WO2005020853A2

WO2005020853A2 - Intraocular lens injector

Info

Publication number: WO2005020853A2
Application number: PCT/GB2004/003672
Authority: WO
Inventors: Paul Sinding
Original assignee: Fulcrum (Medical Devices) Limited
Priority date: 2003-08-29
Filing date: 2004-08-27
Publication date: 2005-03-10
Also published as: GB2405344A; WO2005020853A3; GB0320341D0

Abstract

An intraocular lens injector is disclosed. The injector comprises an elongate barrel (2) having a longitudinal axis, a plunger (3) insertable into the barrel (2) and slideable relative thereto in an axial direction from a first position to an intermediate position in response to the application of an axially directed load towards a lens (10) located in a lens holder (5) at one end of the barrel (2), and an actuator (9) rotatably mounted in the barrel (2) which is engaged by the plunger (3) in said intermediate position so that further movement of the plunger (3) relative to the barrel (2) in said axial direction is achieved in response to rotation of the actuator (9), to push a lens (10) disposed in said lens holder (5) into the eye.

Description

Intraocular Lens Injector

Description

The present invention relates to an intraocular lens injector for use in the introduction of a deformable artificial lens into the eye.

In the field of ocular surgery, one of the most common operations is the removal of cateracts and approximately 180,000 cateract operations are performed each year in the UK alone. One method of treating cateracts is to remove and replace the existing lens with an artificial one. The use of artificial deformable intraocular lenses in the treatment of cataracts and other problems affecting the normal functioning of the eye have become widespread and numerous lens introducing devices are known which can fold the lens ready for insertion through a small incision made in the eye. Once inserted, the lens unfolds and the lens introducing device may then be used to manipulate the lens to position it in the correct orientation within the eye. Many lenses are provided with thread like tails called hapsics that extend from the lens and which are used to centralise and hold the lens in the correct position. It is important to ensure that the lens is positioned correctly within the injector prior to insertion so that the hapsics assume the correct position in the eye once the lens has been inserted and so that subsequent movement of the lens following insertion can be kept to a minimum. Movement of the lens to position it within the eye immediately following insertion is often referred to as "dialling-in" the lens.

Various types of lens injectors are known. In a pre-loaded lens injector, the intraocular lens is pre-loaded in the lens injector for the purpose of storage and shipping. The lens injector together with the lens is therefore sealed as a unit during manufacture and is ready for use and so the step of loading the lens into the lens injector prior to insertion of the lens into the eye is eliminated. This type of lens injector is discarded after a single use as it is not possible to re-load the injector with a new lens. Another type of lens injector system provides a re-usable lens injector and a dedicated pre-loaded lens cartridge. The lens is inserted into the dedicated cartridge during manufacture and then sealed. The cartridge and the lens injector are constructed so that they mechanically cooperate with each other so that the surgeon only needs to remove the cartridge containing the lens from its sealed container and attach it to the lens injector to make it ready for use and so the lens can be injected straight from the cartridge into the eye. This type of pre-loaded lens injector has the advantage that only the cartridge is disposed of after each use and the lens injector may be sterilised and re-used. Another type of manually loaded lens injector is often used when the lens is not pre-mounted in a dedicated lens cartridge. In this type of lens injector, the lens is removed from its packaging using forceps or the like and is manually positioned and oriented in the lens injector ready for use by the surgeon. It should be noted that the lens is only folded to enable it to pass through the incision immediately prior to injection into the eye. Therefore, preloaded lens injectors or lens cartridges containing lenses in their unfolded state must be provided with means to enable the lens to be folded so that it is ready for insertion.

It will be appreciated that any surgery on the eye requires very small and precise movements on behalf of the ocular surgeon to ensure that trauma to the patient and damage to the ocular tissues and/or to the intraocular lens to be implanted is minimised or avoided. The reasons for minimising damage to the ocular tissues will be obvious. However, as the cost of the lens makes up a significant proportion of the total cost of the operation, the importance of ensuring that the lens is not wasted due to mishandling, incorrect insertion or inadvertent loss of sterility must not be underestimated. Therefore, it is important to ensure that maximum control of the device used to inject and manipulate the lens is maintained at all times throughout the procedure and to ensure that the surgeon is fully aware of the orientation and position of the lens prior to and during insertion so that minimal movement or "dialling-in" of the lens is necessary once the lens has been released from the device into the eye. A minimal amount of movement of the lens once inserted is also important to ensure that the hapsics remain undamaged and locate the lens correctly.

In addition to the need for enhanced control and movement of the lens injector during injection and positioning of the lens, it is also becoming increasingly important to provide a less expensive alternative to conventional lens injectors which are often formed from relatively expensive materials and have a complicated construction and/or manufacturing process. Due to their cost and complexity, such devices must be re-used and so need to be thoroughly sterilised between operations.

A disadvantage with conventional lens injectors is that they do not provide a sufficiently precise degree of control that is required to facilitate exact positioning and insertion of the lens into the eye. Furthermore, many of them are expensive to manufacture and clean. There is therefore a need for a lens injector that has a simple construction and assembly and which is easy to use and provides the surgeon with the ability to precisely control the movement of the lens from the injector into the eye. The ease by which the device may be used to carry out the procedure and prevent lens insertion errors is becoming increasingly important as more operations of this type are being performed by persons having more general medical qualifications rather than by experienced ocular surgeons.

The present invention seeks to provide a lens injector of all known types, such as those described above, which overcomes or substantially alleviates the disadvantages with known lens injectors.

According to the present invention, there is provided an intraocular lens injector comprising an elongate barrel having a longitudinal axis, a plunger insertable into the barrel and slideable relative thereto in an axial direction from a first position to an intermediate position in response to the application of an axially directed load towards a lens located in a lens holder at one end of the barrel, and an actuator rotatably mounted in the barrel which is engaged by the plunger in said intermediate position so that further movement of the plunger relative to the barrel in said axial direction can be achieved in response to rotation of the actuator to push a lens disposed in said lens holder into the eye. In a preferred embodiment of the invention, further movement of the plunger relative to the barrel can only be achieved in response to rotation of the actuator. This construction has the advantage that the plunger can initially be moved by pushing it through the barrel only up to an intermediate position. The intermediate position may be, for example, at the point where the tip of the plunger is about to make contact with a folded lens. Once this point has been reached, the plunger and actuator engage and the plunger can then be moved forward or backward in small precisely controlled increments by rotating the actuator.

In a preferred embodiment, the plunger extends through the actuator and has a screw thread formed along a portion of its length.

Preferably, the plunger is configured so that the unthreaded portion of the plunger slides through the actuator as it moves from the first to the intermediate position.

Advantageously, the actuator is internally threaded such that the screw thread on the plunger engages with the internal thread on the actuator when the intermediate position has been reached. The corresponding threads on the actuator and plunger therefore mesh when the actuator is rotated to move the plunger beyond the intermediate position to push the lens out of the holder.

The intraocular lens injector according to the invention can be used in an alternative mode of operation by removing the actuator from the barrel. In this embodiment, the plunger can shde past the intermediate position in response to the application of an axially directed load to directly push a lens from said lens holder into the eye.

The lens injector of the invention is therefore highly flexible because it can be used to inject the lens simply by applying an axial force to the plunger as well as by initially applying an axial force to the plunger and subsequently rotating the actuator to inject the lens into the eye.

In an alternative embodiment of the invention, further movement of the plunger relative to the barrel from said intermediate position can be achieved in response to both rotation of the actuator and/or in response to the application of an axially directed load towards the lens. This has the advantage that the user is able to move the plunger beyond the intermediate position by either applying an axial force to the end of the plunger, or by fine, incremental rotation of the actuator, or a combination of both as (s)he feels is appropriate under the circumstances. The plunger is conveniently positioned adjacent to the actuator and has a series of ribs formed along a portion of its length, and may be configured so that the portion without ribs slides past the actuator as it moves from the first position to the intermediate position. In a preferred embodiment, the actuator has a ridged outer surface such that the ribs on the plunger engage with the ridges on the actuator when the intermediate position has been reached, and conveniently, rotation of the actuator causes the ridges on the actuator and the ribs on the plunger to mesh to cause the plunger to move relative to the barrel beyond the intermediate position

The actuator is preferably received in an aperture in the barrel between the ends thereof. In a particularly preferred construction, the actuator is received in an aperture in the barrel close to the lens holder. This has the advantage that the lens injector can be held, and the actuator rotated, using one hand. Furthermore, placement of the actuator close to the lens holder enables more precise control of the injector and reduces vibration due to the shorter angle of movement attributed to its position. In conventional lens injectors, the screw knob is located at the end of the barrel away from the lens holder. This means that both hands must be used to advance the plunger — one to wind the knob and the other to hold the barrel. In addition, this known arrangement increases the tendency for the user to wobble the tip when the knob is wound.

The actuator preferably comprises a tubular thumbwheel mountable for rotation about its longitudinal axis coaxial with the longitudinal axis of the barrel. In one embodiment, the lens injector includes an insert which is conveniently disposed in the barrel and includes a frame to rotatably mount the actuator. The outer surface of the actuator may be knurled or have some other kind of roughened surface to enable it to be rotated easily in the surgeon's fingers.

The actuator may alternatively comprise a cylindrical thumbwheel mountable for rotation about its central axis which is perpendicular to the longitudinal axis of the barrel. A lens holder extends from one end of the handle or barrel. In a preferred embodiment, the lens holder comprises a pair of forceps. The forceps are particularly advantageous as they enable the surgeon to pick-up a lens and then inject it using the same tool, i.e. there is no need for the surgeon to load the lens injector by picking up a lens with a separate pair of forceps.

Preferably, the forceps comprise a pair of spaced integrally formed arms coupled together at one end and having a jaw at the tip of each arm, the arms being resiliently deformable in response to the application by a user of an inwardly directed load to the arms to close the jaws to pick up and fold a lens therebetween ready for insertion.

The lens injector advantageously includes locking means to lock the arms with the jaws in their closed position when the user releases the arms, to retain the lens between the jaws.

In one embodiment, the lens holder is mounted on the insert disposed in the barrel and protruding from one end thereof.

Each jaw of the forceps may be formed with a pair of oppositely opposed curved grooves to receive and orient a lens therebetween.

In a particularly preferred arrangement, a recess is formed in each jaw which together form a passageway when the head portions are closed to enable the plunger to pass through the passageway between the jaws and engage the lens to push it out from between the jaws and into the eye. The recess in each jaw is aligned with the path of travel of the tip of the plunger.

In another embodiment, a cap is attachable to the barrel or insert so as to cover the lens holder. The cap may be wholly or partially transparent to enable the position and orientation of the lens to be seen through it. The cap prevents the lens from popping out of the jaws of the forceps and, even if it does, the lens remains captured within the cap. The cap preferably includes a nozzle through which the lens passes from the lens holder into the eye when pushed by the plunger.

In another embodiment, the cap is operable to lock the arms in their closed position.

In an alternative embodiment, the lens holder comprises a pre-loaded cartridge connected to the end of the barrel or to the insert.

Preferably, the cartridge and the barrel include co-operating means for releasably connecting a replaceable cartridge to the barrel or to the insert.

In a preferred embodiment, the cartridge is integrally formed with a cap having a nozzle, the plunger being movable through the cartridge to push the lens through the nozzle and inject it into the eye.

In one arrangement, the cartridge includes a sealing member disposed between the lens and the plunger, the sealing member being slideable within a passage in the cartridge in response to the apphcation of force thereto by the plunger into contact with the lens to push the lens out of the cartridge.

The present invention also provides a method of operating an intraocular lens injector according to the invention to inject an intraocular lens into the eye, comprising the steps of applying an axially directed load to the plunger to move it from the first into the intermediate position and, subsequently rotating the actuator to further move the plunger beyond the intermediate position to cause the plunger to push a lens mounted in the lens holder into the eye.

According to another aspect of the invention, there is provided an intraocular lens injector comprising an elongate barrel having a longitudinal axis, a plunger and a lens holder mounted to one end of the barrel, the plunger being moveable in an axial direction within the barrel towards said end to push a lens from said lens holder into the eye, wherein the lens holder comprises a pair of forceps operable to pick up and fold a lens ready for insertion.

Preferably, the forceps comprise a pair of spaced integrally formed arms coupled together at one end and having a jaw at the tip of each arm, the arms being resiliently deformable in response to the application by a user of an inwardly directed load to the arms to close the space between the jaws to pick up and fold a lens ready for insertion.

The lens injector may include locking means to lock the arms with the jaws in their closed position when the user releases the inwardly directed load applied to the arms.

The lens holder is conveniently mounted on an insert disposed in the barrel.

The jaws preferably extend at an angle relative to the remainder of the arms. This enables the barrel of the lens injector to be held in an ergonomic orientation when a lens is picked up between the jaws. A preferred angle of the jaws relative to the arms from which they extend is 135 degrees.

A curved groove is preferably formed in each head portion to receive and orient a lens therebetween.

In a preferred embodiment, a recess is formed in each jaw which together form a passageway when the jaws are closed to enable the plunger to pass through the passageway between the jaws and engage the lens to push it out from between the jaws and into the eye.

In one embodiment, the lens injector includes a cap attachable to the barrel over the lens holder. Advantageously, the cap includes a nozzle through which the lens passes from the lens holder into the eye when pushed by the plunger. The nozzle assists in further folding or orientating the lens ready for insertion.

In a preferred embodiment, the barrel and the actuator are made of a rigid plastic such as polycarbonate or acrylonitrile-butadiene-styrene (ABS) copolymer.

The tip of the plunger is advantageously made of a deformable plastic such as polypropylene. Alternatively, the lens holder, the cap and the plunger may all be made of a deformable plastic such as polypropylene.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIGURE 1 shows a front perspective view of an assembled lens injector according to a first embodiment of the invention;

FIGURE 2 shows a front perspective view of the lens injector shown in Figure 1 with the barrel omitted for clarity;

FIGURE 3 shows a perspective view of the actuator seen in Figures 1 and 2; FIGURE 4 shows a perspective view of the plunger seen in Figures 1 and 2;

FIGURE 5 shows a perspective view of the insert seen in Figures 1 and 2;

FIGURE 6 shows a perspective view of the forceps seen in Figure 1 and 2;

FIGURE 7 shows a perspective view of a cap; and

FIGURE 8 shows a perspective view of the barrel; FIGURE 9 shows a front perspective exploded view of a lens injector according to a second embodiment of the invention;

FIGURE 10 shows a front perspective view of the lens injector shown in Figure 9 with the barrel omitted for clarity;

FIGURE 11 shows a perspective view of the plunger seen in Figures 9 and 10; FIGURE 12 shows a perspective view of the forceps seen in Figures 9 and 10;

FIGURE 13 shows a perspective exploded view of the barrel seen in Figure 9; and

FIGURE 14 shows a perspective view of the actuator seen in Figures 9 and 10. Referring now to the drawings, there is illustrated in Figure 1 , an assembled lens injector 1 having a handle or barrel 2 and an elongate plunger 3 within the barrel 2 and shown protruding from either end thereof. A lens holder 5 in the form of a pair of forceps is mounted to an insert 6 seated within the proximal end 7 of the barrel 2. The barrel 2 has a window 8 to facilitate access to an actuator 9 rotatably mounted within the barrel 2. A lens 10 is shown in its folded orientation ready for insertion through an incision made in the eye (not shown) between jaws 11 of the forceps 5. The lens 10 has trailing hapsics 10a which serve to locate and stabilise the lens 10 within the eye.

As can be seen especially from Figure 2, the actuator 9 is removably and rotatably seated in a frame 12 that forms part of the insert 6. When the insert 6 is located within the proximal end 7 of the barrel 2, the frame 12 surrounds the window 8 and the actuator may be attached to the frame 12 by inserting it through the window 8 until it chps into place within the frame 12. The window 8 may be formed in one side or on both sides of the barrel 2 so that access to the actuator 9 can be obtained through either window 8. In this arrangement, the actuator 9 can be inserted and/or removed through only one of the windows 8.

The actuator 9 comprises a tubular thumbwheel having a knurled outer surface 13a and a threaded inner wall 13. The plunger 3 has a tip 14 and is partially formed from a cylindrical rod 15 which has a threaded section 16 at one end remote from the tip 14, leaving the remaining portion 17 of the rod unthreaded. The tip 14 contacts and pushes a lens 10 out of the forceps 5 and into the eye when the plunger 3 is advanced towards the lens 10.

A thumb plate 19 is spaced from the rod 15 by an enlarged elongate section 18 which provides additional strength to the plunger 3 and provides space to enable graphics indicating the position of the plunger 3 relative to the barrel 2 to be moulded or applied to the plunger 3. Section 18 has flattened side walls 19a which locate against complimentary shoulders or walls (not shown) on the inside of the barrel 2 to prevent rotation of the plunger 3 within the barrel 2. The thumb plate 19 facilitates the application of pressure to the plunger 3 to move it in an axial direction indicated by arrow "A" in Figure 2 relative to the barrel 2.

As can be most clearly seen from Figures 1 and 2, the plunger 3 passes through the tubular actuator 9 and the insert 6 and protrudes from the proximal end 7 of the barrel 2 towards the lens 10. The unthreaded portion 17 of the plunger 3 and the actuator 9 are dimensioned so that the unthreaded portion 17 is free to slide through the actuator 9 in response to the apphcation of an axially directed load to the plate 19 in the direction of Arrow "A". More specifically, the diameter of the unthreaded portion 17 is smaller than the diameter of the tubular opening through the actuator 9. However, the threaded section 16 of the rod 15 will not pass through the actuator 9 as a result of applying an axial load to the plate 19 and so further movement of the plunger 3 towards the lens 10 by this method is prevented. Instead, further movement of the plunger 3 in the axial direction is controlled by the actuator 9 which can be rotated so that the thread 13 on the actuator 9 and the threaded section 16 on the plunger 3 mesh and move the plunger 3 relative to the barrel 2 further toward the lens 10. It will be appreciated that movement of the plunger in this way enables its position to be controlled very precisely and incrementally. The plunger 3 shown in Figures 1 and 2 is positioned at the point at which the unthreaded section 17 has passed through the actuator 9 and the threaded section 16 on the plunger 3 has just engaged the thread 13 on the actuator 9 so that further movement of the plunger 3 towards the lens 10 can only be achieved by rotating the actuator 9. It will be appreciated that the tip 14 of the plunger 3 is located only just behind the lens 10 in this position so that rotation of the actuator 9 will immediately cause the tip 14 to make contact with the lens 10 to push it out from between the jaws 11 and into the eye.

It will be appreciated that the lens injector can also be used with the actuator 9 removed from the frame 12. In this mode, the plunger 3 can be pushed in an axial direction so that the tip 14 engages the lens 10 and forces the lens 10 out of the lens holder 5 without requiring any rotation of the actuator 9. The insert 6 can be more clearly seen in Figure 5 and includes a head portion 20 having a shoulder 21 that engages with the proximal end 7 of the barrel 2 when seated therein, and a stem 22 extending from the head portion 20 towards the frame 12 to mount the actuator 9. A bore 23 extends through the head portion 20 and stem 22 to form a passage for the rod 15. The insert 6 may be permanently seated within the proximal end 7 of the barrel 2. Alternatively, it can be made so that it is removable therefrom for cleaning or replacement.

The forceps 5 will now be described with particular reference to Figure 6. They comprise a pair of integrally formed arms 24 spaced from each other and joined together at their base 25. Each arm 24 has a raised pad 26 on its outer surface to facilitate the application of pressure thereto by the user in the direction of arrows "B" to squeeze the arms 24 together so that they resiliently deform and the jaws 11 at the end of each arm 24 close together. Each jaw 11 is angled with respect to the arms 24 so that a lens 10 may be picked up between the jaws 11 whilst the barrel 2 is maintained at an ergonomic or comfortable angle within the user's hand. A groove 27 is formed in the gripping face of each jaw 11 to receive and locate the edges of a lens 10 therein. The grooves 27 may be curved to conform to the shape of the lens 10.

A second recess 28 extends through the gripping face of each jaw 1 intersecting the groove 27 that locates the lens 10. These recesses 28 have their longitudinal axes aligned with the path of travel of the plunger 3 so that, when the jaws 11 are closed and the plunger 3 moved forward by rotating the actuator 9, they act as a passageway for the plunger 3 between the jaws 11 so that the tip 14 of the plunger 3 can be brought into contact with the lens 10 and pushed out from between the jaws 11 into the eye.

The base 25 of the forceps 5 clips onto the insert 6 before the insert 6 is located in the proximal end 7 of the barrel 2, as shown in Figure 2, and the arms 24 locate in openings 29 formed on either side of the head portion 20. The head portion 20 therefore serves to guide and support the arms 24 and prevents them from twisting during movement. The insert 6 and the arms 24 may also include co-operating means (not shown) such as a detent and corresponding lug that engage when the arms 24 are deformed to close the jaws 11 so that, when the pressure on the arms 24 is released, they do not spring back into their non-deformed state but remain compressed together. A lens 10 disposed between the jaws 11 is therefore captured and cannot escape if the user's grip on the arms 24 is released.

The lens injector 1 also includes a cap 30 which attaches to the head portion 20 of the insert and covers the arms 24 and jaws 11 of the forceps 5. The cap 30 further protects a lens 10 captured between the jaws and prevents loss of the lens 10 even if it does escape from the jaws 11. The cap 30 may be wholly or partially transparent so that the exact position and orientation of the lens 10 can be seen without having to remove the cap 30. Furthermore, the cap 30 has a nozzle 31 through which the lens 10 may be pushed by the plunger 3 into the eye. The nozzle 31 serves to further fold or orientate the lens 10 as it is injected into the eye from the injector 1.

It will be appreciated that the forceps 5 are not limited to use with a lens injector 1 of the type described and may also be used with a lens injector 1 which relies entirely on a sliding or a screw fed plunger 3. Therefore, in another embodiment of the invention there is a lens injector which is provided with forceps for picking up and folding a lens ready for insertion but which is operated entirely by a sliding plunger or, alternatively a screw fed plunger. In this embodiment, the forceps may be mounted to an insert which does not have a frame to receive an actuator. Alternatively, the forceps may have a base which is integrally formed with the insert that locates in the proximal end of the barrel.

In another unillustrated embodiment, the insert, the forceps and the actuator may all be replaced with an integral or removable lens cartridge. If the lens cartridge is integral with the injector, the lens may be pre-loaded during manufacture and supplied ready for operation so that the step of mounting the lens in the cartridge is eliminated. Alternatively, the lens cartridge may be detachably connected to the barrel so that the barrel can be re-used. It is envisaged that a lens supplier will manufacture lenses and place them in a dedicated cartridge ready for use so that the user of the lens injector only has to remove the cartridge from its sterile packaging and connect it to the barrel. Once the lens has been ejected from the cartridge, that cartridge is thrown away and can be replaced with a fresh one containing a new lens. The barrel 2 may be provided with an insert similar or identical to the insert previously described and can be used with or without the actuator to advance the plunger beyond an intermediate position in response to rotation of said actuator. The insert and the cartridge may have cooperating means thereon to facilitate the connection of the cartridge to the injector.

The cartridge may incorporate a seal or bung which is engaged by the plunger and pushed into contact with the lens to force it out of the cartridge and either through a nozzle integrally formed with the cartridge or through the nozzle formed in a separate cap. This arrangement has the benefit that the plunger does not come into direct contact with the lens itself at any time.

A perspective view of the barrel is shown in Figure 8. The proximal end 7 of the barrel can be seen into which locates the insert 6. A pair of elongate apertures 32 extend rearwardly from the proximal end 7 into which locate the pads 26 on the arms 24 so that pressure can be applied to the arms 24 via the pads 26 even when a cap 30 is located in position over the forceps 5.

The distal end of the barrel 2 is provided with two opposed arcuate shaped cut-outs 33 to receive the index and middle finger of the user with the thumb pushing down on the thumb plate 19 of the plunger 3. The cut outs 33 are arcuately shaped so that the lateral force needed to grip the barrel 2 is in balance with the relative force needed to push the plunger 3. Many conventional injectors have two lateral protrusions that allow large forces to be placed by the thumb onto the plunger 3 resulting in the plunger 3 being advanced too quickly. The arcuate shaped cut-outs 33 balances the ratio of forces such that the surgeon has to maintain a lateral finger grip force as well as a downward force on the plunger 3 at the same time thereby making it less Ukely that the surgeon will place an excessive force on the plunger 3 for fear of the injector 1 slipping out of his hand. The barrel 2 preferably has an ovoid shaped cross-section so that the orientation of the jaws 11 is clearly apparent from the orientation of the barrel 2.

The location of the actuator 9 allows the lens injector 1 to be operated with one hand. By placing the actuator 9 closer to the proximal end of the barrel 2, control of the plunger 3 is made more steady as any vibration is reduced due to the shorter angle of movement attributed to its position. Conventional lens injectors that use a screw method to advance the plunger have the screw knob mounted at the distal end of the barrel requiring two hands to advance the plunger. In addition, the potential to wobble the tip is increased as the distance between the screw knob and the tip becomes greater.

Referring now to the Figures 9 - 14, there is illustrated a second embodiment of the invention. Figure 9 shows an exploded view of a lens injector 100 having a handle or barrel 102 and an elongate plunger 103 positionable within the barrel 102. The barrel 102 is formed of two separate portions, a first portion 102A and a second portion 102B. A lens holder 105 in the form of a pair of forceps is mounted to an insert 106, both of which are seated within the proximal end 107 of the barrel 102. The first and second portions 102A, 102B of the barrel 102 both have a recess 108A, 108B formed in one side which align when the two portions 102A, 102B are fitted together to form a window 108 to facilitate access to an actuator 109 rotatably mounted within the barrel 102. A lens (not shown) can be held between jaws 111 of the forceps 105 as previously described with reference to the first embodiment of the invention.

The barrel 102 is more clearly shown in Figure 13. The two portions of the barrel 102A, 102B 'snap-fit' together to form the barrel 102. The first portion 102A has shafts 140 extending perpendicularly from its inner surface, each shaft 140 having an enlarged head 141. The second portion 102B has tubular portions 142 (see Figure 9) extending perpendicularly from its inner surface that are positioned such that when the two portions of the barrel 102A, 102B are aligned to be fitted together, the enlarged heads 141 of the shafts 140 locate within the tubular potions 142 and engage therewith to 'snap-fit' the barrel portions 102B, 102B together. As can be seen from Figures 9, 10 and 14, the actuator 109 comprises a cylindrical thumbwheel having a ridged outer surface 113A and a central hole 113 that extends through the actuator. The actuator 109 is removably and rotatably seated in the second portion 102B of the barrel 102. The second barrel portion 102B has a spindle 143 extending perpendicularly from the recess 108B, which is received in the central hole 113 of the actuator 109 so that the actuator 109 can freely rotate on said spindle 143.

Referring particularly to Figure 11, the plunger 103 has a tip 114 and is partially formed from a cylindrical rod 115. A ribbed section 116 is formed along one end remote from the tip 114 and comprises a series of annular rings spaced from one another. The remaining portion 117 of the rod is smooth. The tip 114 contacts and pushes the lens (not shown) out of the forceps and into the eye when the plunger 103 is advanced towards the lens.

A thumb plate 119 is spaced from the rod 115 by an enlarged elongate section 118 which provides additional strength to the plunger 103 and provides space to enable graphics indicating the position of the plunger 103 relative to the barrel 102 to be moulded or apphed to the plunger 103. The elongate section 118 has flattened side walls 119a which locate against complimentary shoulders or walls (not shown) on the inside of the barrel 102 to prevent rotation of the plunger 103 within the barrel 102. The thumb plate 119 facilitates the apphcation of pressure to the plunger 103 to move it in an axial direction indicated by arrow "X" in Figure 11 relative to the barrel 102.

As can be most clearly seen from Figure 9, the actuator 109 is located adjacent to the plunger 103 and the ridged surface 113A of the actuator 109 engages with the ribbed section 116 of the plunger 103 and acts as a 'rack-and-pinion' mechanism. The tip 114 of the plunder 103 protrudes from the proximal end 107 of the barrel 102 towards the jaws 111 of the forceps 105. The plunger 103 is axially slidable within the barrel 102 by the application of an axially directed load to the plate 119 in the direction of Arrow "X". Movement of the plunger 103 in the axial direction is also controlled by the actuator 109 which can be rotated so that the ridges 113A on the actuator 109 mesh with the ribbed section 116 on the plunger 103 to move the plunger 103 relative to the barrel 102. The ridges 113A on the actuator 109 also act to improve the grip between the surface of the actuator 109 and the finger or thumb of a person using the device. It will be appreciated that movement of the plunger 103 by rotation of the actuator 109 enables the position of the plunger 103 to be controlled very precisely and incrementally. The location of the actuator 109 allows the lens injector 100 to be operated with one hand, with the actuator being operable using either the thumb or the forefinger, depending on the orientation of the injector 100. As described earlier in reference to the first embodiment, by placing the actuator 109 closer to the proximal end of the barrel 102, the user has much steadier control of the plunger 103 compared to conventional lens injectors that use a screw method to advance the plunger and have the screw knob mounted at the distal end of the barrel

An essential functional difference of this mechanism from that of the first embodiment of the invention described above, is that the plunger 103 can be moved axially though its entire range of motion, from fully retracted so that the tip 114 is inside the barrel 102, to fully extended where the tip 114 is beyond the jaws 111 of the forceps 105, by either applying an axial force to the thumb plate 119, or by rotating the actuator 109, or a combination of both. Unlike the first embodiment described above, the actuator 109 does not need to be removed from the barrel 102 if the user wishes to only move the plunger 103 by applying an axial force to the base plate 119. In this case, the actuator 109 simply free-wheels as its ridged surface 113A meshes with the ribbed section 116 of the plunger as the axial force slides the plunger 103 within the barrel 102. This increases the versatility of the injector 100, as the user does not need to decide before performing an operation which mode of plunger movement (i.e. pressing the thumb plate or rotating the actuator) (s)he wishes to employ. The forceps 105 and the insert 106 of this second embodiment, and the way the integrate with the barrel 102 of the invention are identical to the forceps 5 and insert 6 of the first embodiment as described above, so no further definition of these components or their function in manipulating a lens will be given here. Furthermore, the lens injector 100 of the second embodiment also includes a cap which is identical to the cap 30 of the first embodiment and is used in exactly the same manner as previously described.

The distal ends of the each portion 102A, 102B of the barrel 102 are provided with two opposed arcuate shaped cut-outs 133 to receive the index and middle finger of the user with the thumb pushing down on the thumb plate 119 of the plunger 103. These are identical to the cut-outs 33 in the barrel 2 of the first embodiment previously described.

It will be appreciated from the foregoing that the present invention provides an improved lens injector 1 /100 which provides the surgeon with an enhanced degree of control. The injector 1/100 also has a simple construction and can be formed from relatively inexpensive materials which renders it disposable after only one or several uses.

Many modifications and variations of the invention falling within the terms of the following claims will be apparent to those skilled in the art and the foregoing description should be regarded as a description of the preferred embodiments only.

Claims

1. An intraocular lens injector comprising an elongate barrel having a longitudinal axis, a plunger insertable into the barrel and slideable relative thereto in an axial direction from a first position to an intermediate position in response to the application of an axially directed load towards a lens located in a lens holder at one end of the barrel, and an actuator rotatably mounted in the barrel which is engaged by the plunger in said intermediate position so that further movement of the plunger relative to the barrel in said axial direction can be achieved in response to rotation of the actuator to push a lens disposed in said lens holder into the eye.

2. An intraocular lens injector according to claim 1 wherein further movement of the plunger relative to the barrel from said intermediate position can only be achieved in response to rotation of the actuator.

3. An intraocular lens injector according to claim 2, wherein the plunger extends through the actuator and has a screw thread formed along a portion of its length.

4. An intraocular lens injector according to claim 3, wherein the plunger is configured so that the unthreaded portion of the plunger shdes through the actuator as it moves from the first to the intermediate position.

5. An intraocular lens injector according to claim 4, wherein the actuator is internally threaded such that the screw thread on the plunger engages with the actuator when the intermediate position has been reached.

6. An intraocular lens injector according to claim 5, wherein rotation of the actuator causes the thread on the actuator and the thread on the plunger to mesh to cause the plunger to move relative to the barrel beyond the intermediate position in said axial direction.

7. An intraocular lens injector according to any preceding claim, wherein the actuator is removable from the barrel to enable the plunger to slide past the intermediate position in response to the application of an axially directed load to directly push a lens from said lens holder into the eye in an alternative mode of operation.

8. An intraocular lens injector according to claim 7 wherein an insert is disposed in the barrel and said insert includes a frame to rotatably mount the actuator.

9. An intraocular lens injector according to any preceding claim, wherein the actuator comprises a tubular thumbwheel mountable for rotation about its longitudinal axis coaxial with the longitudinal axis of the barrel.

10. An intraocular lens injector according to claim 1 wherein further movement of the plunger relative to the barrel from said intermediate position can be achieved both in response to rotation of the actuator and/or in response to the apphcation of an axially directed load on the plunger towards the lens.

11. An intraocular lens injector according to claim 10 wherein the plunger is positioned adjacent to the actuator and has a series of ribs formed along a portion of its length.

12. An intraocular lens injector according to claim 11 wherein the plunger is configured so that the portion without ribs shdes past the actuator as it moves from the first position to the intermediate position.

13. An intraocular lens injector according to claim 12 wherein the actuator has a ridged outer surface such that the ribs on the plunger engage with the ridges on the actuator when the intermediate position has been reached.

14. An intraocular lens injector according to claim 13 wherein rotation of the actuator causes the ridges on the actuator and the ribs on the plunger to mesh to cause the plunger to move relative to the barrel beyond the intermediate position.

15. An intraocular lens injector according to any of claims 1 or 10-14 wherein the actuator comprises a cylindrical thumbwheel mountable for rotation about its central axis which is perpendicular to the longitudinal axis of the barrel.

16. An intraocular lens injector according to any preceding claim, wherein the actuator is received in an aperture in the barrel between the ends thereof.

17. An intraocular lens injector according to any preceding claim, wherein the lens holder extends from one end of the barrel.

18. An intraocular lens injector according to claim 17, wherein the lens holder comprises a pair of forceps.

19. An intraocular lens injector according to claim 18, wherein the forceps comprise a pair of spaced integraUy formed arms coupled together at one end and having a jaw at the tip of each arm, the arms being resihently deformable in response to the apphcation by a user of an inwardly directed load to the arms to close the space between the jaws to pick up and fold a lens therebetween ready for insertion.

20. An intraocular lens injector according to claim 19, including locking means to lock the arms with their jaws in their closed position when the user releases the arms to retain the lens between the jaws.

21. An intraocular lens injector according to claim 19 or 20, wherein the lens holder is mounted on an insert disposed in the barrel.

22. An intraocular lens injector according to any of claims 19 to 21, wherein the jaws extend at an angle relative to the remainder of the arms.

23. An intraocular lens injector according to any of claims 19 to 22, wherein a pair of oppositely opposed curved grooves are formed in the jaws to receive and orient a lens therebetween.

24. An intraocular lens injector according to any of claims 19 to 23, wherein a recess is formed in each jaw which together form a passageway when the jaws are closed to enable the plunger to pass through the passageway between the jaws and engage the lens to push it out from between the jaws and into the eye.

25. An intraocular lens injector according to any of claims 19 to 24, including a cap attachable to the barrel over the lens holder.

26. An intraocular lens injector according to claim 25, wherein the cap includes a nozzle through which the lens passes from the lens holder into the eye when pushed by the plunger.

27. An intraocular lens injector according to claim 25 or 26, wherein the cap locks the arms in their closed position.

28. An intraocular lens injector according to claim 17, wherein the lens holder comprises a pre-loaded cartridge connected to the end of the barrel.

29. An intraocular lens injector according to claim 28, wherein the cartridge and the barrel include co-operating means for releasably connecting a replaceable cartridge to the barrel.

30. An intraocular lens injector according to claim 28 or 29, wherein the cartridge is integrally formed with a cap and includes a nozzle, the plunger being movable through the cartridge to push the lens through the nozzle and inject it into the eye.

31. An intraocular lens injector according to any of claims 28 to 30, wherein the cartridge includes a seaUng member disposed between the lens and the plunger, the seaUng member being slideable in response to the application of force by the plunger into contact with the lens to push the lens out of the cartridge.

32. A method of operating an intraocular lens injector according to any preceding claim to inject an intraocular lens into the eye, comprising the steps of applying an axially directed load to the plunger to move it from the first into the intermediate position and, subsequently rotating the actuator to further move the plunger beyond the intermediate position to cause the plunger to push a lens mounted in the lens holder into the eye.

33. An intraocular lens injector according to any preceding claim wherein the barrel and the actuator are made of a rigid plastic such as polycarbonate or an acrylonitrile-butadiene-styrene copolymer (ABS) material.

34. An intraocular lens injector according to any preceding claim wherein the plunger tip is made of a deformable plastic such as polypropylene.

35. An intraocular lens injector according to any of claims 1 — 33 wherein the lens holder, the cap and the plunger are made of a deformable plastic such as polypropylene

36. An intraocular lens injector comprising an elongate barrel having a longitudinal axis, a plunger and a lens holder mounted to one end of the barrel, the plunger being moveable in an axial direction within the barrel towards said end to push a lens from said lens holder into the eye, wherein the lens holder comprises a pair of forceps operable to pick up and fold a lens ready for insertion.

37. An intraocular lens injector according to claim 36, wherein the forceps comprise a pair of spaced integrally formed arms coupled together at one end and having a jaw at the tip of each arm, the arms being resiUently deformable in response to the apphcation by a user of an inwardly directed load to the arms to close the space between the jaws to pick up and fold a lens ready for insertion.

38. An intraocular lens injector according to claim 37, including locking means to lock the arms with their jaws in their closed position when the user releases the inwardly directed load apphed to the arms.

39. An intraocular lens injector according to any of claims 36 to 38, wherein the forceps are mounted on an insert disposed in the barrel.

40. An intraocular lens injector according to any of claims 36 to 39, wherein the jaws extend at an angle relative to the remainder of the arms.

41. An intraocular lens injector according to any of claims 37 to 40, wherein a curved groove is formed in each jaw portion to receive a lens therebetween.

42. An intraocular lens injector according to any of claims 37 to 41, wherein a recess is formed in each jaw which together form a passageway when the jaws are closed to enable the plunger to pass between the jaws through the passageway and engage the lens to push it out from between the jaws and into the eye.

43. An intraocular lens injector according to any of claims 37 to 42, including a cap attachable to the barrel over the lens holder.

44. An intraocular lens injector according to claim 43, wherein the cap includes a nozzle through which the lens passes from the lens holder into the eye when pushed by the plunger.

45. An intraocular lens injector according to claim 43 or 44, wherein the cap locks the arms in their closed position.

46. An intraocular lens injector according to any of claims 36 to 45 wherein the barrel is made of a rigid plastic such as polycarbonate or an acrylonitrile-butadiene- styrene copolymer (ABS) material.

47. An intraocular lens injector according to any of claims 36 to 46 wherein the tip of the plunger is made of a deformable plastic such as polypropylene.

48. An intraocular lens injector according to any of claims 36 to 46 wherein the lens holder, the plunger and the cap are made of a deformable plastic such as polypropylene

49. An intraocular lens injector substantially as hereinbefore described with reference to the accompanying drawings.

50. A method of operating an intraocular lens injector substantially as hereinbefore described.