Abstract:
An IOL injector device allows for both powered and manual delivery of an IOL. The injector has a tubular housing. A plunger is longitudinally disposed within the housing and has first and second ends. The first end is disposed towards the front end of the housing. A drive system is coupled to the housing. The drive system causes longitudinal translation of the plunger along the primary axis of the housing. A normally engaged clutch system is coupled to the drive system. The normally engaged clutch system allows manual disengagement of the drive system. A knob coupled to the plunger allows for manual operation of the injector.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/367,440 filed Jul. 25, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to a device for delivering an intraocular lens into an eye. The device has both a powered modality of operation and a manual modality of operation. The manual modality of operation may at any time override the powered modality of operation while providing the same accuracy and safety of known manual threaded lens delivering devices. 
         [0003]    The human eye functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a crystalline lens onto a retina. The quality of the focused image depends on many factors including the size and shape of the eye, and the transparency of the cornea and the lens. When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an artificial intraocular lens (IOL). 
         [0004]    In the United States, the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, an opening is made in the anterior capsule and a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. The vibrating cutting tip liquefies or emulsifies the lens so that the lens may be aspirated out of the eye. The diseased lens, once removed, is replaced by an artificial lens. 
         [0005]    The IOL is injected into the eye through the same small incision used to remove the diseased lens. An insertion cartridge of an IOL injector is loaded with the IOL, the tip of the insertion cartridge is inserted into the incision, and the lens is delivered into the eye. Many IOLs manufactured today are made from a polymer with specific characteristics. These characteristics allow the lens to be folded, and when delivered into the eye, allow the lens to unfold into the proper shape. Several manual injector devices are available for implanting these lenses into the eye. However, threaded-type manual injectors require the use of two hands, which is cumbersome and tedious. Syringe-type injectors produce inconsistent injection force and displacement. Thus, improved devices and methods are needed for delivering IOLs into the eye. 
       SUMMARY OF THE INVENTION 
       [0006]    Various embodiments of the present invention provide an intraocular lens injector that can operate in dual mode—capable of motor powered operation and manual operation. Automated and manual modes of operation can occur at any time of lens insertion, the manual mode preferably overriding the automated mode of operation. 
         [0007]    The injector of present invention may incorporate a detachable powering mechanism, always being able to operate in manual modality regardless of the availability of the powering module. 
         [0008]    The injector of the present invention is may incorporate a mechanical clutching or motor detaching mechanism. 
         [0009]    Because of the mechanical nature of the clutching system acting as a safety clutch, a variety of powering motors can be used such as spring motor, pneumatic motor, electric motor, and others. 
         [0010]    Embodiments of the present invention include various devices for implanting an intraocular lens (IOL) into a selected position inside an eye, as well as methods for controlling such a device. According to an exemplary embodiment, an IOL injection device comprises a tubular housing with a plunger longitudinally disposed within the tubular housing. The plunger is longitudinally translated frontwards and rearwards, with respect to a front end of the housing, by a drive system disposed within or detachably coupled to the housing and comprising a motor. In a preferred embodiment an electric motor is used, but the drive system can incorporate other driving mechanisms such as a spring motor, a pneumatic motor, etc. with corresponding control system. The drive system is effectively coupled to transmit kinetic energy to a lens injecting plunger. 
         [0011]    The device is configured so that when the plunger is translated towards the front of the device, its tip engages an intraocular lens insertion cartridge mounted at or near the front end of the housing. The plunger tip, which may in some embodiments be a removable plastic sleeve that snap fits to a push rod, passes through the insertion cartridge to fold and displace an intraocular lens disposed within, and to inject the folded lens into the selected location inside an eye. 
         [0012]    In an embodiment incorporating an electric motor as the drive mechanism, the IOL injection device further comprises a control circuit, electrically connected to the electric motor and configured to start translation of the plunger, responsive to user input. The motor is coupled to the plunger by means of a clutching mechanism in normally engaged condition. In normal powered operation, the motor transmits mechanical power across the engaged clutching mechanism to the plunger producing forward or rearward displacement of the plunger body. If increased resistance to plunger displacement occurs, an increase in torque occurs at clutch disk level. The clutch mechanism is factory set to disengage or slide above torque levels considered safe for operation. Optionally a user can adjust the torque required for the clutch mechanism to slide or disengage. The clutching mechanism can also incorporate two different engage-disengage preset threshold torque levels one for forward and another for rearward plunger directions. 
         [0013]    A lever or command can be effective to mechanically disengage the powering drive mechanism from the lens injecting plunger, removing in this way the resistance required to manually slide the clutching mechanism. This action restores the normal feedback of resistance provided to the fingers of the operator when using the injector in manual mode of operation. 
         [0014]    An overrunning clutch or freewheel mechanism can be incorporated to the injector power transmission mechanism allowing manual override of the powered drive mechanism with minimal increase in injection resistance when operating in the direction of injection, providing enhanced tactile resistance feedback during manually assisted lens injection. With this mechanism, the driving motor always becomes engaged in backward operation and manual drive is always required to retract the plunger, typically requiring disengagement of a torque limiter for plunger retraction. 
         [0015]    When using selected powering motors such as those known as “direct drive” without a gearbox, there is no need for a disengage mechanism for manual operation, as the resistance added to manually activate the unpowered motor is negligible. However, the absence of a mechanical clutching mechanism imposes the need of an electronic fault detection system to detect increased resistance during operation. 
         [0016]    The motor controller can incorporate rotational speed control and monitoring. The control circuit can monitor the rotational speed of the electric motor, based on the counter-electromotive force, and can detect fault conditions, such as no-load, excessive load, clutch sliding, end-of-forward travel and end-of-rearward travel. The control circuit can operate the motor in ramp mode, progressively increasing plunger speed when started, and resetting the initial speed every time injection is stopped and restarted. 
         [0017]    In an exemplary method for controlling a device for implanting an intraocular lens in the lens capsule of an eye, wherein the device comprises a plunger longitudinally disposed inside a tubular housing and an electric drive system including an electric motor and configured to cause longitudinal translation of the plunger along a primary axis of the housing, longitudinal translation of the plunger is initiated responsive to user input. As a safety feature, translation of the plunger is stopped when and if the normally engaged clutch mechanism disengages reactive to an increased resistance to plunger displacement acting as a programmed torque limiter. 
         [0018]    Conditions that trigger clutch disengagement may include excessive resistance to forward translation of the plunger and excessive resistance to rearward translation of the plunger. Increased resistance for plunger displacement converts into increased torque at clutch level. If the preset disengagement level is surpassed the clutch stops transmitting motor power to the plunger acting as a safety clutch. Preset disengagement torque levels can be set by design different for forward and for rearward plunger motion. Regardless of the clutch being engaged or disengaged, the injector can always be operated manually in the conventional manner known for manual IOL injectors. 
         [0019]    The powering mechanism can be detachably coupled to the injector body in a way that when coupled motor power can be effectively transmitted to the plunger to operate both in powered and manual mode, but also allowing the injector to operate in manual-only modality when the powering mechanism is detached. 
         [0020]    In one embodiment of the present invention, an intraocular lens injector comprises: a tubular housing having a primary axis extending between a front end and a rear end of the housing; a plunger longitudinally disposed within the housing and having first and second ends, the first end being disposed towards the front end of the tubular housing; a drive system coupled to the housing, the drive system configured to cause longitudinal translation of the plunger along the primary axis of the housing; a normally engaged clutch system coupled to the drive system, the normally engaged clutch system allowing manual disengagement of the drive system; and a knob coupled to the plunger, the knob allowing manual operation of the injector. 
         [0021]    Of course, those skilled in the art will appreciate that the present invention is not limited to the above features, advantages, contexts or examples, and will recognize additional features and advantages upon reading the following detailed description and upon viewing the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. 
           [0023]      FIG. 1  is a side view of a manually operated IOL injection apparatus of the prior art. 
           [0024]      FIG. 2  is a side view of a dual mode IOL injection apparatus according to the principles of the present invention. 
           [0025]      FIG. 3  is a schematic cross sectional view of a dual mode injector at the plane of the gear mechanism taken from B-B in  FIG. 4 . 
           [0026]      FIG. 4  is a lateral cross sectional view of the proximal portion of a dual mode injector taken from A-A in  FIG. 3 . 
           [0027]      FIG. 5   a  and  FIG. 5   b  are lateral cross sectional views of the proximal portion of a dual mode injector according to the principles of the present invention. 
           [0028]      FIG. 6  is a perspective view of a dual mode IOL injection device according to the principles of the present invention. 
           [0029]      FIG. 7  is a perspective view of the proximal portion of a dual mode injector incorporating a clutch mechanism according to the principles of the present invention. 
           [0030]      FIG. 8  is a perspective view of the powering portion of a dual mode injector including an electric micro-motor, reduction gearbox and gear according to the principles of the present invention. 
           [0031]      FIG. 9  is a perspective view of a spring powered embodiment of a dual mode injector according to the principles of the present invention. 
           [0032]      FIG. 10  is a perspective view of the powering portion of a dual mode injector including a spring powered mechanism according to the principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. 
         [0034]      FIG. 1  illustrates a handheld intraocular lens (IOL) injection device of the prior art 100 for implanting an IOL into the anterior capsule of the eye. The IOL injection device  100  also comprises a cartridge mount  118 , which holds a removably mounted insertion cartridge  120  typically press fitted into position. Injection cartridge  120  is usually a disposable polymeric component adapted to accommodate an unfolded IOL lens  122  and to fold and displace the lens as a plunger tip  125  is translated forward from a body  115  of injector  100  and through the insertion cartridge  120 . 
         [0035]    An operator counter rotates a knob  126  until a male thread  128  is released from a receiving female thread  129  fixedly disposed inside injector housing  115 . Once thread  128  is released, the operator further pulls backward to retract plunger  124  to its rearward stop position. With plunger  124  in this position, operator can then insert IOL cartridge  120  into its locking position in cartridge mount  118  with IOL  122  properly loaded inside cartridge  120 . Some cartridges  120  may come with IOL  122  pre-loaded from factory. The operator pushes knob  126  axially displacing plunger  124  until thread  128  engages female thread  129 . At this point IOL  122  will have been pushed by plunger tip  125  inside cartridge  120  into a pre-delivery position. The distal opening of cartridge  120  is inserted into a surgical wound and knob  126  is rotated clockwise to controllably deliver IOL  122  in a desired intraocular location. Injector  100  (with locked cartridge  120 ) is removed from the eye completing the IOL injection procedure. Tactile feedback allows the operator to sense the force required to advance IOL  122  though the lumen of cartridge  120 , thus allowing the operator to detect abnormal situations such as increased resistance (that may be created by a number of conditions such as improper lubrication, misaligned IOL, improper matching between cartridge  120  and IOL  122  dimensions, etc). The operator can evaluate the nature of the condition and perform the corrective actions required. This may require injector withdrawal, position correction or even continuing with the procedure without corrective actions taken based on the experience of the operator. Correlation between the detected injection force and the visual inspection of IOL  122  traveling inside transparent cartridge  120  allows the operator to judge the need of corrective actions under different scenarios. Detection of an increased force of injection will not always require aborting the injection process. 
         [0036]      FIG. 2  is a side view of a dual mode IOL injection apparatus according to the principles of the present invention. IOL injection device  10  facilitates implanting an IOL  22  into a selected location of the eye. IOL injection device  10  includes a cable  12  that carries power and/or control signals from a separate controller module  42 . Controller module  42  may include a user interface  48  and an input device such as a foot pedal, switch or other similar device (not shown). Some embodiments of the present invention may include in a main housing  15  one or more batteries to provide electrical power to the device and/or one or more switches or other user input devices and/or a controller to control the operation of the device. 
         [0037]    The IOL injection device  10  also comprises a cartridge mount  18 , which holds a removably mounted insertion cartridge  20  in a locked position. Cartridge  20  is also shown unmounted as  20   a . Insertion cartridge  20  is typically a transparent disposable polymeric component adapted to accommodate an unfolded IOL and to fold and displace the IOL as the tip  25  of plunger  24  is translated forward from the body of housing  15  and through insertion cartridge  20 . Tip  25  has a smooth surface that gently pushes IOL  22 . In some embodiments, cartridge mount  18  may comprise a metallic “nosecone” that includes a unique cutout to accommodate the IOL cartridge and that is press-fitted to an inner shell of the housing  15 . Some cartridges  20  may come with IOL  22  pre-loaded in unfolded position. 
         [0038]    Plunger  24  is rotation restrained inside housing  15  and has a proximal portion including a male thread portion of threaded plunger shaft  28  and a rotating knob  26 . An axially rotating joint ( 56  in  FIG. 3 ) couples knob  26  and threaded plunger shaft  28  with plunger  24 . One or more longitudinal zones of threaded plunger shaft  28  have been reduced to create a male key  29  matching with a complementary female key ( 37  in  FIG. 3 ) in the center of a clutch disk  32 . This mechanism is designed to allow axial displacement of threaded plunger shaft  28  across clutch disk  32  while producing rotational engagement between clutch disk  32  and threaded plunger shaft  28 . In a preferred embodiment one or more flat areas disposed in a symmetrical manner conform to male key  29 . Clutch disk  32  is rotated by a powered drive mechanism  51  enclosed within a drive mechanism housing  52 . The powering portion of drive mechanism  51  can be detachably coupled to injector housing  15  in a way that injector  10  can operate manually as described in  FIG. 1  when drive mechanism  51  is detached. 
         [0039]      FIG. 3  is a schematic cross sectional view of a dual mode injector at the plane of the gear mechanism taken from B-B in  FIG. 4 . Motor  38  with an optional reduction gearbox  40  transmits rotational power through a shaft  41  to attached motor gear  39 . A clutch drive disk  34  with attached drive disk gear  35  receives rotational power from motor  38 . Drive disk holders  30  shown in  FIG. 4  allow drive disk  34  to rotate coaxially with respect to injector housing  15 . A normally engaged clutching mechanism is conformed between drive disk  34  and clutch disk  32 , held in coaxial position by a rim of drive disk  34 . A factory set compression force exists between disks  34  and  32  with an optional intermediate clutch lining  36 , spring or other clutch coupling media. For example, clutch lining  36  can be complemented or replaced by a compressible washer or other equivalent clutch interface system providing a stable and predictable torque limiter capable of withstanding repeated sterilizations, moisture, debris, etc. Clutch disk center key hole  37  allows plunger  24  to be axially displaced freely and also to rotate freely because the reduced diameter of plunger  24 . Threaded plunger shaft  28  with male key  29  can be freely displaced co-axially inside clutch disk key hole  37 . Clutch disk  32  and threaded plunger shaft  28  are rotationally locked to each other by male key  29  and female key  37 . Any suitable clutch mechanism can be employed to engage and disengage the motor power from the device  10 . For example, in other embodiments of the present invention, instead of a mechanic clutch operating as a torque limiter, the same functionality can be incorporated using an electromagnetic clutch. 
         [0040]      FIG. 4  is a lateral cross sectional view of the proximal portion of a dual mode injector taken from A-A in  FIG. 3 . Housing  15  has an internally fixated female thread  60  receiving plunger  24  in an axially unrestrained manner because of its reduced diameter. Plunger  24  is rotationally restrained by plunger rotation restrainer  23  engaging a slit or flattened segment along the main axis of plunger  24 . Free axial displacement is possible when plunger  24  advances from a fully retracted position until threaded plunger shaft  28  engages with female thread  60 . Free axial travel typically corresponds to the phases of cartridge insertion, IOL folding and advance into a pre-release position. From this point forward, axial displacement of plunger  24  is achieved by a clockwise rotation of knob  26  in which threaded plunger shaft  28  engages female thread  60 . This portion of travel typically corresponds to IOL  22  delivery phase, where maximum control is required. When drive mechanism  51  is operationally attached by a fixation bracket  54 , injector  20  can incorporate the powered mode of operation, overridable by manual operation in forward and reverse direction by disengagement of the torque limiter clutch mechanism. 
         [0041]    To operate injector  10  an operator fully retracts plunger  24  by first counter rotating knob  26  until disengaging threaded plunger shaft  28  from female thread  60 . This operation can be performed in powered mode by providing a plunger retract command into user interface  48 , or in manual mode by grasping and turning knob  26  counterclockwise with a force enough to disengage the torque limiter clutch mechanism and rotate threaded plunger shaft  28  until released from female thread  60 . At this point the operator performs the second step of fully retracting plunger  24  until it is in a rearward stop position. In this embodiment, this second step is always a manual procedure. With injector  10  having plunger  24  in a fully retracted position, the operator can insert an IOL loaded cartridge  22  into cartridge mount  18  in the locking position. Operator then manually advances plunger  24  by pushing and rotating knob  26  until threaded plunger shaft  28  with male key  29  travels across clutch disk  32  with female key  37  and threads threaded plunger shaft  28  minimally into female thread  60 . During this action, plunger tip  25  folds and pushes IOL  22  distally into a pre-insertion position inside cartridge  20 . At this point injector  10  is prepared for powered IOL injection. 
         [0042]    After inserting the distal opening of cartridge  20  into a surgical incision in the eye, the operator provides an insertion command through user interface  48  to controller  42 . Controller  42  provides power and control signals through cable  12  to produce forward actuation of motor  38 . Controller  42  monitors the operation of motor  38  to detect proper operation and overload conditions. Relevant fault conditions such as motor malfunction or overload can be reported to the operator using user interface  48  to provide, for example, an audible or luminous warning signal. Motor rotational energy is transmitted through optional gearbox  40 , and gear  39  to drive disc  34  which in turn transmits rotary power across the normally engaged clutch mechanism to clutch disk  32  with female key  37  acting as a torque limiter. When properly set, female key  37  has been manually engaged with male key  29  and threaded plunger shaft  28  has been minimally threaded into female thread  60 . Following an operator command, drive mechanism  51  produces clockwise rotation of clutch disk  32  and threaded plunger shaft  28 . Clockwise rotation of thread  60  by disk  32  produces forward displacement of plunger  24  as threaded plunger shaft  28  threads into female thread  60 , controllably injecting IOL  22  into a selected position inside the eye. An operator can use a foot pedal or other input device from user interface  48  to command controller  42  to initiate lens injection, adjust plunger speed, accelerate, decelerate, stop and shift direction of operation. In this way, a high degree of control can be achieved during IOL injection. 
         [0043]    In other embodiments, custom operation commands can be programmed into controller  42  according to operator preferences. Controller  42  can be programmed to deliver control signals to motor  38  that allow a non-uniform speed of operation. For example, motor speed can follow a ramp function progressively increasing motor speed after each activation cycle while resetting to low speed every time the system is restarted from the stop position for increased control. Other functions are possible. The operator can at any time stop or reverse the direction of plunger translation by providing the corresponding command using user interface  48 . Plunger tip  25  travels into the eye being operated is physically limited in the same manner it is limited in manually operated IOL injectors of the prior art by reaching a fixed end-of-travel position determined by male thread length. At any time during powered operation, the operator can manually override powered operation simply by holding or rotating knob  26  in a desired direction. When holding knob  26  in a fixed position while clutch disk  32  is engaged and motor  38  is rotating, the torque limiter clutch mechanism disengages the translation of stopping plunger  24 . Furthermore, regardless of motor activity, manual rotation of knob  26  in a clockwise direction with male and female threads  28  and  60  engaged produces forward translation of plunger  24 , as the clutch mechanism is factory set to a torque release threshold level that always allows manual activation of injector  10  over powered activation of the injector  10 . Similarly, manual counterclockwise rotation of knob  26  with an engaged threaded plunger shaft  28  will always produce rearward translation of plunger  24  regardless of the activity of drive mechanism  51 . 
         [0044]      FIG. 5   a  and  FIG. 5   b  are lateral cross sectional views of the proximal portion of a dual mode injector according to the principles of the present invention. This embodiment allows an operator to activate a knob with a screw  62  operational to separate or bring together gears  39  and  35 . In one position, knob  62  puts gears  39  and  35  in functional contact engaging rotational power transmission between motor  38  and drive disk  34 . In an alternative position, knob  62  is operational to separate gears  39  and  35  into a non-functional position introducing a gap  64  between gears. In this disengaged position, motor  38  has no loading effect and injector  10  can be manually operated through knob  26  providing optimal tactile feedback of resistance during plunger advance and retraction. Many other engage-disengage mechanisms are possible and the mechanism shown here is only for illustration purposes. Knob  62  can be designed to be operational for disengaging the drive system in one position and for full detachment of the drive system in another position, allowing the injector to be used in manual-only mode when the drive mechanism  51  is fully detached. 
         [0045]      FIGS. 5   a  and  5   b  more clearly show the manual override feature of the present invention. In  FIG. 5   a , the drive motor is engaged, and the injector  10  is operated automatically by motor  38 . In this configuration, motor  38  is coupled via optional gear box  40  and motor shaft  41  to drive gear  39 . As motor  38  rotates so does motor gear  39 . In this manner, motor  38  drives motor gear  39 . If gearbox  40  is employed, then the gear ratio can be increased or decreased such that rotation of motor  38  is slower of faster (respectively) than rotation of motor gear  39 . Typically, a gear box  40  is employed such that a faster rotation of motor  38  results in a slower rotation of motor gear  39  which allows for more precise control of IOL insertion through more precise control of the axial translation of plunger  24 . 
         [0046]    In  FIG. 5   a , motor gear  39  engages drive disk gear  35  which in turn engages the plunger threads on threaded plunger shaft  28 . In this manner, motor gear  39  turns drive disk gear  35  which turns plunger  24 . Because plunger threads on threaded plunger shaft  28  are engaged with female thread  60 , as plunger  24  rotates, it also translates. In this manner, plunger  24  translates axially such that plunger tip  25  contacts the IOL and pushes it out of cartridge  20 . 
         [0047]      FIG. 5   b  shows the device  10  of the present invention in manual mode. In the configuration of  FIG. 5   b , motor gear  39  is disengaged from disk gear  35 . In this case, operation of the device  10  is manual and is accomplished by turning plunger knob  26 . In  FIG. 5   b , an engage-disengage screw  62  is turned so that the motor assembly is moved away from injector body  15 . In this embodiment, engage-disengage screw  62  is coupled to fixation bracket  54 . 
         [0048]    In another embodiment of the present invention, a spring motor can be used as the drive mechanism  51  for injector  10 . An attached or detachable winding lever common to spring motors is used to put the spring powered drive mechanism in a wound condition. A lever suitably positioned can be activated for plunger translation for lens injection. The system can be designed to operate only to inject, or for injection and retraction of the plunger. The same lever used for activation can be designed to indicate to the operator that the spring motor is properly wound for operation. Manual override is always available. An advantage of a spring motor powered IOL injector is wireless operation. Other motors such as pneumatic, piezoelectric, linear electric can be used as the drive mechanism  51  without departing from its scope. 
         [0049]      FIG. 6  is a perspective view of a dual mode IOL injection device according to the principles of the present invention. In  FIG. 6 , plunger knob  26  is fixed to plunger  24  (not shown). Motor gear  39  is engaged with disk drive gear  35 . Drive disc gear  35  is coupled to drive disc  34 . Motor  38  is coupled to motor gear  39  via motor shaft  41  and optional gearbox  40  (not shown). Cable  12  provides power and control signals to motor  38 . Drive mechanism  51  is at least partially enclosed by drive mechanism cover  52 . Injector body  15  has a cartridge mount  18  and cartridge  20 . 
         [0050]      FIG. 7  is a perspective view of the proximal portion of a dual mode injector incorporating a clutch mechanism according to the principles of the present invention. In  FIG. 7 , plunger knob  26  is fixed to plunger  24  (not shown) via threaded plunger shaft  28 . Threaded plunger shaft  28  has a male key  29  that acts as a key as previously described. Motor gear  39  is engaged with disk drive gear  35 . Drive disc gear  35  is coupled to drive disc  34 . Motor  38  is coupled to motor gear  39  via motor shaft  41  and optional gearbox  40  (not shown). Cable  12  provides power and control signals to motor  38 . Drive mechanism  51  is at least partially enclosed by drive mechanism cover  52 . 
         [0051]      FIG. 8  is a perspective view of the powering portion of a dual mode injector including an electric micro-motor, reduction gearbox and gear according to the principles of the present invention. Motor  38  is coupled to motor gear  39  via motor shaft  41  and optional gearbox  40 . Engage-disengage screw  62  is threaded into fixation bracket  54 . Engage-disengage screw  62  can contact housing  15  to hold the motor assembly in place on injection  10 . Drive mechanism  51  is at least partially enclosed by drive mechanism cover  52 . 
         [0052]      FIG. 9  is a perspective view of a spring powered embodiment of a dual mode injector according to the principles of the present invention. Injector body  15  has a cartridge mount  18  and cartridge  20 . Plunger knob  26  is fixed to plunger  24  (not shown) via threaded plunger shaft  28 . Instead of a motor, a wound spring is used to provide the force to plunger  24  through the same gears previously described. In this manner, as the spring unwinds, it turns gears that cause plunger  24  to translate. The same clutch mechanisms previously described may also be used with the spring-driven embodiment of the present invention. 
         [0053]      FIG. 10  is a perspective view of the powering portion of a dual mode injector including a spring powered mechanism according to the principles of the present invention. Plunger knob  26  is fixed to plunger  24  (not shown) via threaded plunger shaft  28 . Threaded plunger shaft  28  has a male key  29  that acts as a key as previously described. Instead of a motor, a wound spring is used to provide the force to plunger  24  through the same gears previously described. In this manner, as the spring unwinds, it turns gears that cause plunger  24  to translate. The same clutch mechanisms previously described may also be used with the spring-driven embodiment of the present invention. 
         [0054]    From the above, it may be appreciated that the present invention provides an improved IOL injection device. The present invention provides an automated IOL injector with manual override capability. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art. 
         [0055]    Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.