Patent Publication Number: US-9414960-B2

Title: Device for use in delivery of ophthalmic lenses

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/476,018 filed on Sep. 3, 2014, which claims priority to GB Application No. 1315707.8, filed Sep. 4, 2013, and GB Application No. 1414832.4, filed Aug. 20, 2014, the disclosures of which are incorporated herein by reference in their entirety. This application is also related by subject matter to U.S. application Ser. No. 13/859,784, filed Apr. 10, 2013, which is also incorporated herein by reference in its entirety. 
    
    
     The present invention relates to the delivery of ophthalmic lenses. 
     Intraocular lenses are implanted into the eye through very small incisions in the eye, usually in the cornea, the lenses being rolled into a spiral or cylindrical shape prior to delivery. 
     Delivery can be carried out using a delivery device which is controlled manually by a surgeon, employing either a one-handed or a two-handed technique. The one-handed technique usually involves delivery of a lens by depression of a plunger by the surgeon to progress the lens through the device and into the eye. This offers the advantage of freeing the surgeon&#39;s other hand for other actions. The two-handed technique of lens delivery usually involves delivery of a lens by rotation of a threaded plunger by the surgeon to produce linear motion in order to progress the lens through the device and into the eye. This technique offers the advantage of greater control of the delivery but with the disadvantage restricting the surgeon&#39;s freedom to perform other tasks using his other hand. 
     Regardless of the technique, or combination of techniques, used, it is important that the surgeon be able to maintain full control over the delivery device, both during and after the lens-insertion phase of the procedure being carried out. 
     The present invention provides a device for use in delivery of ophthalmic lenses, the device comprising a barrel, a plunger receivable in the barrel and movable between a first, withdrawn position and a second, more advanced position and coupling means providing a screw-threaded connection between a portion of the plunger and the barrel, whereby the plunger rotates relative to the barrel in moving from its second to its first position, the plunger having a portion which is rotatable relative to the connection portion of the plunger and is engageable manually by a user for linear movement in the withdrawal direction whilst allowing rotation of the plunger relative to the barrel. 
     Such a device allows a surgeon to return the plunger after a lens-insertion procedure quickly and easily to its withdrawn position by a simple linear manual action. 
     Preferably the rotatable portion has at least one outwardly-extending portion for manual engagement by a user, the outwardly-extending portion more preferably comprising a collar extending around the plunger. 
     Advantageously, the plunger comprises a terminal head portion of larger cross-section than that of the plunger and the rotatable portion is located adjacent the head portion, the rotatable portion preferably being movable into abutment with the head portion in order to urge the plunger in the direction from the second to the first position. 
     The invention also provides a device for use in delivery of ophthalmic lenses, the device comprising a barrel, a plunger receivable in the barrel and moveable between a first, withdrawn position and a second, more advanced position, the plunger having a portion which contacts the interior of the barrel and comprises a resilient member which is carried by the plunger and lies in a plane transverse to the direction of relative movement of the plunger and the barrel, one or more outer surface portions of the resilient member together extending over less than all of the periphery of the plunger and providing the said contact with the barrel. 
     Such a device can reduce, or avoid altogether, any tendency for the plunger to “drop-back” under its own weight into the first position when released. 
     Preferably, the resilient member is annular and, more preferably, is received in a transverse passageway in the plunger. 
     Further, the invention provides a device for use in delivery of ophthalmic lenses, the device comprising a barrel, a plunger receivable in the barrel and moveable between a first, withdrawn position and a second, more advanced position, the plunger having a portion which contacts the interior of the barrel and comprises a resilient annular member which is carried by the plunger and lies in a plane transverse to the direction of relative movement of the plunger and the barrel, an outer surface of the annular member providing the said contact with the barrel and the annular member being received in a transverse passageway in the plunger. 
     Such a device can also reduce, or avoid altogether, any tendency for the plunger to “drop-back” under its won weight into the first position when released. 
     Conveniently, the resilient member lies in a plane substantially perpendicular to the said direction of relative movement. 
     Advantageously, the resilient annular member protrudes from respective opposite ends of the passageway to provide the contact with the barrel. 
     The annular member may be retained in the passageway by contact between the portions of the plunger and respective portions of the annular member intermediate the end portions. 
     Preferably, the annular member is circular in plan in its relaxed condition, more preferably, it is resiliently deformed into an oval shape in plan and its protruding ends are at opposite ends of its major axis. 
     In one arrangement, a single resilient member extends around a respective portion of the periphery of the plunger. 
     In any arrangement, the resilient member may lie in a plane substantially perpendicular to the said direction of relative movement. 
     The resilient member may be C-shaped. 
     Preferably, the resilient member has a laminated structure, an inner layer of which provides a desired degree of resilience and an outermost layer provides a desired degree of friction with the inner surface of the barrel. 
     In any arrangement, the plunger may have an enlarged portion in which the resilient annular member is located, the enlarged portion preferably being a bush located at the leading end of the plunger. 
     Devices according to the invention can be supplied as actuators for fitment to delivery devices of a wide range of types. Alternatively, the devices can themselves be delivery devices. 
     Devices according to the invention may be linearly-operating devices or actuators, or actuators or devices producing a combined linear and rotational output movement. 
    
    
     
       Embodiments of the invention will now be described by way of example with reference to the drawings of this specification, in which: 
         FIG. 1  is a perspective view of an assembly of a delivery device for ophthalmic lenses and an actuator which is an embodiment of the present invention; 
         FIG. 2  corresponds to  FIG. 1  but shows the delivery device and actuator disassembled; 
         FIG. 3  corresponds to  FIG. 2  but shows only the actuator; 
         FIG. 4  is a perspective view showing a plunger and attached delivery needle of the actuator of  FIG. 3 ; 
         FIG. 5  is a section on the line V-V on  FIG. 3 ; 
         FIG. 6  is a diametral section of a resilient annulus shown in  FIG. 5 ; 
         FIG. 7  is an exploded perspective view of a clutch mechanism of the actuator of  FIG. 3 ; 
         FIG. 8  is a cross-section on the line VIII-VIII on  FIG. 7 ; 
         FIG. 9  is a cross-section on the line IX-IX on  FIG. 7 ; 
         FIG. 10  is an exploded perspective view of a modified clutch mechanism; 
         FIG. 11  corresponds to  FIG. 3  but shows the actuator of another embodiment; 
         FIG. 12  corresponds to  FIG. 4  but shows the plunger and delivery needle of the actuator of  FIG. 11 ; and 
         FIG. 13  is a cross-section on the line XIII-XIII on  FIG. 11 . 
     
    
    
       FIG. 1  of the drawings shows an actuator indicated generally at  10  fitted to a delivery device  12  of known type. The delivery device is fitted at its forward end with a lens cartridge  14 , also of known type, which contains a rolled or folded lens located in a tapering cavity. The lens is delivered to a patient&#39;s eye through an opening in the tip of the cartridge  14 . 
       FIG. 2  shows the assembly of  FIG. 1  with the actuator disassembled from the delivery device  12  and the lens cartridge  14  dismounted from the delivery device. It will also be seen from  FIG. 2  that the actuator  10  comprises a barrel  16  which fits inside a sleeve  18  of the delivery device  12 , the barrel  16  and sleeve  18  being secured together by a bayonet connection consisting of a slot  20  in the sleeve  18  and a pin (not visible in the drawings) on the barrel  16 . 
       FIGS. 2 to 4  of the drawings also show that the actuator  10  comprises a plunger  22  which is slidable in the barrel  16 . The plunger  22  (shown in more detail in  FIG. 3 ) comprises a stem  24  which terminates at its rearward end in a cylindrical head  26 , forwardly of which is located a mushroom-shaped collar  27  which is described in more detail hereinafter. The stem  24  terminates at its forward end in a cylindrical bush  28  which is a sliding fit in the interior bore of the barrel  16 , the bush  28  being made from a suitable plastics material such as a polyetheretherketone (PEEK). The bush  28  is freely rotatable on the stem  24  and carries a pin  30  which is received in a longitudinal slot  31  in the barrel  16  to constrain the bush against rotational movement relative to the barrel. The bush  28  has a diametral transverse passage  32  which extends through the bush to produce a pair of opposed slots  33  in the cylindrical outer wall of the bush, each slot extending over an arc subtending an angle of about 120 degrees at the axis of the cylinder. The passage  33  receives a resistant annulus  35  which is formed from polyetheretherketone (PEEK) material. Any other suitable material could be used instead. The resilient annulus  35  is of rectangular cross-section with radiussed outer edges. It is circular in plan in its relaxed state. The annulus  35  is located in the passage  32 , as shown in  FIG. 5  of the drawings. The dimensions of the passage  32  and the annulus  35  are chosen so that the annulus is distorted by the wall portions of the cylindrical bush lying between the slots  33  into an oval shape, as shown in  FIG. 5  of the drawings. The distortion of the annulus  35  into the oval shape results in end portions of the annulus located at opposite ends of its major axis protruding from respective ones of the slots  33  and thereby making contact with the inner surface of the board  16  when the device is assembled. 
     A delivery needle  34  is mounted at its rearward end on the bush  28 , the needle being shaped to be received in the lens cartridge  14  in order to make contact with a folded or rolled lens and to deliver the lens from the cartridge into a patient&#39;s eye as the needle is moved forwards as a result of forward movement of the plunger  22  in the barrel  16 .  FIG. 4  of the drawings shows separately the assembly of the plunger  22  and the delivery needle  34 . 
     The stem  24  of the plunger  22  has a plain forward portion  36 , an intermediate portion  38  having a three-start thread formed by three helical grooves  40  of U-shaped transverse section, and a plain rearward portion on which the mushroom-shaped collar  27  is mounted. For reasons which will become evident hereinafter, the grooves  40  widen at their open, forward ends into flared portions  42  which terminate in respective circumferential openings  44  which extend over arcs of about 100 degrees between rounded ends of the inter-groove ridges  46  which extend over arcs of about 20 degrees, as will be evident from  FIG. 8  of the drawings. In a modification, the plain forward portion  36  of the plunger stem  24  is omitted and the stem  24  is threaded over its entire length as for the intermediate portion  38  described. 
     The collar  27  has a hollow stem portion  46  and an annular head portion  47 . The plain rearward portion of the stem  22  of the plunger  24  passes through the hollow stem portion  46  so the collar is freely rotatable on the stem  22 . The annular head portion  47  has a cross-section very similar to that of the head  26  of the plunger  24  and can be brought into abutment with the underside of the head when urged rearwardly on the stem  22 . The intermediate threaded portion  38  of the stem  24  has a cross-section that is greater than the bore of the stem portion  46  of the collar  27  which is thus captive but freely rotatable on the plain rearward portion of the stem  24  of the plunger  22 . 
     The barrel  16  terminates at its rearward end in a cylindrical cup  50 , just forwardly of which a pair of outwardly-extending ears  52  protrude one to each side. The ears  52  allow the actuator to be held in one hand by a user with the user&#39;s first and second fingers behind the ears and the user&#39;s thumb resting on the head  26  of the plunger  22 . 
     The cup  50  receives a clutch mechanism  54  which is operative to provide coupling between the plunger  22  and the barrel  16  of the actuator  10 . The clutch mechanism  54  is arranged coaxially around the plunger  22 , as can be best seen in  FIG. 7  of the drawings which also shows the rearward end of the barrel  16  and a portion of the plunger  22 . 
     The clutch mechanism  54  includes a PTFE friction-reducing washer  56 , an annular support member  58 , an annular driven member  60  and an end cap  62  which is a press-fit in the rearward end of the cup  50  and is secured against rotation relative thereto. The stem  24  of the plunger  22  extends coaxially through the washer  56 , support member  58 , driven member  60  and end cap  62 . 
     The annular support member  58  is formed with three circumferential turrets  64 , each extending over an arc of approximately 90 degrees. Three arcuate gaps  66  each extending over arcs of about 30 degrees lie between the turrets  64 . Each turret  64  has in it a recess  68  of elongate transverse section. A clutch spring  70  is seated in each recess  68 , each spring  70  consisting of a rectangular-section ring of resilient plastics material. The springs  70  are circular in plan when in a relaxed condition but can be resiliently deformed to be oval in plan. Springs of this type have been found to be particularly simple to form and their rates readily determined and controlled. 
     The springs  70  act on a forward annular face  72  of the driven member  60  and therefore act to bias the support  58  and the driven member  60  apart in the axial direction. 
     The driven member  60  is formed on its forward face  72  with three equidistantly-spaced turrets  74 , each extending over an arc of approximately 30 degrees, as will be seen most clearly in  FIG. 7  of the drawings. The turrets  74  of the driven member are received in the gaps  66  between the turrets  64  of the support member  58 . As can be seen from  FIG. 9 , each turret  74  has a radial bore  76  having an internal circumferential ridge  78 . Each bore  76  receives a respective drive pin  80  which has a circumferential groove  82  which is a snap-fit over the corresponding ridge  78  in the respective bore  76 . Each pin  80  has a hemispherical inner end  84  which projects radially inwardly from the driven member  60 . 
     The driven member  60  is formed on its rearward annular face with a series of castellations  86  which engage a series of corresponding castellations  88  formed on the forward face of the end cap  62 . The springs  70  therefore bias the series of castellations  86 ,  88  into engagement with each other and lock the driven member  60  and end cap  62  together against relative rotational movement. The axial length of the cup  50  is chosen such that the springs  70  are slightly deformed from their circular shapes in this condition of the clutch mechanism, thus providing a small preloading force. 
     The hemispherical end portions  84  of the pins  80  which protrude radially inwardly are positioned so as to be received in a respective one of the grooves  40  formed by the threads of the threaded portion  38  of the plunger  24 , entry of the pins into the grooves being facilitated by the flared end portions of the grooves  40 , when the plunger stem has a plain forward portion  36 . 
     The support member  58 , springs  70  and pins  80  are formed from a suitable engineering plastics material such as a polyetheretherketone (PEEK). The driven member  60  may be formed from a polyetherimide such as that sold under the name ULTEM®. Except as specifically mentioned otherwise, the actuator is made from a suitable titanium alloy. Stainless steel could be used instead. If not formed from a polyetherimide as mentioned, the driven member may be made from a suitable titanium alloy, or stainless steel. 
     The clutch mechanism operates as follows. In the disengaged condition of the mechanism already referred to, the driven member  60  is urged by the springs  70  rearwardly relative to the end cap  62 . The castellations  86 ,  88  are thereby brought into engagement and the driven member  60  and the support member  58  are locked against rotation relative to the end cap  62 . In this condition of the clutch, the forward, plain portion  36  of the plunger  24 , if present, can pass unimpeded through the clutch mechanism and the plunger  24  can be advanced correspondingly axially of the barrel  16 . 
     If the plunger  24  is advanced through the barrel to an extent that its threaded portion  38  passes into the clutch mechanism, the pins  80  engage in respective grooves  40  of the threaded portion  38 . If no plain plunger portion is present, the pins  80  are already in engagement with the grooves  40 . Whilst the clutch mechanism remains engaged, the plunger  22  can be advanced further through the barrel  16  if it is rotated to allow the pins  80  to pass helically along the grooves  40  of the thread. This is achieved in the absence of any significant axial load on the plunger  22 . 
     If however a significant axial load is placed on the plunger  22 , the pins  80 , rather than passing helically along the grooves  40 , engage with the walls of the grooves with the result that the load on the plunger  22  is transferred to the driven member  60  which is shifted axially against the bias of the springs  70  such that the castellations  86 ,  88  disengage to allow the driven member  60  to rotate relative to the end cap  62 . The plunger  22  can now be advanced forwardly relative to the barrel  16  for so long as the axial load is maintained. 
       FIG. 10  shows a modified clutch mechanism, the parts of which corresponding to parts of the mechanism  54  are indicated by reference numerals increased by “100” compared with the reference numerals used for the parts of the mechanism  54 . 
     The modified clutch mechanism  154  comprises a support member  158  and a driven member  160  which are formed integrally as a plastics moulding and which are joined by integral resilient twisted straps  170  corresponding to the springs  70 . The driven member  160  has three circumferentially-spaced turrets  174  which support drive pins  180  in a manner corresponding exactly to that described hereinbefore for the clutch mechanism  54 . The rearward face of the driven member  160  is formed with castellations  186  which engage with castellations  188  on the forward face of the end cap  162 . 
     The modified clutch mechanism operates in a very similar manner to the mechanism  54 , except that the resilient loading is provided by the twisted straps  170  and not the springs  70 . 
     In a further modification (not shown in the drawings), a rolling element thrust bearing such as a needle roller or ball race thrust bearing replaces the PTFE friction-reducing washer shown in  FIG. 7  of the drawings. Such a bearing can reduce friction between the support member  58  and the interior of the cup  50  to a greater extent than the washer  56 . A corresponding modification may also be made to the actuator described with reference to  FIG. 10  of the drawings. 
       FIGS. 11 and 12  of the drawings show an actuator which is a modification of the actuator shown in  FIGS. 2 to 4  of the drawings. Features of the actuator of  FIGS. 11 and 12  which correspond to those of the actuator of  FIGS. 2 to 4  are indicated by reference numerals which are increased by “200” compared with the reference numerals used in  FIGS. 2 to 4 . The features which are identical will not be described further in this specification. 
     As can be seen from  FIG. 13  of the drawings, the bush  228  of the actuator shown in  FIGS. 11 and 12  has a recess  260  which extends over approximately 330 degrees of the periphery of the bush. 
       FIGS. 11 to 13  of the drawings show that the recess  260  receives a C-shaped resilient element  262 , which is formed laminated in two layers, an inner layer  216   a  being of titanium alloy to provide a suitable spring rating and an outer  216   b  being of PEEK material provide a bearing surface which is in contact over its outer periphery with the interior surface of the barrel  216  of the actuator shown in  FIGS. 11 to 13 . 
     The dimensions of the recess  260  and the C-shaped member  262  are chosen so that the C-shaped member is in contact with the interior of the barrel  216  over the portion extending between the respective edges of the slot  231 . In  FIG. 13 , the barrel is not shown so the C-shaped element  262  is in its relaxed condition, in which it protrudes as shown from the recess  260 . The C-shaped member thus provides a similar degree of resistance to the movement of the plunger in the barrel as does the resilient element  35  shown in  FIGS. 2 to 4  of the drawings. 
     The use of the actuators shown in  FIGS. 1 to 9 ,  FIG. 10  and  FIGS. 11 to 13  in connection with a delivery device for the insertion of a rolled ophthalmic lens into the human eye will now be described. 
     An actuator having a clutch mechanism  54  as shown in  FIG. 7  or a clutch mechanism  154  as shown in  FIG. 10  is assembled to a delivery device  12  as shown in  FIGS. 1 and 2 , the delivery device being fitted with a lens cartridge  14  as also shown in  FIGS. 1 and 2 . Either device may have a resilient element as described with reference to  FIGS. 1 to 10  or a resilient element as described with reference to  FIGS. 11 to 13 . Advancement of the plunger  22  or  222  of the actuator  10  through the barrel  16  or  216  of the actuator causes the delivery needle  34  or  234  to pass into the lens cartridge  14  (in  FIG. 2 ) with the result that the rolled ophthalmic lens contained in the cartridge  14  is delivered outwardly through the aperture in the tip of the cartridge  14 . 
     During the first portion of the stroke of movement of the plunger  22  or  222 , any plain, unthreaded forward portion  36  or  236  of the stem  24  or  224  of the plunger  22  or  222  passes through the clutch mechanism  54  or  154  without contact, allowing the delivery needle  34  or  234  to be advanced rapidly and with little resistance, as is desirable during the initial phase of lens delivery before the tip of the needle  34  or  234  contacts the rolled lens in the cartridge  14 . During this initial phase, the surgeon may hold the delivery device and actuator with his first and second fingers behind the ears  52  or  252  and his thumb on the head  26  or  226 . 
     In the next phase of the delivery process, the threaded portion  38  of the plunger stem  24  or  224  engages, or is already engaged, with the clutch mechanism  54  or  154  as described above. The surgeon now has the option as he wishes either to continue the forward movement of the plunger in the actuator barrel in a one-handed operation which results in an axial loading on the plunger  22  or  222  with the effect that the clutch mechanism  54  or  154  disengages and the plunger can continued to be moved forwardly through the delivery device. Alternatively, if he wishes, the surgeon can continue to hold the barrel  16  or  216  of the actuator in one hand and then, by twisting the head  26  or  226  of the plunger  22  or  222  advance the needle to deliver the lens from the cartridge  14 . In this case, in the absence of substantial axial loading on the plunger, the clutch  54  or  154  remains engaged and the twisting movement of the plunger stem  24  or  224  results in further forward movement of the plunger with the pins  80  or  180  of the clutch mechanism  54  or  154  engaged in the grooves  40  or  240  of the threaded portion of the plunger stem. This allows the surgeon, according to his choice, to control the second stage of the insertion operation in a two-handed operation involving a rotary motion of the plunger  22  or  222  relative to the barrel  16 . The particularly advantageous feature of allowing the surgeon at his choice to employ a one-handed or a two-handed technique of lens delivery is therefore provided by the actuator of the present invention. 
     It is desirable that, during the insertion phase described, if the surgeon relaxes or relieves his grip on the plunger, the plunger does not move rearwardly under its own weight. The reason for this being desirable is that it prevents the needle  34  or  234  from losing contact with the lens, such loss of contact leading possibly to damaging contact with one or both of the haptics of the lens on re-engagement therewith. 
     In the device described with references to  FIGS. 1 to 10 , the contact between the opposed ends of the distorted annulus  35  and the interior of the barrel  16  provides a suitable frictional restraining force which can be determined by an appropriate choice of dimension and material of the annulus. In the device described with reference to  FIGS. 11 to 13 , the contact between the C-shaped member  262  and the interior of the barrel  216  provides a similar frictional force which can again be determined by an appropriate choice of dimension and material by the C-shaped member  262 . The plunger and needle are in each case thereby prevented from “falling-back” in the barrel when the forward force is relieved or removed. 
     It is also desirable that the surgeon be able to return the plunger  22  or  222  quickly and easily to its rearward or retracted position after completion of an insertion procedure, to ready it for the next insertion operation. In all the embodiments described, this can be achieved readily and rapidly by placing two fingers on the forward-facing surface of the head  47  or  247  of the collar  27  or  227  and pulling the head rearwardly into contact with the head  26  or  226  of the plunger  22  or  222 . Continued rearward movement of the collar will result in rearward movement of the plunger which, as a result of the engagement of the threaded portion  38  or  238  with the barrel  16  or  216  by way of the clutch mechanism  54  or  154 , will rotate within the collar  27  or  227 . Rotation of the plunger in the surgeon&#39;s hands or the need to apply a rotatory movement to the plunger are avoided. Convenience of use is thereby improved.