Abstract:
A device for injecting an intraocular lens (IOL) into an eye, the device having an injector body including a lumen and an open tip wherethrough the IOL is expressed from the device. An IOL loading bay is located in the passageway wherein the IOL is positioned and compressed. In a first aspect of the invention, the passageway diameter increases from a point adjacent the loading bay to the open tip to reduce compressive force on the IOL as it travels through the lumen. In another aspect of the invention, the plunger tip has a shape and diameter which has a close, sliding fit with the shape and diameter of the passageway to reduce the chance of the IOL becoming wedged between the plunger tip and the passageway wall as the plunger tip engages and advances the IOL through the passageway.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to ophthalmic surgical devices and methods. More particularly, the present invention relates to a device and method for inserting an intraocular lens (IOL) into an eye. 
     IOLs are artificial lenses used to replace the natural crystalline lens of the eye when the natural lens has cataracts or is otherwise diseased. IOLs are also sometimes implanted into an eye to correct refractive errors of the eye in which case the natural lens may remain in the eye together with the implanted IOL. The IOL may be placed in either the posterior chamber or anterior chamber of the eye. IOLs come in a variety of configurations and materials. Some common IOL styles include the so-called open-looped haptics which include the three-piece type having an optic and two haptics attached to and extending from the optic; the one-piece type wherein the optic and haptics are integrally formed (e.g., by machining the optic and haptics together from a single block of material); and also the closed looped haptic IOLs. Yet a further style of IOL is called the plate haptic type wherein the haptics are configured as a flat plate extending from opposite sides of the optic. The IOL may be made from a variety of materials or combination of materials such as PMMA, silicone, hydrogels and silicone hydrogels, etc. 
     Various instruments and methods for implanting the IOL in the eye are known. In one method, the surgeon simply uses surgical forceps having opposing blades which are used to grasp the IOL and insert it through the incision into the eye. While this method is still practiced today, more and more surgeons are using more sophisticated IOL inserter devices which offer advantages such as affording the surgeon more control when inserting the IOL into the eye. IOL inserter devices have recently been developed with reduced diameter insertion tips which allow for a much smaller incision to be made in the cornea than is possible using forceps alone. Smaller incision sizes (e.g., less than about 3 mm) are preferred over larger incisions (e.g., about 3.2 to 5+ mm) since smaller incisions have been attributed to reduced post-surgical healing time and complications such as induced astigmatism. 
     Since IOLs are very small and delicate articles of manufacture, great care must be taken in their handling. In order for the IOL to fit through the smaller incisions, they need to be folded and/or compressed prior to entering the eye wherein they will assume their original unfolded/uncompressed shape. The IOL inserter device must therefore be designed in such a way as to permit the easy passage of the IOL through the device and into the eye, yet at the same time not damage the delicate IOL in any way. Should the IOL be damaged during delivery into the eye, the surgeon will most likely need to extract the damaged IOL from the eye and replace it with a new IOL, a highly undesirable surgical outcome. 
     Thus, as explained above, the IOL inserter device must be designed to permit easy passage of the IOL therethrough. It is equally important that the IOL be expelled from the tip of the IOL inserter device and into the eye in a predictable orientation and manner. Should the IOL be expelled from the tip too quickly or in the wrong orientation, the surgeon must further manipulate the IOL in the eye which could result in trauma to the surrounding tissues of the eye. It is therefore highly desirable to have an inserter device which allows for precise loading of the IOL into the inserter device and which will pass and expel the IOL from the inserter device tip and into the eye in a controlled, predictable and repeatable manner. 
     To ensure controlled expression of the IOL through the tip of the IOL inserter device, the IOL must first be loaded into the IOL inserter device. The loading of the IOL into the inserter device is therefore a precise and very important step in the process. Incorrect loading of an IOL into the inserter device is oftentimes cited as the reason for a failed IOL delivery sequence. Many IOL injector devices on the market today require the IOL to be loaded into the injector at the time of surgery by the attending nurse and/or surgeon. Due to the delicate nature of the IOL, there is a risk that the nurse and/or surgeon will inadvertently damage the IOL and/or incorrectly load the IOL into the injector device resulting in a failed implantation. Direct handling and/or loading of the IOL into the injector by the nurse and/or surgeon is therefore undesirable. 
     In a typical IOL inserter device, the IOL inserter utilizes a plunger having a tip which engages the IOL (which has been previously loaded and compressed into the inserter lumen) to pass it through the inserter lumen. The IOL thus interfaces with the plunger tip as well as the lumen of the inserter device. The lumen typically is dimensioned with a narrowing toward the open tip thereof in order to further compress the IOL as it is advanced through the lumen. The tip of the lumen is sized for insertion through the surgical incision which, as stated above, is presently preferred in the sub 3 mm range. Thus, an inserter lumen will typically be dimensioned larger at the load area of the IOL and gradually decrease in diameter to the tip of the lumen where the IOL is expressed into the eye. It will be appreciated that the compressed diameter of the IOL at the lumen tip is the same as the inner diameter of the lumen tip, preferably sub 3 mm as stated above. Each of these component interfaces are dynamic in the sense that the forces acting between the interfacing components (i.e., the IOL, the plunger tip and the inserter lumen) will vary as the IOL is pushed through the lumen. Control of these dynamic forces is therefore of utmost importance or otherwise the IOL may be damaged during delivery due to excessive compressive forces acting thereon. For example, as the IOL is advanced by the plunger through an ever-decreasing diameter lumen, the IOL is being compressed while at the same time the forces necessary to push the IOL through the lumen increase. This may lead to excessive force between the plunger tip and the IOL resulting in possible damage to the IOL and/or uncontrolled release of the IOL from the lumen tip. Also, the force of the plunger tip may cause the IOL to twist and/or turn as it is moved through the inserter whereby the force between the IOL and the plunger tip and/or the inserter lumen may uncontrollably increase to the point of IOL damage. 
     Various inserter devices have been proposed which attempt to address these problems, yet there remains a need for an IOL inserter and method which reduces the likelihood of IOL damage during delivery through the injector device. 
     SUMMARY OF THE INVENTION 
     The injector comprises a device body having a longitudinal passageway (lumen) defined by an inner passageway wall terminating at an open tip. A plunger having a longitudinal plunger shaft and a plunger tip telescopes with the lumen of the device body. A loading bay is located in the lumen wherein an IOL is positioned and compressed. In a first aspect of the invention, the lumen increases in diameter from a point adjacent the loading bay to the open tip. This allows the IOL to gradually expand as it is advanced through the passageway by the plunger tip. This reduces forces on the IOL and thus reduces the chance of IOL damage caused by excessive forces exerted thereon during IOL delivery through and out the device. At the same time, the outer diameter of the device body along the same length remains constant at the desired diameter (e.g., sub 3 mm) so that the eye incision size need not be increased even though the inner diameter of the passageway is increasing. It will be appreciated that a compressed IOL will naturally seek a position of less compressive force. Thus, once the IOL is initially advanced by the plunger, the increasing diameter of the passageway adjacent the loading bay urges the IOL to continue to move in that direction (i.e., toward the open tip). The amount of force required to advance the IOL therethrough is thereby reduced and the goal of less force on the IOL during delivery through the inserter device is realized. 
     In another aspect of the invention, the cross-sectional shape of the plunger tip is substantially the same as the cross-sectional shape and slightly smaller than the diameter of the inner wall defining the lumen along the length where the IOL travels. As such, the plunger tip is in close, sliding relation to the passageway. This reduces the likelihood that the IOL can become wedged between the plunger tip and the passageway wall, a problem of prior injector designs having relatively large spacing between the plunger tip and inner lumen wall. 
     The injector includes means for compressing, rolling or otherwise forcing the IOL into a smaller cross-section for delivery through the injector. In a preferred embodiment of the invention, the injector device includes a compressor which extends laterally of the IOL loading bay of the injector body. The compressor is movable between fully open and fully closed positions and is initially in the open position. Once the IOL is positioned in the loading bay of the passageway, the compressor is moved to the closed position which compresses the IOL. The plunger is advanced at the proximal end of the injector device causing the tip of the plunger to engage the proximal end of the compressed IOL. As the plunger is advanced further, the IOL is pushed through the open distal tip of the injector body and expressed into the eye in the intended manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an IOL injector according to one embodiment of the invention; 
         FIG. 2A  is an enlarged, plan view of the loading bay portion of the injector of  FIG. 1  showing an IOL positioned therein ready for compression; 
         FIG. 2B  is an enlarged, cross-section view taken generally along the line  2 B- 2 B of  FIG. 1  and showing an IOL compressed therein; 
         FIG. 2C  is a fragmented view in cross-section of an alternate embodiment of the device tip showing a stepped increase in the inner diameter of the lumen; 
         FIG. 2D  is the same cross-sectional view as  FIG. 2B  but showing an alternate embodiment of the IOL injector; 
         FIG. 3A  is an enlarged perspective view of the loading bay area of the injector device of  FIG. 1 ; 
         FIG. 3B  is a cross-sectional view taken through the IOL loading bay of the injector device with the compressor drawer in the fully open position; 
         FIG. 3C  is a cross-sectional view taken along the line  3 C- 3 C of  FIG. 3A ; 
         FIG. 3D  is the view of  FIG. 3C  with the compressor drawer shown in the fully closed position; and 
         FIG. 3E  is a side elevational view of the retainer and IOL coupled together. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the Figures, a representative IOL injector device is indicated generally by the reference numeral  10 . The injector device  10  includes an injector body  12  having a longitudinal lumen  14  extending from the proximal end  16  to distal end  18  thereof. The lumen may assume any desired cross-sectional shape although circular or oval shapes are preferred. Proximal end  16  may include a finger hold flange  17  preferably configured with a straight edge  17   a  as shown for resting device  10  on a flat surface. A plunger  20 , having distal and proximal lengths  20   a ,  20   b , respectively, and a distal plunger tip  22  (see  FIG. 2A ) and proximal thumb press  24 , telescopes within lumen  14  for engaging and pushing the IOL  30  through lumen  14  and out of distal tip  18   a . The IOL delivery sequence will be explained in more detail below. It is understood that the overall configuration of the injector body  12  may vary from that shown and described herein. It is furthermore understood that the components of the injector device  10  may be made of any suitable material (e.g., polypropylene) and may be wholly or partly opaque, transparent or translucent to better visualize the IOL within the injector device and the IOL delivery sequence. 
     Injector body  12  further includes an opening  26  which opens into lumen  14 . Opening or “IOL loading bay”  26  accepts an IOL  30  therein for delivery of the IOL out distal tip  18   a . In one possible embodiment, device  10  includes an IOL retainer  40  ( FIGS. 3A-E ) used for loading the IOL  30  into loading bay  26 . Retainer  40  will be described herein in relation to injector device  10  for purposes of description, it being understood other IOL loading methods may be employed (including simply placing IOL  30  in loading bay  26  with a pair of forceps, for example). The retainer  40  and another embodiment of an IOL retainer are seen in commonly owned co-pending application Ser. Nos. 10/651,785 and 10/813,862, both of which are incorporated by reference herein. As explained in more detail in these copending applications, retainer  40  and IOL  30  may be coupled and packaged together or coupled to and packaged with an injector device  12  such that the surgeon or nurse need not handle and/or manipulate the IOL directly when loading the IOL  30  into the device  10 . 
     As seen best in  FIG. 3E , IOL retainer  40  includes one or more, but preferably two optic support elements  42   a  and  42   b  each having a groove  42   a′ ,  42   b′  or other feature for releasably supporting the IOL optic  31  at the periphery  31   a  thereof. Alternatively or in addition to the optic support elements, one or more, but preferably two haptic support elements  44   a  and  44   b  are provided on retainer  40 , each of which include a finger  44   a′ ,  44   b′  or other feature for releasably supporting one or more, but preferably two haptics  33   a  and  33   b  which attach to and extend from the optic  31 . In this regard, it is understood that the IOL configuration shown and described herein is for discussion purposes only, and that the present invention is not to be limited thereby. The invention may be easily adapted to IOLs of any configuration and type (e.g., IOLs with plate, open or closed loop haptics, anterior chamber IOLs, posterior chamber IOLs, accommodating IOLs (including single and double lens types), etc.). The overall configuration of the IOL retainer  40  may thus likewise vary so as to be cooperatively configured with and releasably hold the particular IOL configuration being used with the device. 
     The IOL retainer  40 , with IOL  30  releasably held thereby, is removably attached to the injector body  12  at IOL loading bay  26  as seen in  FIG. 3A . This may be done via suitable mechanical holding features which will removably connect the retainer  40  to the injector body  12 , examples including friction fit, snap fit, interference fit, cooperative tabs and catches, detents, etc. As seen in  FIG. 3A , retainer  40  is held in place at opening  26  via a friction fit between the surfaces defining opening  26  and the opposite outer wall surfaces  41   a  and  41   b  of retainer  40 . It will be seen that when retainer  40  and IOL  30  are coupled together and attached to injector body  12 , IOL optic  31  is unstressed and furthermore does not touch any part of the injector body  12 . 
     When retainer  40  and IOL  30  are coupled together and attached to injector body  12 , a stripper finger  50  is then moved between the IOL optic  31  and the center wall surface  46  of retainer  40  as seen best in  FIGS. 3A and 3C . The primary function of the stripper finger  50  is to prevent the IOL  30  from lifting with the retainer  40  when the retainer is detached from the injector body (this operation will be described below). In a preferred embodiment of the invention, the stripper finger  50  is attached to the compressor drawer  60  which is movable with respect to injector body  12  between a fully open position as seen in  FIG. 3B , a mid-way position seen in  FIG. 3C , and the fully closed position seen in  FIG. 3D . The stripper finger  50  is located between the IOL optic  31  and center wall surface  46  when the compressor  60  is in the mid-way position. When the compressor drawer  60  is moved to the fully closed position, the stripper finger  50  moves therewith and comes to rest in a position laterally adjacent the injector body  12  as seen in  FIG. 3D . 
     Referring to  FIGS. 1 and 2B , it is seen that the plunger  20  includes distal and proximal plunger shaft lengths  20   a ,  20   b , respectively, having a plunger tip  22  at the distal end thereof and a thumb press  24  at the proximal end thereof for manually operating the injector device. The plunger tip  22  is configured for engaging the IOL optic  31  at the periphery  31   a  thereof as the plunger  20  is advanced toward the distal tip  18   a  of the injector body  12 . It is very important that the plunger tip  22  not damage the IOL optic  31 . The plunger tip  22  is thus designed to prevent damage to the IOL optic  31 . In one embodiment, the plunger tip  22  may be configured with the same cross-sectional shape and slightly smaller diameter as the lumen  14  along the length where the IOL  30  travels (i.e., from the IOL loading bay  26  to the distal tip  18   a ). As such, there is a close, sliding fit between the plunger tip  22  and lumen  14  and the chance of the IOL becoming wedged between these two surfaces is reduced significantly. In this embodiment of plunger  20 , the inside diameter of lumen  14  may either remain constant from loading bay  26  to distal tip  18   a , or increase in diameter as in the embodiment of  FIGS. 2B and 2D  to be described below. It is understood that other plunger tip designs may be used with the present invention as desired. It is furthermore preferred that the plunger shaft is rotationally fixed within lumen  14  to prevent unexpected rotation of the shaft (and thus the tip  22 ) with the lumen  14 . The plunger shaft may be rotationally fixed by forming the proximal shaft length  20   b  and lumen  14  non-circular in cross-section or by including rotational fixing elements on the lumen inner wall and plunger shaft (e.g., longitudinal flange on the plunger having a sliding fit within a longitudinally extending groove provided on the lumen inner wall). 
     In a particularly advantageous embodiment, the proximal length  20   b  of the plunger shaft is provided with one or more elongated fingers  23   a ,  23   b  forming springs which are biased radially outwardly against the interior wall of lumen  14  (see  FIGS. 1 and 6 ). The purpose of spring fingers  23   a ,  23   b  is to provide proper centering of the plunger shaft and tip, as well as tactile resistance between the plunger  20  and the lumen  14  as the plunger  20  is advanced therethrough. In the storage position, the plunger  20  is retracted to the position shown in  FIG. 1 . To ensure the plunger is not unintentionally dislodged from the injector body or unintentionally advanced within lumen  14 , the spring free ends are located within respective openings  21   a ,  21   b  (opening  21   b  not shown) formed in the injector body  12  adjacent the proximal end  16  thereof. When it is time to use the device, the surgeon presses upon the thumb press  24  whereupon the free ends, assisted by their slanting edge faces, disengage from respective openings  21   a ,  21   b , allowing the plunger to be freely advanced in a controlled manner through lumen  14 . The bias of the spring fingers  23   a ,  23   b  against the interior wall of the lumen  14  provides the surgeon with continuous tactile feedback allowing the surgeon to advance the plunger (and thus the IOL) through the lumen  14  in a very concise and controlled manner. This feature is described more fully in our copending application Ser. No. 10/744,981. 
     Referring to the leading haptic  33   a , it is important that the leading haptic not become “bunched up” inside the injector tip  18  as the IOL  30  is being pushed therethrough. One way to prevent this from happening is to straighten the leading haptic  33   a  within tip  18 . To accomplish this, a haptic puller  80  is provided which is the subject of commonly assigned U.S. Pat. No. 6,491,697, the entire disclosure of which is hereby incorporated by reference. Haptic puller  80  has a shaft  82 , tip  84  and finger pull  86 . At assembly, the tip  84  is inserted into the injector tip with the finger pull  86  located outwardly adjacent thereto (see  FIG. 4 ). The tip  84  is configured with a groove to engage the leading haptic  33   a  (see  FIG. 2A ). At the time of use of device  10 , the haptic puller  80  is grasped at finger pull  86  and pulled away from the injector body  12 , thereby engaging and straightening the leading haptic  33   a  within tip  18 , whereupon the haptic puller  80  may be discarded. 
     To ensure the leading haptic  33   a  becomes engaged with the haptic puller tip  84  when the IOL retainer  40  is removed from injector body  12 , the haptic puller tip  84  is positioned in injector tip  18  in alignment with the leading haptic  33   a  as it is held by the haptic supporting element  44   a  of IOL retainer  40 . Thus, upon detaching IOL retainer  40  from the injector body  12 , the leading haptic  33   a  releases from the haptic supporting element  44   a  and falls into place on the haptic puller tip  84  as shown in  FIG. 2A . 
     To load the IOL into the delivery position seen in  FIG. 2A , the nurse or surgeon grasps and removes IOL retainer  40  from injector body  12 . This is accomplished by manually grasping finger grip  41  and pulling the retainer  40  away from the injector body  12  as shown by directional arrow in  FIG. 3D . As described above, the stripper finger  50  acts to prevent the IOL  30  from lifting together with retainer  40 . Thus, the IOL optic  31  will release from the IOL optic support element  42   a ,  42   b  and the leading and trailing haptics  33   a ,  33   b  will release from their respective haptic support elements  44   a ,  44   b . Once the retainer  40  has been fully detached from injector body  12 , it may be discarded or recycled. With the IOL  30  thus fully released from retainer  40 , the IOL optic  31  comes to rest in the loading bay area  27  of the injector lumen  14  with the leading haptic  33   a  engaging the haptic puller tip  84  as described above. In this regard, it is noted that upon release of the IOL  30  from the retainer  40 , IOL  30  will drop slightly in lumen  14 . This is seen best in  FIGS. 3C and 3D  where in  FIG. 3C , IOL  30  is held by retainer  40  with the optic periphery  31   a  located slightly above groove  14   a  which is formed in and extends longitudinally along the inside wall of lumen  14 . Upon removal of retainer  40  and release of IOL  30  therefrom, the optic periphery  31   a  becomes aligned with groove  14   a  along one side of the lumen. Then, upon moving compressor drawer  60  to the fully closed position seen in  FIG. 3D , the opposite edge of the optic periphery  31   a  becomes engaged in groove  60   a  of drawer  60 . Thus, lumen  14  together with lumen groove  14   a , drawer groove  60   a , and drawer top wall  60   b  compresses and encases IOL optic  31  within lumen  14 . The locating of the optic periphery  31   a  inside opposite grooves  14   a  and  60   a  ensures a planar delivery of the IOL  30  through lumen  14  and out tip  18 . This manner of IOL planar delivery is described in more detail in commonly assigned U.S. Pat. No. 6,491,697 referred to above. 
     As seen best in  FIG. 2B , in one embodiment of the invention, the inner diameter of lumen  14  increases between IOL loading bay  26  and open distal tip  18   a  while the outer diameter remains substantially constant. Thus, at a location adjacent loading bay  26 , the inner diameter d 1  is less than the inner diameter d 2  adjacent open tip  18   a  while the outer diameter d 3  of distal tip  18  remains substantially constant between these two points. This design is opposite to many prior art inserters which have a decreasing diameter toward the distal tip. In the prior art, the decreasing diameter is used to further compress the IOL so that the tip can fit through a very small incision in the eye (e.g., sub 3 mm). The inventors herein found that by decreasing the tip diameter as in prior art designs, greater force is needed to push the IOL through and out the device which often causes damage to the delicate IOL and/or undesired lens orientation/rotation. Thus, rather than decreasing the diameter to compress the IOL, the device body  12  herein includes an IOL loading chamber  26  and compressor drawer  60  which together compress the IOL to a desired compression size which is slightly smaller than the compression size when it exits tip  18   a . The outer diameter d 3  of distal tip  18  is set to the desired incision size (e.g., sub 3 mm) and remains substantially constant from loading bay  26  to open tip  18   a . With the inner lumen diameter increasing from the loading bay  26  to the open tip  18   a , the compressed IOL will be urged in the distal direction (toward open tip  18   a ) since it will naturally seek a position of least compressive stress. Thus, once the plunger  20  starts advancing IOL  30  toward distal tip  18 , the IOL  30  is also “pulled” in the same distal direction by the increasing diameter of the inner wall of lumen  14 . This reduces the amount of force required to be applied by the plunger  20  against IOL  30  to expel it from device  10 , and thereby reduces the chance of IOL damage caused by excessive plunger force. It is noted that the increasing diameter of the inner wall of lumen  14  at tip  18  may be gradual as shown in  FIG. 2B , or it may be stepped at one or more junctions “S” seen in  FIG. 2C  as desired. 
     Attention is also turned to  FIG. 2D  which shows another embodiment of the invention. In the embodiment of  FIG. 2B  described above, the inside diameter of the lumen increases while the outer diameter remains substantially constant. This is accomplished by thinning the wall of the tip  18  where the thickness t 1  adjacent loading bay  26  is greater than the thickness t 2  adjacent open tip  18   a . In the embodiment of  FIG. 2D , the thickness of the tip wall t 3  remains substantially constant from loading bay  26  to open tip  18   a  while the inner diameters d 5  and d 6  and outer diameters d 4  to d 7  increase from loading bay  26  to open tip  18   a . This is accomplished by a radial tapering out of the tip adjacent open tip  18   a . In this embodiment, it is still desirable to maintain a small diameter at open tip  18   a  (e.g., sub 3 mm) where the tip is inserted into the incision in the eye and the IOL exits the device. This requires that the outer diameter d 4  and inner diameter d 5  adjacent loading bay  26  be smaller than the corresponding outer and inner diameters d 3  and d 1  of the  FIG. 2B  embodiment, respectively. Thus, in the embodiment of  FIG. 2D , the IOL optic  31  will be initially compressed by compressor  60  to a greater degree than in the embodiment of  FIG. 2B . It is also noted that in both embodiments  2 B and  2 D, the length of tip  18  may be made shorter than in prior art embodiment requiring a long transition zone for successively compressing the IOL toward the open tip. This is because in the embodiments of  FIGS. 2B and 2D , the IOL is subjected to successively decreasing forces as it travels toward the open tip  18   a  (rather than increasing forces imparted by the prior art devices described above), and is thus capable of a quick travel through and out the device without damage. 
     Prior to removing retainer  40 , closing drawer  60  and compressing the IOL  30  inside the injector body, it may be desirable to apply viscoelastic to the area surrounding the IOL  30  to ease delivery of the IOL through the injector body. This is a common practice in the industry and the amount and location of viscoelastic application varies according to the instructions for use provided with the device as well as the desires of the surgeon. In any event, in a preferred embodiment, one or more viscoelastic access ports are provided on the injector device to facilitate application of the viscoelastic in the area of the IOL. One or more access ports P 1  may thus be provided in the form of a through-hole in stripper finger  50 . The access port P 1  is accessible via an injection nozzle inserted into visco port P 1 . Port P 1  also acts to stabilize optic  31  as it is being stripped from retainer  40  as described more fully in copending application Ser. No. 10/813,862. Alternatively or in addition to access ports P 1 , one or more access ports P 2  may be provided at any desired location through the wall of tip  18  (see  FIGS. 3B-D ). Alternatively or in addition to visco ports P 1  and P 2 , visco may be applied in loading bay  26  at the openings P 3  and P 4  defined between the optic and haptic support elements of retainer  40  (see  FIG. 3A ). Once the viscoelastic has been applied as desired, retainer  40  is removed and the compressor drawer  60  is moved to the fully closed position whereupon the IOL optic  31  is compressed and ready for delivery through a small incision formed in an eye. The fully closed position of compressor drawer  60  and compressed position of the IOL  30  is seen in  FIG. 3D  as described above. Compressor drawer  60  is slidably received between cooperatively formed drawer slides  61   a ,  61   b  extending laterally from injector body  12  adjacent opening  26 . Detents or other features (not shown) may be provided on the facing surfaces of drawer slides  61   a ,  61   b  and compressor drawer  60  to assist in maintaining drawer  60  in the fully open and mid-way positions, respectively. Such drawer holding features are especially useful in preventing unintentional sliding and/or complete closing of compressor drawer  60  prior to the time needed (e.g., during storage or opening of device  10  from its associated packaging). 
     At this time, the haptic puller  80  is pulled away from the injector body  12  and the leading haptic  33   a  is straightened within injector tip  18 . If desired or required, the plunger  20  may be advanced slightly prior to removing the haptic puller  80 . The surgeon inserts the injector tip  18   a  into the incision cut into the eye and begins advancing the plunger  20 . As the plunger  20  is advanced, the plunger tip  22  engages the optic periphery  31   a  and pushes IOL  30  distally. Upon continued advancement of the plunger  20 , the IOL  30  is pushed through the injector tip  18   a  and is finally expressed therefrom and into the eye ( FIG. 7 ).