear, the intermediate portion 426c may be curved along its length, bent at various points along its length, or assume any suitable configuration that positions the distal end portion 426b of the elongated shaft <NUM> on a different plane from the proximal portion <NUM>. In aspects, the intermediate portion 426c may be flexible and/or transitionable between an angled position relative to the proximal and distal end portions 426a, 426b, and a coaxial configuration therewith. In aspects, the intermediate portion 426c or various portions of the elongated shaft <NUM> may be manually transitionable or fabricated from shape memory material that allows the elongated shaft <NUM> to transition from an otherwise coaxial configuration into the angled configuration as illustrated.

The distal end portion 426b of the elongated shaft <NUM> has a length from about <NUM> to about <NUM> and, in some aspects, the distal end portion 426b may have a length of about <NUM> or about half the diameter of a cornea measured between points "A" and "B. " The distal end portion 426b has a bottom portion <NUM> configured to be oriented toward a human eye, and an upper portion <NUM> disposed on an opposite side of the distal end portion 426b. The bottom portion <NUM> defines an opening <NUM> therein that is disposed at about a midpoint between opposite ends "C," "D" of the distal end portion 426b. The opening <NUM> may be configured as an arcuate cutout in the bottom portion <NUM> of the distal end portion 426b. In aspects, the opening <NUM> may assume any suitable configuration. The upper portion <NUM> of the distal end portion 426b has an inner surface <NUM> and an opposed outer surface <NUM>. The inner surface <NUM> may form a concave depression <NUM> and the outer surface <NUM> may form a convex protuberance <NUM>. The concave depression <NUM> and the convex protuberance <NUM> overlap the opening <NUM>. The concave depression <NUM> provides for more space into which the snare <NUM> may retract, as will be described.

The snare <NUM> of the ophthalmic surgical instrument <NUM> is movable relative to and within the elongated shaft <NUM> via an actuation mechanism (not shown), similar to the actuation mechanism described above. The snare <NUM> has a cutting segment, such as, for example, a looped segment <NUM> configured to protrude out of the opening <NUM> when the looped segment <NUM> is in a dilated configuration. It is contemplated that due to the additional space provided by the concave depression <NUM> in the distal end portion 426b of the elongated shaft <NUM>, the looped segment <NUM> of the snare <NUM> may be entirely or substantially received in the elongated shaft <NUM> when in the contracted configuration. It is contemplated that a distance of about <NUM> may be defined between a point "H" of the upper portion <NUM> and a point "G" of the convex protuberance <NUM>. As such, the looped segment <NUM> may have about <NUM> additional space into which it may retract.

The looped segment <NUM> defines a length parallel with the central longitudinal axis "X2" defined by the distal end portion 426b of the elongated shaft <NUM>. Due to the length of the opening <NUM> of the elongated shaft <NUM> being substantially smaller than the length of the looped segment <NUM> in the dilated configuration, a majority of the length of the looped segment <NUM> overlaps with the bottom portion <NUM> of the elongated shaft <NUM> when the looped segment <NUM> is in the dilated configuration. In this way, during use of the ophthalmic surgical instrument <NUM>, the bottom portion <NUM> of the elongated shaft <NUM> hangs over a majority of the looped segment <NUM>, such that the elongated shaft <NUM> sits on a lens "L" during lens fragmentation to prevent upward movement of the lens "L" as the looped segment <NUM> is constricted thereabout.

In operation, a small incision "E" in the edge of a cornea is made to provide access to an anterior chamber and an anterior surface "AS" of a cataractous lens "L" of a patient's eye. As is typical, the incision "E" is anterior to an anterior surface "AS" of the lens "L. " A capsulorhexis is made through the anterior surface of a lens capsule of the patient's eye providing surgical access to the cataractous lens "L.

With the snare <NUM> of the ophthalmic surgical instrument <NUM> in the contracted configuration, as shown in <FIG>, the elongated shaft <NUM> is inserted through the corneal incision "E" and the capsulorhexis to position the distal end portion 426b of the elongated shaft <NUM> in an overlapping arrangement with the anterior surface "AS" of the lens "L," and position the looped segment <NUM> of the snare <NUM> anterior to a central location of the anterior surface "AS" of the lens "L. " Due to the distal end portion 426b being angled relative to the proximal portion <NUM>, the distal end portion 426b is naturally positioned in flush engagement with the anterior surface "AS" of the lens "L" while the proximal portion <NUM> extends through the incision "E.

Once the looped segment <NUM> is in the appropriate position, the looped segment <NUM> is transitioned from the contracted configuration to the dilated configuration, similar to that shown in <FIG>. With the looped segment <NUM> in the deployed configuration, the looped segment <NUM> of the snare <NUM> naturally encircles the lens, due to the shape memory material from which the looped segment <NUM> is fabricated, so that the plane defined by the looped segment <NUM> bisects the lens. With the looped segment <NUM> of the snare <NUM> disposed about the lens "L," and the elongated shaft <NUM> overlaying and contacting the anterior surface "AS" of the lens "L," the looped segment <NUM> is transitioned from the dilated configuration to the contracted configuration, dividing the lens into two hemispherical sections.

During contraction of the looped segment <NUM> about the lens "L," the looped segment <NUM> may exert a proximally-oriented force on the lens "L. " However, since the distal end portion 426b of the elongated shaft <NUM> is in position over the lens "L," the elongated shaft <NUM> resists and/or prevents elevation and/or tilting of the lens "L" notwithstanding the proximally/anteriorly-oriented force exerted thereon by the closing snare <NUM>. If the proximal and distal end portions 426a, 426b of the elongated shaft <NUM> were coaxial instead of being disposed on different planes, the distal end portion 426b would be set at an upward angle relative to the lens "L," which would result in an unevenly dispersed force being exerted on the lens "L" during contraction of the looped segment <NUM> about the lens "L.

With reference to <FIG>, another embodiment of a snare <NUM> of an ophthalmic surgical instrument <NUM> is illustrated, similar to the snares described above. Due to the similarities between the snare <NUM> of the present embodiment and the snares described above, only those elements of the snare <NUM> deemed necessary to elucidate the differences from snares described above will be described in detail. It is contemplated that the snare <NUM> may be incorporated into the ophthalmic surgical instruments <NUM>, <NUM>, <NUM>, <NUM> described above or any other suitable hand-held or robotically operated ophthalmic surgical instrument.

The ophthalmic surgical instrument <NUM> generally includes a housing <NUM>, an elongated shaft <NUM> extending distally from the housing <NUM>, and the snare <NUM> for severing lenticular tissue. The elongated shaft <NUM> is dimensioned for passage through a corneal incision and has a proximal end portion 526a and a distal end portion 526b formed with or otherwise coupled to the proximal end portion 526a. The proximal end portion 526a may be integrally formed with or attached to the handle housing <NUM>.

The snare <NUM> of the ophthalmic surgical instrument <NUM> is movable relative to and within the elongated shaft <NUM> via an actuation mechanism (not shown), similar to the actuation mechanisms described above. The snare <NUM> generally includes a wire <NUM>, a light source <NUM>, and a fiber optic cable <NUM>. The wire <NUM> has a first end 530a configured to be coupled to the actuation mechanism, and a second end 530b fixed to or otherwise coupled to the housing <NUM> or the elongated shaft <NUM>. In aspects, the second end 530b of the wire <NUM> is fixed to the distal end portion 526b of the elongated shaft <NUM>.

The wire <NUM> has a looped segment <NUM> configured to protrude out of an opening <NUM> of the distal end portion 526b of the elongated shaft <NUM> when the looped segment <NUM> is in a dilated configuration. The looped segment <NUM> has a cutting segment <NUM> forming the bottom of the looped segment <NUM>. The cutting segment <NUM> may have a different diameter (e.g., smaller) or shape (e.g., sharpened) than the remainder of the looped segment <NUM>. In aspects, the cutting segment <NUM> may have the same thickness and shape as the remainder of the looped segment <NUM>.

The wire <NUM> is fabricated from a pliable, metal material, such as, for example, nickel-titanium or any other suitable superelastic material. In aspects, the wire <NUM> may be fabricated from any suitable ductile material. The wire <NUM> defines a channel or bore <NUM> centrally therethrough. The channel <NUM> of the wire <NUM> has a diameter from about <NUM> to about <NUM> and, in some aspects, about <NUM>. The channel <NUM> is configured to accommodate the fiber optic cable <NUM> therein. In aspects, rather than the wire <NUM> having the fiber optic cable <NUM> disposed therein, an inner surface <NUM> of the wire <NUM> that defines the channel <NUM> may be coated with a material having a high refractive index (e.g., glass, plastic, or a combination thereof) to facilitate passage of light therethrough.

The cutting segment or bottom <NUM> of the looped segment <NUM> of the wire <NUM> has a portion, such as, for example, a port <NUM> defined therein. The port <NUM> is in communication with the channel <NUM> to allow light to pass from the channel <NUM> and out of the cutting segment <NUM>. The port <NUM> is formed at a bottom-most apex <NUM> of the looped segment <NUM>, such that the port <NUM> is disposed in overlapping alignment with the opening <NUM> in the elongated shaft <NUM> when the looped segment <NUM> assumes its dilated configuration. In this way, when light is emitted through the port <NUM>, a clinician may be better able to identify the location of the cutting segment <NUM> of the wire <NUM>. The port <NUM> may be filled with a light-permeable material <NUM>, such as, for example, glass, transparent ceramics, clear plastics, etc. The light-permeable material <NUM> allows light to pass through the port <NUM> while prohibiting fluids and surgical debris from entering the wire <NUM>. The channel <NUM> of the wire <NUM> may be closed at the second end 530b thereof or, in some aspects, the wire <NUM> may have a plug <NUM> disposed at a location adjacent and proximally of the port <NUM> to ensure light passes out of the port <NUM>. In aspects, the wire may have a plurality of ports formed therein.

The light source <NUM> may be an LED, a compact fluorescent lamp, an incandescent light bulb, or any other suitable source of light. The light source <NUM> is in communication with the channel <NUM> of the wire <NUM>. For example, the light source <NUM> may be attached to the first end 530a of the wire <NUM> and is oriented toward the channel <NUM>. In some aspects, the light source <NUM> may be disposed within the channel <NUM> at any suitable location along the length of the wire <NUM>. In aspects, the light source <NUM> may be disposed within or otherwise adjacent the port <NUM>. The fiber optic cable <NUM> extends through the channel <NUM> and has a proximal end 534a attached to the light source <NUM> and a distal end 534b terminating adjacent the port <NUM>. The fiber optic cable <NUM> is configured to pass light from the light source <NUM> and to the port <NUM> of the cutting segment <NUM>.

In operation, a small incision in the edge of a cornea "C" (<FIG>) is made to provide access to an anterior chamber and an anterior surface "AS" of a cataractous lens "L" of a patient's eye. As is typical, the incision is anterior to the anterior surface "AS" of the lens "L. " A capsulorhexis is made through the anterior surface "AS" of the lens capsule of the patient's eye providing surgical access to the cataractous lens "L. " As shown in <FIG>, a portion of the anterior surface "AS" of the lens "L" may be removed to form a cavity "CA. " The cavity "CA" renders the lens "L" more permeable to light, thereby giving a clinician a better view behind the eye.

The elongated shaft <NUM> is inserted through the corneal incision and the capsulorhexis to position the distal end portion 526b of the elongated shaft <NUM> in an overlapping arrangement with the anterior surface "AS" of the lens "L," and position the looped segment <NUM> of the wire <NUM> anterior to a central location of the anterior surface "AS" of the lens "L. " The light source <NUM> may be activated either prior, during, or after positioning the looped segment <NUM> adjacent the anterior surface "AS" of the lens "L. " The light emitted from the light source <NUM> is passed through the length of the wire <NUM> via the fiber optic cable <NUM> and out of the bottom <NUM> of the looped segment <NUM> via the port <NUM>.

The looped segment <NUM> of the wire <NUM> is transitioned from the contracted configuration to the dilated configuration and guided around the lens "L" to position the cutting segment/bottom <NUM> of the looped segment <NUM> adjacent a posterior surface "PS" of the lens "L. " The clinician is able to use the light emitted from the port <NUM> to appropriately position the cutting segment <NUM> relative to the lens "L. " With the looped segment <NUM> in the selected position, which is verified using the light transmitted out of the bottom <NUM> of the looped segment <NUM>, the looped segment <NUM> is transitioned from the dilated configuration to the contracted configuration, thereby severing the lens "L.

With reference to <FIG>, another embodiment of an ophthalmic surgical instrument <NUM> is illustrated, similar to the ophthalmic surgical instruments described above. Due to the similarities between the ophthalmic surgical instrument <NUM> of the present embodiment and the ophthalmic surgical instruments described above, only those elements of the ophthalmic surgical instrument <NUM> deemed necessary to elucidate the differences from ophthalmic surgical instruments described above will be described in detail.

The ophthalmic surgical instrument <NUM> generally includes a housing <NUM> and a snare <NUM> operably coupled to the housing <NUM> and configured for severing lenticular tissue. The housing <NUM> of the ophthalmic surgical instrument <NUM> has a handle body <NUM> and a cannulated body, such as, for example, a hollow, elongated shaft <NUM> extending distally from the handle body <NUM>. The elongated shaft <NUM> is dimensioned for passage through a corneal incision and has a proximal end portion 626a integrally formed with or attached to the handle body <NUM>, and a distal end portion 626b having a closed distal tip <NUM>. The distal end portion 626b may be bent or curved relative to the remainder of the elongated shaft <NUM> to more suitably position the distal end portion <NUM> within a corneal incision.

The elongated shaft <NUM> has an upper surface 632a and an opposing bottom surface 632b configured to be oriented toward and positioned in contact with an eye. The bottom surface 632b of the elongated shaft <NUM> defines a first opening, such as, for example, a proximal opening <NUM>, and a second opening, such as, for example, a distal opening <NUM> therein. The proximal and distal openings <NUM>, <NUM> are in communication with a hollow interior <NUM> (<FIG>) of the elongated shaft <NUM> and are spaced longitudinally from one another along a longitudinal axis defined by the elongated shaft <NUM>. The proximal and distal openings <NUM>, <NUM> are each disposed proximally of the distal tip <NUM> and are formed in the distal end portion 626b of the elongated shaft <NUM>. The proximal and distal openings <NUM>, <NUM> are generally oval, but it is contemplated that the proximal and distal openings <NUM>, <NUM> may assume any suitable shape, such as, for example, circular, elongated, square, or the like. In aspects, the distal opening <NUM> may be shorter or longer than the proximal opening <NUM>.

Due to the proximal and distal openings <NUM>, <NUM> being longitudinally spaced from one another, the bottom surface 632b of the elongated shaft <NUM> has a surface, such as, for example, a cutting surface <NUM>, disposed between and interconnecting the proximal and distal openings <NUM>, <NUM>. The cutting surface <NUM> may be arcuate, flat, or assume any suitable shape.

The snare or wire <NUM> of the ophthalmic surgical instrument <NUM> includes a first end portion 612a and a second end portion 612b. The second end portion 612b of the wire <NUM> is movable relative to and within the elongated shaft <NUM> via an actuation mechanism (not shown), similar to the actuation mechanisms described above, while the first end portion 612a of the wire <NUM> is fixed relative to the housing <NUM>. The first end portion 612a of the wire <NUM> may be fixed to an inner surface of the elongated shaft <NUM> adjacent the proximal opening <NUM> by crimping, welding, adhesives, mechanical interlocks, or any other suitable structure or method. In other aspects, the second end portion 612b of the wire <NUM> may be fixed whereas the first end portion 612a of the wire <NUM> may be axially movable. In other embodiments, both the first and second end portions 612a, 612b may be axially movable.

The wire <NUM> has a cutting segment, such as, for example, a looped segment <NUM> protruding through and out of the proximal and distal openings <NUM>, <NUM> of the elongated shaft <NUM>. The looped segment <NUM> of the wire <NUM> is transitionable, via axial movement of the second end portion 612b of the wire <NUM>, between a dilated configuration, as shown in <FIG>, and an insertion or contracted configuration, as shown in <FIG>. For example, a proximal retraction of a lever (not shown) of the housing <NUM> moves the second end portion 612b of the snare <NUM> proximally and into the interior <NUM> of the elongated shaft <NUM> via the distal opening <NUM>, thereby reducing the diameter of the looped segment <NUM>. In contrast, a distal advancement of the lever moves the second end portion 612b of the wire <NUM> distally and out through the distal opening <NUM> of the elongated shaft <NUM>, thereby increasing the diameter of the looped segment <NUM> of the wire <NUM>.

The looped segment <NUM> has a predefined shape dimensioned to closely encircle a lens when the looped segment <NUM> is in the dilated configuration. The looped segment <NUM> defines a length parallel with the longitudinal axis of the elongated shaft <NUM>. A majority of the length of the looped segment <NUM> is in side-by-side, parallel relation with the bottom surface 632b of the elongated shaft <NUM>. Further, a majority of the looped segment <NUM> (i.e., at least half) is disposed proximally of the distal tip <NUM> of the elongated shaft <NUM>. In this way, during use of the ophthalmic surgical instrument <NUM>, the bottom surface 632b of the elongated shaft <NUM> hangs over a majority of the looped segment <NUM>, such that the elongated shaft <NUM> sits on a lens during lens fragmentation to prevent upward movement of the lens as the looped segment <NUM> is constricted thereabout.

In operation, a small incision in the edge of a cornea is made to provide access to an anterior chamber and an anterior surface of a cataractous lens of a patient's eye. A capsulorhexis is made through the anterior surface of a lens capsule of the patient's eye providing surgical access to the cataractous lens. With the snare <NUM> of the ophthalmic surgical instrument <NUM> in the contracted configuration, as shown in <FIG>, the elongated shaft <NUM> is inserted through the corneal incision and the capsulorhexis to position the distal end portion 626b of the elongated shaft <NUM> in an overlapping arrangement with the anterior surface of the lens, and the looped segment <NUM> of the wire <NUM> is positioned adjacent the anterior surface of the lens.

Once the looped segment <NUM> is in the appropriate position, the second end portion 612b of the snare <NUM> is advanced distally and out from within the interior <NUM> of the elongated shaft <NUM> through the distal opening <NUM>, thereby transitioning the looped segment <NUM> from the contracted configuration to the dilated configuration, as shown in <FIG>. With the looped segment <NUM> in the dilated configuration, the snare <NUM> may be rotated about its longitudinal axis (e.g., via rotation of the entire ophthalmic surgical instrument <NUM> or via a rotation mechanism (not shown)) to rotate the looped segment <NUM> circumferentially about the lens to encircle the lens and position the looped segment <NUM> relative to the lens so that the plane defined by the looped segment <NUM> bisects the lens. Upon rotating or otherwise positioning the snare <NUM> in the selected position, the lens is disposed between the looped segment <NUM> and the cutting surface <NUM> of the bottom surface 632b of the elongated shaft <NUM>.

With the looped segment <NUM> of the snare <NUM> disposed about the lens, and the elongated shaft <NUM> overlaying and in contact with the anterior surface of the lens, the looped segment <NUM> is transitioned from the dilated configuration toward the contracted configuration. As the looped segment <NUM> moves toward the contracted configuration, a cutting section <NUM> (<FIG>) of the looped segment <NUM> cooperates with the cutting surface <NUM> of the elongated shaft <NUM> to apply a cutting force on the lens, thereby dividing the lens into two hemispherical sections. Nearing the end of the transition of the looped segment <NUM> toward the contracted configuration, a distal edge <NUM> (<FIG>) of the cutting surface <NUM> may act as a fulcrum allowing the looped segment <NUM> to be pulled closer to the bottom surface 632b of the elongated shaft <NUM>, causing the cutting section <NUM> of the looped segment <NUM> to become taught and straight against the cutting surface <NUM>. As such, the cutting surface <NUM> acts in a similar manner as a cutting block or board where the cutting section <NUM> of the looped segment <NUM> acts as the knife.

With reference to <FIG>, another embodiment of a snare, such as, for example, a wire <NUM> is illustrated, similar to the snare <NUM> described above. It is contemplated that the snare <NUM> may be incorporated into the elongated shaft <NUM> described above. The snare <NUM> has a looped segment <NUM> having a curvature along a majority of its length that matches a curvature of a lens of a human eye. The snare <NUM> differs from the snare <NUM> in that the looped segment <NUM> of the snare <NUM> has a linear, cutting section <NUM> disposed adjacent the proximal opening <NUM> in the elongated shaft <NUM>.

Upon transitioning the looped segment <NUM> to the contracted configuration, as shown in <FIG>, the linear, cutting section <NUM> of the looped segment <NUM> extends between the proximal and distal openings <NUM>, <NUM> and engages the cutting surface <NUM> of the elongated shaft <NUM>. Due to the cutting section <NUM> being linear, more of the cutting section <NUM> contacts the lens as the looped segment <NUM> moves toward the contracted configuration.

With reference to <FIG>, another embodiment of an ophthalmic surgical instrument <NUM>' is illustrated, similar to the ophthalmic surgical instrument <NUM> described above. The ophthalmic surgical instrument <NUM>' generally includes an elongated shaft <NUM>' and the wire or snare <NUM> of <FIG> operably coupled to the elongated shaft <NUM>'. The elongated shaft <NUM>' has a bottom surface <NUM>' defining a proximal opening <NUM>', a distal opening <NUM>', and an intermediate opening <NUM>' disposed between and spaced from the proximal and distal openings <NUM>', <NUM>'. As such, the bottom surface <NUM>' has a first section 632a' extending between and interconnecting the proximal opening <NUM>' and the intermediate opening <NUM>', and a second section 632b' extending between and interconnecting the intermediate opening <NUM>' and the distal opening <NUM>'. The first and second sections 632a', 632b' function as support surfaces for the eye during a transition of the looped segment <NUM> of the snare <NUM> from the dilated configuration to the contracted configuration, as will be described below.

In operation, the elongated shaft <NUM>' is positioned on an anterior surface of a lens of an eye, such that at least the first and second sections 632a', 632b' of the bottom surface <NUM>' of the elongated shaft <NUM>' is in contact with the anterior surface. The looped segment <NUM> of the snare <NUM> is transitioned toward the contracted configuration, as shown in <FIG>, to sever the lens of the eye in a similar manner described above. Due to the presence of the intermediate opening <NUM>' in the elongated shaft <NUM>', the cutting section <NUM> of the looped segment <NUM> is permitted to cut entirely through the lens as it passes into the intermediate opening <NUM>' in the bottom surface <NUM>'. While the looped segment <NUM> cuts through the lens, the first and second sections 632a', 632b' of the bottom surface <NUM>' exert a reactionary force (in a posterior direction) on the lens to prevent the lens from being lifted, thereby further facilitating cutting of the lens.

With reference to <FIG>, another embodiment of an elongated shaft <NUM> of an ophthalmic surgical instrument is illustrated, similar to the elongated shaft <NUM> of <FIG>. The elongated shaft <NUM> defines a proximal opening <NUM> in a bottom surface <NUM> thereof, and a distal opening <NUM>. The looped segment <NUM> of the snare <NUM> extends through each of the proximal and distal openings <NUM>, <NUM>. The bottom surface <NUM> has a cutting surface <NUM> extending between the proximal and distal openings <NUM>, <NUM>. The difference between the elongated shaft <NUM> and the elongated shaft <NUM> of <FIG> is that the distal opening <NUM> is defined in a distally-facing surface <NUM> of a distal tip <NUM> of the elongated shaft <NUM>.

With reference to <FIG>, another embodiment of an elongated shaft <NUM> of an ophthalmic surgical instrument is illustrated, similar to the elongated shaft <NUM> of <FIG>. The elongated shaft <NUM> defines a proximal opening <NUM> in a bottom surface <NUM> thereof, and a distal opening <NUM>. The looped segment <NUM> of the snare <NUM> extends through each of the proximal and distal openings <NUM>, <NUM>. The bottom surface <NUM> has a cutting surface <NUM> extending between the proximal and distal openings <NUM>, <NUM>. The difference between the elongated shaft <NUM> and the elongated shaft <NUM> of <FIG> is that the distal opening <NUM> has a scooped configuration and extends along a length of an opened distal tip <NUM> of the elongated shaft <NUM>.

Claim 1:
An ophthalmic surgical instrument (<NUM>) for severing a lens of an eye, comprising:
an elongated shaft (<NUM>) including a distal end portion defining a first opening (<NUM>) and a second opening (<NUM>), the first and second openings (<NUM>, <NUM>) being spaced from one another along a longitudinal axis (<NUM>) defined by the elongated shaft (<NUM>); and
a wire (<NUM>) extending along the elongated shaft (<NUM>) and including a cutting segment (<NUM>) extending through the first and second openings (<NUM>, <NUM>), wherein the cutting segment (<NUM>) is configured to move between a contracted configuration, and a dilated configuration, in which the cutting segment (<NUM>) assumes a diameter approximating a diameter and shape of a lens of an eye, the cutting segment (<NUM>) being configured to sever the lens upon moving toward the contracted configuration,
characterized in that the elongated shaft (<NUM>) has a bottom surface (632b) and that the first and second openings (<NUM>, <NUM>) are disposed on the bottom surface (632b) and aligned with one another along the longitudinal axis.