Patent Publication Number: US-2023157813-A1

Title: Intraocular lens injector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/838,946, filed Dec. 12, 2017 and claims the benefit of U.S. Provisional Application No. 62/446,194, filed Jan. 13, 2017, and claims the benefit U.S. Provisional Application No. 62/469,682, filed Mar. 10, 2017, the entire contents of each being incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to systems, apparatuses, and methods for intraocular lens injectors. Particularly, the present disclosure relates to systems, apparatuses, and methods for intraocular lens injectors including features for lifting a leading haptic of an intraocular lens for improved intraocular lens folding performance. 
     BACKGROUND 
     The human eye in its simplest terms functions to provide vision by transmitting and refracting light through a clear outer portion called the cornea, and further focusing the image by way of the lens onto the retina at the back of the eye. The quality of the focused image depends on many factors including the size, shape and length of the eye, and the shape and transparency of the cornea and lens. When trauma, age or disease cause the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. The treatment for this condition is surgical removal of the lens and implantation of an artificial intraocular lens (“IOL”). 
     Many cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, an opening is made in the anterior capsule and a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. The vibrating cutting tip liquefies or emulsifies the lens so that the lens may be aspirated out of the eye. The diseased lens, once removed, is replaced by an artificial lens. 
     The IOL is injected into the eye through the same small incision used to remove the diseased lens. An IOL injector is used to deliver an IOL into the eye. 
     SUMMARY 
     According to one aspect, the disclosure describes an intraocular lens injector that may include an injector body and a plunger. The injector body may include a bore defined by an interior wall, a longitudinal axis extending centrally along the injector body, and a distal end portion. The distal end portion may include a first sidewall; a second sidewall disposed opposite the first sidewall; a third sidewall extending between the first sidewall and the second sidewall; and a fourth sidewall opposite the third sidewall, the first sidewall, second sidewall, third sidewall, and fourth sidewall joined to define passage forming a portion of the bore. The injector body may also include a first ramp formed on an interior surface of the passage along the first sidewall and laterally offset from the longitudinal axis. The first ramp may be disposed at a position within the passage to contact a leading haptic of an intraocular lens. The first ramp may include a first leading surface being sloped and inwardly extending from the interior surface into the passage and a first peak disposed at a distal end of the first ramp disposed at a distal end of the first leading surface. The intraocular lens injector may also include a plunger slideable within the bore defined by the interior wall. 
     The aspects of the present disclosure may include one or more of the following features. The first leading surface may include a first plurality of steps therealong. Each of the first plurality of steps may include a rise and a run. The rise and run of each of the steps is uniform. At least one of the rise and run of at least one step of the first plurality of steps may be different from the rise and the run of another of the steps of the first plurality of steps. The injector body may also include a compartment configured to receive the intraocular lens. The compartment may adjoins and be in fluid communication with the passage. A threshold may be defined between the passage and the compartment. A proximal end of the first leading surface of first ramp may be located along at the threshold. 
     One or more of the following features may also be included in the various aspects of the present disclosure. A second ramp may be formed on the interior surface of the passage along the second sidewall and adjacent to the first ramp. The first ramp and the second ramp may be integrally formed. The second ramp may include a second leading surface, and the second leading surface may be sloped and extend inwardly from the interior surface of the passage. The second ramp may also include a second peak disposed at a distal end of the second leading surface. The second leading surface may include a second plurality of steps. Each of the second plurality of steps may include a rise and a run. The rise and run of each of the steps may be uniform. At least one of the rise and run of at least one step of the second plurality of steps may be different from the rise and the run of another of the steps of the second plurality of steps. The first leading surface and the second leading surface may be integrally formed. The first ramp further may include a first trailing surface disposed distally of the first peak. The first trailing surface may have a positive slope. A second ramp may be formed on the interior surface of the passage along the second sidewall and adjacent to the first ramp. The second ramp may include a second leading surface that is sloped and that extends inwardly from the interior surface of the passage, a second peak disposed at a distal end of the second leading surface, and a second trailing surface. The second trailing surface may have a positive slope. The first trailing surface and the first trailing surface may be integrally formed. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an example intraocular lens injector. 
         FIG.  2    shows a longitudinal cross-sectional view of the intraocular lens injector of  FIG.  1   . 
         FIG.  3    is a perspective view of a distal portion of an example injector body of the intraocular lens injector of  FIG.  1   . 
         FIG.  4    is a cross-sectional view of the distal portion of the injector body shown in  FIG.  3   . 
         FIG.  5    is an example cross-sectional shape of a nozzle of an intraocular lens injector. 
         FIG.  6    shows a cross-sectional view of an intraocular lens receiving compartment formed in an injector body. 
         FIG.  7    shows a perspective view of an intraocular lens receiving compartment formed in an injector body. 
         FIG.  8    is a cross-sectional view of a plunger. 
         FIG.  9    is a bottom view of a plunger. 
         FIG.  10    is a partial perspective view showing tabs and a plunger lock of an example intraocular lens injector. 
         FIG.  11    is a detail view of an example plunger tip of plunger. 
         FIG.  12    shows an example interior surface of a door enclosing a lens-receiving compartment of an intraocular lens injector. 
         FIG.  13    is a detail view of the distal end portion of the IOL injector showing a demarcation designating a pause position of an IOL being advanced through the IOL injector. 
         FIG.  14    is a view of a distal end portion of an IOL injector with an IOL located therein at a pause position. 
         FIG.  15    is a detail view of an example IOL injector showing an opening at an interface between a compartment into which an IOL is received and an internal bore of an injector body, the detail view being transverse to a longitudinal axis of the IOL injector, and the detail view showing a flexible wall portion in contact with an injector rod. 
         FIG.  16    is a partial cross-sectional view of an example IOL injector. 
         FIG.  17    shows an example IOL. 
         FIG.  18    is a perspective view of an example plunger tip. 
         FIG.  19    is a side view of the example plunger tip of  FIG.  18   . 
         FIG.  20    is a top view of the example plunger tip of  FIG.  18   . 
         FIG.  21    is a side view of a distal end portion of an example IOL injector. 
         FIG.  22    is a cross-sectional view taken along line A-A of  FIG.  21   . 
         FIG.  23    is a plan view of the distal end portion of the IOL injector of  FIG.  21   . 
         FIG.  24    is a cross-sectional view taken along line B-B of  FIG.  23   . 
         FIG.  25    is a detail view of a ramp formed in an interior passage of a distal end portion of an IOL injector. 
         FIG.  26    is a cross-sectional view taken along line C-C of  FIG.  23   . 
         FIG.  27    is a detail view of a ramp formed in an interior passage of a distal end portion of an IOL injector. 
         FIG.  28    shows an example lifting feature disposed within an interior passage of an IOL injector operable to lift a leading haptic of an IOL during advancement of the IOL. 
         FIG.  29    shows another example lifting feature disposed within an interior passage of an IOL injector operable to lift a leading haptic of an IOL during advancement of the IOL. 
         FIGS.  30 - 33    illustrate lifting of a leading haptic of an IOL by a ramp form on an interior surface of a distal end portion of an IOL injector as the IOL is advanced through an interior passage of the IOL injector. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the implementations illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one implementation may be combined with the features, components, and/or steps described with respect to other implementations of the present disclosure. 
     The present disclosure relates to systems, apparatuses, and methods for delivering an IOL into an eye. Particularly, the present disclosure relates to systems, apparatuses, and methods for intraocular lens injectors having features to improve leading haptic lift during intraocular lens folding.  FIGS.  1  and  2    show an example IOL injector  10  that includes an injector body  20  and a plunger  30 . The injector body  20  defines a bore  40  extending from a proximal end  50  of the injector body  20  to a distal end portion  60  of the injector body  20 . The plunger  30  is slideable within the bore  40 . Particularly, the plunger  30  is slideable within bore  40  in order to advance an IOL, such as IOL  70 , within the injector body  20 . The IOL injector  10  also includes a longitudinal axis  75  disposed centrally through the body  20 . The longitudinal axis  75  may extend along the plunger  30  and define a longitudinal axis of the plunger  30 . 
     The injector body  20  includes a compartment  80  operable to house an IOL prior to insertion into an eye. In some instances, a door  90  may be included to provide access to the compartment  80 . The door  90  may include a hinge  100  such that the door  90  may be pivoted about the hinge  100  to open the compartment  80 . The injector body  20  may also include tabs  110  formed at the proximal end  50  of the injector body  20 . The tabs  110  may be manipulated by fingers of a user, such as an ophthalmologist or other medical professional, to advance the plunger  30  through the bore  40 . 
       FIGS.  3 - 5    illustrate details of the distal end portion  60  of the injector body  20 . In some instances, the distal end portion  60  has a tapered exterior surface. Further, the distal end portion  60  includes a passage  64  that tapers towards a distal opening  125 . The injector body  20  also includes a nozzle  120  at the distal end portion  60 . The nozzle  120  is adapted for insertion into an eye so that an IOL may be implanted. An IOL is expelled from distal opening  125  formed in the nozzle  120 . As shown in  FIG.  5   , the nozzle  120  may have an elliptical cross section. Additionally, the nozzle  120  may include a beveled tip  130 . The compartment  80 , passage  64 , and opening  125  may define a delivery passage  127 . A size of the delivery passage  127  may vary along its length. That is, in some instances, a height H1 of the passage may change along a length of the delivery passage  127 . The variation in size of the delivery passage  127  may contribute to the folding of the IOL as it is advanced therealong. 
     In some instances, the injector body  20  may include an insertion depth guard  140 . The insertion depth guard  140  may form a flanged surface  150  that is adapted to abut an exterior eye surface. The insertion depth guard  140  abuts an eye surface and, thereby, limits an amount by which the nozzle  120  is permitted to extend into an eye. In some implementations, the flanged surface  150  may have a curvature that conforms to the outer surface of an eye. For example, the flanged surface  150  may have a curvature that conforms to a scleral surface of the eye. In other instances, the flanged surface  150  may have a curvature that corresponds to a corneal surface of the eye. In still other instances, the flanged surface  150  may have a curvature, part of which corresponds to a scleral surface and another part that corresponds to a corneal surface. Thus, the flanged surface  150  may be concave. In other instances, the flanged surface  150  may be flat. In still other instances, the flanged surface  150  may be convex. Further, the flanged surface  150  may have any desired contour. For example, the flanged surface  150  may be a curved surface having radii of curvature that vary along different radial directions from a center of the flanged surface  150 . In still other instances, the flanged surface  150  may define a surface that has varying curvature along different radial directions as well as curvature that varies along one or more particular radial directions. 
     In  FIG.  3   , the insertion depth guard  140  is shown as a continuous feature that forms a continuous flanged surface  150 . In some implementations, the insertion depth guard  140  may be segmented into a plurality of features or protrusions forming a plurality of eye-contacting surfaces. These eye-contacting surfaces may work in concert to control the depth to which the nozzle  120  may penetrate an eye. In other implementations, the insertion depth guard  140  may be omitted. 
       FIG.  6    shows a cross-sectional detail view of the compartment  80  and a portion of bore  40  of the example injector body  20  shown in  FIG.  2   . The bore  40  is defined by an interior wall  298 . The interior wall  298  includes a tapered portion that includes a first tapered wall  301  and a second tapered wall  303 . The tapered portion of the interior wall  298  defines an opening  170  at an interface  172  between the bore  40  and the compartment  80 . The opening  170  includes a height H2. A distal end portion  211  of the plunger rod  210  has a height of H3. In some instances, height H2 may be larger than height H3, such that, initially, there is no interference between the plunger rod  210  and the interior wall  298  at the opening  170 . In other instances, height H2 may be equal to or larger than height H3, such that the plunger rod  210  and the opening  170  initially have an interference fit. In some implementations, the first tapered wall  301  includes a flexible wall portion. In the example shown, the flexible wall portion  162  is an obliquely-extending, flexible portion of the interior wall  298  and, particularly, of the first tapered wall  301 . As shown in  FIG.  7   , in some instances, portions of the first tapered wall  301  are removed, forming voids  163  that flank the flexible wall portion  162 . Thus, in some instances, the flexible wall portion  162  may extend in a cantilevered manner. 
     Referring again to  FIG.  6   , in some instances, the flexible wall portion  162  may be sloped toward the distal end portion  60  of the injector body  20 . In some instances, an angle B defined by the flexible wall portion  162  and the longitudinal axis  75  may be in the range of 20° to 60°. For example, in some instances, the angle B may be 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, or 60°. Further, the angle B may be greater or smaller than the defined range or anywhere within the recited range. Moreover, the scope of the disclosure is not so limited. Thus, the angle B may be any desired angle. 
     The injector body  20  may also include a contoured ramp  180  formed along an interior receiving surface  190  of the compartment  80 . Generally, the interior receiving surface  190  is the surface on which an IOL, such as IOL  70 , is placed when loaded into the IOL injector  10 .  FIG.  7    is a perspective view of a portion of the example injector body  20  shown in  FIG.  2   . The door  90  is not shown. In some instances, a vertical distance C between a tip of the flexible wall portion  162  and the top of the contoured ramp  180  may correspond with a height H3 of a distal end portion  211  of the plunger rod  210 . In other instances, the distance C may be greater or less than the height H3 of the distal end portion  211  of the plunger rod  210 . The flexible wall portion  162  and contoured ramp  180  are discussed in more detail below. In some implementations, the flexible wall portion  162  may be omitted. For example, in some implementations, the flexible wall portion may be unnecessary, as the plunger  30  and the associated plunger rod  210  maintain are configured such that a plunger tip, e.g., plunger tip  220  discussed in more detail below, remains in contact with the contoured ramp  180  during advancement of the plunger  30 . 
     As also shown in  FIG.  7   , the injector body  20  may include a contoured surface  192  that is offset from the receiving surface  190 . A wall  194  is formed adjacent to the contoured surface  192 . A freely extending end  452  of a haptic  450 , shown in  FIG.  17   , contacts the contoured surface  192  when IOL  70  is received into the compartment  80 . 
     Referring to  FIGS.  1  and  8 - 9   , the plunger  30  may include a body portion  200 , a plunger rod  210  extending distally from the body portion  200 , and a plunger tip  220  formed at a distal end  230  of the plunger rod  210 . The plunger  30  may also include a flange  240  formed at a proximal end  250  of the body portion  200 . A biasing element  260  may be disposed on the plunger  30 . In some instances, the biasing element  260  may be a spring. In some implementations, the biasing element  260  may be disposed adjacent to the flange  240 . A proximal end  262  may be fixedly attached at the body portion adjacent to the flange  240 . In other instances, the biasing element  260  may be disposed at another location along the body portion  200 . In still other implementations, the biasing element  260  may be formed or otherwise disposed on the injector body  20  and adapted to engage the plunger  30  at a selected location during advancement of the plunger  30  through bore  40 . Still further, in other implementations, the biasing element  260  may be omitted. 
     The flange  240  may be used in concert with the tabs  110  to advance the plunger  30  through the injector housing  20 . For example, a user may apply pressure to tabs  110  with two fingers while applying opposing pressure to the flange  240  with the user&#39;s thumb. A surface of the flange  240  may be textured in order to provide positive gripping by a user. In some instances, the texture may be in the form of a plurality of grooves. However, any desired texture may be utilized. 
     The body portion  200  may include a plurality of transversely arranged ribs  270 . In some instances, the ribs  270  may be formed on both a first surface  280  and a second surface  290  of the body portion  200 , shown in  FIG.  1   . In other instances, the ribs  270  may be formed on only one of the first surface  280  and second surface  290 . A longitudinally extending rib  300  may also be formed on one or both of the first and second surfaces  280 ,  290 . 
     In some instances, the body portion  200  may also include one or more protrusions  202 , as shown in  FIG.  9   . The protrusions  202  may extend longitudinally along a length of the body portion  200 . The protrusions  202  may be received grooves  204  formed in the injector body  20 , as shown in  FIG.  1   . The protrusions  202  and grooves  204  interact to align the plunger  30  within the bore  40  of the injector body  20 . 
     The body portion  220  may also include cantilevered members  292 . The cantilevered members  292  may extend from a distal end  294  of the body portion  200  towards the proximal end  250 . The cantilevered members  292  may include flared portions  296 . The cantilevered members  292  may also include substantially horizontal portions  297 . The flared portions  296  are configured to engage the interior wall  298  of the injector body  20  that defines the bore  40 , as shown in  FIG.  2   . Engagement between the cantilevered members  292  and the interior wall  298  generates a force resistive to advancement of the plunger  30  and provides a tactile feedback to the user during advancement of the plunger  30 . For example, in some implementations, the resistive force generated by contact between the cantilevered members  292  and the interior wall  298  may provide a baseline resistance that resists advancement of the plunger  30 . 
     In some instances, the plunger rod  210  may include an angled portion  212 . The distal end portion  211  may form part of the angled portion  212 . The angled portion  212  may define an angle, A, within the range of 1° to 5° with the longitudinal axis  75 . In some instances, the angle A maybe 2°. In some instances, the angle A may be 2.5°. In still other instances, the angle A may be 3°, 3.5°, 4°, 4.5°, or 5°. Further, while the above values of A are provided as examples, the angle A may be greater or less than the indicated range or any value in between. Thus, the angle A may be any desired angle. 
     The angled portion  212  ensures that the plunger tip  220  contacts and follows the receiving surface  190  as the plunger  30  is advanced through the bore  40 . Particularly, the angle A defined by the angled portion  212  exceeds what is needed to cause the plunger tip  220  to contact the interior wall  298  of the bore  40 . That is, when the plunger  30  is disposed within the bore  40 , engagement between the plunger tip  220  and the interior wall  298  causes the angled portion  212  to bend inwardly due to the angle A. Consequently, the angled portion  212  ensures that the plunger tip  220  properly engages the haptics and optic of an IOL being inserted from the IOL injector  10 . This is described in greater detail below. Although the angled portion  212  is shown as being a substantially straight portion bent at an angle relative to the remainder of the plunger rod  210 , the scope is not so limited. In some instances, a portion of plunger rod  210  may have a continuous curvature. In other instances, an entire length of the plunger rod  210  may be bent or have a curvature. Further, the amount of angular offset from the longitudinal axis  75  or amount of curvature may be selected in order to provide a desired amount of engagement between the plunger tip  220  and the interior surfaces of the injector body  20 . 
     The biasing element  260  may be affixed to the body portion  200  adjacent to the flange  240 . In some instances, the biasing element  260  may form a hoop  310  extending distally along the body portion  200  that functions as a spring to resist advancement of the plunger  30  when the hoop  310  engages the injector body  20 . The biasing element  260  may also include a collar  261  that defines a channel  320  through which the body portion  200  extends. Thus, in operation, as the plunger  30  is advanced through the bore  40  of the injector body  20  (i.e., in the direction of arrow  330  shown in  FIG.  2   ), a distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20  at a selected location along the stroke of the plunger  30 . As the injector  30  is further advanced, the biasing element  260  is compressed and the channel  320  permits the distal end  265  of the biasing element  260  to move relative to the body portion  200 . Similarly, the channel  320  permits relative movement between the body portion  200  and the distal end  265  of the biasing element  260  during proximal movement of the plunger  30  (i.e., in the direction of arrow  340 , also shown in  FIG.  2   ). 
     Referring to  FIGS.  2 ,  9 , and  10   , the IOL injector  10  may also include a plunger lock  350 . The plunger lock  350  is removably disposed in a groove  360  formed in one of the tabs  110 . The plunger lock  350  includes a protrusion  370  formed at one end thereof. The plunger lock  350  may include a single protrusion  370 , as shown in  FIG.  2   . In other instances, the plunger lock  350  may include a plurality of protrusions  370 . For example,  FIG.  10    illustrates an example plunger lock  350  having two protrusions  370 . In other instances, the plunger lock  350  may include additional protrusions  370 . 
     When installed, the protrusion  370  extends through an aperture  375  formed in the injector body  20  and is received into a slot  380  formed in the plunger  30 . When the plunger lock  350  is installed, the protrusion  370  and slot  380  interlock to prevent the plunger  30  from moving within the bore  40 . That is, the installed plunger lock  350  prevents the plunger  30  from being advanced through or removed from the bore  40 . Upon removal of the plunger lock  350 , the plunger  30  may be freely advanced through the bore  40 . In some instances, the plunger lock  350  may include a plurality of raised ribs  390 . The ribs  390  provide a tactile resistance to aid in removal from and insertion into groove  360 . 
     The plunger lock  350  may be U-shaped and define a channel  382 . The channel  382  receives a portion of the tab  110 . Further, when fitted onto the tab  110 , a proximal portion  384  of the plunger lock  350  may be outwardly flexed. Consequently, the plunger lock  350  may be frictionally retained on the tab  110 . 
     Referring to  FIGS.  2  and  8   , in some implementations, the body portion  20  may include shoulders  392  formed in bore  40 . The shoulders  392  may be formed at a location in the bore  40  where the bore  40  narrows from an enlarged proximal portion  394  and a narrower distal portion  396 . In some instances, the shoulder  392  may be a curved surface. In other instances, the shoulder  392  may be defined a stepped change in the size of bore  40 . 
     The cantilevered members  292  may engage the shoulder  392 . In some implementations, the flared portion  296  of the cantilevered members  292  may engage the shoulder  392 . In some instances, a location at which the cantilevered members  292  engage the shoulder  392  may be one in which the slot  380  aligns with the aperture  375 . Thus, in some implementations, engagement between the cantilevered members  292  and shoulder  392  may provide a convenient arrangement for insertion of the plunger lock  350  to lock the plunger  30  in place relative to the injector body  20 . In other implementations, the slot  380  and the aperture  375  may not align when the cantilevered members  292  engage the shoulder  392 . 
     As the plunger  30  is advanced through the bore  40 , the flared portion  296  of the cantilevered members  292  may be inwardly displaced to comply with the narrowed distal portion  396  of the bore  40 . As a result of this deflection of the flared portion  296 , the cantilevered members  292  apply an increased normal force to the interior wall  298  of the bore  40 . This increased normal force generates a frictional force that resists advancement of the plunger  30  through bore  40 , thereby providing tactile feedback to the user. 
     Referring to  FIGS.  1  and  2   , the IOL injector may also include an IOL stop  400 . The IOL stop  400  is received into a recess  410  formed in an outer surface  420  the door  90 . The IOL stop  400  may include a protrusion  430  that extends through an opening  440  formed in the door. The protrusion  430  extends between a haptic and optic of an IOL loaded into the compartment  80 . As shown in  FIGS.  1  and  17   , the IOL  70  includes haptics  450  and an optic  460 . The protrusion  430  is disposed between one of the haptics  450  and the optic  460 . The IOL stop  430  may also include a tab  435 . The tab  435  may be gripped by a user for removal of the IOL stop  430  from the injector body  20 . 
     The IOL stop  400  may also include an aperture  470 . The aperture  470  aligns with another opening formed in the door  90 , for example opening  472  shown in  FIG.  13   . The aperture  470  and second opening  472  in the door  90  form a passageway through which a material, such as a viscoelastic material, may be introduced into the compartment  80 . 
     The IOL stop  400  is removable from the door  90 . When installed, the IOL stop  400  prevents advancement of the IOL, such as IOL  70 . Particularly, if advancement of the IOL  70  is attempted, the optic  460  contacts the protrusion  430 , thereby preventing advancement of the IOL  70 . 
       FIG.  11    shows an example plunger tip  220 . The plunger tip  220  may include a first protrusion  480  and a second protrusion  490  extending from opposing sides. The first and second protrusions  480 ,  490  define a first groove  500 . The first groove  500  defines a surface  502 . A second groove  510  is formed within the first groove  500 . The first groove  500 , particularly in combination with the first protrusion  480 , serves to capture and fold a trailing haptic of an IOL. The second groove  510  functions to capture and fold an optic of an IOL. 
     A side wall  520  of the plunger tip  220  may be tapered. The tapered side wall  520  may provide a nesting space for a gusseted portion of the trailing haptic of an IOL. The gusseted portion of the haptic tends to remain proximal to the IOL optic. Thus, the tapered side wall  520  may provide a nesting space that promotes proper folding of the IOL during delivery into an eye. 
       FIGS.  18 - 20    show another example plunger tip  220 . This plunger tip  220  includes a first protrusion  600 , a second protrusion  602 , and a groove  604 . The first protrusion extends at an oblique angle θ from longitudinal axis  606 . In some instances, the angle θ may be between 25° to 60°. In other instances, the angle θ may be lower than 25° or larger than 60°. In other instances, the angle θ may be between 0° to 60°. In still other implementations, the angle θ may be between 0° and 70°; 0° and 80°; or 0° and 90°. Generally, the angle θ may be selected to be any desired angle. For example, the angle θ may selected based on one or more of the following: (1) a size, such as a height, of passage  64  formed within the nozzle  60 ; (2) the height of the compartment  80 ; (3) how the height of the passage  64  and/or compartment varies along their respective lengths; and (3) the thickness of the plunger tip  220 . The second protrusion  602  may include a tapered portion  608 . The tapered portion  608  is operable to engage an optic of an IOL, such as optic  460  shown in  FIG.  17   . The optic may slide along the tapered surface so that the optic may be moved into the groove  604 . As a result, the second protrusion  602  is positioned adjacent to a surface of the optic. 
     The example plunger tip  220  shown in  FIGS.  18 - 20    also include a surface  610  that may be similar to the surface  502 . The surface  610  is adapted to contact and displace a trailing or proximally extending haptic, such as haptic  450  shown in  FIG.  17   , so that the haptic folds. In some instance, the surface  610  may be a flat surface. In other instances, the surface  610  may be a curved or otherwise contoured surface. The example plunger tip  220  may also include a side wall  612  and support surface  613 . Similar to the side wall  520 , the side wall  612  may be tapered, as shown in  FIG.  20   . In some instances, the side wall  612  may include a first curved portion  614 . The first curved portion  614  may receive a bent portion of the trailing haptic that remains proximal to the optic during folding. The trailing haptic is supported by support surface  613  during the folding process. The side wall  612  may also include a second curved surface  615 . 
     The obliquely-extending first protrusion  600  effectively increases a height H4, as compared to the plunger tip  220  shown in  FIG.  11   , for example. This increased height H4 improves the ability of the plunger tip  220  to capture the trailing haptic during advancement of the plunger  30 . In operation, as the plunger  30  is advanced distally, the distal end  618  engages an interior wall of the delivery passage  127  due to changes in the height H1 of the delivery passage  127 . As the height H1 decreases, the first protrusion  600  pivots about hinge  620 , effectively reducing the total height H4 of the plunger tip  220 . As the first protrusion  600  pivots about hinge  620  and rotated in a direction towards the second protrusion  602 , the first protrusion  600  captures the trailing haptic between the optic of the IOL and the first protrusion  600 . Therefore, with the first protrusion  600  pivotable about the hinge  620 , the size of the plunger tip  220  is able to adapt and conform to the changing height H1 of the delivery passage  127  as the IOL is advanced distally and folded. 
       FIG.  12    shows an interior surface  530  of door  90 . The surface  510  may include a ridge  530 . The ridge  530  may include a curved portion  540 . In the example illustrated, the curved portion  540  extends proximally and inwardly towards the longitudinal axis  75 . The curved portion  540  is configured to overlay a portion of a trailing haptic of an IOL, which promotes proper folding of the IOL when the plunger  30  is advanced through the injector body  20 . 
     In operation, the plunger lock  350  may be inserted into the groove  360  to lock the plunger  30  in position relative to the injector body  20 . An IOL, such as IOL  70 , may be loaded into the compartment  80 . For example, the door  90  may be opened by a user and a desired IOL inserted into the compartment  80 . The door  90  may be closed upon insertion of the IOL into the compartment  80 . In some instances, an IOL may be preloaded during manufacturing. 
     The IOL stop  400  may be inserted into the recess  410  formed in the door  90 . Viscoelastic material may be introduced into the compartment  80  via the aligned aperture  470  and corresponding opening formed in the door  90 . The viscoelastic material functions as a lubricant to promote advancement and folding of the IOL during advancement and delivery of the IOL into an eye. In some instances, the viscoelastic material may be introduced into the compartment  80  at the time of manufacturing. 
     The IOL stop  400  may be removed from the recess  410  formed in the door  90 , and the plunger lock  350  may be removed from the groove  360 . The plunger  30  may be advance through the bore  40 . Sliding engagement between the cantilevered members  292  and the interior wall  298  of the injector body  20  generates a resistive force that resists advancement of plunger  30 . In some instances, the plunger  30  may be advanced through the bore  40  until the plunger tip  220  extends into the compartment  80 . For example, the plunger  30  may be advanced until the plunger tip  220  is adjacent to or in contact with the IOL. In other instances, the plunger  30  may be advanced through the bore  40  such that the IOL is partially or fully folded. Further, the plunger  30  may advance the IOL to a position within the nozzle just short of being ejected from the distal opening  125 . For example, in some instances, advancement of the plunger  30 , prior to insertion of the nozzle  120  into a wound formed in the eye, may be stopped at the point where the distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20 . 
       FIG.  21    shows the distal end portion  60  of the IOL injector  10 .  FIG.  22    is a cross-sectional view of the distal end portion  60  of the IOL injector  10  taken along line A-A. Longitudinal axis  75  is shown in  FIG.  22    and extends centrally along the passage  64  such that the longitudinal axis  75  divides the distal end portion  60  symmetrically in  FIG.  22   . Referring to  FIGS.  21  and  22   , the distal end portion  60  includes a first sidewall  700 , a second sidewall  702  opposite the first sidewall  700 , a third sidewall  704  disposed between the first and second sidewalls  700  and  702 , and a fourth sidewall  706  opposite the third sidewall  704  and also disposed between the first and second sidewalls  700  and  702 . The sidewalls  700 ,  702 ,  704 , and  706  define the passage  64 . 
     In order to provide improved folding of an IOL, such as IOL  70 , a ramp  708  is formed on an interior surface  710  of the first sidewall  700 . Referring to  FIGS.  22 ,  23 , and  28   , the ramp  708  includes a peak  709 , a leading surface  712  disposed proximally the peak  709 , and a trailing surface  713  disposed distally of the peak  709 . The peak  709  extends along a width of the ramp  708  and separates the leading surface  712  from the trailing surface  713 . The peak  709  represent a portion of the ramp  708  with the largest separation from plane C, shown in  FIG.  24    and discussed in more detail below. As is readily apparent, the leading surface  712  of the ramp  708  increases the lift, i.e., displacement in the direction of arrow  709 , of a leading haptic of an IOL (e.g., leading haptic  450  of IOL  70 , shown in  FIG.  10   ) at a much faster rate as the IOL is advance through the passage  64  than would otherwise be provided by the surface  710  if the ramp  708  were omitted. The ramp  708  operates to mitigate or eliminate improper folding of the leading haptic during folding of the IOL within the IOL injector  10 . For example, the ramp  708  may avoid improper folding in which the leading haptic remains distal to an in contact with a leading edge  728  (shown in  FIG.  24   ) of the optic  460  during folding of the IOL  70 . Thus, the ramp  708  is operable to lift the leading haptic  450  above the optic  460  such that the haptic  450  is able to be folded over the optic  460  as the IOL  70  is folded prior to being expelled from the IOL injector  10  and into an eye for implantation. 
     As shown in  FIG.  22   , the ramp  708  is laterally offset from the longitudinal axis  75 , which forms a centerline along the IOL injector  10 , towards the third sidewall  704 . The location of the ramp  708  is such that a freely extending end of a leading haptic of an IOL, such as freely extending end  452  of haptic  450  of IOL  70  extending digitally from the optic  460 , encounters the ramp  708  as the IOL is advance along the delivery passage  127  by the plunger  30 . 
       FIG.  23    is a plan view of the distal end portion  60  of the IOL injector  10  showing the second sidewall  702 .  FIG.  24    is a cross-sectional view of the distal end portion  60  taken along line B-B shown in  FIG.  22   . The line B-B represents a plane passing through a portion of the ramp  708  having the largest distance between a point along the peak  709  and the plane C, shown in  FIG.  24   . H5 represents the maximum dimension between the ramp  708  and the plane C. The ramp  708  is positioned within the passage  64  to contact and engage the freely extending end of the leading haptic. In the illustrated example, the ramp  708  is disposed distally of the threshold  65  between the compartment  80  and the passage  64 . The ramp  708  begins at a proximal end indicated by point  705 . In some instances, a longitudinal distance G between the point  705  and the peak  709  (which, in some instances, may be coincident with point  707 , described in more detail below) may be within the range of 0.5 mm to 1.5 mm. Thus, in some implementations, the distance G may be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm. However, the distance G may be selected to be any value within the indicated range or a value larger or smaller than the indicated range. Line  710  corresponds to an interior surface of the first sidewall  700  defining the passage  64  away from and not forming part of the ramp  708 . A length L of the ramp  708  along the cross-section shown in  FIG.  24    may be within the range of 8 mm to 10 mm. In other implementations, the length L of the ramp  708  may be greater than 10 mm or less than 8 mm. 
     Referring to  FIGS.  30 - 33    illustrates the operation of the ramp  708  in lifting the leading haptic  450  above optic  460  as the IOL  70  is advanced within the IOL injector  10 . In operation, as the plunger rod  210  advances the IOL  70  along the delivery passage  127 , the freely extending end  452  of the leading haptic  450  contacts and rides along a leading surface  712  of the ramp  708 . As the IOL  70  is continued to be advanced, the leading haptic  450  is lifted as it rides along the leading surface  712 . Lifting of the leading haptic  450  continues until the leading haptic  450  has obtained a sufficient height above the optic  460  of the IOL. For example, a height obtained by the leading haptic  450  as a result of riding along the leading surface  712  of the ramp  708  may be selected to ensure that leading haptic avoids being trapped forward or distal of a leading edge  714  of the optic  460 . Further, a position of the leading surface  712  of the ramp  708  longitudinally along the distal end portion  60  and a slope of the leading surface  712  may be selected such that the leading haptic  450  achieves a desired height above the optic  460  before or simultaneous with curling of the lateral edges  453  (shown in  FIG.  14   ) of the optic  460  as the optic  460  begins to fold. A ramp  708  configured in such a way ensures that the freely extending end  452  of the leading haptic  450  is tucked proximal to the leading edge  714  of the optic and between the folded lateral sides  453  thereof. An illustration of this folding arrangement of the leading haptic relative to the optic is shown in  FIG.  19   . 
     In the example shown in  FIG.  24   , the leading surface  712  is a smooth surface. That is, in some implementations, the leading surface  712  may be free of discontinuities or rapid changes in curvature. However, the scope of the disclosure is not so limited. In some implementations, the leading surface  712  of the ramp  708  may have stepped surface.  FIG.  25    shows a detail cross-sectional view of an example leading surface  712  of the ramp  708  in which the leading surface  712  includes a plurality of steps  716 . In some instances, the leading surface  712  may be formed entirely of steps  716 . In other instances, the leading surface  720  may have a plurality of steps along only a portion of its length. In other implementations, the sizes of one or more steps  716  may vary from the sizes of one or more other steps  716  of the leading surface  712 . 
     In some implementations, each of the steps  716  includes a rise  718  and a run  720 . The run  720  extends in a direction parallel to a longitudinal axis  75  of the IOL injector  10 , while the rise  718  extends in a direction perpendicular to the longitudinal axis  75  of the IOL injector  10 . In some implementations, the rise  718  of one or more of the steps  716  may have a length in the range of 0.2 to 0.5 mm. Particularly, the length of the rise  718  may be 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. However, these dimensions are merely examples. In other implementations, the length of the rise  718  may be larger or smaller than the indicated range. That is, in some instances, the rise  718  may be larger than 0.5 mm or smaller than 0.2 mm. 
     The run  720  of one or more of the steps  716  may have a length in the range of 0.2 to 0.5 mm. Particularly, the length of the run  720  may be 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. However, these dimensions are merely examples. In other implementations, the length of the run  720  may be larger or smaller than the indicated range. That is, in some instances, the run  720  may be larger than 0.5 mm or smaller than 0.2 mm. 
     Although  FIG.  25    shows an example leading surface  712  having a plurality of steps  716  that are uniform in size. Thus, in some implementations, with the leading surface  712  having a plurality of steps  716  with uniform sizes, the leading surface  712  defines a linear slope. However, the scope of the disclosure is not so limited. Rather, in other instances, one or more of the rise  718 , the run  720 , or both the rise  718  and run  720  of one or more of the steps  716  may be different than one or more other steps  716 . In some instance, the run  718  of the steps may decrease in the distal direction along the leading surface  712 . In other implementations, the run  718  of the steps may increase in the distal direction along the leading surface  712 . In some instances, the rise  718  of the steps may increase in the distal direction along the leading surface  712 . In other implementations, the rise  718  of the steps may decrease in the distal direction along the leading surface  712 . In instances where the rise  718  and run  720  of one or more of the steps  716  varies, the leading surface  712  may define an overall curved surface or, more generally, a non-linear surface. In some implementations, the stepped leading surface  712  may be arranged to form an overall parabolic shape to the leading surface  712 . An overall parabolic shape of the leading surface  712  may alter an amount of lift imparted to the leading haptic  450  as a distance traveled by the leading haptic  450  in the distal direction changes. Particularly, the amount of lift imparted to the leading haptic  450  may increase per rate of movement of the leading haptic  450  in the distal direction along the longitudinal axis of the passage  64  of the distal end portion  60 . However, the overall shape defined by the leading surface  712  may be any desired shape. For example, the leading surface  712  may have an inclined undulating surface, an inclined flat surface, or any other desired surface. 
     An overall slope of the ramp  708  is defined by a line  703  extending from a point  705 , a proximal end of the ramp  708 , to a point  707  wherein the line  705  tangentially touches the peak  709  of the ramp  708 . The slope line  703  is angularly offset from the plane C by an angle T. In some instances, the angle T may be between 17° and 27°. Particularly, in some instances, the angle T may be 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, or 27°. However, the angle T may be selected to be any value within the indicated range or a value larger or smaller than the indicated range. 
     Referring to  FIGS.  22 ,  24 , and  25   , the trailing surface  713  of the ramp  708  gradually recedes into the interior surface  710  of the first sidewall  700 . In the example shown in  FIG.  24   , the trailing surface  713  has a positive slope as the trailing surface  713  extends distally. In some examples, the positive slope of the trailing surface  713  is provided for manufacturability of the IOL injector  10  and, particularly, for the distal end portion  60 . In the case of injection molding, for example, a positive slope of the trailing surface  713  provides a draft angle that facilitates manufacturing of the distal end portion  60 . However, the trailing surface  713  need not have a positive slope. In other implementations, the trailing surface  713  may have a neutral slope, i.e., a slope of zero, or a negative slope. In still other implementations, the trailing surface  713  of the ramp  708  may be omitted. 
     In some implementations, the third sidewall  704  may also include ramp  722  formed on an interior surface thereof, as shown in  FIG.  22   . In some instances, the ramp  722  may blend with the ramp  708 . For example, in some instances, the ramp  722  may be a continuation of the ramp  708  that continues from the inner surface of the first sidewall  700  onto the inner surface of the third sidewall  704 . In some implementations, the ramp  722  may be omitted. 
     The ramp  722  includes a leading surface  723 , a trailing surface  725 , and a peak  727  disposed between the leading surface  723  and the trailing surface  725 . Similar to the peak  709 , the peak  727  extends along a width of the ramp  722  and separates the leading surface  723  from the trailing surface  725 .  FIG.  26    is a cross-sectional view of the distal end portion  60  taken along line C-C shown in  FIG.  23   . The line C-C represents a plane that passes through the peak  709  of the ramp  708  and the peak  727  of the ramp  722 . While peaks  709  and  727  are aligned in the example distal end portion  60  illustrated in  FIG.  21 - 26   , the scope of the disclosure is not so limited. Rather, the peaks  709  and  727  may be offset. In some instances, the peak  709  may be disposed proximally of the peak  727 . In other instances, the peak  709  may be disposed distally of the peak  727 . 
     As shown in  FIG.  26   , the peak  723  of the ramp  722  is disposed at an angle relative to vertical axis  729 , whereas the peak  709  of the ramp  708  is parallel with the horizontal axis  731 . However, in other implementations, the peak  709  may be angled relative to the horizontal axis  731 . In some instances, the peak  723  may be parallel with the vertical axis  729 . Referring to  FIG.  22   , a surface  724  corresponding to an inner surface of the passage  64  of a distal end portion  60  that omits the ramp  722  is illustrated. Consequently, the difference in topography experienced by a leading haptic, such as leading haptic  450 , in instances with the ramp  722  as opposed to those without the ramp  722  is apparent. As shown in  FIG.  26   , the surface  710  joins with surface  724  to form a representation of a continuous surface that would otherwise exist in the passage  64  if the ramps  708  and  722  were omitted. 
     The freely extending end  452  of the leading haptic  450  engages the ramp  722  as the IOL  70  is advance within the passage  64  and operates to restrict distal movement of the leading haptic  450  as the leading haptic  450  is being lifted by the ramp  708 . As the IOL  70  continues to advance, the leading haptic  450  engages the leading surface  723  of the ramp  722 . As a result, the distal movement of the leading haptic  450  is temporarily reduced or stopped such that the leading haptic  450  is folded over the surface  726  of the optic  460 . As advancement of the IOL  70  continues, a point is reached where the force applied to the leading haptic  450  in the distal direction as a result of advancement of the IOL  70  exceeds a resistive force applied to the leading haptic  450  by the ramp  722 . As a result, the leading haptic  450  is deflected and forced past the ramp  722  with the leading haptic  450  folded over the optic  460  and adjacent to the surface  726 . The point at which the leading haptic  450  is moved past the ramp  722  and folded over the surface  726  of the optic  460  occurs just prior to folding of the lateral sides  453  of the optic  460 . The folded lateral sides  453  of the optic  460  capture the leading haptic  450  therebetween and maintain the leading optic  450  in a folded configuration. 
     As explained above, the ramp  708  and the ramp  722  may join into a single topographical feature present within the passage  64 . In other implementations, the ramp  708  and the ramp  722  may be separate features formed in the passage  64 . Further, the leading surface  723  of the ramp  722  may be a smooth surface, i.e., free discontinuities or rapid changes in curvature. However, like the leading surface  712  of the ramp  708 , the leading surface  723  of the ramp  722  may have a stepped surface.  FIG.  27    shows a detail view the ramp  722  shown in  FIG.  22   . The ramp  722  includes a stepped leading surface  723  having a plurality of steps  730 . In some instances, the leading surface  723  may be formed entirely of steps  730 . In other instances, the leading surface  723  may have a plurality of steps along only a portion of its length. In other implementations, the sizes of one or more steps  730  may vary from the sizes of one or more other steps  730  of the leading surface  723 . 
     In the instances where the ramp  708  and the ramp  722  are joined, one of the leading surface  712  of the ramp  708  and the leading surface  723  of the ramp  722  may include one or more steps while the other of the leading surface  712  of the ramp  708  and the leading surface  723  of the ramp  722  may omit steps. In some instances, both the leading surface  712  and the leading surface  723  may include one or more steps. In still other implementations, both the leading surface  712  and the leading surface  723  may omit steps. 
     In instances wherein the leading surface  712  of the ramp  708  and the leading surface  723  of the ramp  722  include a plurality of steps, the rise and run of the steps of each of the leading surfaces  712  and  723  may be the same or the rise and run of each of the leading surfaces  712 ,  723  may vary from each other. Further, a slope of each of the leading surfaces  712  and  723  may be the same or different from one another. In some instances, the rise and run of the steps on each of the leading surfaces  712  and  723  may vary both between the leading surfaces  712  and  723  and on each of the leading surfaces  712  and  723 . 
     Each of the steps  730  includes a rise  732  and a run  734 . The run  734  extends in a direction parallel to a longitudinal axis  75  of the IOL injector  10 , while the rise  732  extends in a direction perpendicular to the longitudinal axis  75  of the IOL injector  10 . In some implementations, the rise  732  of one or more of the steps  730  may have a length in the range of 0.2 to 0.5 mm. Particularly, the length of the rise  732  may be 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. However, these dimensions are merely examples. In other implementations, the length of the rise  732  may be larger or smaller than the indicated range. That is, in some instances, the rise  732  may be larger than 0.5 mm or smaller than 0.2 mm. In instances where the rise  718  and run  720  of one or more of the steps  716  varies, the leading surface  712  may define an overall curved surface or, more generally, a non-linear surface. 
     The run  734  of one or more of the steps  730  may have a length in the range of 0.2 to 0.5 mm. Particularly, the length of the run  734  may be 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. However, these dimensions are merely examples. In other implementations, the length of the run  734  may be larger or smaller than the indicated range. That is, in some instances, the run  734  may be larger than 0.5 mm or smaller than 0.2 mm. 
     Although  FIG.  27    shows an example leading surface  723  having a plurality of steps  730  that are uniform in size. Thus, in some implementations, with the leading surface  723  having a plurality of steps  730  with uniform sizes, the leading surface  723  defines a linear slope. However, the scope of the disclosure is not so limited. Rather, in other instances, one or more of the rise  732 , the run  734 , or both the rise  732  and run  734  of one or more of the steps  730  may be different than one or more other steps  730 . In some instance, the run  734  of the steps may decrease in the distal direction along the leading surface  723 . In other implementations, the run  734  of the steps may increase in the distal direction along the leading surface  723 . In some instances, the rise  732  of the steps may increase in the distal direction along the leading surface  712 . In other implementations, the rise  732  of the steps  730  may decrease in the distal direction along the leading surface  723 . In instances where the rise  732  and run  734  of one or more of the steps  730  varies, the leading surface  723  may define an overall curved surface or, more generally, a non-linear surface. In some implementations, the stepped leading surface  723  may be arranged to form an overall parabolic shape to the leading surface  723 . However, the shape of the leading surface  723  may be any desired shape. For example, the leading surface  723  may have an inclined undulating surface, an inclined flat surface, or any other desired surface. 
       FIG.  27    also shows a plane D that extends parallel to the longitudinal axis  75  of the IOL injector  10 . The plane D passes through a first point  731  defining a proximal end of the ramp  730 . An overall slope of the ramp  730  is defined by a line  733  extending from the point  71  to a point  735  wherein the line  733  tangentially touches the peak  727  of the ramp  730 . The slope line  733  is angularly offset from the plane D by an angle U. In some instances, the angle U may be between 63° and 73°. Particularly, in some instances, the angle U may be 63°, 64°, 65°, 66°, 67°, 68°, 69°, 70°, 71°, 72°, or 73°. However, the angle U may be selected to be any value within the indicated range or a value larger or smaller than the indicated range. 
     In the illustrated example shown in  FIG.  27   , the ramp  722  is disposed distally of the threshold  65  between the compartment  80  and the passage  64 . The ramp  708  begins at a proximal end indicated by point  731 . In some instances, a longitudinal distance H between the point  731  and the peak  709  (which, in some instances, may be coincident with point  735 ) may be within the range of 0.4 mm to 1.4 mm. Thus, in some implementations, the distance H may be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.4 mm. However, the distance H may be selected to be any value within the indicated range or a value larger or smaller than the indicated range. 
     Referring to  FIGS.  22 ,  26 , and  27   , the trailing surface  725  of the ramp  722  gradually recedes into the interior surface  724  of the third sidewall  704 . In the example shown in  FIG.  24   , the trailing surface  725  has a positive slope as the trailing surface  725  extends distally. Similar to the trailing surface  713 , discussed above, in some examples, the positive slope of the trailing surface  725  is provided for manufacturability of the IOL injector  10  and, particularly, for the distal end portion  60 . In the case of injection molding, for example, a positive slope of the trailing surface  725  provides a draft angle that facilitates manufacturing of the distal end portion  60 . However, the trailing surface  725  need not have a positive slope. In other implementations, the trailing surface  725  may have a neutral slope, i.e., a slope of zero, or a negative slope. In still other implementations, the trailing surface  725  of the ramp  722  may be omitted. 
     As shown in  FIG.  26   , a height F of the passage  64  may be within the range of 2.4 mm to 2.6 mm. However, such dimensions are merely illustrative, and the height F of the passage may be greater than 2.6 mm or less than 2.4 mm. Further, a height E of the ramp  722  where the ramp  722  merges into the inner surface of the passage  64  (i.e., the inner surface of the passage  64  that is a continuation of the surface  724 ) may be within the range of 1.5 mm to 1.8 mm. However, in some implementations, the height E may be greater than 1.8 mm or less than 1.5 mm. The height D of the ramp  708  at the peak  709  may be within the range of 0.5 mm to 1.0 mm. As is apparent, the example dimensions provided are for the indicated features at the cross-section along line C-C (shown in  FIG.  27   ). Thus, in some implementations, the height E of the ramp  722  may be within the range of 57% to 75% of the height E of the passage  64 . Also, in some implementations, the height F of the ramp  708  may be within the range of 19% and 42% of the height E of the passage  64 . Again, though, the indicated ranges are illustrative only, and the heights D and E of the ramps  708  and  722 , respectively, relative to the height F of the passage  64  may be selected to be any desired amount. 
       FIG.  28    shows another example lifting feature  800  disposed within the delivery passage  127  operable to lift the leading haptic  450  of IOL  70  over surface  726  of the optic  460 . In some implementations, the lifting feature  800  may be disposed in the passage  64  of the distal end portion  60 . For example, the lifting feature  800  may be attached to an upper surface (within the context of  FIG.  29   ). That is, in some instances, the lifting feature  800  may be attached to a surface of the passage  64  that is adjacent to the interior surface  530  of the door  90  (shown in  FIG.  12   ) and opposite the receiving surface  190  (shown in  FIG.  6   ). In the illustrated example, the lifting feature  800  is secured to an interior surface  802  of the passage  64 . The lifting feature  800  includes a base  804 , a pivoting portion  806 , and a hinge  808  connecting the pivoting portion  806  to the base  804 . Positions I through V shown in  FIG.  28    illustrate folding of the leading haptic  450  as the IOL  70  is advanced through the passage  64  relative to the optic  460 . 
     At position I, the pivoting portion  806  of the lifting feature  800  is shown in an initial, undisturbed configuration with the leading haptic  450  just beginning to engage the pivoting portion  806 . At position II, the leading haptic  450  is shown lifted in the direction of arrow  810  by an inclined surface  812  formed on the pivoting portion  806 . Additionally, the lifting feature  800  also causes displacement of the leading haptic  450  towards the optic  460 . In the context of advancement of the IOL  70 , movement of the leading haptic  450  towards the optic  460  means that the lifting feature  800  retards or slows advancement of the leading haptic  450  relative to the optic  460 , resulting in the relative movement of the leading haptic  450  towards the optic  460 . 
     As a result of the engagement with the leading haptic  450 , the pivoting portion  806  is shown slightly deflected distally in a direction of arrow  814 . At position III, the leading haptic  450  is shown lifted to a maximum amount by the lifting feature  800  along with the pivoting portion  806  displaced to a greater extent distally. Position III also shows a leading edge  816  of the optic  460  positioned below the leading haptic  450  (in the context of the view shown in  FIG.  28   ). At position IV, the leading haptic  450  is shown folded over the surface  726  and the pivoting portion  806  is further folded distally. At position V, the leading haptic  450  is shown fully folded over the surface  726  of the optic  460 . The pivoting portion  806  is shown proximal of the leading haptic  450 . Consequently, as the IOL  70  is advanced, a point is reached where the pivoting portion  806  pivots about hinge  808  to permit the leading haptic  450  to distally pass the folding feature  800 . Thus, the folding feature  800  is operable to lift and fold the leading haptic  450  while also being operable to bend and permit the leading haptic  450  to distally move past the folding feature. As folding of the IOL  70  continues, the pivoting portion  806  remains bent about the hinge  808  to permit passage of the remainder of the IOL  70 . 
     In some implementations, the inclined surface  812  may be a smooth surface. In other implementations, the inclined surface  812  may include a plurality of steps similar to the steps  716  shown in  FIGS.  25  and  27   , for example. 
     In some implementations, the folding feature  800  may be formed of a flexible material having a hardness less than a material forming the IOL  70 . Thus, the folding feature  800  is formed of a material that permits the IOL  70  to contact and slide against the folding feature  800  but prevent damage to the folding feature. However, in other implementations, the folding feature  800  may be formed of a material having a hardness that is greater that a material forming the IOL  70 . For example, the folding feature  800  may be designed so as to eliminate sharp edges to avoid damaging the IOL  70  even though the material forming the folding feature  800  has a higher hardness than the material forming the IOL  70 . 
       FIG.  29    illustrates another example lifting feature  900  disposed within the delivery passage  127  operable to lift the leading haptic  450  of IOL  70  over surface  726  of the optic  460 . In some implementations, the lifting feature  900  may be disposed in the passage  64  of the distal end portion  60 . For example, the lifting feature  900  may be attached to a lower surface (within the context of  FIG.  29   ). That is, in some instances, the lifting feature  900  may be attached to a surface of the passage  64  that is opposite to the interior surface  530  of the door  90  (shown in  FIG.  12   ) and adjacent the receiving surface  190  (shown in  FIG.  6   ). In the illustrated example, the lifting feature  900  is secured to an interior surface  902  of the passage  64 . 
     The lifting feature  900  includes a base  904 , a pivoting portion  906 , and a hinge  908  connecting the pivoting portion  906  to the base  904 . The pivoting portion  906  has a “V” shape that defines a first inclined surface  910  and a second inclined surface  912 . The leading haptic  450  of the IOL  70  engages and slides along the first and second inclined surfaces  910  and  912  so as to lift the leading haptic  450  above (in the context of  FIG.  32   ) the surface  762  of the optic  460 . 
     Positions I through III shown in  FIG.  29    illustrate folding of the leading haptic  450  as the IOL  70  is advanced through the passage  64  relative to the optic  460 . At position I, the pivoting portion  906  of the lifting feature  900  is shown in an initial, undisturbed configuration with the leading haptic  450  just beginning to engage the pivoting portion  906 . At position II, the leading haptic  450  is partially folded and lifted in the direction of arrow  914  by the first and second inclined surfaces  910  and  912  formed on the pivoting portion  906 . As a result of the engagement with the leading haptic  450 , the pivoting portion  906  is shown deflected distally in a direction of arrow  916  relative to the base  904 , resulting in the inclined surface  912  forming a ramp that operates to further lift the leading haptic  450  above the top corner of the leading edge of the optic  760  (as viewed in the context of  FIG.  29   ). As is also illustrated at II, the lifting feature  900  also causes displacement of the leading haptic  450  towards the optic  460 . In the context of advancement of the IOL  70 , movement of the leading haptic  450  towards the optic  460  means that the lifting feature  900  retards or slows advancement of the leading haptic  450  relative to the optic  460 , resulting in the relative movement of the leading haptic  450  towards the optic  460 . At position III, the leading haptic  450  is shown lifted above and folded over the optic such that the leading haptic  450  is located adjacent to the surface  762  of the optic  460 . The folding feature  900  is shown on a side of the optic  460  opposite the leading haptic  450 . 
     In some implementations, one or both of the inclined surfaces  910  and  912  may be a smooth surface. In other implementations, one or both of the inclined surfaces  910  and  912  may include a plurality of steps similar to the steps  716  shown in  FIGS.  25  and  27   , for example. 
     As the IOL  70  continues to advance along the passage  64 , the optic  460  presses against and slides over the folding feature  900  such that the pivoting portion  906  is further folded over. Similar to the folding feature  800 , the folding feature  900  may be formed of a flexible material having a hardness less than a material forming the IOL  70 . However, in other implementations, the folding feature  900  may be formed of a material having a hardness that is greater that a material forming the IOL  70 . Similar to the folding feature  800 , discussed above, in some instances, the folding feature  800  may be designed so as to eliminate sharp edges to avoid damaging the IOL  70  even though the material forming the folding feature  800  has a higher hardness than the material forming the IOL  70 . Thus, the folding feature  900  is formed of a material that permits the IOL  70  to contact and slide against the folding feature  900  but prevent damage to the folding feature. 
     Advancement of the plunger  30  through the injector body  20  is discussed below with reference to  FIGS.  1 ,  6 , and  11   . In some instances, dimensional tolerances between the plunger  30  and the injector body  20  may permit relative movement between the plunger  30  and the injector body  20  such that the distal end portion  211  is able to move within bore  40  in the direction of arrows  471 ,  472  (referred to hereinafter as “tolerance movement”). In instances, particularly those in which the plunger  30  includes angled portion  212 , the plunger tip  220  normally remains in contact with the interior wall  298  even if the plunger  30  experiences tolerance movement as the plunger  30  advances through bore  40 . Thus, in some instances, notwithstanding any tolerance movement, the plunger tip  220  remains in contact with the interior wall  298 . Accordingly, the second tapered wall  303  directed and centers the plunger tip  220  into the opening  170 . 
     If the plunger  30  experiences tolerance movement such that the plunger tip  220  no longer contacts the interior wall  298  of the bore  40 , the first tapered wall  301 , which includes the flexible wall portion  162 , directs and centers the plunger tip  220  into the opening  170  formed at the interface  172 , resulting in contact between the plunger tip  220  and the second tapered wall  303 . When the plunger  30  becomes fully engaged with the injector body  20 , the tolerance movement is substantially reduced or eliminated, ensuring that the plunger tip  220  remains engaged with the second tapered wall  303  and contoured ramp  180 . In some instances, full engagement between the plunger  30  and the injector body  20  occurs when the cantilevered members  292  are fully engaged with the interior wall  298  of the bore  40 . Consequently, in instances where tolerance movement may exist, upon full engagement between the plunger  30  and the injector body  20 , the flexible wall portion  162  no longer influences the position of the plunger  30 . In any case, once the plunger tip  220  advances through opening  170 , the flexible wall portion  162  no longer affects the directional path of plunger  30  nor any part thereof. 
     As the plunger tip  220  is advanced through the compartment  80  in sliding contact with the receiving surface  190 , the first groove  500  of the plunger tip  220  is positioned to engage the trailing haptic of IOL, such as trailing haptic  450  of IOL  70 , as shown in  FIG.  6   . As the plunger tip  220  is further advanced, the plunger tip  220  encounters the contoured ramp  180  and is forced vertically towards the door  90 . This vertical displacement of the plunger tip  220 , while remaining in contact with the receiving surface  190 , both folds the trailing haptic up over the optic of the IOL as well as align the second groove  510  of the plunger tip  220  with a trailing edge of the haptic. Particularly, the surface  502  of the plunger tip  220  contacts and displaces the haptic  450  as the plunger tip  220  is passed along the contoured surface  180 , thereby folding the trailing haptic  450 . As the trailing haptic  450  folds, the contoured surface  192  and wall  194  work in concert to both locate the freely extending end  452  of the trailing haptic  450  above and over the optic  460 . The profile of the contoured surface  192  operates to lift the trailing haptic  450  as the plunger tip  220  is displaced towards the distal end portion  60  of the injector body  20 . The wall  194  constrains lateral movement of the freely extending end  452  of the trailing haptic  450 , which cause the haptic to move distally relative to the optic  460 . Consequently, the trailing haptic  450  is both raised above and folded over the optic  460  as the plunger tip  220  contacts the trailing haptic  450  and follows along the contoured ramp  180 . As the plunger tip  220  is further advanced, the second groove  510  accepts the trailing edge of the optic  460 , and the plunger tip  220  is displaced vertically away from the door  90  due to a combination of influences from both the decreasing slope of the contoured ramp  180  and the angled portion  212  of the plunger rod  210 . Movement of the plunger tip  220  in the manner described provides for improved engagement and folding of the IOL  70 . 
       FIG.  13    is a detail view of a portion of the distal end portion  60  of the injector body  20 . The distal end portion  60  includes a tapered portion  62  and the insertion depth guard  140 . The distal end  265  of the biasing element  260  may engage the proximal end  50  of the injector body  20  to define a pause location of the folded or partially folded IOL. The nozzle  120  may include a demarcation  1900  that provides a visual indication of the pause position. For example, in the example shown in  FIG.  13   , the demarcation  1900  is a narrow ridge or line that encircles all or a portion of the distal end portion  60 . In some instances, the demarcation  1900  may be disposed between the tapered portion  62  and the insertion depth guard  140 . At least a portion of the injector body  20  may be formed form a transparent or semi-transparent material that permits a user to see an IOL within the injector body  20 . Particularly, the distal end portion  60  of the injector body  20  may be formed from a transparent material to permit observation of the IOL as it is moved therethrough by the plunger  30 . 
       FIG.  14    shows a view of the distal end portion  60  of the IOL injector  10  with IOL  70  located therein at a pause position. As shown in  FIG.  14   , the pause position of the IOL may be defined as a location where the distal edge  462  of optic  460  of the IOL  70  substantially aligns with the demarcation  1900 . A haptic  450  or a portion thereof may extend beyond the demarcation  1900 . Again, the pause position may also correspond to the initial engagement of the distal end  265  of the biasing element  260  with the proximal end  50  of the injector body  20 . Therefore, the pause location may be jointly indicated by positioning of the IOL, or part thereof, relative to the demarcation  1900  and the initial contact between the distal end  265  of the biasing element  260 . 
     In other instances, a location of the IOL relative to the distal opening  12  of the nozzle  120  when the distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20  may vary. In some instances, the IOL may be partially ejected from the distal opening  125  when the distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20 . For example, in some instances, approximately half of the IOL may be ejected from the distal opening  125  when the distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20 . In other instances, the IOL may be contained wholly within the IOL injector when the distal end  265  of the biasing element  260  contacts the proximal end  50  of the injector body  20 . 
       FIG.  15    shows a cross sectional view of the opening  170  formed at the interface  172 . In some instances, the opening  170  may define a “T” shape. The plunger tip  220  is shown disposed at the opening  170  with the flexible wall portion  162  contacting a surface  214  the plunger rod  210 . In some instances, the cross section of the plunger rod  210  increases towards the proximal end of the plunger rod  210 . Thus, as the plunger rod  210  is advanced through the opening  170 , the plunger rod  210  fills the opening as a result of the increasing cross section. Portions  173  and  175  of the opening  170  are filled by flanges  213 ,  215  (shown in  FIG.  9   ). 
     As the opening  170  is filled by the increasing cross section of the plunger rod  210  as the plunger rod  210  is advanced distally through the injector body  20 , the flexible wall portion  162  is flexed in the direction of arrow  471  to permit passage of the plunger rod  210 , as shown in  FIG.  16   . Further, as a result of the angled portion  212  of the plunger rod  210 , the contoured ramp  180 , and the folding of IOL  70  as it is advanced through the IOL injector  10 , the plunger tip  220  is made to follow a defined path through the compartment  80 , the distal end portion  60 , and nozzle  120  uninfluenced by the flexible wall portion  162 . 
       FIG.  16    shows the flexible wall portion  162  being flexed in the direction of  471  as the plunger rod  210  continues to advance distally through the IOL injector  10 . Further,  FIG.  16    also shows the plunger tip  220  engaged with IOL  70  such that trailing haptic  450  is received into the first groove  500  at a location offset from the second groove  510 , and the proximal edge of the optic  460  is received into the second groove  510 . 
     As the IOL  70  is advanced through the passage  64  of the distal end portion  60 , the IOL  70  is folded into a reduced size to permit passage of the IOL  70  through the nozzle  120  and into the eye. During folding of the IOL  70 , a resistive force on the plunger  30  is increased. Once the IOL  70  is fully folded  70 , the resistive force on the plunger  30  generally reduces. 
     A wound may be formed in the eye. The wound may be sized to accommodate the nozzle  120  of the IOL injector  10 . The nozzle  120  may be inserted into the wound. The nozzle  120  may be advanced through the wound until the flanged surface  150  of the insertion depth guard  140  abuts the exterior surface of the eye. Contact between the insertion depth guard  140  and the exterior surface of the eye limits the depth to which the nozzle  120  may be inserted into the eye, preventing unnecessary stress on the edges of the wound as well as preventing enlargement of the wound due to over insertion of the IOL injector  10 . Consequently, the insertion depth guard  140  operates to reduce additional trauma to the eye and enlargement of the wound. 
     With the nozzle properly positioned within the eye through the wound, the user may complete delivery of the folded IOL into the eye. Referring to  FIG.  2   , as advancement of the plunger  30  continues, the biasing element  260  is compressed. Compression of biasing element  260  increases a resistive force to advancement of the plunger  30 , also referred to as plunging force. This additional resistance to advancement of the plunger  30  diminishes changes to the plunging force associated with the folding of the IOL prior to insertion into the eye. Further, in some instances, the biasing element  260  may be made to contact the injector body  120  when, or proximate to when, the IOL  70  has fully folded so that the a reduction in resistive force that may result from the IOL  70  being fully folded may be offset by the compression of the biasing element  260 . This increase in resistive force provided by compression of the biasing element  260 , particularly in light of a reduction that may result due to the IOL  70  being fully folded, provides improved tactile feedback to a user, such as a medical profession, during delivery of the IOL  70  into an eye. This improved tactical feedback provides the user with improved control during delivery of the IOL  70 , which may prevent rapid expulsion of the IOL  70  into the eye. 
     As a result, the user is able to provide a smooth application of force without experiencing any sudden or rapid changes in advancement of the plunger  30 . Such sudden or rapid changes may result in the IOL being rapidly expelled from an injector. Rapid expulsion of an IOL into an eye may cause damage, such as perforation of the capsular bag. Such damage may increase the time required to compete the surgical procedure and may increase the harm caused immediately and post operatively to the patient. Upon insertion of the IOL into the eye, the IOL injector  10  may be withdrawn from the eye. 
     Although the disclosure provides numerous examples, the scope of the present disclosure is not so limited. Rather, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure.