fig1 illustrates an intraocular lens delivery system 100 according to a particular embodiment of the present invention . the delivery system 100 includes an injector body 102 having a bore 104 along with a plunger 200 to advance an intraocular lens within the injector body 102 . as used within this specification , the term “ injector body ,” an example of which is injector body 102 , refers to any portion , components , or collection of components enclosing a bore 104 through which the plunger 200 advances when pushing the intraocular lens . the term “ plunger ” describes any component advanced through the bore 104 to push an intraocular lens through the injector body , which can be ( but need not be ) connected to other components of the intraocular lens delivery system 100 . in particular , plungers 200 of various embodiments of the present invention may be made compatible with the lens delivery systems described in detail in u . s . pat . no . 7 , 156 , 854 to brown et al ., which is incorporated herein by reference . in particular embodiments , the entire injector body 102 may be formed as a single piece from a suitable material , which may include , for example , polypropylene or polyethylene . in other embodiments , the injector body 102 may be formed by coupling part of a reusable handpiece that forms a continuous bore 104 to a disposable cartridge holding the intraocular lens having a nozzle portion for injecting the intraocular lens through a surgical incision . various embodiments may also include a lubricious coating within the bore 104 of the injector body 102 to facilitate advancement of the intraocular lens . however , one difficulty with previous intraocular lens delivery systems is that the plungers may also slide too easily within the bore 104 , thus removing any real tactile feedback during advancement of the intraocular lens . particular embodiments of the present invention provide a solution to this difficulty by producing a resistance to advancement of the plunger 200 , as described in greater detail below . the plunger 200 pushes the intraocular lens by advancing a shaft 202 of the plunger 200 through the bore 104 . coupled to the plunger 200 are two deflectable members 204 on opposite sides of the plunger 200 . fig2 a and 2b show additional views of the deflectable members 204 of fig1 . in the depicted embodiment , the deflectable members 204 are arc - shaped , resilient extensions from the shaft 202 of the plunger 200 . the peaks of the deflectable member 204 are configured to contact and to be deflected by an inner wall of the injector body 102 when the plunger 200 is placed within the bore 104 . the resulting force from the deflection of the deflectable members 204 helps to position the plunger 200 within the bore 104 so that the shaft 202 of the plunger 200 is reliably oriented relative to the intraocular lens . the deflectable members 204 also fit sufficiently tightly within the bore 104 that , when the deflectable members 204 are compressed by the inner wall of the injector body 102 , the friction against the inner wall resists advancement of the plunger 200 . this produces a tactile resistance to the plunger 200 sliding through the bore 104 , which in turn both assists the surgeon in realizing when the plunger 200 is correctly engaged in the intraocular lens delivery system 100 and provides a steady resistance that facilitates controlled application of force during the lens delivery process . because the resistance varies with the force produced by deflection of the deflectable members 204 , it is possible to adjust a design for the deflectable members 204 in order to vary the resistance of the intraocular lens delivery system 100 . advantageously , the force can be adjusted to correspond to a desired “ feel ” for surgeons . for example , the resistance may be calibrated based on a survey of physicians to evaluate what resistance feels most suitable . in another example , typical resistance forces for handpieces of intraocular lens delivery systems preferred by various surgeons can be measures , and the deflectable members 204 can be adjusted to produce a suitable resistance . in yet another example , multiple different resistance values can be selected for multiple intraocular lens delivery systems 100 , allowing physicians to choose plungers 200 that are relatively “ stiff ” ( i . e ., having high resistance to advancement ) or plungers 200 that are relatively “ yielding ” ( i . e ., having lower resistance to advancement ). the deflectable members 204 can be formed separately from the plunger 200 or formed simultaneously as a single piece with the plunger 200 from a selected material suitable for use in ophthalmic applications , e . g ., polypropylene . forming the plunger 200 with the deflectable members 204 as a single piece has an advantage in reducing the number of manufacturing steps using techniques such as injection molding . the resistance force created by the deflectable members 204 can then be adjusted by varying the shape of the deflectable members 204 with respect to a selected material , so that plungers 200 with characteristic resistances can be produced . alternatively , the same shape for the deflectable members 204 could be used with a variety of selected materials of different resiliency . in general , any adjustment known to be suitable to change the resistance of the plunger 200 to advancement may be employed . multiple deflectable members 204 placed along the plunger 200 could also be used to help the stability of the plunger 200 . thus , for example , one pair of deflectable members 204 could be placed closer to a distal end of the plunger 200 (“ distal ” in this context referring to an end of the plunger 200 configured to be placed nearest the incision during lens injection ), while another pair is placed nearer to a proximal end (“ proximal ” referring to the end farthest from the incision during lens injection ). such configurations of deflectable members 204 can help to keep the plunger 200 aligned within the bore 104 as it is advanced . fig3 is a flowchart 300 illustrating an example method of manufacturing an intraocular lens delivery system 100 according to a particular embodiment of the present invention . at step 302 , a desired resistance to advancement of a plunger 200 for the intraocular lens delivery system 100 is determined . the desired resistance may be determined based on a survey of physicians using various designs , force measurements of lens delivery systems used by the physicians , theoretical calculations based on the overall sources of resistance in the system 100 , or a combinations of these techniques and / or any other suitable techniques for determining the value . at step 304 , a shape for at least two deflectable members 204 is determined so that the deflectable members 204 hold the plunger 200 within the bore 104 and provide the predetermined resistance to advancement of the plunger 200 . the deflectable members 204 may be designed according to any of the various considerations described above , including consideration of the material for the deflectable members 204 in determining the shape of the deflectable members 204 . steps 302 and 304 may also be repeatedly iteratively , such as particular designs being made and evaluated by physicians providing feedback used in the next design iteration . finally , at step 306 , the intraocular lens delivery system 100 is manufactured . suitable manufacturing techniques may include injection molding , press formation , lathing , or any other technique known for forming the material in the art . in a variation of the method presented above , multiple plungers 200 for intraocular lens delivery systems 200 with different resistances can be manufactured by selecting different forces at step 302 . in particular embodiments of this variant method , step 302 may include selection of multiple resistance values based on considerations similar to the ones described above to provide for different surgical needs . likewise , multiple designs for the deflectable members 204 may be determined that correspond to the different resistances , and step 306 would then include the manufacture of multiple plungers 200 along with injector bodies 102 that may be either common to the various plungers 200 or customized to work with plungers 200 having particular deflectable members 204 . although this particular variation has been described in detail , it should also be understood that other variations to the manufacturing method consistent with the description of the various embodiments of the intraocular lens delivery system 100 described herein could also be employed . while certain embodiments of the present invention have been described above , these descriptions are given for purposes of illustration and explanation . variations , changes , modifications and departures from the devices and methods disclosed above may be adopted without departure from the scope of the present invention as claimed .
an intraocular lens delivery system includes an injector body having a bore surrounded by an inner wall . the system further includes a plunger configured to fit within the bore . the system also includes a plurality of deflectable members connected to the plunger and configured to contact the inner wall and to be deflected when the plunger is inserted within the bore . the deflectable members center the shaft and , when inserted within the injector body , contribute to producing a predetermined force resisting advancement of the plunger when deflected in the bore .