Abstract:
Phacoemulsification needles are configured to cause eccentric or wobble-type motion by being formed to distribute the mass of the needle non-uniformly. In one version the non-uniform property is created by angling the needle&#39;s aspiration passage with respect to the needle axis. In another, the needle tip walls are formed with non-uniform thicknesses, with or without including an off-axis configuration with respect to the needle aspiration passageway. In another, the needle tip walls are formed in a scalloped configuration. In another, external protuberances or “bumps” are formed on the needle tip exterior wall surfaces. In another, the needle tip walls have weighted inserts placed therein. In another, the needle tip is formed with skewed bevels and ridges. In another, the needle body is formed with non-uniformly shaped segments. In another, a portion of the needle tip is twisted with respect to the rest of the tip.

Description:
This application claims priority from U.S. patent application Ser. No. 61/246,864 filed Sep. 29, 2009 and entitled “Apparatus and Method for Phacoemulsification”, which is a continuation-in-part of application Ser. No. 12/263,315, filed 31 Oct. 2008, now U.S. Pat. No. 9,132,033 which is claims priority from application Ser. No. 60/984,375, filed 1 Nov. 2007, all of which are incorporated herein, by reference, in their entirety, for all purposes as is fully set forth herein. 
    
    
     FIELD OF THE INVENTION 
     This disclosure relates to surgical instruments and surgical techniques used in eye surgery and more particularly, to phacoemulsification apparatus and methods for their use. 
     BACKGROUND OF THE INVENTION 
     A common ophthalmological surgical technique is the removal of a diseased or injured lens from the eye. Earlier techniques used for the removal of the lens typically is required a substantial incision to be made in the capsular bag in which the lens is encased. Such incisions were often on the order of 12 mm in length. 
     Later techniques focused on removing diseased lenses and inserting replacement artificial lenses through as small an incision as possible. For example, it is now a common technique to take an artificial intraocular lens (IOL), fold it and insert the folded lens through the incision, allowing the lens to unfold when it is properly positioned within the capsular bag. Similarly, efforts have been made to accomplish the removal of the diseased lens through an equally small incision. 
     One such removal technique is known as phacoemulsification. A typical phacoemulsification tool includes a handpiece to which is attached a hollow needle. Electrical energy is applied to a piezoelectric crystal to vibrate the needle at ultrasonic frequencies in order to fragment the diseased lens into small enough particles to be aspirated from the eye through the hollow needle. Commonly, an infusion sleeve is mounted around the needle to supply irrigating liquids to the eye in order to aid in flushing and aspirating the lens particles. 
     It is extremely important to properly infuse liquid during such surgery. Maintaining a sufficient amount of liquid prevents collapse of certain tissues within the eye and attendant injury or damage to delicate eye structures. As an example, endothelial cells can easily be damaged during such collapse and this damage is permanent because these cells do not regenerate. Some benefits of using as small incision as possible during such surgery are the minimization of leakage of liquid during and after surgery to help prevent tissue collapse, faster healing time and decreased post-operative astigmatism. 
     Phacoemulsification needles and tips are well represented in the prior art. Needles and tips of varying configurations are well known. A particular shape for a tip or needle is often dictated by the type of handpiece with which the needle is to be used. 
     U.S. Pat. No. 5,725,495 (Strukel et al) teaches and describes a phacoemulsification handpiece, sleeve and tip illustrating a wide variety of tip configurations and needle cross-sectional configurations. 
     U.S. Pat. No. 6,007,555 (Devine) teaches and describes an ultrasonic needle for surgical emulsification. The needle and its tip are shown in both circular and oval configurations. 
     U.S. Pat. No. 6,605,054 (Rockley) teaches and describes a multiple bypass port phacoemulsification tip having multiple aspiration ports and a single discharge port to infuse liquid into the eye. 
     U.S. Pat. No. 5,879,356 (Geuder) teaches and describes a surgical instrument for crushing crystalline eye lenses by means of ultrasound and for removing lens debris by suction which demonstrates the use of a sleeve positioned concentric to the needle and having a pair of discharge ports formed thereon. 
     U.S. Pat. No. 5,645,530 (Boukhny) teaches and describes a phacoemulsification sleeve, one variation of which has a bellows portion attached to a discharge port ring which directs an annular flow of liquid around the needle and into the eye. The use of the bellows is intended to, allow the sleeve to absorb spikes, in liquid pressure during the operation. 
     Published U.S. Patent Application No. 2003/0004455(Kadziauskas) teaches and describes a bi-manual phacoemulsification needle using separate emulsification and aspiration needles inserted into the eye simultaneously during surgery. 
     Published U.S. Patent Application No. 2006/0217672 (Chon) teaches and describes a phacoemulsification tip that is swaged or crimped at its distal end. The tip is intended for use with a handpiece producing torsional motion and the crimping forms cutting edges at the distal end. 
     Many phacoemulsification needles and tips are designed for use with handpieces that vibrate the needle longitudinally at relatively low frequencies. In addition to, longitudinal vibration, certain handpieces sold by Alcon, Inc. of Ft, Worth, Tex. claim to impart a torsional motion to the needle at an oscillation vibration frequency of about 100 cycles/second. There are also handpieces that provide torsional oscillation of the phacoemulsification tip at frequencies of about 32,000 cycles/second. 
     Use of the torsional-type, handpiece has called for phacoemulsification needle tip designs differing from those used with the longitudinal-type handpiece. For example, needles having been designed with tips that are shaped, swaged, and angled to take advantage of the needle motion created by the handpiece. 
     Many surgeons favor phacoemulsification needles having the straight tip design commonly used with longitudinal hand pieces. The great majority of surgeons use longitudinal handpieces rather than torsional hand pieces, often because torsional phacoemulsification equipment is more expensive than longitudinal equipment, and thus find themselves unable to take advantage of the enhanced phacoemulsification results claimed in torsional phaco. 
     Forming a needle tip in an off-axis position relative to the axis of the aspiration passageway extending through the needle body causes eccentric, motion or “wobble” during torsional phacoemulsification and improves the efficiency of phacoemulsification while retaining the straight-tip configuration. Surprisingly, I have also found that forming the tip in such an off-axis position also increases the efficiency of phacoemulsification when using a longitudinal hand piece. Preliminary clinical examinations indicate that using an off-axis needle with a longitudinal hand piece may be more efficient than using the same needle with a torsional hand piece providing 100% torsional action, where efficiency is measured by the energy dissipated during phacoemulsification. When used herein, the term “dissipated energy” refers to the amount of energy, most commonly measured in joules, used by the hand piece during phacoemulsification. Lower dissipated energy readings mean that less heat is being produced during phacoemulsification which lowers the possibility of thermal damage to the delicate eye tissues. 
     There are known phacoemulsification apparatus, such as the Infiniti® Vision System manufactured by Alcon Laboratories of Ft. Worth, Tex. which allow the surgeon to choose between using torsional motion, longitudinal motion, or a blend thereof in a single hand piece. A common blended setting uses, torsional motion two-thirds of the time, and longitudinal motion one-third of the time. It is believed that the “blended” motion produces a more three-dimensional effect because of the back-and-forth motion imparted during longitudinal phacoemulsification and the eccentric motion produced at the tip during torsional phaco. 
     Use of an off-axis tip with a longitudinal hand piece appears to create a hybrid type of phacoemulsification motion without using the more complex and expensive torsional phacoemulsification apparatus. I have also determined that the eccentric or wobble type of motion can be imparted to a phacoemulsification needle with no flare at the tip by forming the central aspiration passageway within the needle body in an off-axis position. It is also expected that similar results will be obtained using a straight phacoemulsification needle having an aspiration passageway that is formed with a cross sectional configuration different than the cross-section configuration of the needle body itself, and that these results will be further amplified if the passageway is also placed off-axis. 
     While the following describes a preferred embodiment or embodiments of the present invention, it is to be understood that such description is made by way of example only and is not intended to limit the scope of the present invention. It is expected that alterations and further modifications, as well as other and further applications of the principles of the present invention will occur to others skilled in the art to which the invention relates and, while differing from the foregoing, remain within the spirit and scope of the invention as herein described and claimed. Where means-plus-function clauses are used in the claims such language is intended to cover the structures described herein as performing the recited functions and not only structural equivalents but equivalent structures as well. For the purposes of the present disclosure, two structures that perform the same function within an environment described above may be equivalent structures. 
     I have determined that an eccentric or “wobble” motion can be imparted to a phacoemulsification needle by constructed the needle to include anomalies in distribution of the needle&#39;s mass. In other words, the needle is manufactured in a manner in which the distribution of mass about the needle&#39;s major axis is not uniform. 
     In accordance with the preferred embodiment of the present invention, the needle itself is formed with the central aspiration passageway angles with respect to the central axis of the needle body. 
     In another embodiment the needle with an angled aspiration passageway is combined with a flared tip that is centered on the needle body. 
     In another embodiment, an off-axis aspiration passageway is combined with a needle tip wherein the tip itself is formed with non-uniform distribution of mass. 
     In yet another embodiment, the needle tip having a non-uniform distribution of mass is combined with a passageway that is coaxial with axis of the needle body. 
     In another embodiment a bump or selected number of bumps is formed on the external surface of the needle tip to create a non-uniform distribution of mass. 
     In yet another embodiment the portion of the needle is formed from a metal having a first density while the remaining portion is formed from a metal having a different density. 
     In yet another embodiment, the portion of the needle is drilled away and the resulting aperture is plugged with a metallic plug having a density different than that of the density of the main needle body. 
     In another embodiment, a series of needle tips having non-uniform skewed ridges on double beveled needle tips. 
     In another embodiment, a portion of the needle body is formed with a diameter larger than the remaining portion. 
     In another embodiment, the distal portion of the needle body is formed a larger diameter, a larger portion of which is offset. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further aspects of the present invention will be best understood by reference to the accompanying drawings in which like numbers are used to identify like parts, and which are presented to illustrate the aspects of the invention although not necessarily to actual scale, wherein: 
         FIG. 1  is a drawing showing prior art straight oval- and square-shaped tips; 
         FIG. 2  is a drawing showing several prior art needle cross-sectional configurations; 
         FIG. 3  is a lateral schematic view of a phacoemulsification needle embodying the present invention; 
         FIG. 4  is a sectional view of the needle of  FIG. 3 ; 
         FIG. 5  is an end view taken along  5 - 5  of  FIG. 4 ; 
         FIG. 6  is a partial lateral schematic view of the needle of  FIG. 5 ; 
         FIG. 7  is a lateral view of a needle tip having a circular cross-section; 
         FIG. 8  is a partial lateral schematic view of the needle tip of  FIG. 7 ; 
         FIG. 9  is a partial lateral view of a variation of the tip shown in  FIG. 6 ; 
         FIG. 10  is a partial lateral view of a variation of the tip shown in  FIG. 8 ; 
         FIG. 11  is a perspective view of the needle of  FIG. 3 ; 
         FIG. 12  is an enlarged view of the tip of  FIG. 11 ; 
         FIG. 13  is a bottom view of  FIG. 12 ; 
         FIG. 14  is an illustration of the end of a prior art straight needle tip during torsional motion; 
         FIG. 15  is an illustration of the and of a needle tip constructed in accordance with the present invention and used with torsional motion; 
         FIG. 16  is an end view showing a needle having a triangular offset tip; 
         FIG. 17  is an end view of a needle having a pentagonal offset tip with the aspiration passageway formed at an apex to adjacent sides of the pentagon; 
         FIG. 18  is a view of  FIG. 17  showing the aspiration passageway positioned along one side of the pentagonal tip; 
         FIG. 19  is an end view of a square tip showing the aspiration passageway positioned at an apex of two adjacent sides of the square; 
         FIG. 20  is an end view of a square tip extending from a needle body having a circular outer cross-section and an aspiration passageway with an oval cross-section; 
         FIG. 21  is a lateral sectional view of a portion of a straight, unflared phacoemulsification needle having a circular exterior cross-section shape and an internal aspiration passageway having an oval cross-sectional shape; 
         FIG. 22  is an end view of the needle of  FIG. 21 ; 
         FIG. 23  is a lateral sectional view of a portion of a straight, unflared phacoemulsification needle having an oval cross-sectional shape with an aspiration passageway having a circular cross-sectional shape and offset toward one end of the needle body; 
         FIG. 24  is an end view of the needle of  FIG. 23 ; 
         FIG. 25  is a lateral view of a phacoemulsification needle with an angled tip formed off-axis to the needle body; 
         FIG. 26  is a view along  26 - 26  of  FIG. 25 ; 
         FIG. 27  is an enlarged view of a flared phacoemulsification needle tip; 
         FIG. 28  is an enlarged view of  FIG. 27 ; 
         FIG. 29  is a microscopic view of a portion of the outer surface of the tip of  FIGS. 27 and 28  after roughening and polishing; 
         FIG. 30  is a microscopic view of a portion of the inner surface of the tip of  FIGS. 27 and 28  after roughening and polishing; 
         FIG. 31  is a partial lateral view of a prior art phacoemulsification needle in contact with a nucleus; 
         FIG. 32  is another partial lateral view of the prior art phacoemulsification needle shown in  FIG. 31 ; 
         FIG. 33  is a partial lateral view of a phacoemulsification needle according to the present invention in contact with a nucleus; 
         FIG. 34  is another partial lateral view of the present invention shown in  FIG. 33 ; 
         FIG. 35  is a partial sectional view of a phacoemulsification needle having an angled aspiration passageway and a symmetrical flared tip; 
         FIG. 36  is a partial sectional view of a phacoemulsification needle having an angled aspiration passageway and a non-flared tip; 
         FIG. 37  is a partial sectional view of a phacoemulsification needle having an angled aspiration passageway and an asymmetrical flared tip; 
         FIG. 38  is a partial sectional view of a flared asymmetrical phaco tip; 
         FIG. 39  is an end view of the tip of  FIG. 38 ; 
         FIG. 40  is a partial sectional view of another embodiment of an asymmetrical needle tip; 
         FIG. 41  is an end view of the needle of  FIG. 40 ; 
         FIG. 42  is a partial sectional view of another embodiment of an asymmetrical needle tip; 
         FIG. 43  is an end view of the tip of  FIG. 42 ; 
         FIG. 44  is a partial sectional view of yet another embodiment of an asymmetrical needle tip; 
         FIG. 45  is an end view of the tip of  FIG. 44 ; 
         FIG. 46  is a partial sectional view of another embodiment of an asymmetrical needle tip; 
         FIG. 47  is an end view of the tip of  FIG. 46 ; 
         FIG. 48  is a partial sectional view of yet another embodiment of an asymmetric needle tip; 
         FIG. 49  is an end view of the tip of  FIG. 48 ; 
         FIG. 50  is an end view f the tip of  FIG. 48  showing the tip in a second selected offset; 
         FIG. 51  is an end view of a rectangular tip showing a selected offset; 
         FIG. 52  is an end view of a square needle tip showing a selected offset; 
         FIG. 53  is a partial sectional view of yet another embodiment of an asymmetric needle tip; 
         FIG. 54  is an end view of the tip of  FIG. 53 ; 
         FIG. 55  is a partial lateral sectional view of a needle tip having a bump formed thereon; 
         FIG. 56  is an end view of the tip of  FIG. 55 ; 
         FIG. 57  is a partial sectional view or a bump formed on a non-flared needle tip; 
         FIG. 58  is a view along line  58 - 58  of  FIG. 57 ; 
         FIG. 59  is a partial lateral sectional view of a flared needle tip having a bump formed thereon; 
         FIG. 60  is a view along  60 - 60  of  FIG. 59 ; 
         FIG. 61  is a partial lateral sectional view of a needle tip having an indentation formed thereon; 
         FIG. 62  a view along  62 - 62  of  FIG. 61 ; 
         FIG. 63  is a partial elevational view of a composite unflared needle tip; 
         FIG. 64  is a partial elevational view a needle tip having a plug; 
         FIG. 65  is a partial elevational view of the needle of  FIG. 64 ; 
         FIG. 66  is a partial sectional view of the tip wall of  FIG. 65  showing the plug set therein; 
         FIG. 67  is a partial elevational view of a flared composite tip; 
         FIG. 68  is another partial elevational view of the tip of  FIG. 67 ; 
         FIG. 69  is a partial elevational view showing an insert port formed on a flared needle tip; 
         FIG. 70  is an enlarged portion of  FIG. 69 ; 
         FIG. 71  is a top plan view of a tip having multiple skewed ridges and bevels; 
         FIG. 72  is a view taken at a of  FIG. 71 ; 
         FIG. 73  is a view taken at b of  FIG. 71 ; 
         FIG. 74  is a view taken at e of  FIG. 71 ; 
         FIG. 75  is a view taken at d of  FIG. 71 ; 
         FIG. 76  is another embodiment of a tip having skewed and multiple bevels; 
         FIG. 77  is a view of a of  FIG. 76 ; 
         FIG. 78  is a view at b of  FIG. 76 ; 
         FIG. 79  is a view at c of  FIG. 76 ; 
         FIG. 80  is a view at d of  FIG. 76 ; 
         FIG. 81  is a lateral elevation of a phacoemulsification needle having an asymmetric needle body; 
         FIG. 82  is a sectional view of the needle of  FIG. 81 ; 
         FIG. 83  is a lateral elevation of a phacoemulsification needle having an enlarged distal needle body portion; 
         FIG. 84  is a sectional view of the needle of  FIG. 83 ; 
         FIG. 85  is a lateral elevation of a phacoemulsification needle having an asymmetrical weight affixed to the needle body portion; 
         FIG. 86  is a sectional view of the needle of  FIG. 85 ; 
         FIG. 87  is a lateral elevation of a phacoemulsification needle having a symmetrical weight affixed to the needle body portion; and 
         FIG. 88  is an enlarged partial sectional view of the needle of  FIG. 87 ; 
         FIG. 89  is a lateral view of portion of a phacoemulsification needle having a twisted tip; 
         FIG. 90  is a view along  90 - 90  of  FIG. 89 ; and 
         FIG. 91  is a view along  91 - 91  of  FIG. 89 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , the numeral  10  indicates generally a prior art phacoemulsification needle tip as shown in U.S. Pat. No. 6,007,555 (Devine), entitled “Ultrasonic Needle for Surgical Emulsification”, issued Dec. 28, 1999. Needle  10  is straight and terminates in an unflared mouth  12  defined by a lip  14  at the end of needle body  16 , with lip  14  and needle body  16  formed as having an oval cross-section configuration. 
     Referring to  FIG. 1 , the numeral  18  indicates generally a prior art straight, unflared phacoemulsification needle tip from U.S. Pat. No. 6,007,555, having a mouth  20  defined by a lip  22  at the end of needle  24 . The cross-sectional configuration of needle  18  and mouth  20  is a rectangle. 
     Referring now to  FIG. 2 , the numeral  26  identifies several prior art straight phacoemulsification needles as described in U.S. Pat. No. 5,725,495, with needle  28  having a circular cross-section as shown at  30 , needle  32  having a triangular cross-section as shown at  34  and needle  36  having an octagonal cross-section as shown at  38 . As seen at  30 ,  34  and  38  of  FIG. 2 , needles  28 ,  32  and  36  have exterior shapes or cross-sections identical to the shape and cross-section of the aspiration passageways formed therethrough. 
     Both tips  10  and  18  in  FIG. 1  exemplify one form of a “straight” needle tip, that is, a tip that is coaxial with or centered on the hollow aspiration passageway formed through the needle body and which have no flare or enlargement at the tip. Other straight tips are known which have needle tips that are flared, or larger in cross-sectional area than the needle&#39;s aspiration passageway yet which are centered on the passageway. 
     Phacoemulsification needles are sometimes referred to as “tips”. Our use of the term “tip” throughout refers to that end of the needle intended to be inserted into the eye. The remaining portion of the phacoemulsification needle will generally be referred to as the needle body. 
     Referring now to  FIG. 3 , the numeral  40  indicates generally a phacoemulsification needle having a flared needle tip  42  larger in cross-section than and formed integrally with a distal end of a hollow needle body  44 . At a proximal end thereof, needle body  44  has a needle end  46  which terminates in a mount  48  which allows needle  40  to be attached to a phacoemulsification handpiece. Commonly, mount  48  is threaded and screws onto a phacoemulsification handpiece. In the example shown, needle body  44  has a square cross-section with a longitudinally-extending central axis  50 . 
     Referring now to  FIG. 5 , needle  40  is shown in lateral cross-section, illustrating the communication of aspiration passageway  64  with tip  42 . 
     Referring now to  FIG. 4 , an enlarged detail of tip  42  is shown. As seen in both  FIGS. 5 and 6 , tip  42  has a mouth  52  defined by a lip  54  which, as shown in  FIG. 3 , is formed at an angle  146  to a plane that is normal to axis  50 . The angle shown is one of choice: lip  54  can also be formed on the plane that is perpendicular to axis  50  or formed in any number of other configurations corresponding generally to the configurations of known straight tips presently used with longitudinally-vibrating hand pieces. 
     As viewed in  FIG. 5 , tip  42  has a lead portion  56  and a trailing portion  58 , with lead portion  56  being that part of lip  54  that extends longitudinally forward past trailing portion  58 , while trailing portion  58  is that part of lip  54  that extends the least distance forward. In the example shown in  FIG. 5 , trailing portion  58  is substantially co-linear with the outer surface  60  of needle body  44 , while lead portion  56  is offset by a distance  62  from the outer surface  60  of needle body  44 . The effect of forming lip  54  at the angle shown place lead portion  56  at the farthest point body axis  50 . 
     Referring now to  FIGS. 5 and 6 , an aspiration passageway  64  of needle body  44  s shown centered on axis  50 . Tip mouth  52  is shown defined by lip  54  with lead point  56  and training point  58 . In the example shown, tip  42  has its own tip axis  66  extending therethrough. As seen in  FIGS. 4 and 5 , in this example, axes  50  and  66  do not coincide but are offset by a distance  68 . As also seen in  FIG. 6 , the cross-sectional area of tip  42  is larger than the cross-sectional area of needle body  44  when viewed in a plane perpendicular to axis  50 . 
     In a preferred example needle body  44  is 1.0 mm exterior diameter with a wall thickness of 0.10 mm, leaving an interior diameter of 0.80 mm. Tip  42  has an exterior diameter of 1.10 mm and a wall thickness of 0.10 mm. The lateral distance from the point at which tip  42  begins to enlarge outward from needle body  44  to lead point  56  is 1.80 mm, while offset distance  62  is 0.30 mm. 
     Referring now to  FIGS. 7 and 8 , a second example of a needle tip formed on needle  40  is shown. Needle tip  70  is square in cross-sectional shape and is formed integrally with a hollow needle body  72 . In this example shown, needle body  72  has a circular cross-section with a longitudinally-extending central axis  74 . 
     Referring to  FIG. 7 , an enlarged detail of tip  70  is shown. As seen in both  FIGS. 7 and 8 , tip  70  has a mouth defined by a lip  78  which, in the example shown in  FIG. 7 , is formed at an angle  148  to axis  74 . The angle shown is one of choice: lip  78  can also be formed perpendicular to axis  74  or any number of other configurations corresponding generally to the configurations of known straight tips presently used with longitudinally-vibrating hand pieces. 
     As viewed in  FIG. 7 , tip  70  has a lead lip portion  80  and a trailing lip portion  82 , with lead portion  80  being that part of lip  78  that extends longitudinally past trailing portion  82 , while trailing portion  82  is that part of lip  78  that extends the least distance longitudinally forward. In the example shown in  FIG. 7 , trailing lip portion  82  is substantially co-linear with the outer surface  84  of needle body  72 . The effect of forming lip  78  at angle  148  is to place lead lip portion  80  farthest from needle body axis  74 . 
     Referring now to  FIG. 8 , the interior of needle body  72  is shown. Needle body  72  has a central aspiration passageway  76  extending therethrough, centered on axis  74 . In the example shown, tip  70  has its own central axis  92 , which, as seen in  FIGS. 7 and 8  is offset from needle body axis  74  by a distance  94 . As also seen in  FIG. 8 , the cross-sectional area of tip  70  is greater than the cross-sectional area of needle body  72  when viewed in a plane perpendicular to axis  74 . 
     Referring now to  FIG. 9  the numeral  94  identifies a phacoemulsification needle constructed substantially as described with respect to  FIGS. 3, 4, 5, and 6 . Needle  94  has a tip  96  formed with a circular cross-section and integral with needle body  98 . Needle body  98  has a central axis  100 . 
     Tip  96  has a square mouth  102  which, in this example, is formed at an angle  104  to axis  100 . In this example, angle  104  is measured 30° in a direction opposite to that of angle  146  of mouth  52  as shown in  FIG. 3 . This angle is a matter of choice and other angles can be used as well. In this configuration, tip  96  has a lead point  106  and a trailing point  108 , corresponding in description to points  56 ,  58  described above. In this example, lead point  106  is collinear with outer surface  110  of needle body  98  while trailing point  108  is offset from outer surface  110  by a distance  112 . 
     Referring now to  FIG. 10  the numeral  114  identifies a phacoemulsification needle constructed substantially as described with respect to  FIGS. 7 and 8 . Needle  114  has a tip  116  formed with a circular cross-section and integral with needle body  118 . Needle body  118  has a central axis  120 . 
     Tip  116  has a circular mouth  122  which, in this example, is formed at an angle  124  to a plane normal to axis  120 . In this example, angle  124  is measured 30° in a direction opposite to that of angle  148  of mouth  74  as shown in  FIG. 6 . In this configuration, tip  116  has a lead lip portion  126  and a trailing lip portion  128 , corresponding in description to lip portions  80 ,  82  described above. In this example, lead lip portion  126  includes a portion of outer surface  130  of needle body  118  while trailing lip portion  128  is offset from outer surface  130  by a distance  132 . 
     Referring now to  FIG. 11 , a perspective view of needle  40  is shown with needle body  72  terminating at one end of tip  70  and at the other end at threaded mount  48 .  FIG. 12  is an enlarged perspective view of tip  70  showing the square configuration of, leading and trailing portions  78 ,  80 .  FIG. 13  is a bottom view of tip  70 . 
     The efficacy of having the tip axes in each of the foregoing examples be non-coincident with, or offset from, the needle body axes is demonstrated in  FIGS. 14 and 15 . Using a circular tip as an example, the numeral  134  in  FIG. 14  identifies a prior art straight phacoemulsification tip having a circular cross-section defined by mouth  136  integral with and extending from needle body  138 . Hollow needle body  138  has a central, longitudinally-extending axis  140 . The geometry of tip  134  is such that axis  140  is also a central, longitudinally-extending axis for tip  134 . When needle body  138  with tip  134  is attached to a phacoemulsification handpiece that produces torsional motion about axis  140  the pattern of vibration is generally as shown in  FIG. 14 , with tip  134  exhibiting little side-to-side or eccentric motion. In other words, lip  36  tends to move in a generally uniform motion about axis  140 . 
     Referring now to  FIG. 15 , tip  42  of  FIG. 4  is shown, with circular lip  54  and a needle body axis  50  and tip axis  66 . When tip  42  is subjected to torsional or longitudinal motion, lip  54  moves eccentrically, or “wobbles”, in part because tip  42  has a rotation that is not centered on tip axis  66 . This produces movement of lip  54  shown by paths  142  and  144 , creating an enhanced cutting or emulsifying effect on the tissue contacted by tip  42 . Thus, a straight phacoemulsification needle with a flared tip can be used with torsional or longitudinal motion. 
     The “wobble” effect can be altered by changing the offset distance between the tip axis and the needle body axis, and by changing the geometry of the tip, by using different cross-sectional shapes such as triangular or polygonal. 
     Referring now to  FIG. 16 , the numeral  150  identifies a phacoemulsification tip having a triangular cross-sectional configuration terminating at a lip  152  and communicating with a needle aspiration passageway  154  having an axis  156 . Tip  150  has a central tip axis  158  offset from axis  156  by an offset distance  160 . 
     Referring now to  FIG. 17 , the numeral  162  identifies a phacoemulsification tip having a pentagonal cross-section terminating at a lip  164 . Tip  162  communicates with a needle aspiration passageway  166  proximate apex  168 . Passageway  166  has a central axis  170  and a tip  162  has a central axis  172  offset from axis  170  by an offset distance  174 . 
     Referring now to  FIG. 18 , the numeral  176  identifies a phacoemulsification tip having a pentagonal cross-sectional shape terminating in a lip  178 . A needle aspiration passageway  180  extends to tip  176  proximate tip wall  182 . Passageway  180  has a central axis  184  while tip  176  has a central axis  186  offset form axis  184  by offset distance  188 . 
     Referring now to  FIG. 19 , the numeral  190  identifies a phacoemulsification tip having a square cross-sectional shape terminating in a lip  192 . A needle aspiration passageway  194  is formed proximate apex  198  of tip  192 . Passageway  194  has a central axis  198  while tip  190  has a central axis  200  offset form axis  198  by an offset distance  202 . 
     Phacoemulsification tips may also be formed on needle bodies that are non-circular in cross-section. 
     Referring now to  FIG. 20 , the numeral  204  identifies a phacoemulsification tip having a square cross-sectional shape terminating in a lip  206 . Tip  204  extends from a needle body  208  having a circular cross-sectional shape. Needle body  208  has an oval-shaped needle aspiration passage  210  having a central axis  212  while tip  204  has a central axis  214  offset from axis  212  by an offset distance  216 . 
     The forgoing examples have shown tips with flared shapes, that is, tips with cross-sectional shapes that are larger in size than the cross sectional shape of the needle body. Similar results are predicted for certain phacoemulsification needles with no flared tip that is the terminus of the needle is the same cross-sectional shape as the needle body. 
     Referring now to  FIG. 21 , the numeral  224  identifies a straight phacoemulsification needle having a needle body  226  through which an aspiration passageway  228  is formed. As shown in  FIG. 22 , passageway  228  has an oval cross-sectional shape and has a central axis  230 . Needle body  226  has a central axis  232  offset from passageway axis  230  by an offset distance  234 . 
     Referring now to  FIG. 23 , a straight phacoemulsification needle  238  has a needle body  240  formed with an oval cross-section. Passageway  242  has a central axis  244  and needle body  240  has a central axis  246  offset from axis  244  by an onset distance  248 . 
     While the needle bodies referred to in the foregoing examples have been referred to as circular in cross-section it should be understood that different cross-sectional shapes can also be used. 
     The foregoing examples have demonstrated round and square eccentric tips. Other tip cross-sectional shapes can also be used and the tips can be made with various orientations. For example, tip  70  can be rotated around tip axis  92  to create a different orientation. It is expected that the wobble effect will be manifested when the axis of the tip is offset from the axis of the needle body no matter what configuration is used. 
     Lips such as those shown at  50  and at  78  may also be polished to a smooth finish to add a protective feature. Phacoemulsification efficacy may also be enhanced by roughening a portion of the outer surface of the tips herein detailed. 
     Offsetting the tip of an angled phacoemulsification needle tip increases efficiency as compared to a symmetrically fashioned tip. Phacoemulsification needles having flared tips that are angled with respect to the needle body are known in the art. Heretofore, such tips have been formed such that the bent portion of the needle body met the flared tip such that the tip was symmetrical about the needle body. 
     Referring now to  FIG. 25  the numeral  252  identifies a portion of a phacoemulsification needle which includes a tip  254  and a needle body  256 . Needle body  256  has a longitudinal axis  258  and an aspiration passageway  260  extending along its length. Tip  254  has an axis  262  that is centered on the tip opening  264 . In this example, the tip has a square cross-section. 
     A bend  266  is formed on needle body  256  and, as shown in  FIG. 25 , tip  254  is formed with a first wall portion  268  that is coextensive with bend  266  and first needle body portion  270 . Tip  254  has a second wall portion  272  that is offset from bend  266  and needle bodyportion  274 . Secondary needle body axis  276  is shown as positioned the same distance  278  from first wall portion  268  as the distance  280  that axis  258  is positioned from first needle body portion  270 . 
     Referring now to  FIG. 26 , an end view of tip  254  is shown takes as a view perpendicular to line  26 - 26  of  FIG. 25 . Axes  276  and  262  are shown to offset one from the other by a distance  282 . This offset increases the eccentric motion exhibited by tip  254  and makes phacoemulsification more efficient. 
     The safety and efficiency of phacoemulsification tips embodying the foregoing aspects of the present invention are enhanced when the inner and outer surfaces of the phacoemulsification tip is roughened, as by sandblasting, and where the lip of the tip mouth is polished to round the lip and remove burrs which can damage delicate tissue in the eye, such as the posterior capsule, which may be contacted by the needle tip during phaco. 
     The square tip  70  shown in  FIGS. 11, 12, and 13  is exemplary of the type of surfaces to which the roughening process is applied. 
     As seen in  FIG. 12 , tip  70  has an upper face  284 , a left lateral face  286 , a lower face  288  and a right lateral face  290 . The identifiers “left” and “right” are used here to designate those faces as seen by one viewing  FIG. 12 . As can be appreciated, tip  70  has four external faces, all of which are roughened, beginning at and extending away from lip  78 . 
     As further seen in  FIG. 12 , tip  70  has an inner tip surface  292  extending rearward toward needle body  72  and aspiration passageway  64 . It is a feature of the present invention that the inner tip surface  292  is also roughened, as by sandblasting. The inner and outer surfaces of tip  70  are modified by roughening to create an uneven geometry providing numerous projections which are engaged by the tissue being emulsified as tip  70  is driven in its eccentric, or “wobble” motion. 
     It is another feature of the present invention to enhance the safety of the tips described herein by highly polishing the lip of each. Referring to  FIG. 27  the numeral  294  identifies a phacoemulsification needle having a flared tip  296  terminating at a lip  298 . In the example shown, tip  296  has a circular cross-section but the following description applies to the various tips of varying geometry described herein. Tip  296  is intended to be representative of phacoemulsification tips as customarily manufactured. Tip  296  is shown in a magnified view. 
     A portion of lip  298  is seen in  FIG. 28  in a more highly magnified view. The surface  300  of lip  298  is seen to meet tip  296  at substantially a right angle, forming a roughened edge  302 . The same configuration creates a roughened edge  304 , formed where lip surface  300  and tip inner surface  306  meet. Tip surface  300  is also characterized by upstanding ridges such as those identified by the numeral  308 . 
     Edges  302  and  304 , and ridges  308  are somewhat analogous to the “flashing” or “burrs” created when metallic workpieces are cut or severed. Because of the relatively thin metallic material from which phacoemulsification needles are formed, such edges and ridges are themselves thin and sharp, certainly sharp enough to snag corneal tissue when a phacoemulsification needle is inserted through a corneal incision. They are also sharp enough to damage delicate eye tissue, such as the posterior capsule, if the needle tip is brought into contact with the capsule during surgery. 
     I have determined that a process of rounding and highly polishing and smoothing the lips of phacoemulsification needle tips of the type described herein reduces the likelihood that delicate eye tissue will be damaged during phaco, particularly if the needle is being sued with a handpiece that produces torsional or elliptical motion. 
     Referring now to  FIG. 29  the numeral  310  identifies the outer surface of tip  296  after a roughening procedure has been performed. As can be seen, surface  310  is “pitted” to create a much larger surface area for contact with tissue to be phacoemulsified. 
       FIG. 29  also shows a portion  312  of lip  298  after polishing. Lip surface  314  now meets outer surface  310  at a rounded edge  316 , much smoother and snag-free than the roughened edge  302  shown in  FIG. 28 . 
     In like fashion, a portion of inner surface  318  of tip  296  is shown after a roughening procedure has been performed.  FIG. 30  also shows a portion  320  of lip  298  after polishing. Lip surface  322  now meets inner surface  318  at a rounded edge  324 , such smoother and snag free than the roughened edge  304  shown in  FIG. 28 . 
     The elements of surface finish are described by Quality Magazine as form, waviness and roughness. These elements, as they are present in the surface finish on the lips of the needles described herein, are rounded and smoothed to a degree sufficient to avoid the snagging of the tip on tissue in the eye, particularly the tissue through which the corneal incision is made and the tissue forming the capsular bag. 
     While the roughening procedure has been preferably described as sandblasting, other types of operations to create a controlledly roughened surface may also be used. In like fashion, other forms of polishing or smoothing devices and procedures can also be used to satisfactorily prepare the lip of each such phacoemulsification needle tip. 
     Referring now to  FIGS. 31 and 32 , the numeral  1270  identifies generally a lens nucleus undergoing phacoemulsification using a conventional phacoemulsification handpiece imparting only longitudinal motion to straight phacoemulsification needle  1272 . As described previously, in longitudinal phacoemulsification a needle  1272  is alternately moved in forward and reverse directions at high speed. Phacoemulsification is more efficient when needle  1272  is in contact with nucleus  1270 , particularly with traditional longitudinal phaco, because, as seen in  FIG. 31 , the cutting of nucleus  1270  occurs when needle  1272  moves forward to contact nucleus  1270 . When the needle is drawn in the reverse direction it tends to lose contact with nucleus  1270 , creating a gap  1274 . 
     The procedure has several readily noticeable consequences. The forward motion and subsequent contact of needle  1272  with nucleus  1270  can repulse nucleus  1270  and also the fragments into which nucleus  1270  is cut, making more difficult and time-consuming the collection of the fragments through aspiration passageway  1276 . 
     During phaco, viscoelastic support gel is injected into the lens capsule and the anterior and posterior chambers of the eye. One example of such a gel is Staarvisc© II, manufactured by Staar Surgical Company of Monrovia, Calif. Presence of a gel in the lens capsule helps support and protect the thin walls of the capsule. Using gel, in the posterior chamber helps protect the delicate endothelial cells which, if damaged, do not regenerate. During surgery, movement of the gel is readily noticeable when needles such as needle  1272  are vibrating. In particular, it can be seen that the gel present in the posterior chamber of the eye is moved or agitated even though needle  1272  is within the lens capsule. 
     As a general rule, the longer a phacoemulsification procedure lasts the more energy is expended and the more heat is produced by the ultrasound energy imparted to the needle. More efficient phacoemulsification is accomplished when the lens is fragmented more quickly, the fragmented lens particles are aspirated more quickly and cleanly and less heat is produced. As previously described, one measure of efficiency is the total dissipated energy: less energy is used if the procedure is shorter and one of the ways the procedure can be shortened is to make aspiration more effective. Another measure of efficiency is to observe such occurrences as the uninterrupted aspiration of particles and the “quietness” of the operating environment, meaning the relative lack of turbulence observed in the supporting gel, both in the lens capsule and the posterior chamber. This lack of turbulence can be quite important when, for example, a surgeon is required to use a less than optimal support material, one that may be more susceptible to breakdown during high speed vibration. One such substance is methyl cellulose which is not as viscous or cohesive as a gel such as Staarvisc© II. 
     Preliminary clinical observations have confirmed that the use of an off-axis phacoemulsification needle with a handpiece producing longitudinal motion results in significantly more efficient phaco. Operation times have been shorter, dissipated energy levels have been lower and the operating environment has been observed to be quieter, with much less agitation of the supporting gel and much less repulsion of the fragmented lens particles. This has resulted in markedly “clear” phacoemulsification results, meaning that the capsule is clearer of unaspirated particles and the supporting gel has provided better protection to the capsule and the endothelial cells. 
     An ultrasonic handpiece providing longitudinal and torsional motion to a phacoemulsification needle is described in United States Patent Publication 2006/0036180 (Boukhny, et al.), entitled “Ultrasonic Handpiece”. As the application states, the two modes cannot be activated simultaneously: the handpiece is switchable between the torsional and longitudinal modes. A computer-controlled console allows the surgeon to select alternating time periods for torsional and longitudinal motion, resulting in an effective “blended” motion. The characteristic of such a blended motion are altered when the time periods are altered. For example, a different cutting action and cutting characteristics will result when torsional motion comprises 50 per cent of the operating time than when it comprises 75 per cent. 
     A phacoemulsification control system described in United States Patent Publication 2008/0294087 (Steen, et al.), assigned to Advanced Medical Optics, Inc. of Santa Ana, Calif. describes a system that imparts a longitudinal motion and lateral motion to the needle by forming the needle with an asymmetric needle mount. Such an arrangement is believed to exhibit certain characteristics of traditional longitudinal phaco, such as the tendency for the needle to lose frontal contact with the nucleus when the needle is moved away from the nucleus, the repulsion of nuclear particles and the tendency to transmit energy to agitate the viscoelastic gel inserted into the eye. 
     Combining an off-axis tip with a handpiece utilizing longitudinal motion appears to create a hybrid type of tip activity that exhibits some of the characteristics of this blended motion yet exhibits marked improvements in efficiency over systems which utilize modifications to longitudinal handpieces to achieve blended motion. 
     A phacoemulsification needle having an off-axis construction is mounted to a phacoemulsification handpiece capable of producing longitudinal motion. The geometry of the needle can include needle bodies with centered or off-axis aspiration passageways, needle bodies with centered or off-axis aspiration passageways having different cross-sectional shapes than the needle bodies, with such needles having straight or angled needle tips formed off-axis to the needle body aspiration passageway, with such tips being flared or unflared. 
     Referring now to  FIGS. 33 and 34  the numeral  1278  identifies a phacoemulsification needle constructed and moved in accordance with the invention described above.  FIG. 33  illustrates a straight, unflared needle  1278  as it is being moved in the forward direction during longitudinal motion, showing the tip embedded in nucleus  1280  with the tip mouth  1282  in contact with nucleus  1280 .  FIG. 34  illustrates needle  1278  in a rearward direction during longitudinal phaco. As seen herein, tip mouth  1282  remains in contact with nucleus  1280 . It is believed that the hybrid motion created by combining longitudinal motion of the needle with an off-axis needle or tip allow the aspiration suction to keep tip mouth  1282  in contact with nucleus  1280 , greatly reducing repulsion, of the nucleus and making aspiration more efficient. 
     With repulsion reduced the surgeon spends less time “chasing” emulsified lens particles with the tip mouth in order to ultimately aspirate them. Reduced agitation of the gel helps to protect the eye and preserve the field of vision. Phacoemulsification is thus quieter, more efficient and less expensive for the surgeon. 
     Referring now to  FIG. 35 , the numeral  1284  identifies a phacoemulsification needle having a needle body  1286  and a flared tip  1288 . Needle body  1286  has a central axis  1290  extending therethrough. When the term “central axis” is used, it refers to an axis that is a locus of points about which the outer dimensions of the needle body are symmetrical. An aspiration passageway  1292  is formed through needle body  1286  and communicates with tip  1288 . Aspiration passageway  1292  has a central axis  1294  extending therethrough, and as seen in  FIG. 35 , axes  1290  and  1294  meet at an angle and are not coincident, meaning that aspiration passageway  1292  is said to be angled with respect to needle body  1286 . 
     Referring to  FIG. 36 , the numeral  1296  identifies phacoemulsification needle having a needle body  1298  which terminates at an unflared tip  1300 . Needle body  1298  has a needle body axis  1302  extending centrally therethrough. An aspiration passageway  1304  is formed at an angle within needle body  1298  and extending through tip  1300  with aspiration passageway axis  1306  meeting axis  1302  at an angle. 
     Referring now to  FIG. 37 , the numeral  1308  identifies a phacoemulsification needle having a needle body  1310  terminating at a flared, offset tip  1312 . Needle body  1310  has a central axis  1314 . An angled aspiration passageway  1316  is formed through needle body  1310  and terminates at tip  1312 . Aspiration passageway  1316  has a central axis  1318  of which meets axis  1314  at an angle. 
     In this embodiment, the “wobble” effect is produced by both the angled aspiration passageway  1316  and the offset tip  1312 . 
     Referring now to  FIG. 38 , the numeral  1320  identifies a phacoemulsification needle having a needle body  1322  and a flared asymmetrical tip  1324 . Tip  1324  has an outer wall  1326  and an inner wall  1328  as seen in  FIG. 39 , the distance between outer wall  1326  and inner wall  1328  varies about the inner circumference of tip  1324 . In this embodiment, lower wall portion  1330  is at a maximum thickness and tapers upwardly so that wall portion  1332  positioned 180 degrees from lower wall portion  1330  is at a minimum thickness. 
     As further seen in  FIG. 38 , a land or offset  1334  is also formed with a tip  1320  creating another area of non-uniform distribution of tip mass. 
     Referring now to  FIG. 40 , the numeral  1336  having a needle body  1338  and a flared asymmetric tip  1340 . As described in connection with 
       FIG. 38 , tip  1340  has an outer wall  1342  and an inner wall  1344 , and the distance between inner and outer wall  1342  and  1344  varies around the circumference of tip  1340 . As seen in  FIG. 40 , the lowermost wall portion  1346  is greater in dimension than upper wall portion  1348 . 
     A lip cutout  1350  is formed in lower wall portion  1346  which, as seen in  FIGS. 40 and 41  increases the non-uniform distribution of tip mass. 
     Referring to  FIG. 42 , the numeral  1352  identifies a phacoemulsification needle having a needle body  1354  and a flared asymmetrical tip  1356 . As seen in  FIG. 43 , tip  1356  has a square cross sectional shape. Tip  1356  has an outer wall  1358  and an inner wall  1360  configured as described above in connection with  FIGS. 38 and 40  to create a lower wall section  1362  of significantly greater thickness than upper wall portion  1364 . A land or offset  1365  is formed in lower wall section  1362  which adds to the non-uniformity of the tip mass distribution. In this embodiment of the needle  152 , there is an aspiration passage central axis  1366  that is offset from central tip axis  1368  by an offset distance  1370 . 
     Referring now to  FIG. 44 , the numeral  1372  identifies a phacoemulsification needle having a body  1374  and a flared asymmetrical tip  1376 . As described above, tip  1376  is formed with an outer wall  1378  and an inner wall  1380  to form a lower wall portion  1382  of significantly greater thickness than upper wall  1384 . A land or offset  1386  is formed in lower wall portion  1382 . As seen in  FIG. 45 , tip  1376  is rectangular in cross-sectional shape and in this embodiment, aspiration passageway  1388  has a central axis  1390  which is offset from central tip axis  1392  by an offset  1394 . Referring now to  FIG. 46 , the numeral  1396  identifies a phacoemulsification needle having a needle body  1398  and a flared symmetrical tip  1400  formed with a front bevel  1402 . As seen in  FIG. 47 , tip  1400  has a round cross-sectional shape. 
     As previously discussed, tip  1400  has a lower wall portion  1404  of significantly greater thickness than upper wall portion  1406  and a land or offset  1408  formed in lower wall portion  1404 . As seen in  FIG. 47 , although tip  1400  is symmetrically shaped and centered on aspiration passageway  1410 , it is still constructed with a non-uniform distribution of tip mass that provides the desired wobble effect. 
     Referring now to  FIG. 48 , the numeral  1412  identifies a phacoemulsification needle having a needle body  1414  and a flared tip  1416 . As seen in  FIG. 49 , tip  1416  has a trapezoidal cross-sectional shape. As seen in  FIG. 48 , tip  1416  is formed with a lower wall portion  1418  that is substantially thicker than upper wall portion  1420 . In the embodiment shown, as shown in  FIG. 49 , lower wall portion  1418  is of a substantially thicker construction while sidewall portions  1422 ,  1424  are substantially identical in thickness to upper wall portion  1420 . In this embodiment, aspiration passageway  1426  has a central axis  1428  which is offset from central axis  1430  of tip  1416  by an offset distance  1432 . An offset  1434  is formed in lower wall portion  1418  to create a more pronounced non-uniformity of tip mass distribution. 
     Referring now to  FIG. 50  the numeral  1436  identifies a phacoemulsification needle constructed in accordance with the above description for  FIGS. 48 and 49 . In this embodiment, tip  1438  is offset to place aspiration passage  1426  closer to lower wall portion  1418 , creating an offset  1440 . 
     Referring now to  FIG. 51 , the numeral  1442  identifies a phacoemulsification needle having a rectangular tip constructed in accordance with the descriptions accompanying  FIG. 45 . In this embodiment, aspiration passageway  1446  is positioned closer to lower wall portion  1448  to produce an alternate offset to that shown in  FIG. 45 . 
     Referring are now to  FIG. 52 , the numeral identifies a phacoemulsification needle having a tip  1452  with a square cross-section constructed in accordance with the descriptions accompanying  FIG. 43 . In this embodiment aspiration passageway  1454  is shown in an alternate position closer to lower wall portion  1456 . 
     Referring now to  FIG. 53 , the numeral  1458  identifies a phacoemulsification needle having a needle body  1460  and a flared tip  1462 . As seen in  FIGS. 53 and 54 , inner wall  1464  of tip  1462  is formed in a “scalloped” shape with a “peak”  1466  creating a somewhat upside-down apple-shaped cross-sectional shape, thus enhancing the non-uniform distribution of tip mass. 
     Referring now to  FIG. 55 , the numeral  1468  identifies a phacoemulsification needle having a needle body  1470  and a tip  1472 , with an outer wall  1474 . In this embodiment, non-uniform tip mass distribution is created by the formation of one or more protuberances, or “bumps”  1476  on outer wall  1474 .  FIG. 56  shows the positioning of a single bump  1476 . If more than a single bump is formed, it is preferable that the pattern of bumps be on-symmetrical to maximize the wobble effect. 
     It should be understood that although the embodiments shown depict specific wall configurations the invention should not be so limited. Selected walls or wall portions of the phacoemulsification needle can be manufactured to various thicknesses to produce the non-uniform distribution of needle mass described herein. 
     Referring now to  FIG. 57 , the numeral  1478  identifies a phacoemulsification needle having a needle body  1480  terminating in a non-flared tip  1482 . In this embodiment, tip  1482  has a beveled lip  1484 . As seen in  FIG. 57 , a bump  1486  is formed on tip  1482  on that portion of tip wall  1488  coextensive with the leading edge  1490  of beveled lip  1484 . This same embodiment is shown in  FIG. 58 , although it should be understood that the placement of bump  1486  or others like it can be made in a number of different locations and configurations. 
     Referring now to  FIG. 59 , the numeral  1492  identifies a phacoemulsification needle having a needle body  1494  and a flared, symmetrical needle tip  1496  having a beveled lip  1498 . A bump  1500  is formed on outer tip wall  1502  as described above. Bump  1500  is also seen in  FIG. 60 . 
     Creating tip mass non-uniformity can also be accomplished by forming inwardly-extending projections as well. Referring now to  FIG. 61 , the numeral  1504  identifies a phacoemulsification needle having a needle body  1506  and a flared tip  1508 . Wall  1510  of tip  1508  has formed therein an inwardly-extending ridge portion  1512  proximate beveled lip  1514 . As seen in  FIGS. 61 and 62 , ridge portion  1512  has an inwardly extending portion  1516 , a depending portion  1518 , and a pair of opposed side portions  1520  and  1522 . 
     Non-uniform distribution of mass in a phaco tip can also be achieved while keeping a typical tip construction. Referring now to  FIG. 63 , the numeral  1526  identifies a phacoemulsification needle having tip wall segments  1528  and  1530 , joined together at longitudinally-extending seams  1532  and  1534 . In the embodiment shown, wall segment  1528  is formed from a material having a density differing from that of wall segment  1530 . For example, well segment  1528  can be formed from gold, while segment  1530  can be formed from titanium. Even though a symmetrical needle design has been selected, the weights of segments  1528  and  1530  differ sufficiently to produce a wobble effect when needle  1526  is vibrated. 
     Referring now to  FIGS. 64 and 65 , then numeral  1536  identifies a phacoemulsification needle having an outer wall  1538  formed from a first selected material. A plug  1540 , formed from is second material, is fit into a previously-formed aperture in wall  1538 . The densities of said first and second materials differ sufficiently to produce a non-uniform material distribution of mass sufficient to produce a wobble effect when needle  1536  is vibrated. 
       FIG. 66  is a partial side sectional view showing the insertion of plug  1540  through wall  1538 . 
     Referring now to  FIGS. 67 and 68 , the numeral  1542  identifies a phacoemulsification needle having a needle body  1544  and a flared tip  1546  formed from a first material. An insert strip  1548  formed from a second material is secured within a previously-formed slot in sidewall  1550  of tip  1546 . Needle body  1544  and insert strip  1548  are of sufficiently different densities to produce a non-uniform material distribution of mass sufficient to produce a wobble effect when needle  1546  is vibrated. 
     Referring now to  FIG. 69  the numeral  1552  identifies a phacoemulsification needle having a needle body  1554  and a needle tip  1556 . An aperture  1558  is shown having been formed in sidewall  1560 . 
     Referring now to  FIG. 70  the numeral  1562  identifies a block of material with a different density than that of the material forming tip  1556 . A plug  1564  is shown being punched out from block  1562 , sized and shaped to be press-fit into aperture  1558  to form the tip described above with respect to  FIGS. 64 and 65 . 
     Although the plugs and strips described above have been shown to have specific shapes these shapes are exemplary only. Other shapes can be selected depending upon the desired geometry and operating characteristics of the needle being designed. Combinations of more than two desired materials can also be used. 
     Referring now to  FIGS. 71 through 80 , variations of phacoemulsification needles and tips are shown embodying the principles of the present invention by forming thereon non-uniform or skewed bevels and ridges to produce a desired wobble motion. 
     Referring now to  FIG. 71 , the numeral  1566  identifies a phacoemulsification needle tip having a square cross-sectional shape with a lip  1568  defining a tip mouth  1570 . Tip  1566  has a first side  1572 , a second side  1574 , a third side  1576 , and a fourth side  1578 . 
     In  FIG. 72 , side  1572  is shown. As seen in  FIG. 72 , lip  1568  is beveled so that viewed from direction a it appears to be slanted. A skewed ridge  1580  is formed on side  1572  and can be formed either on interior surface  1582  or outer surface  1584  of tip  1566 . 
     Referring now to  FIG. 73 , side  1574  is shown, with lip  1568  seen as extending straight across. Ridge  1586  extends across either interior surface  582  or outer surface  1584 . 
     Referring now to  FIG. 74 , side  1576  is shown, with lip  1568  seen as sloping downward from left to right. Ridge  1588  extends across either interior surface  1582  or outer surface  1584 . 
     Referring now to  FIG. 75 , is shown, with lip  1568  seen as extending straight across. Ridge  1590  extends across either interior surface  1582  or outer surface  1584 . 
     Referring now to  FIG. 76 , the numeral  1592  identifies a phacoemulsification needle having a round cross-sectional shape having exterior wall segments  1594 ,  1596 ,  1598 , and  1600 . For purposes of this description we shall assume that each wall segment is one-fourth of the total circumference of needle  1592 . 
     Outer and inner sidewalls  1602  and  1604 , define a lip  1606  which, in turn, defines a tip mouth  1608 . 
     In  FIG. 77 , side portion  1594  is shown. As seen in  FIG. 77 , lip  1606  is beveled so that viewed from direction a it appears to be slanted. A skewed ridge  1610  is formed on side portion and can be formed either on interior wall  1602  or exterior wall  1604  of needle  1592 . 
     Referring now to  FIG. 78 , side portion  1596  is shown, with lip  1606  seen as curving straight across. Skewed ridge  1612  can be formed either on interior wall  1602  or exterior well  1604  of needle  1592 . 
     Referring now to  FIG. 79 , side portion  1598  is shown, with lip  1606  shown as sloping downward from left to right. Skewed ridge  1614  can be formed either on interior wall  1602  or exterior wall  1604  of needle  1592 . 
     Referring now to  FIG. 80 , side portion  1600  is shown, with lip  1606  seen as curving from left to right. Skewed ridge  1616  can be formed either on interior well  1602  or exterior wall  1604  of needle  1592 . 
     Referring now to  FIG. 81  the numeral  1616  identifies a phacoemulsification needle having a needle body  1618  and an extended asymmetric tip  1620 . Lengthening tip  1620  created a longitudinal non-uniformity of needle mass as well as the non-uniformity inherent in the asymmetric configuration of tip  1620 . As seen in  FIG. 82 , it is the ratio of distance “a” (the effective length of tip  1620 ) to the distance “b” (the effective length of needle body  1618 ) that will determine the extent of the wobble motion imparted to needle  1616 . 
     Referring now to  FIG. 83  the numeral  1622  identifies a phacoemulsification needle having a needle body  1624  and an extended needle tip  1626 . In the embodiment shown needle tip  1626  is symmetrical, yet it is expected that the extended length of tip  1626  will produce a wobble motion when needle  1622  is vibrated. Referring now to  FIG. 84  it is the ratio of distance “a” the effective length of tip  1626 ) to the distance “b” (the effective length of needle body  1624 ) that will determine the extent of the wobble motion imparted to needle  1622 . 
     Referring now to  FIG. 85  and  FIG. 86 , the numeral  1628  identifies a phacoemulsification needle having a needle body  1630  with a needle mount  1632  at its proximal end and a needle tip  1634  at its distal end. A wobble motion is imparted by the attachment of an asymmetrical weight  1636  on needle body  1630  intermediate mount  1632  and tip  1634  and the vibration of needle  1628  by a selected handpiece. In the embodiment shown, weight  1636  is asymmetrical relative to needle body  1630 , meaning that the distribution of the mass of weight  1636  is non-uniform about the needle body axis  1638 . 
     As seen in both  FIGS. 85 and 86 , at least a portion of weight  1636  extends outward from the outer surface  1640  of needle body  1630 . One or more grooves  1642  may be formed in weight  1636  to act as channels for the flow of irrigating liquid through an irrigation sleeve (not shown) mounted to needle  1628 . 
     Weight  1636  may be integrally formed with needle body  1630  or may be attached thereto. If attached, weight  1636  may be formed from material having a different density than that used to form needle  1628 , adding to the wobble effect. 
     As seen in  FIG. 86 , the placement of weight  1636  along needle body  1630  may be varied, with the distances “a” and “b” selected to create a desired amount and character of wobble. 
     Referring now to  FIG. 87 , the numeral  1644  identifies a phacoemulsification needle having a needle body  1646  with a needle mount  1648  at its proximal end and a needle tip  1650  at its distal end. A wobble motion is imparted by the attachment of a symmetrical weight  1652  on needle body  1646  intermediate mount  1648  and tip  1650  and the vibration of needle  1644  by a selected handpiece. In the embodiment shown, weight  1652  is symmetrical relative to needle body  1646 , meaning that the distribution of the mass of weight  1652  is uniform about the needle body axis  1654 . In this embodiment it is the non-uniformity of mass along axis  1654  that creates the wobble effect. 
     As seen in both  FIGS. 87 and 88 , at least a portion of weight  1652  extends outward from the outer surface  1656  of needle body  1646 . One or more grooves  1658  may be formed in weight  1652  to act as channels for the flow of irrigating liquid through an irrigation sleeve (not shown) mounted to needle  1644 . 
     Weight  1652  may be integrally formed with needle body  1646  or may be attached thereto. If attached, weight  1652  may be formed from material having a different density than that used to form a needle  1644 , adding to the wobble effect. 
     As seen in  FIG. 88 , the placement of weight  1652  along needle body  1646  may be varied, with the distances “a” and “b” selected to create a desired amount and character of wobble. 
     While weights  1636  and  1652  are shown in a selected position it is a feature of the present invention that such weights can be moved along the needle body to adjust the character of the wobble. For example, as seen in  FIGS. 87 and 88 , a series of grooves or detents can be formed along needle body  1646 . As seen in  FIG. 88 , a corresponding ring or peg  1662  can be formed on weight  1652  positioned and sized to register with selected of said detents, such as detent  1664 . Other methods of positioning and securing weight  1652  along needle body  1646  can also be used. Weight  1652  can then be positioned as desired along needle body  1646  to adjust the vibrational characteristics of the needle. 
     While the embodiments illustrate weights  1636  and  1652  in a selected shape, it should be understood that said weights can be formed in a variety of cross-sectional and longitudinal configurations, such as square, triangular, oval and irregular shapes as well. 
     It is also contemplated that the surfaces of weights  1636  and  1652  may be fluted to provide flow paths for the irrigating liquid. 
     Another embodiment of the present invention creates the wobble effect by putting one or more twists into the phacoemulsification needle tip creating a somewhat fluted configuration. 
     Referring now to  FIG. 89 , the numeral  1666  identifies a port of a phacoemulsification needle having a needle body  1668  and a flared needle tip  1670 . For the purposes of this description, tip  1670  is illustrated as having a square cross-section. During the manufacturing process, tip  1670  is twisted such that the section identified at  90 - 90  of  FIG. 89  is turned to a position approximately 90 degrees from that of the section identified by  91 - 91  of  FIG. 89 . 
     Referring to  FIG. 90 , tip  1670  is viewed from  90 - 90  of  FIG. 89  showing that the first section  1672  of tip  1666  is rotated approximately 90 degrees with reference to rearmost section  1674 . 
     Referring now to  FIG. 91 , the tip  1670  is viewed from  91 - 91  of  FIG. 89  showing that the remaining portion of tip  1670  is not twisted. 
     While the foregoing examples have used a flared tip with a square cross-section and a single twist, it contemplated that other cross-sectional shapes can be used as well and it is also contemplated that the number of twists can be varied, as can be the rotation or each twist. For example, in the example shown in  FIG. 89 , first section  1672  may have been twisted to an angle of 30 degrees with respect to rearmost section  1674 . The twisting of tip  1670  creates an additional irregularity in the shape of needle  1666  adding to the wobble effect. 
     The foregoing has described various embodiments of the present invention as they relate to non-uniform distribution of mass in constructing a phacoemulsification needle. It is expected that these embodiments can be combined to add efficacy to a needle design. For example, the skewed ridges of  FIGS. 71-80  can be added to the various tip designs described herein. Plugs of differing material can be added to the designs shown herein, as described in connection with  FIGS. 63-70 , as well as bumps as described in connection with  FIGS. 55-60 . Angled aspiration passageways such as described in connection with  FIGS. 35-37 . 
     The foregoing variations are expected to be effective with handpieces producing longitudinal, torsional, elliptical or other eccentric motions and are expected to demonstrate increased efficiency during the phacoemulsification process. 
     Thus, needles embodying the present invention create a hybrid motion in dependent of the type of handpiece and control console used. For those instruments designed to create a torsional vibratory motion, needles embodying the present invention create tip motion having a wider cutting range, covering more area. As observed, this hybrid motion appears to exhibit an energy focused more at the tip of the needle surface area, reducing wasted energy. The increase in efficiency exhibited by needles embodying the present invention has been demonstrated by comparing the cumulative dissipated energy levels for a handpiece using both the current and conventional needles to perform the same procedure. Use of the needles disclosed herein results in significantly reduced chatter, repulsion and thermal damage. 
     It is expected that the principles described herein can also be applied to other surgical instruments as well, such as those used for liposuction and coronary plaque removal. While the present invention has been described in the context of cataract removal, it should be understood that the principles of the present invention can be applied to the removal of different types of tissue as well such as tumors and the like. 
     The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.