Patent Publication Number: US-2023157873-A1

Title: Vitrectomy probe

Description:
DESCRIPTION OF THE RELATED ART 
     Microsurgical procedures frequently require precision cutting and/or removing of various body tissues. For example, certain ophthalmic surgical procedures may require cutting and removing portions of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibrils that are often attached to the retina. Therefore, cutting and removing the vitreous may need to be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself. In particular, delicate operations such as mobile tissue management (e.g. cutting and removal of vitreous near a detached portion of the retina or a retinal tear), vitreous base dissection, and cutting and removal of membranes may be particularly difficult. 
     Microsurgical cutting probes used in posterior segment ophthalmic surgery may include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, a port extending radially through the outer cutting member near the distal end of the outer cutting member, and a port extending radially through the inner cutting member near the distal end of the inner cutting member. Vitreous humor and/or membranes may be aspirated into the open port of the outer cutting member and the inner member may be actuated to distally extend the inner cutting member. As the inner cutting member extends distally, cutting surfaces on both the inner and outer cutting members may cooperate to cut the vitreous and/or membranes, and the cut tissue may then be aspirated away through the inner cutting member. Vitreous and/or membranes may then be aspirated into the open ports of both the outer and inner cutting members and the inner member may be actuated to proximally retract the inner cutting member. The inner and outer cutting members may cooperate to again cut vitreous and/or membranes and aspirate the cut tissue away. 
     A distance between the distal end of the outer cutting member to a nearest cutting edge of the outer port is referred to as the port to tip distance (PTTD). The PTTD may be a function of the over travel of the inner cutting member, the thickness of the outer cutting member cap (at the distal end of the outer cutting member) and the necessary clearance between the inner cutting member and the cap. Typical vitrectomy cutters have a PTTD in a range of 0.009 to 0.025 inches for flat ended vitrectomy probes. 
     SUMMARY 
     In various embodiments, a vitrectomy probe may include an outer cutting tube with an outer port side opening and an inner cutting tube positioned inside the outer cutting tube. The inner cutting tube may have an open distal end with a cutting edge. The vitrectomy probe may further include a diaphragm (located inside a drive chamber) coupled to the inner cutting tube. The diaphragm may move back and forth inside the drive chamber as air is alternately supplied (by a pneumatic drive line) and vented on either side of the diaphragm. Movement of the diaphragm may thus cause the inner cutting tube to oscillate inside the outer cutting tube such that the open distal end of the inner cutting tube moves back and forth across the outer port side opening to cut tissue entering the outer port side opening. The inner cutting tube may also have a flat upper edge, perpendicular (or, for example, approximately in a range of 70-110 degrees) to an inner tube longitudinal axis, on the portion of the inner cutting tube that cuts across the outer port side opening. The diaphragm may have an open-stroke side with a first contact surface that contacts an inner drive chamber wall when the inner cutting tube is in a retracted position and a closed-stroke side with a second contact surface that contacts an opposing inner drive chamber wall when the inner cutting tube is in an extended position. The first contact surface may have a material (e.g., silicone or a similar material) with a lower hardness than the second contact surface (which may include, for example, polycarbonate, polysulfone, or a similar material). 
     In some embodiments, the pneumatic drive line may couple the vitrectomy probe to a surgical console to deliver air to the probe drive chamber from the surgical console. In some embodiments, the pneumatic drive line may include an internal bore with a non-uniform cross-section along a length of the pneumatic drive line. The pneumatic drive line may have a first segment and a second segment (the first segment defining a first passageway having a first diameter and the second segment defining a second passageway having a second diameter). The first diameter may be different than the second diameter. 
     In some embodiments, the inner cutting tube may have a distal side port with a distal side port cutting edge. As the inner cutting tube retracts inside the outer cutting tube, tissue entering the outer port side opening may also enter the distal side port of the inner cutting tube to be cut by the distal side port cutting edge as the inner cutting tube is retracted in the outer cutting tube. 
     In some embodiments, an aspiration tubing may be coupled to the inner cutting tube to apply a vacuum to the inner cutting tube. The aspiration tubing may include a first aspiration tubing and a second aspiration tubing coupled to the first aspiration tubing. The second aspiration tubing may be coupled to the vitrectomy probe on a distal end and coupled to the first aspiration tubing on a proximal end. In some embodiments, the second aspiration tubing may have a lower hardness than the first aspiration tubing and may be shorter than the first aspiration tubing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate embodiments of the devices and methods disclosed herein and, together with the description, serve to explain the principles of the present disclosure. 
         FIG.  1    is an illustration of an exemplary surgical system according to one aspect of the present disclosure consistent with the principles and teachings described herein. 
         FIG.  2    is a box diagram of aspects of the exemplary surgical system of  FIG.  1   , according to an embodiment. 
         FIG.  3    is an illustration of an exemplary vitrectomy probe in cross-section operable in accordance with the principles and teachings described herein. 
         FIG.  4   a - b    illustrate various vitrectomy probe distal end configurations, according to various embodiments. 
         FIG.  5    illustrates a diaphragm and drive shaft, according to an embodiment. 
         FIGS.  6   a - b    illustrate opposing sides of a diaphragm, according to an embodiment. 
         FIG.  7    illustrates a cross section of the diaphragm chamber in a vitrectomy probe, according to an embodiment. 
         FIG.  8    illustrates an inner cutting tube bend, according to an embodiment. 
         FIG.  9    illustrates a stiffener on the outer cutting tube, according to an embodiment. 
         FIG.  10    illustrates tubing segments coupling the probe to a surgical console, according to an embodiment. 
         FIG.  11    illustrates a cross section of the pneumatic and aspiration tubing segments, according to an embodiment. 
         FIGS.  12   a - c    illustrate vitrectomy probe distal ends, according to various embodiments. 
         FIGS.  13   a - b    illustrate measurements for the outer cutting tube of the vitrectomy probe, according to various embodiments. 
         FIGS.  14   a - c    illustrate measurements for the outer cutting tube and inner cutting tube of the vitrectomy probe, according to an embodiment. 
         FIGS.  15   a - d    illustrate measurements for the outer cutting tube and inner cutting tube of the vitrectomy probe, according to an embodiment of the inner tube having a flattened edge feature. 
         FIGS.  16   a - d    illustrate configurations of the outer cutting tube and inner cutting tube of the vitrectomy probe, according to various embodiments. 
         FIG.  17    is an illustration of a partial cross-sectional view of stepped pneumatic drive lines usable with the surgical system shown in  FIG.  2   , according to an embodiment. 
         FIG.  18    is an illustration of a partial cross-sectional view of a sleeve coupling the stepped pneumatic drive line shown in  FIG.  17   , according to an embodiment. 
         FIG.  19    illustrates a flowchart of a method for operating a vitrectomy probe, according to an embodiment. 
     
    
    
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the principles of the present disclosure. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG.  1    illustrates a vitrectomy surgical system console, generally designated  100 , according to an exemplary embodiment. The surgical console  100  may include a base housing  102  and an associated display screen  104  showing data relating to system operation and performance during a vitrectomy surgical procedure. In an embodiment, the base housing  102  may be mobile, for example including wheels to facilitate movement as necessary. In an alternative embodiment, the base housing  102  may not include wheels. The surgical console  100  may include a vitrectomy probe system  110  that includes a vitrectomy probe  112 , as will be discussed in more detail below with respect to subsequent figures. 
       FIG.  2    is a schematic of exemplary components of the vitrectomy probe system  110 , according to an embodiment. The probe system  110  may include the vitrectomy probe  112 , a pneumatic pressure source  120 , a probe driver shown as an adjustable directional on-off pneumatic driver  122 , a muffler  124 , and a controller  126 . In an embodiment, the controller  126  may be a processor that includes one or more processing cores capable of performing parallel or sequential operations. Alternatively, the controller  126  may be a dedicated piece of hardware such as an application specific integrated circuit (ASIC), to name just a few examples. The source  120 , the driver  122 , the muffler  124 , and the probe  112  may be in fluid communication with each other along lines representing flow paths or flow lines. The controller  126  may be in electrical communication with the driver  122 . In an embodiment, the controller  126  may control operation of both the driver  122  and various aspects of the probe  112 , including the frequency of oscillation by way of the actuator as well as a flow rate of fluid to/from the surgical site. 
       FIG.  3    shows a partial cross-sectional illustration of an exemplary vitrectomy probe, for example the vitrectomy probe  112  introduced in  FIGS.  1  and  2   . In this example, the vitrectomy probe  112  may be a pneumatically driven probe that operates by receiving pneumatic pressure alternating through first and second ports  140  and  142 . The probe  112  may include as its basic components a cutter  150  has an outer cutting tube  152  (also known as a needle), an inner cutting tube  154  shown in a non-sectional side view, and a probe actuator or motor shown here as a reciprocating air driven diaphragm  156 , all at least partially encased by a housing  158  in an enclosed drive chamber  175 . The housing  158  may include an end piece  160  at the probe proximal end with the first and second air supply ports  140 ,  142  and one suction port  162  to provide aspiration of materials from the cutter  150 . 
     In an embodiment, the vitrectomy probe system&#39;s pneumatic driver  122  ( FIG.  2   ) may be a standard four-way on-off valve. The pneumatic driver  122  may have a solenoid that operates to move the driver to one of the two on-off positions depicted in the example of  FIG.  2   . Here, the pneumatic driver  122  may be in a position to provide pneumatic pressure to the first port  140  ( FIG.  3   ), and to vent pneumatic pressure from the second port  142  ( FIG.  3   ). In this position, pneumatic pressure may pass from the pressure source  120 , through the on-off pneumatic driver  122 , and to the first port  140  where the pneumatic pressure provides pneumatic power to the vitrectomy probe  112 . At the same time, pneumatic pressure at the second port  142  may pass through the on-off pneumatic driver  122  to the muffler  124  where it is exhausted, for example, to the atmosphere. In the other position, the on-off pneumatic driver  122  may allow pneumatic pressure to pass from the pressure source  120  to the second port  142 , where the pneumatic pressure provides pneumatic power to the vitrectomy probe  112 . At the same time, pneumatic pressure at the first port  140  may vent through the on-off pneumatic driver  122  to the muffler  124  where it is exhausted to the atmosphere. The on-off pneumatic driver may be configured to receive operating signals from the controller  126 . 
     In operation, pneumatic pressure may be directed alternately from the source  120  to the first and second ports  140 ,  142  to operate the vitrectomy probe  112 . The on-off pneumatic driver  122  may alternate between its two positions very rapidly to alternatingly provide pneumatic pressure to the first and second ports  140 ,  142 . Although shown with a single pneumatic driver  122 , other embodiments include two pneumatic drivers, one associated with each of the two ports  140 ,  142 . These embodiments may operate similar to the manner described, with the drivers being configured to independently receive operating signals from the controller  126  ( FIG.  2   ). Yet other arrangements are contemplated. 
     Returning to  FIG.  3   , the cutter  150  may extend from the housing  158  and may include a distal end  166 , shown in  FIG.  4   a    in greater detail below. The outer cutting tube  152  and the inner cutting tube  154  may both be cylindrical tubes with a hollow bore. As seen in  FIGS.  4   a - b   , the distal ends (needle caps  173 ) of the outer cutting tube  152  may include beveled (i.e., angled) ends. In some embodiments, the distal ends (needle caps  173 ) of the outer cutting tubes may be flat. The distal ends of the outer cutting tube  152  may be closed using, for example, spin closed machining, adhesive, welding (e.g., laser welding), etc. For example, the beveled end may be closed by laser welding a pieced onto the angled end. In some embodiments, the inner cutting tube  154  may additionally have an open end, such as depicted in  FIGS.  4   a - b    as a distal port  170 . 
     Generally, the inner cutting tube  154  may oscillate within the outer cutting tube  152  in response to the probe actuator. In an embodiment, the inner cutting tube  154  may be driven by air pressure directed on opposing sides of the diaphragm  156 . In one example of operation, if air pressure is increased at the first port  140 , the diaphragm  156  may move distally, displacing the inner cutting tube  154  relative to the outer cutting tube  152 , thereby moving a first cutting edge  157  on a distal end of the inner cutting tube  154  in the distal direction and cutting tissue. This may cut any vitreous material which may have been aspirated into a tissue-receiving outer port  168  of the outer cutting tube  152 . In some embodiments, the first cutting edge  157  may be formed on a flared distal end of the inner cutting tube  154  (as illustrated in  FIGS.  4   a - b   ). In some embodiments, the distal end of the inner cutting tube  154  may not be flared. The vitreous may be aspirated through a distal opening  170  of the inner cutting tube  154 . In some embodiments, the vitreous may also be aspirated through distal port  172  in the side of inner cutting tube  154   b . “ 154   a ” used in the Figures to depict inner cutting tube with no side distal port  172 , and “ 154   b ” used in the Figures to depict inner cutting tube with a side distal port  172  (“ 154   a ” and “ 154   b ” are generally referred to as “ 154 ” in the drawings and the specification when the expressed detail may apply to both “ 154   a ” and “ 154   b ”). Venting the pressure at the first port  140  and increasing the pressure at the second port  142  may move the diaphragm  156  proximally, moving a second cutting edge  151  facing a proximal direction near the distal end of the inner cutting tube  154   b  in the proximal direction, cutting any vitreous material which may have entered the outer port  168  of the outer cutting tube  152  and the side distal port  172  of the inner cutting tube  154   b  while at least partially aligned. 
       FIG.  5    illustrates the diaphragm  156  and drive shaft  174 , according to one embodiment. The diaphragm  156  may include an open-stroke side  176  (i.e., the side of the diaphragm  156  making contact with a proximal enclosed drive chamber wall  181  (see  FIG.  7   ) when the inner cutting tube  154  is in a retracted (proximal-most) position with respect to the outer cutting tube  152 ). The diaphragm  156  may also include a closed-stroke side  178  (i.e., the side of the diaphragm  156  making contact with a distal enclosed drive chamber wall  182  when the inner cutting tube  154  is in an extended (distal-most) position with respect to the outer cutting tube  152 ). 
     As seen in  FIGS.  6   a - b   , in some embodiments, the diaphragm  156  may include a first contact surface (e.g., proximal stops  179 ) and a second contact surface (e.g., distal stops  180 ) on opposing sides of the diaphragm  156 . In some embodiments, the proximal/distal stops  179 / 180  may come in contact with their respective drive chamber walls  181 / 182 . For example, proximal stops  179  may make contact with the proximal enclosed drive chamber wall  181  when the inner cutting tube  154  is in a retracted/proximal most position. Distal stops  180  may make contact with the distal enclosed drive chamber wall  182  when the inner cutting tube  154  is in an extended/distal most position. The stops  179 / 180  may be made of a rigid material (e.g., polycarbonate, polysulfone, or a similar material) or a relatively soft material (e.g., silicone or a similar material). In some embodiments, the stops  179 / 180  may be made of the same material. In some embodiments, the stops may be made of different materials. For example, proximal stops  179  may be made of a soft material (e.g., silicone or a similar material) and distal stops  180  may be made of a rigid material (e.g., polycarbonate, polysulfone, or a similar material). In another embodiment, proximal stops  179  may be made of a rigid material (e.g., polycarbonate, polysulfone, or a similar material) and distal stops  180  may be made of a soft material (e.g., silicone or a similar material). In some embodiments, the softer material may reduce noise from the impact of the contact surfaces of the diaphragm  156  against the chamber walls  181 / 182 . Rigid material may be used to provide a more consistent stop (e.g., the distal stops  180  may be made of a rigid material to insure the inner cutting tube  154  stops short of a distal end of the outer cutting tube  152 . By making the proximal stop of a relatively soft material and the distal stops of a rigid material, the probe may have a quieter operation and keep a reliable stopping distance between the inner and outer cutting tubes. 
     While three distal stops  180  are shown, other numbers of stops may be used (e.g., 1 stop or more such as 10 stops distributed on the contact surface) (even more stops may be used). While the distal stops  180  are shown as elliptical, other shapes of stops  180  are also possible (e.g., rectangular). While three proximal stops  179  are shown, other numbers of stops may be used (e.g., 1 stop or more such as 10 stops distributed on the contact surface) (even more stops may be used). While the proximal stops  179  are shown as three arc segments of a circular rise on the diaphragm  156 , other shapes of stops  179  are also possible (e.g., rectangular). In some embodiments, the diaphragm  156  may be made of the same material as one or more of the stops  179 / 180 . For example, the distal stops  180  may be extensions of the diaphragm material while the proximal stops  179  may include material coupled to the diaphragm (e.g., silicone overmolded, attached through adhesive, snapped onto, etc. the diaphragm  156 ). As seen in  FIG.  7   , in some embodiments, the proximal stops  179  may be extensions of the diaphragm material while the distal stops  180  may include material coupled on the diaphragm  156 . For example, the diaphragm  156  made be made of a silicone material that has the proximal stops formed thereon with rigid distal stops coupled to the diaphragm  156  (e.g., overmolded onto the silicone (or the silicone overmolded onto the rigid distal stops), attached through adhesive, snapping onto the silicone, etc.) As seen in  FIG.  7   , the distal stops  180  and a central receiving portion  183  (receiving the drive shaft  174 ) may be made of a rigid material (such as polycarbonate, polysulfone, or a similar material) and the diaphragm  156  (e.g., made of silicone or a similar material) may include silicone portions for the proximal stops  179  that are molded onto the rigid material to form an integrated piece. The circular recesses shown near the proximal stops  179  may be used as part of the molding process. In some embodiments, the proximal stops  179  may be a continuous circular rise on the diaphragm  156 . 
       FIG.  8    illustrates an inner cutting tube  154  bend, according to an embodiment. In some embodiments, the inner cutting tube  154  may have a slight bend to bias the first cutting edge  157  against the inside wall of the outer cutting tube  152  to insure a cutting action on the vitreous entering the port  168 . In some embodiments, the angle may vary according to the size of the outer cutting tube  152 . For example, for 23 gauge outer cutting tubes  152 , the bend angle (C) may be approximately 3.5 degrees with a bend length (B) (i.e., distance from the distal end of the inner cutting tube  154  to the bend) of approximately 0.110 inches. Other bend angles (C) and bend lengths (B) for 23 gauge outer cutting tubes are also contemplated (e.g., a bend angle (C) approximately in a range of 2.0 degrees to 5.0 degrees or approximately in a range of 3.0 to 4.0 degrees and a bend length (B) approximately in a range of 0.065 to 0.15 inches or approximately in a range of 0.1 to 0.13 inches). As another example, for 25 gauge outer cutting tubes  152 , the bend angle (C) may be approximately 4.7 degrees with a bend length (B) of approximately 0.060 inches. Other bend angles (C) and bend lengths (B) for 25 gauge outer cutting tubes are also contemplated (e.g., a bend angle (C) approximately in a range of 2.8 degrees to 6.5 degrees or approximately in a range of 4.0 to 5.5 degrees and a bend length (B) approximately in a range of 0.035 to 0.15 inches or approximately in a range of 0.05 to 0.07 inches). As a further example, for 27 gauge outer cutting tubes  152 , the bend angle (C) may be approximately 4.3 degrees with a bend length (B) of approximately 0.050 inches. Other bend angles (C) and bend lengths (B) for 27 gauge outer cutting tubes are also contemplated (e.g., a bend angle (C) approximately in a range of 2.6 degrees to 6.0 degrees or approximately in a range of 3.7 to 4.9 degrees and a bend length (B) approximately in a range of 0.03 to 0.07 inches or approximately in a range of 0.04 to 0.06 inches). As another example, for a dual port probe (e.g., see  FIG.  4   b   ), the bend angle (C) may be approximately 3.2 degrees and the bend length (B) may be approximately 0.050 inches. Other bend angles (C) and bend lengths (B) for dual port probes are also contemplated (e.g., a bend angle (C) approximately in a range of 1.9 degrees to 4.5 degrees or approximately in a range of 2.7 to 3.7 degrees and a bend length (B) approximately in a range of 0.03 to 0.07 inches or approximately in a range of 0.04 to 0.06 inches). 
     While example dimensions/measurements and dimensions/measurement ranges are provided throughout the application, these dimensions/measurements should not be construed as limiting as they only present a possible set of dimensions/measurements. Other dimensions/measurements are also contemplated. 
     As shown in  FIG.  9   , the outer cutting tube  152  may have support from a stiffener  200  extending around the base of the outer cutting tube  152  at the probe body. In some embodiments, the probe may not include a stiffener  200 . The length (L) of the outer cutting tube from the probe body to the distal end may vary according to the size of the outer cutting tube  152 . For example, for 23 or 25 gauge outer cutting tubes  152 , the length (L) may be approximately 1.25 inches. Other lengths (L) are also contemplated (e.g., length (L) for a 23 or 25 gauge outer cutting tube may be approximately in a range of 0.75 to 1.75 inches or approximately in a range of 1.1 to 1.4 inches). The 23 and 25 gauge outer cutting tubes may not include stiffeners  200  (or they may include stiffeners  200 ). In an embodiment of the 25 gauge outer cutting tube length with a stiffener  200 , the length (L) may be approximately 1.063 inches. Other lengths (L) are also contemplated (e.g., length (L) for a 25 gauge outer cutting tube with a stiffener may be approximately in a range of 0.65 to 1.5 inches or approximately in a range of 0.9 to 1.2 inches). As a further example, for 27 gauge outer cutting tubes  152  with stiffeners  200 , the length (L) may be approximately 1.023 inches. Other lengths (L) are also contemplated (e.g., length (L) for a 27 gauge outer cutting tube with a stiffener may be approximately in a range of 0.6 to 1.4 inches or approximately in a range of 0.85 to 1.2 inches). Other lengths (L) are also possible. For example, length (L) for all gauges with or without a stiffeners may be approximately in a range of 0.1 to 3 inches. 
       FIG.  10    illustrates tubing segments coupling the probe  112  to a surgical console  100 , according to an embodiment. As seen in  FIG.  10   , in some embodiments, the probe  112  may be coupled to the surgical console  100  by three lines (an aspiration tube  1001  and two pneumatic tubes  1002   a - b ). The pneumatic tubes  1002   a - b  may include a plastic tubing extending from the console  100 . In some embodiments, the pneumatic tubes  1002   a - b  may have a hardness approximately in a range of 50-120 Shore A hardness (e.g., a hardness of 80 Shore A). Other hardnesses are also contemplated. In some embodiments, the pneumatic tubing  1002   a - b  may each have a length TL of 84 inches. Other lengths are also contemplated (e.g., the length TL may be approximately in a range of 50 to 120 inches or approximately in a range of 70 to 100 inches). 
     In some embodiments, the aspiration tube  1001  may include two or more tubing segments  1011   a - b . The aspiration tubing segments  1011   a - b  may be coupled together through a tubing connector  1007 . The connector  1007  may connect to each tubing segment through a friction fit (e.g., ends of the tubing segments  1011   a - b  may slide over respective receiving male connector segments and stay secured through friction between the inner surface of the tubing and the male connector segments). Other attachments are also contemplated (e.g., adhesive, crimping, etc.) In some embodiments, the tubing segments  1011   a - b  may be a single continuous tube that has properties that transition at a point along the tubing or gradually along at least a portion of the tubing. In some embodiments, the aspiration tubing segments  1011   a - b  may have different lengths. For example, the tubing segment  1011   a  from the console  100  to the connector  1007  may be substantially longer than the tubing segment  1011   b  from the handpiece  112 . As one example of relative lengths, the aspiration tubing segment  1011   a  from the console  100  to the connector  1007  may have a length of approximately 79 inches and the aspiration tubing segment  1011   b  from the connector  1007  to the handpiece  112  may have a length SL of approximately 5 inches. Other lengths are also contemplated. For example, the aspiration tubing segment  1011   a  from the connector  1007  to the console  100  may have a length approximately in a range of 45 to 110 inches or approximately in a range of 65 to 95 inches. The aspiration tubing segment  1011   b  from the connector  1007  to the handpiece  112  may have a length SL approximately in a range of 3 to 7 inches or approximately in a range of 4 to 6 inches. In some embodiments, the aspiration tubing segments  1011   a - b  may have different hardnesses. For example, the longer aspiration tubing segment  1011   a  from the console  100  to the connector  1007  may have a higher hardness than the shorter aspiration tubing segment  1011   b  from the connector  1007  to the handpiece. For example, in one embodiment, the hardness of the longer aspiration tubing segment  1011   a  may be approximately 80 Shore A hardness and the hardness of the shorter aspiration tubing segment  1011   b  may be approximately 40 Shore A hardness. Other hardnesses are also contemplated. For example, the hardness of the longer aspiration tubing segment  1011   a  may be approximately in a range of 50 to 115 Shore A hardness or approximately in a range of 70 to 95 Shore A hardness. The hardness of the shorter aspiration tubing segment  1011   b  may be approximately in a range of 25 to 55 Shore A hardness or approximately in a range of 35 to 45 Shore A hardness. In some embodiments, the shorter, lower hardness aspiration tubing segment may also make the handpiece  112  easier to handle by the surgeon (versus a handpiece coupled through a high hardness tubing). The lower hardness tubing may be more flexible than the higher hardness tubing. 
     As seen in  FIG.  11   , the pneumatic tubing  1002   a - b  and aspiration tubing  1001  may be coupled together through at least a portion of their lengths. For example, the tubing may be coupled together through being coextruded or through an adhesive along the lengths of tubings to hold them together. In some embodiments, an angle α between centerpoints of the coupled pneumatic tubing  1002   a - b  may be approximately 90 degrees as shown in  FIG.  11   . Other values of a are also contemplated (e.g., approximately in a range of 55 degrees to 125 degrees or approximately in a range of 75 to 100 degrees). In some embodiments, an angle β between the centerpoints of the coupled pneumatic tubing  1002   a - b  and aspiration tubing  1001  may be approximately 75 degrees as shown in  FIG.  11   . Other values of β are also contemplated (e.g., approximately in a range of 45 degrees to 105 degrees or approximately in a range of 65 to 85 degrees). In some embodiments, the pneumatic tubing  1002   a - b  and aspiration tubing  1001  may not be coupled together along their lengths. 
     In some embodiments, the pneumatic tubing  1002   a - b  and aspiration tubing  1001  may have indicators on the tubing to indicate the tubing type. For example, stripes  1005   a - b  may be included along at least a portion of the tubing lengths. In some embodiments, a blue stripe  1005   a  may indicate an aspiration tubing  1001 . A black stripe  1005   b  may be used to indicate a first pneumatic tubing  1002   a  and a grey stripe  1005   c  may be used to indicate the second pneumatic tubing  1002   b . In some embodiments, the stripes may be approximately 0.060 inches in width SW. Other widths SW are also contemplated (e.g., approximately in a range of 0.035 to 0.085 inches or approximately in a range of 0.05 to 0.07 inches). Other indicators are also contemplated. 
     As further seen in  FIG.  11   , the inner diameter ØPD of the pneumatic tubing  1002   a - b  may be approximately 0.075 inches. Other diameters are also contemplated (e.g., approximately in a range of 0.045 to 0.10 inches or approximately in a range of 0.065 to 0.085 inches). In some embodiments, the inner diameter ØAD of the aspiration tubing  1001  may be approximately 0.06 inches. Other diameters are also contemplated (e.g., approximately in a range of 0.035 to 0.085 inches or approximately in a range of 0.05 to 0.07 inches). In some embodiments, the pneumatic tubing  1002   a - b  and aspiration tubing  1001  may all have the same outer diameter ØOD of approximately 0.125 inches. Other outer diameters ØOD are also contemplated (e.g., approximately in a range of 0.075 to 0.18 inches or approximately in a range of 0.10 to 0.15 inches). In some embodiments, the pneumatic tubing  1002   a - b  or aspiration tubing  1001  may have different diameters than the other of the pneumatic tubing  1002   a - b  or aspiration tubing  1001 . 
       FIGS.  12   a - c    illustrate vitrectomy probe distal ends, according to various embodiments.  FIG.  12   a    illustrates a cross section of the eye with a vitrectomy probe.  FIG.  12   b    illustrates a close-up of a flat distal tip vitrectomy probe near the retina (e.g., at a port edge tip to retinal (PTRD) distance X from the retina). The PTRD is the shortest distance between the port edge and the retina. As seen in  FIG.  12   c   , the user can position the port closer (e.g., a PTRD distance Y where Y&lt;X) to the retina of the eye if the distal end of the vitrectomy probe is beveled. For example, X may be 0.018 inches while Y may be 0.008 inches. Other X and Y values are also contemplated. When using the vitrectomy probe, the user may want to remove vitreous as close to the retina as possible without cutting the retina itself. The beveled tip may allow shaving or dissection of tissue/membranes near the retina. The beveled tip may also allow the user to lift and pick membranes without having to switch to another instrument. 
       FIGS.  13   a - b    illustrate some measurements for the outer cutting tube  152  of the vitrectomy probe, according to various embodiments. As seen in  FIG.  13   a   , in some embodiments of the flat tip (where angle Q 1 , from a distal end surface of the outer cutting tube  152  to an extended back surface line  190  of the outer cutting tube that is opposite the outer port side opening, is 90 degrees), the port edge to distal probe tip (PTTD) measurement F 1  may be approximately 0.009 inches for 23, 25, and 27 gauge probes. Other PTTD measurements F 1  are also contemplated. For example, PTTD measurement F 1  may be approximately in a range of 0.003 to 0.015 inches, approximately in a range of 0.003 to 0.0085 inches, approximately in a range of 0.005 to 0.025 inches, or approximately in a range of 0.008 to 0.010 inches. In some embodiments, the PTTD measurement F 1  may be a function of over travel of the inner cutting tube  154  (i.e., how far the inner cutting tube  154  travels inside the outer cutting tube  152  during the distal most portion of the inner cutting tube  154  movement), thickness of the needle cap  173 , and clearance between the inner cutting tube  154  and the cap  173  (i.e., the distance between the distal most end of the inner cutting tube  154  and the cap  173  at the distal most point of the inner cutter tube&#39;s travel inside the outer cutting tube  152 ). In some embodiments, the port edge tip to retinal distance (PTRD) F 2  for the flat tip may be approximately 0.021 inches for a 23 gauge probe, approximately 0.018 inches for a 25 gauge probe, and approximately 0.016 inches for a 27 gauge probe. Other PTRD distances for flat tips F 2  are also contemplated (e.g., F 2  may be approximately in a range of 0.01 to 0.03 inches for the various gauge probes). As seen in  FIG.  13   b   , in some embodiments of the beveled tip, the PTRD for the beveled tip B 2  (at an angle Q 2 , from a distal end surface of the outer cutting tube  152  to an extended back surface line  190  of the outer cutting tube that is opposite the outer port side opening, is approximately 60 degrees) may be approximately 0.009 inches for a 23 gauge probe, approximately 0.008 inches for a 25 gauge probe, and approximately 0.007 inches for a 27 gauge probe. Other PTRD measurements B 2  are also contemplated (for example, angle Q 2  may be approximately in a range of 20 to 80 degrees with a PTRD measurement B 1  approximately in a range of 0.005 inches to 0.010 inches for 23, 25, and 27 gauge probes). Other PTRD measurements B 2  are also contemplated (e.g., PTRD may be approximately in a range of 0.003 to 0.015 inches, approximately in a range of 0.003 to 0.0085 inches, approximately in a range of 0.005 to 0.025 inches, or approximately in a range of 0.008 to 0.010 inches for angle Q 2  approximately in a range of 20 to 80 degrees). In some embodiments, an angle Q 2  of approximately 60 degrees may result in the PTTD of the probe being approximately equal to the PTRD. 
       FIGS.  14   a - c    illustrate some measurements for the outer cutting tube  152  and inner cutting tube  154   b  of the vitrectomy probe, according to various embodiments. The outer port side opening  168  may have an approximate diameter OPDP 1  of 0.015 inches. Other diameters are also contemplated (e.g., approximately in a range of 0.009 to 0.02 inches or approximately in a range of 0.013 to 0.017 inches). The port opening  168  may be circular, elliptical, or some other shape. The outer port opening depth OPD 1  may be approximately 0.0045 in. Other outer port opening depths OPD 1  are also contemplated (e.g., approximately in a range of 0.0027 to 0.063 inches or approximately in a range of 0.0038 to 0.0052 inches). The outer port radius OPR 1  may be approximately 0.008 inches. Other outer port radius OPR 1  are also contemplated (e.g., approximately in a range of 0.0048 to 0.0112 inches or approximately in a range of 0.0068 to 0.0092 inches). The proximal port edge angle Pα 1  may be approximately 50 degrees. Other proximal port edge angles Pα 1  are also contemplated (e.g., approximately in a range of 30 to 70 degrees or approximately in a range of 40 to 60 degrees). The inner diameter ID 1  of the outer cutting tube  152  may be approximately 0.0131 inches. Other inner diameters ID 1  are also contemplated (e.g., approximately in a range of 0.0079 to 0.018 inches or approximately in a range of 0.011 to 0.015 inches). The outer diameter OD 1  of the outer cutting tube  152  may be approximately 0.0165 inches. Other outer diameters OD 1  are also contemplated (e.g., approximately in a range of 0.010 to 0.023 inches or approximately in a range of 0.014 to 0.019 inches). 
     As seen in  FIG.  14   b   , a port depth D 3  of the distal port  172  of the inner cutting tube  154   b  may be approximately 0.004 inches. Other port depths D 3  are also contemplated (e.g., approximately in a range of 0.0024 to 0.0056 inches or approximately in a range of 0.034 to 0.0046 inches). An inner cutter inner diameter IOD 1  of the inner cutting tube  154   b  may be approximately 0.0127 inches with a flare out to 0.0130 inches at the first cutting edge  157 . Other inner cutter inner diameters IOD 1  are also contemplated (e.g., approximately in a range of 0.0076 to 0.018 inches or approximately in a range of 0.011 to 0.015 inches). Other flare outs to the first cutting edge  157  are also contemplated (e.g., approximately in a range of 0.0078 to 0.02 inches or approximately in a range of 0.010 to 0.014 inches). The inner tube distal port to edge measurement G 1  may be approximately 0.005 inches. In another embodiment, the inner tube port to edge measurement G 1  may be approximately 0.006 inches. Other inner port to edge measurements G 1  are also possible (e.g., G 1  may be approximately in a range of 0.003 inches to 0.012 inches or approximately in a range of 0.003 to 0.007 inches or approximately in a range of 0.004 to 0.006 inches). The inner tube proximal port to edge measurement H 1  may be approximately 0.0155 inches. Other inner tube proximal port to edge measurements H 1  are also contemplated (e.g., approximately in a range of 0.0093 to 0.022 inches or approximately in a range of 0.013 to 0.018 inches). The inner port edge angle IPα 1  may be approximately 50 degrees. Other port edge angles α 1  are also contemplated (e.g., approximately in a range of 30 to 70 degrees or approximately in a range of 40 to 60 degrees). As seen in  FIG.  14   c   , the inner cutting tube port width PW 1  may be approximately 0.009 inches. Other inner cutting tube port widths PW 1  are also contemplated (e.g., approximately in a range of 0.0054 to 0.013 inches or approximately in a range of 0.0077 to 0.011 inches). 
       FIGS.  15   a - d    illustrate measurements for the outer cutting tube  152  and inner cutting tube  154   c  of the vitrectomy probe  112 , according to an embodiment of the inner tube having a flattened edge feature  185 . The dimensions not specified in  FIGS.  15   a - d    may have the same value or value ranges as their counterpart dimensions specified in  FIGS.  14   a - c   . The port edge to distal probe tip (PTTD) measurement F 2  may be approximately 0.0098 inches for 23, 25, and 27 gauge probes. Other PTTD measurements F 2  are also contemplated. For example, PTTD measurement F 2  may be approximately in a range of 0.0058 to 0.0137 inches, approximately in a range of 0.0083 to 0.011 inches, approximately in a range of 0.003 to 0.015 inches, approximately in a range of 0.003 to 0.0085 inches, approximately in a range of 0.005 to 0.025 inches, or approximately in a range of 0.008 to 0.010 inches. The port opening  168  may be circular, elliptical, or some other shape. The proximal port edge angle OPα 2  may be approximately 50 degrees. Other proximal port edge angles OPα 1  are also contemplated (e.g., approximately in a range of 30 to 70 degrees or approximately in a range of 40 to 60 degrees). The distal port edge angle ODα 2  may be approximately 45 degrees. Other proximal port edge angles ODα 2  are also contemplated (e.g., approximately in a range of 25 to 65 degrees or approximately in a range of 35 to 55 degrees). The outer tube upper edge radius UER 2  may be approximately 0.002 inches. Other outer tube upper edge radius UER 2  are also contemplated (e.g., approximately in a range of 0.0012 to 0.0028 degrees or approximately in a range of 0.0017 to 0.0023 degrees). The thickness of the distal outer tube wall T 2  may be approximately 0.0022 inches. Other thicknesses T 2  are also contemplated (e.g., approximately in a range of 0.0013 to 0.0031 degrees or approximately in a range of 0.0018 to 0.0025 degrees). The outer tube diagonal distance J 2  may be approximately 0.010 inches. Other outer tube diagonal distances J 2  are also contemplated (e.g., approximately in a range of 0.006 to 0.014 degrees or approximately in a range of 0.0085 to 0.0115 degrees). The inner diameter ID 2  of the outer cutting tube  152  may be approximately 0.0131 inches. Other inner diameters ID 2  are also contemplated (e.g., approximately in a range of 0.0079 to 0.018 inches or approximately in a range of 0.011 to 0.015 inches). The outer diameter OD 2  of the outer cutting tube  152  may be approximately 0.0165 inches. Other outer diameters OD 2  are also contemplated (e.g., approximately in a range of 0.010 to 0.023 inches or approximately in a range of 0.014 to 0.019 inches). 
     As seen in  FIG.  15   b   , the inner tube proximal port to edge measurement H 2  may be approximately 0.0138 inches. Other inner tube proximal port to edge measurements H 2  are also contemplated (e.g., approximately in a range of 0.0083 to 0.019 inches or approximately in a range of 0.012 to 0.016 inches). The inner tube distal port to edge measurement G 2  may be approximately 0.0047 inches. Other inner port to edge measurements G 2  are also possible (e.g., G 2  may be approximately in a range of 0.0028 inches to 0.0066 inches or approximately in a range of 0.004 to 0.0055 inches). The port edge angle IPα 2  may be approximately 50 degrees. Other port edge angles IPα 2  are also contemplated (e.g., approximately in a range of 30 to 70 degrees or approximately in a range of 40 to 60 degrees). The outer port edge angle OPEα 2  may be approximately 59 degrees. Other port edge angles OPEα 2  are also contemplated (e.g., approximately in a range of 35 to 85 degrees or approximately in a range of 50 to 70 degrees). The inner tube flattened edge feature  185  may have a depth ED 1  of approximately 0.002 inches. Other depths ED 1  are also contemplated (e.g., approximately in a range of 0.0012 to 0.0028 inches or approximately in a range of 0.0017 to 0.0023 inches). The inner port depth IPD 1  may be approximately 0.004 inches. Other inner port depths IPD 1  are also contemplated (e.g., approximately in a range of 0.0024 to 0.0056 inches or approximately in a range of 0.0034 to 0.0046 inches). The proximal edge of the inner port may have a radius IPR 2  of approximately 0.00205 inches. Other proximal edge radius IPR 2  are also contemplated (e.g., approximately in a range of 0.00123 to 0.0287 inches or approximately in a range of 0.00174 to 0.00236 inches). The inner tube inner diameter IND 2  may be approximately 0.0096 inches. Other inner tube inner diameters IND 2  are also contemplated (e.g., approximately in a range of 0.0058 to 0.013 inches or approximately in a range of 0.0082 to 0.011 inches). The inner tube outer diameter IOD 2  of the outer cutting tube  152  may be approximately 0.0122 inches. Other outer diameters IOD 2  are also contemplated (e.g., approximately in a range of 0.0073 to 0.017 inches or approximately in a range of 0.010 to 0.014 inches). 
       FIG.  15   c    illustrates the inner cutting tube  154   c  and outer cutting tube  152  in a cutting cycle at a point where an edge offset OFF 1  is approximately 0 inches.  FIG.  15   d    illustrates the inner cutting tube  154   c  and outer cutting tube  152  in a cutting cycle at a point where an edge offset OFF 2  is approximately 0.0043 inches. With the edge offset OFF 1  of approximately 0 inches, the distal edge clearance DEC 1  between the distal edge of the inner tube  154   c  and the inside distal surface of the outer tube  152  may be approximately 0.0084 inches. Other distal edge clearance DEC 1  are also contemplated (e.g., approximately in a range of 0.0050 to 0.012 inches or approximately in a range of 0.0071 to 0.0097 inches). With the edge offset OFF 2  of approximately 0.0043 inches, the distal edge clearance DEC 2  between the distal edge of the inner tube  154   c  and the inside distal surface of the outer tube  152  may be approximately 0.0041 inches. Other distal edge clearance DEC 2  are also contemplated (e.g., approximately in a range of 0.0025 to 0.0057 inches or approximately in a range of 0.0035 to 0.0047 inches). As further seen in  FIG.  15   c   , the tube clearance Cl between the inner tube  154   c  and the outer tube  152  may be approximately 0.0005 inches. Other tube clearances C  1  are also contemplated (e.g., approximately in a range of 0.0003 to 0.0007 inches or approximately in a range of 0.00042 to 0.00058 inches). 
     As seen in  FIGS.  16   a - d   , in some embodiments, port to distal probe tip measurement F 1  may be approximately in a range of 0.003 to 0.012 inches. As another example, F 1  may be approximately in a range of 0.001 to 0.015 inches, approximately in a range of 0.003 to 0.015 inches, approximately in a range of 0.003 to 0.0085 inches, approximately in a range of 0.005 to 0.025 inches, or approximately in a range of 0.008 to 0.010 inches. In some embodiments, bevel angle BA 1  and BA 2  may be approximately in a range of 15 to 75 degrees. As another example, bevel angles BA 1  and BA 2  may be approximately in a range of 5 to 90 degrees. In some embodiments, G 1  may be approximately 0.006 inches. Other G 1  measurements are also contemplated (e.g., approximately in a range of 0.0035 to 0.0085 inches or approximately in a range of 0.005 to 0.007 inches). As seen in  FIGS.  16   c - d   , embodiments of the inner cutting tube  154  may include a flat upper edge  185 , perpendicular (or, for example, approximately in a range of 70-110 degrees) to an inner tube longitudinal axis  194 , on the portion of the inner cutting tube  154  that cuts across the outer port side opening  168 . Other angles for the flat upper edge are also contemplated. In some embodiments, the flat upper edge  185  may decrease the potential of the inner cutting tube  154  snagging or “hanging” up on the outer cutting tube  152  as the inner cutting tube  154  shears back and forth across the outer port side opening  168 . As seen in  FIGS.  16   c - d   , the distal portions of the inner cutting tube  154  may include the flared edge. In some embodiments, the inner cutting tube  154  may not be flared. 
       FIG.  17    is an illustration of a partial cross-sectional view of stepped pneumatic drive lines usable with surgical console  100  to drive vitrectomy probe  112 . As shown, surgical console  100  and vitrectomy probe  112  may be coupled to stepped pneumatic drive lines  402  and  404  (which may be used in place of pneumatic tubes  1002   a - b ). Stepped pneumatic drive lines  402  and  404  may be used in system  100  to drive the vitrectomy probe  112 . 
     Stepped pneumatic drive line  402  will be described below. The features discussed with respect to stepped pneumatic drive line  402  may be present in and equally applicable to stepped pneumatic drive line  404 . As such, similar reference numerals have been used in  FIG.  17    to identify similar features with respect to stepped pneumatic drive lines  402  and  404 . 
     Also, even though  FIG.  17    shows two separate stepped pneumatic drive lines  402  and  404  powering vitrectomy probe  112 , other embodiments utilize a single stepped pneumatic drive line or more than two stepped pneumatic drive lines. Thus, no limitation to the number of stepped pneumatic drive lines is implied herein to power vitrectomy probe  112 . 
     Stepped pneumatic drive line  402  may have a first segment  406  and a second segment  408 . The first segment  406  may have a proximal end  410  that is coupled to surgical console  100  via console ports and a distal end  412  that is coupled to the second segment  406  via a sleeve  414 , or coupler. Additionally, the first segment may include an internal bore  416 , or passageway extending from the proximal end  410  to the distal end  412  of the first segment  406 . 
     Although sleeve  414  is shown coupling the first segment  406  and the second segment  408 , it is contemplated that any other means can be used to couple the two segments together. For example, in other embodiments one of the segments may be configured to be slid into the other segment thereby coupling the segments without the use of sleeve  414 . Additionally, in other embodiments, the pneumatic drive line  402  may be manufactured as a continuous drive line having the two or more segments with the stepped configuration. In such an embodiment, the pneumatic drive line may not require the sleeve coupling the segments because the segments have been manufactured into a continuous drive line having the stepped configuration. 
     As shown, first segment  406  may have a substantially constant outside diameter OD 1  from the proximal end  410  to the distal end  412  of the first segment  406 . By way of example, and not by limitation, OD 1  may be about 0.250 inches. Moreover, OD 1  may range from about 0.15 inches to about 0.5 inches. However, other dimensions for OD 1  are contemplated thereby no implied limitation is set forth herein. 
     Additionally, internal bore  416  of first segment  406  may have a substantially constant inside diameter ID 1  extending from the proximal end  410  to the distal end  412  of the first segment  406 . By way of example, and not by limitation, ID 1  may be about 0.150 inches. Moreover, ID 1  may range from about 0.1 inches to about 0.3 inches. However, other dimensions for ID 1  are contemplated thereby no implied limitation is set forth herein. 
     Second segment  408  may have a proximal end  418  that is coupled to the first segment  406  via sleeve  414  and a distal end  420  that is coupled to vitrectomy probe  112 . Additionally, the second segment  408  may include an internal bore  422 , or passageway extending from the proximal end  418  to the distal end  420  of the second segment  408 . 
     As shown, second segment  408  may have a substantially constant outside diameter OD 2  from the proximal end  418  to the distal end  420  of the second segment  408 . By way of example, and not by limitation, OD 2  may be about 0.125 inches. Furthermore, OD 2  may range from about 0.05 inches to about 0.20 inches. However, other dimensions for OD 2  are contemplated thereby no implied limitation is set forth herein. 
     Additionally, internal bore  422  of second segment  408  may have a substantially constant inside diameter ID 2  extending from the proximal end  418  to the distal end  420  of the second segment  408 . By way of example, and not by limitation, ID 2  may be about 0.06 inches. Furthermore, ID 2  may range from about 0.01 inches to about 0.150 inches. However, other dimensions for ID 2  are contemplated thereby no implied limitation is set forth herein. 
     Accordingly, the second segment  408  may be “stepped” down relative to the first segment  406 . In that regard, the outside diameter OD 1  of the first segment  406  may be greater than the outside diameter OD 2  of the second segment  408 . Moreover, the inside diameter ID 1  of the first segment  406  may be greater than the inside diameter ID 2  of the second segment  408 . Therefore, because the second segment  408  may be “stepped” down from the first segment  406 , the passageway extending through stepped pneumatic drive line  402  may have a non-uniform cross-section and/or diameter as the pneumatic drive line extends from surgical console  100  to vitrectomy probe  112 . While two segments are shown, in some embodiments, any number of segments may be used (e.g., 3, 4, 5, etc.) In some embodiments, the segments may have an increasing internal diameter closer to the console  100 . In some embodiments, the outside diameter may also change (e.g., increase for the segments closer to the console) with each segment (or may remain the same). 
     Based on this stepped configuration, stepped pneumatic drive line  402  may increase the performance of vitrectomy probe  112  in comparison to other pneumatic instruments using traditional pneumatic drive line tubing. As discussed above, traditional pneumatic drive line tubing may have a constant inside diameter along the length of the tubing. Thus, the size of the passageway within the tubing may remain the same as the pressurized gas travels from the surgical console to the surgical instrument. 
     By contrast, stepped pneumatic drive line  402  may have a non-constant or non-uniform inside diameter (or cross-section) along the length of the drive line. The use of a non-constant inside diameter may allow stepped pneumatic drive line  402  to be optimized based on its functional needs along its length. Because stepped pneumatic drive line  402  may be considered closed at its end coupled to vitrectomy probe  112  and is being driven from the end of the line coupled to console  100 , the driven end of stepped pneumatic drive line  402  may have a higher gas flow requirement. Thus, in order to optimize gas flow, the driven end of stepped pneumatic drive line  402  may have a larger diameter than the closed end. 
     Here, first segment  406  may have a larger inside diameter ID 1  for internal bore  416  than the inside diameter ID 2  for internal bore  422  of segment  408 . As such, internal bore  416  may allow for a larger volume of pressurized gas to be received into the line from console  100  where high flow of pressured gas is most important in order to optimize pneumatic performance. 
     Additionally, as discussed above, the use of a non-constant inside diameter may allow stepped pneumatic drive line  402  to be optimized based on its functional needs along its length. In that regard, because traditional pneumatic drive lines have constant diameters, the portion of the drive line adjacent the vitrectomy probe  112  may have the same large inside diameter required at the other end being driven by the surgical console  100 . As such, the tubing may have a larger than ideal size and mass and as a result the tubing may typically not be as flexible as would be desirable near the vitrectomy probe  112 . 
     Stepped pneumatic drive line  402  may address this issue. As discussed above, stepped pneumatic drive line  402  may include second segment  408  having a smaller inside diameter ID 2  and outside diameter OD 2  than the inside diameter ID 1  and outside diameter OD 1  of segment  406 . As such, stepped pneumatic drive line  402  may provide a smaller drive line (e.g. second segment  408 ) adjacent the vitrectomy probe  112  where high flexibility and low mass may be important for a user of vitrectomy probe  112 . In some embodiments, the stepped pneumatic drive line may include a larger diameter in the pneumatic line segment closer to the surgical console  100  while having a step down in diameter (e.g., via a connector) with the last approximately 12 inches (proximal to the vitrectomy probe  112 ) being approximately 0.125 inches in outer diameter and 0.06 inches in inner diameter (other lengths of last segments (e.g., greater or less than 12 inches) and other diameters are also contemplated). Therefore, stepped pneumatic drive line  402  tubing may be configured to optimize pneumatic performance with larger diameters near the console  100  while providing greater flexibility and low mass near the vitrectomy probe  112 . 
       FIG.  18    shows a partial cross-sectional view of sleeve  414  coupling the distal end  412  of the first segment  406  to the proximal end  418  of the second segment  408 . As shown, sleeve  414  may have a proximal bore  502 , connecting bore  504 , or middle bore, and a distal bore  506 . Proximal bore  502  may be sized and shaped for receiving distal end  412  of the first segment  406 . 
     Moreover, proximal bore  502  is defined in part by interior surface  508  of sleeve  414 . In that regard, interior surface  508  may be tapered or sloped towards connecting bore  504 . As a result, distal end  412  of the first segment  406  may be coupled to sleeve  414  via a press-fit or sealing engagement by the tapered interior surface  508  applying a coupling force against the distal end  412 . 
     Additionally, proximal bore  502  may include stops  510 . Stops  510  may prevent the distal end  412  from extending into connecting bore  504 . In that regard, distal end  412  of the first segment  406  may abut against the stops  510  when fully inserted into sleeve  414 . Thus, stops  510  may prevent over insertion of distal end  412  into sleeve  414 . 
     Distal bore  506  may be sized and shaped for receiving proximal end  418  of the second segment  408 . Distal bore  506  may be defined in part by interior surface  516  of sleeve  414 . In that regard, interior surface  516  may be tapered or sloped towards connection bore  504 . As a result, proximal end  418  of the second segment  408  may be coupled to sleeve via a press-fit or sealing engagement by the tapered interior surface applying a coupling force against the proximal end  418 . 
     Additionally, distal bore  506  may include stops  518 . Stops  518  may prevent the proximal end  418  from extending into connecting bore  504 . In that regard, proximal end  418  of the second segment  408  may abut against the stops  518  when fully inserted into sleeve  414 . Thus, stops  518  may prevent over insertion of proximal end  418  into sleeve  414 . 
     As shown, connecting bore  504  may be positioned between the proximal bore  502  and the distal bore  506 . Connecting bore may have a conical shape. In that regard, interior surface  520  may define connecting bore  504  and may taper toward distal bore  506 . As such, opening  512  of connecting bore  504  adjacent the proximal bore  502  may have a larger diameter than opening  514  adjacent the distal bore  506 . Moreover, opening  512  may have a diameter substantially similar to the inside diameter ID 1  of internal bore  416  of the first segment  406 . Additionally, opening  514  may have a diameter substantially similar to the inside diameter ID 2  of internal bore  422  of the second segment  408 . Because of the sizing of openings  512  and  514  and the conical shape of connecting bore  504 , a seal may be formed between internal bore  416  of the first segment and internal bore  422  of the second segment  408  that enables pressurized gas to flow therethrough. 
     Other tapered tubing is also contemplated. For example, tapered pneumatic drive line may continuously taper from the surgical console  100  to the vitrectomy probe  112 . In other words, an exterior surface of the pneumatic drive line and an interior surface defining a bore may both continuously taper from a proximal end to a distal end of a tapered pneumatic drive line. In some embodiments, the interior surface may taper while the exterior surface remains constant. 
       FIG.  19    illustrates a flowchart of a method for operating the vitrectomy probe, according to an embodiment. The elements provided in the flowchart are illustrative only. Various provided elements may be omitted, additional elements may be added, and/or various elements may be performed in a different order than provided below. 
     At  1901 , a trocar cannula may be inserted into the eye. In some embodiments, the trocar cannula may be inserted into a region of the eye that will allow instruments inserted through the trocar cannula to access the vitreous and retina. 
     At  1903 , a vitrectomy probe may be inserted through the trocar cannula and into the eye. 
     At  1905 , the vitrectomy probe may be activated and vitreous entering the port on the vitrectomy probe may be removed through aspiration from the vitrectomy probe. 
     At  1907 , the vitrectomy probe may be removed from the cannula. 
     Various modifications may be made to the presented embodiments by a person of ordinary skill in the art. Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.