Patent Publication Number: US-6217584-B1

Title: Method and a system for performing cataract surgery

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of devices for eye surgery in general and to the field of devices for cataract surgery in particular. 
     BACKGROUND OF THE INVENTION 
     Surgical removal of cataract is well known in the art. In cataract surgery, the content of the eye lens is completely removed leaving only the posterior lens capsule, in which an artificial lens may be subsequently installed. It is appreciated that one of the main risks in cataract surgery is a potential damage, e.g. rupture, of the lens capsule. In the past, it was common practice to “freeze” the entire lens using appropriate means and then, to remove the lens in its entirety via a large opening which is formed in the cornea, specifically, along the Cornea Limbus. This procedure resulted in damage to the lens capsule and to the vitreous body and is, therefore, no longer in use. 
     Presently, there are a number of known methods for removing cataract. FIG. 1 schematically illustrates a cross-sectional view of a human eye  10  during cataract surgery in accordance with one, commonly used, prior art method. A surgical instrument  12  and, optionally, a manipulation device  14 , are inserted into eye lens  20  via cornea  16 , a preferably dilated pupil  18  and an opening formed in the anterior capsule of lens  20 . As is known in the art, lens  20  includes a core  28 , known as the nucleus, which is formed of a relatively hard tissue. Core  28  is surrounded by a layer  26  of relatively soft, jell-like tissue, known as the cortex, which fills lens capsule  24 . 
     The soft tissue in cortex layer  26  is typically removed gradually using a vacuum suction device and/or a “scooping” device (not shown in the drawings). To remove nucleus  28 , the hard tissue is typically, first, broken into small fragments and/or dissolved using appropriate instruments and/or solutions and, then, removed gradually by suction and/or “scooping” as described above. Alternatively, the entire nucleus can be removed in one piece, however, this requires cutting a large opening in the cornea. 
     FIG. 1 illustrates one method of breaking nucleus  28  using directional ultrasonic transmission. According to this method, instrument  12  includes a device  25 , generally known as a Phacoemulsifier (Hereinafter: “Phaco”), which transmits intense ultrasonic energy into nucleus  28 . The crushing effect of the ultrasonic transmission of Phaco device  25  is typically enhanced by a stream of liquid  22  supplied from an external sleeve  23  of instrument  12 , which liquid typically includes a dissolving agent. It is appreciated that, during surgery, a constant supply of liquids is generally required to compensate for escape of intraocular liquids and/or to assist in dissolving the content of lens  20 . In the example shown in FIG. 1, the supply of liquid  22  via sleeve  3  is utilized both as a dissolving agent and as a compensatory liquid supply. However, it is appreciated that a separate liquid supply may additionally or alternatively be used. 
     Manipulation device  14  typically includes a thin, pointed instrument. For example, The thin pointed instrument can be a needle or a spatula, which provide partial counter-support to the operation of instrument  12  on nucleus  28 . Such a device enables the surgeon to manipulate nucleus  28  by pushing it to a desired position and to temporarily support the nucleus at the desired position. However, it should be noted that the ability of the surgeon to manipulate and control nucleus  28  using device  14  is limited, due to various physical parameters. For example, the “angle of the attack” of device  14  on the traction between device  14  and the surface of nucleus  28  can be manipulated, using device  14 , only by pushing and not by pulling. 
     Medical follow up studies reveal that the quality of the post-operative optical results depends on the size of the incision made during surgery, where smaller incisions are usually associated with better post-operative results. 
     An additional development favoring the reduction of the incision size is the availability of foldable artificial lenses which can be introduced into the eye and inserted into the capsula while folded inside a needle-like device of relatively small diameter. 
     Unfortunately, ultrasonic systems such as the Phacoemulsifier are relatively expensive. Moreover, during the operation, the surgeon cannot observe a clearly defined border of the crushing action of the Phaco device  25 . Thus, the inexperienced surgeon might inadvertently damage the posterior capsule of the lens, resulting in poorer post-operative results. 
     Additionally, the geometry of the crushing zone around the tip of the Phaco device  25  is not constant and varies for different sonication intensities, while having no visible cue which the surgeon can use to determine the precise crushing range from the tip of the Phaco device  25 . 
     Consequently, there is a steep learning curve for the surgeon, requiring a relatively long training period and resulting in lower quality of the post-operative results during the training period. 
     Furthermore, in certain cataract cases, the degree of hardening of the cataract nucleus  28  is such that the Phaco device  25  cannot crush it, thus, requiring the surgeon to broaden the small incision in order to remove the whole cataract nucleus. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide an improved device for manipulating tissue during surgery. The manipulation device of the present invention is particularly useful in intraocular surgery, particularly in cataract removal surgery. 
     The present invention provides a device, hereinafter referred to as cryomanipulator, having a selectively activated cryogenic tip designed to be inserted into a surgical site, e.g., into an eye lens, and to contact a tissue to be manipulated, for example the nucleus of an eye lens. In response to the selective activation thereof, the cryogenic tip selectively adheres to a portion of the tissue, die to the freezing of the tissue adjacent the tip. This adherence of the cryogenic tip to the manipulated tissue, at the region of contact therebetween, will be hereinafter referred to as a “freeze-grip”. As long as the cryogenic tip is active, i.e., as long as the freeze-grip is active, the tissue can be securely and conveniently manipulated in any direction, e.g., pushed pulled, twisted, etc., by appropriate movement of the cryomanipulator. When the cryogenic tip is deactivated, the freeze-grip is released and the tip can be moved to a new position or location vis-a-vis the tissue. Thus, by sequentially positioning, activating, deactivating, repositioning the cryomanipulator, the tissue can be manipulated efficiently, quickly and accurately during surgery. 
     The cryomanipulator is preferably used in conjunction with a surgical instrument, for example a Phacoemulsifier device or any other means for crushing hard tissue, which operates on the tissue while the tissue is temporarily supported by the cryomanipulator. It should be noted that the freeze-grip between the cryogenic tip and the tissue provides a firm, stable support to the manipulated tissue, allowing convenient operation of the surgical instrument. 
     In a preferred embodiment of the present invention, the cryomanipulator includes a supply of liquid, preferably an intraocular-compatible liquid, adjacent to or juxtaposed with the cryogenic tip. The supply of liquid expedites the release of the freeze-grip when the cryogenic tip is deactivated, allowing quicker repositioning of the cryomanipulator and, thus, improving the efficiency and accuracy of the cryomanipulator. 
     In some preferred embodiments of the present invention, the cryomanipulator includes a heating device juxtaposed with the cryogenic tip. The heating device is preferably activated when the cryogenic tip is deactivated. The heat provided by the heating device expedites the release of the freeze-grip, improving the manipulation efficiency of the cryomanipulator. 
     In some preferred embodiments of the present invention, the cryomanipulator includes an open sleeve which surrounds the cryogenic tip and the heating device, if used. Preferably, the sleeve includes a removable sleeve. In one preferred embodiment of the present invention, the sleeve is associated with a source of a predetermined liquid, providing the liquid supply described above. Alternatively, the sleeve may be associated with a vacuum suction device, enabling suction of tissue removed during surgery. Preferably, the sleeve is associated with a flow selector, as is known in the art, which enables switching of the cryomanipulator between a number of modes of operation, e.g., a liquid supply mode and a vacuum suction mode. 
     In some preferred embodiments of the present invention, the cryomanipulator includes a surgical tip, for example a blade juxtaposed with the cryogenic tip to a desired position on the tissue. In the preferred embodiments using a removable sleeve, the surgical instrument preferably mounted on the removable sleeve. 
     There is thus provided, in accordance with a preferred embodiment of the present invention, a device for manipulating tissue during surgery including a manipulator head having a cryogenic tip adapted to engage a region-of-contact of the tissue and to selectively freeze-grip the region of contact. 
     In a preferred embodiment of the present invention, the device further includes a sleeve surrounding the cryogenic tip and having an aperture directed generally towards the region-of-contact. Preferably, the sleeve is associated with a supply of liquid which is expelled through the aperture. Additionally or alternatively, the sleeve is associated with a vacuum suction device which produces suction at the aperture. Preferably, the device has a body and the sleeve is removably mounted on the body. 
     In a preferred embodiment of the invention, the sleeve includes a surgical tip juxtaposed with the cryogenic tip. 
     In a preferred embodiment of the present invention, the manipulator head includes a heating device juxtaposed with the cryogenic tip. Preferably, the device includes means for selectively activating the heating device to heat a vicinity of the region-of-contact. 
     Further, in accordance with a preferred embodiment of the present invention, there is provided a device for manipulating tissue during surgery including: 
     a manipulator head having a cryogenic tip adapted to engage a region-of-contact of the tissue; and 
     means for selectively activating the cryogenic tip to freeze-grip the region of contact. 
     In some preferred embodiments of the present invention, the device further includes means for supplying liquid generally towards the region-of-contact. Additionally or alternatively, the device includes means for heating a vicinity of the region-of-contact. 
     In a preferred embodiment of the present invention, the manipulatory head includes a surgical tip juxtaposed the cryogenic tip. Preferably, the surgical tip includes a blade. 
     In a preferred embodiment of the present invention, the tissue includes an intraocular tissue. Preferably, the intraocular tissue includes a portion of an eye lens. More preferably, the tissue includes at least a portion of the nucleus of the eye lens. 
     The present invention also seeks to provide a device for the breaking (disintegrating) and removing of a cataract which can be inserted into the eye through a relatively small incision. 
     The present invention further seeks to provide a device for breaking and removing a cataract in which the part that comes in contact with the patient&#39;s eye is a disposable part. 
     There is therefore provided, in accordance with a preferred embodiment of the present invention, a device for removing a cataract from an eye while the cataract is in a solid-like state. The device includes a drilling unit for breaking the cataract, and a handle connectable to the drilling unit for enabling an operator to manipulate the drilling unit within the eye. 
     Further, in accordance with a preferred embodiment of the present invention, the drilling unit includes a housing having a bore therewithin and a drill bit rotatably disposed within the bore, and couplable to an external motor. 
     Yet further, in accordance with another preferred embodiment of the present invention, the handle of the device also includes a motor and the drilling unit includes a housing having a bore therewithin and a drill bit rotatably disposed within the bore, wherein the drill bit is couplable to the motor. 
     Still further, in accordance with yet another preferred embodiment of the present invention, the drilling unit further includes a conduit, connectable to an irrigation fluid reservoir, for providing irrigation fluid to the anterior chamber of the eye. 
     Additionally, in accordance with another preferred embodiment of the present invention, the drilling unit further includes a second conduit connectable to a vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     There is therefore also provided, in accordance with another preferred embodiment of the present invention, a drilling unit for removing a cataract from an eye, while the cataract is in a solid-like state. The drilling unit includes a housing having a bore therewithin, a drill bit rotatably disposed within the bore and a conduit for providing irrigation fluid to the anterior chamber of the eye. The drill bit is rotatably couplable to a motor and the conduit is connectable to an irrigation fluid reservoir. 
     Further, in accordance with another preferred embodiment of the present invention, the drilling unit further includes a second conduit connectable to a vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     There is therefore also provided, in accordance with another preferred embodiment of the present invention, a system for removing a cataract from an eye, while the cataract is in a solid-like state. The system includes a drilling unit for breaking the cataract, a handle attachable to the drilling unit for enabling an operator to manipulate the drilling unit within an eye and a motor for powering the drilling unit. 
     further, in accordance with another preferred embodiment of the present invention, the system also includes a reservoir of irrigation fluid for supplying irrigation fluid to the drilling unit. 
     still further, in accordance with yet another preferred embodiment of the present invention, the drilling unit includes a housing having a bore therewithin, a drill bit rotatably disposed within the bore and a conduit for providing irrigation fluid to the anterior chamber of the eye. The conduit is connectable to the reservoir of irrigation fluid and the drill bit is couplable to the motor. 
     Additionally, in accordance with another preferred embodiment of the present invention, the system also includes a vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     Yet further, in accordance with another preferred embodiment of the present invention, the drilling unit further includes a second conduit connectable to the vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     According to yet another preferred embodiment of the present invention, the system also includes at least one controlling unit for controlling the vacuum pump and the motor, for regulating the rate of suction of the vacuum pump and the speed of rotation of the motor. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the drilling unit of the system is a disposable unit. 
     Further, in accordance with another preferred embodiment of the present invention, the drill bit includes a drill blade and the housing of the drilling unit also includes a guard lip protruding from an end of the housing proximal to the drill blade. 
     There is therefore also provided, in accordance with another preferred embodiment of the present invention, a system for removing a cataract from an eye, while the cataract is in a solid-like state. The system includes a drilling unit for breaking the cataract, a handle attachable to the drilling unit for enabling an operator to manipulate the drilling unit within an eye and a motor for powering the drilling unit. 
     Further, in accordance with another preferred embodiment of the present invention, the system also includes a reservoir of irrigation fluid for supplying irrigation fluid to the drilling unit. 
     Still further, in accordance with yet another preferred embodiment of the present invention, the drilling unit includes a housing having a bore therewithin, a drill bit rotatably disposed within the bore and a conduit for providing irrigation fluid to the anterior chamber of the eye. The conduit is connectable to the reservoir of irrigation fluid and the drill bit is couplable to the motor. 
     Additionally, in accordance with another preferred embodiment of the present invention, the system also includes a vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     Yet further, in accordance with another preferred embodiment of the present invention, the drilling unit further includes a second conduit connectable to the vacuum pump for aspiring excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye. 
     According to yet another preferred embodiment of the present invention, the system also includes at least one controlling unit for controlling the vacuum pump and the motor, for regulating the rate of suction of the vacuum pump and the speed of rotation of the motor. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the drilling unit of the system is a disposable unit. 
     Further, in accordance with another preferred embodiment of the present invention, the drill bit includes a drill blade and the housing of the drilling unit also includes a guard lip protruding from an end of the housing proximal to the drill blade. 
     There is therefore also provided, in accordance with still another preferred embodiment of the present invention, a method for removing a cataract from an eye. The method includes the steps of solidifying the cataract and the step of breaking the cataract while it is solidified. 
     Further, in accordance with yet another preferred embodiment of the present invention, the method also includes the steps of irrigating the anterior chamber of the eye with an irrigation fluid and removing excessive irrigation fluid and fragments of the cataract suspended in the irrigation fluid from the anterior chamber of the eye by aspiration. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the step of solidifying includes the step of freezing the cataract. 
     Still Further, in accordance with yet another preferred embodiment of the present invention, the step of solidifying includes the step of freezing the cataract by a cryomanipulator. 
     Further, in accordance with yet another preferred embodiment of the present invention, the step of breaking is performed by a cataract removing device. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the step of breaking includes the step of immobilizing the cataract by freeze-gripping it with the cryomanipulator prior to breaking the cataract. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the step of irrigating and the step of removing are performed by the cataract removing device. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the cataract removing device includes a drilling unit for breaking the cataract and a handle connectable to the drilling unit for manually manipulating the drilling unit within the eye. 
     There is further provided, in accordance with still another preferred embodiment of the present invention, a method for removing a cataract from an eye. The method includes the steps of inserting a cryomanipulator and a surgical instrument through the eye to contact the cataract, immobilizing at least part of the cataract by freeze-gripping it with the cryomanipulator, breaking the cataract into fragments using the surgical instrument and removing the fragments from the eye. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the surgical instrument is a cataract removing device, the cataract removing device includes a drilling unit for breaking the cataract and a handle connectable to the drilling unit for manually manipulating the drilling unit within the eye and wherein the step of immobilizing further includes the step of solidifying at least part of the cataract by freezing at least part of the cataract with the cryomanipulator, and the step of breaking includes breaking the cataract by the drilling unit while at least part of the cataract is immobilized and at least partially frozen by the cryomanipulator. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the step of inserting includes the steps of forming two suitable tracts in the eye, the tracts extending from the sclero-corneal region of the eye through the anterior chamber of the eye to the cataract, introducing the cryomanipulator and the surgical instrument into the eye through the tracts and forming at least one opening in the anterior capsula of the eye for inserting the cryomanipulator and the surgical instrument into the cataract. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, the surgical instrument is a cataract removing device and the step of removing includes aspirating the fragments of the cataract by at least one of the cryomanipulator and the cataract removing device. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, The step of breaking further includes immobilizing at least one of the fragments of the cataract by freeze-gripping it with the cryomanipulator. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, The method further includes the step of manipulating at least part of the cataract within the lens capsula while it is freeze-gripped by the cryomanipulator for facilitating the breaking of the part by the cataract removing device. 
     Furthermore, in accordance with still another preferred embodiment of the present invention, The method further include the step of manipulating at least part of the cataract within the lens capsula while it is freeze-gripped by the cryomanipulator for facilitating the breaking of the part by the surgical instrument. 
     Finally, in accordance with still another preferred embodiment of the present invention, The step of irrigating and the step of removing are performed by the cryomanipulator. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
     FIG. 1 is a schematic, side view, cross-sectional illustration of a human eye during cataract surgery in accordance with the prior art; 
     FIG. 2 is a schematic, side view, cross-sectional illustration of a human eye during cataract surgery using a cryomanipulator in accordance with a preferred embodiment of the present invention; 
     FIG. 3 is a schematic, enlarged, side view illustration of the cryomanipulator of FIG. 2; 
     FIGS. 4A and 4B are, respectively, top view and front view, cross-sectional, schematic illustrations of one preferred variation of a cryomanipulator of FIG. 2; 
     FIGS. 5A and 5B are, respectively, top view and front view , cross-sectional, schematic illustrations of another preferred variation of the cryomanipulator of FIG. 2; 
     FIGS. 6 and 7 are schematic, side view, illustrations of two, respective, preferred mounting configurations of a removable sleeve of the cryomanipulator of FIG. 2; 
     FIG. 8 is a schematic illustration of a preferred electrical circuit for the cryomanipulator of FIG. 2; 
     FIG. 9 is a schematic isometric view of a system for removing cataract in accordance with a preferred embodiment of the present invention; 
     FIG. 10A is a schematic isometric view illustrating the cataract removing device (CRD) of the cataract removing system of FIG. 9; 
     FIG. 10B is a, schematic, isometric view illustrating in detail the tip of the disposable drilling unit which is part of the CRD of FIG. 10A; 
     FIG. 11 is a schematic top view of the CRD of FIG. 10A illustrating the disposable drilling unit assembled with the handle of the CRD; 
     FIG. 12 is a schematic cross section of the disposable drilling unit of FIG. 11 along the line XII—XII; 
     FIG. 13 is a schematic side view of the CRD of FIG. 11 illustrating the disposable drilling unit assembled with the handle of the CRD; 
     FIG. 14 is a schematic, side view, partly cross-sectional illustration of a human eye during cataract surgery, illustrating the cryomanipulator and the CRD positioned within the eye, in accordance with another preferred embodiment of the present invention; 
     FIG. 15 is a schematic isometric view illustrating a different CRD in accordance with an additional preferred embodiment of the present invention; 
     FIG. 16 is a schematic, exploded, isometric view of part of the disposable drilling unit of the CRD of FIG. 15; 
     FIG. 17 is a schematic cross section of the distal shaft  83  of FIG. 16 taken along the lines XVIIB—XVIIB; 
     FIG. 18 is a schematic isometric view of part of the drilling unit of the CRD of FIG. 15; 
     FIG. 19 is a schematic cross section of the distal shaft of the drilling unit of FIG. 18 along the lines XIX—XIX; and 
     FIG. 20 is a schematic isometric view illustrating in detail a battery powered handle of a CRD, in accordance with another preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It is noted that, for a better understanding, like components are designated by like reference numerals throughout the various figures. 
     Reference is now made to FIG. 2, which schematically illustrates a cross-sectional side view of human eye  10  during cataract surgery in accordance with a preferred embodiment of the present invention. A cryomanipulator  50 , described in detail below, and a surgical instrument  32  are inserted into eye lens  20  via cornea  16  and dilated pupil  18 . As is known in the art, lens  20  consists of lens capsule  24 , soft cortex layer  26  and hard nucleus  28 , as described above with reference to FIG.  1 . Surgical instrument  32  may include any surgical instrument known in the art, for example a blade and/or an ultrasonic transmitter such as a Phacoemulsifier (hereinafter: “Phaco”) and/or a “scooping” device. In a preferred embodiment of the present invention, cryomanipulator  50  includes a manipulator head  66  adapted to engage nucleus  28  of lens  20 , at a region of contact  64 , while surgical instrument  32  operates on a region  33  of nucleus  28 . Additionally or alternatively, cryomanipulator  50  may be utilized as a surgical instrument, e.g., for removing tissue from layer  26  and/or for removing tissue separated from region  33 , as explained below. 
     Reference is now made also to FIG. 3 which schematically illustrates an enlarged side-view of cryomanipulator  50 . The cryomanipulator  50  preferably includes a body portion  52  and a sleeve portion  54 , preferably a removable sleeve as described in detail below. In accordance with the present invention, manipulator head  66  includes a selectively-activated cryogenic tip  72  adapted to be in contact with region  64  of nucleus  28 . Tip  72  is preferably selectively activated by a surgeon using a switch  62  on body portion  52 , as described below. When cryogenic tip  72  is activated, the tissue in region  64  freezes and, thereby, adheres to the cryogenic tip. This adherence of tip  72  to region  64  will be hereinafter referred to as a “freeze-grip”. 
     As long as tip  72  is active, the freeze grip enables the surgeon to securely and conveniently manipulate nucleus  28 , by appropriate movement of cryomanipulator  50 . When tip  72  is deactivated, using switch  62 , the freeze-grip is released and tip  72  can be repositioned on a different region on nucleus  28  or on another tissue. Thus, by sequentially positioning, activating, repositioning and deactivating cryogenic tip  72 , nucleus  28  can be efficiently and accurately manipulated during surgery. 
     Cryogenic tip  72  is cooled to a predetermined temperature, preferably on the order of −80° to −60° C., using a cryogenic gas such as carbon dioxide or nitrogen. The cryogenic gas is preferably supplied from a cryogenic gas source (not shown in the drawings) via conduits  58 , which are preferably insulated from the external environment using an insulating layer  76 , as is known in the art. Insulator  76  ensures that only tip  72  will be cooled to the cryogenic temperature upon supply of the cryogenic gas to conduits  58 . The supply of cryogenic gas is preferably controlled by a valve which, in turn is controlled by switch  62 , as described below with reference to FIG.  8 . 
     As described above, in a preferred embodiment of the invention, surgical instrument  32  operates on region  33  while nucleus  28  is temporarily supported by cryomanipulator  50  at region  64 . The freeze-grip between cryogenic tip  72  and region  64  provides a firm, stable support of nucleus  28 , allowing convenient operation of surgical instrument  32 . 
     Sleeve portion  54  includes an aperture  68 , preferably having an “air collector” shaped as outlined in FIGS. 2 and 3, which surrounds cryogenic tip  72  of manipulator head  66 . In one preferred mode of operation, described below, sleeve  54  supplies a stream  75  of a predetermined liquid to the vicinity of region  64 , via aperture  68 . In another preferred mode of operation described below, sleeve  54  collects intraocular tissue via aperture  68 , preferably using a vacuum suction device. Thus, as described below, sleeve  54  is preferably associated with a pipe suction device, as are known in the art. In some preferred embodiment of the present invention, pipe  56  is connected to the liquid source and the vacuum device via a flow selector (not shown in the drawings) which enables convenient switching between the liquid supply mode and the vacuum suction mode. Preferably, the selector further includes an “OFF” mode in which the liquid source and vacuum device are both disconnected. In one preferred embodiment, the flow selector includes a three-way valve as is known in the art. 
     In the liquid supply mode, the liquid supplied to region  64  expedites the release of the freeze-grip when cryogenic tip  72  is deactivated, using switch  62 . This enables quicker repositioning of tip  72 , and, thus, improves the efficiency and accuracy of cryomanipulator  50 . In some preferred embodiment, the flow selector includes a three-way valve as is known in the art. 
     In the liquid supply mode, the liquid supplied to region  64  expedites the release of the freeze-grip when cryogenic tip  72  is deactivated, using switch  62 . This enables quicker repositioning of tip  72  and, thus, improves the efficiency and accuracy of cryomanipulator  50 . In some preferred embodiments of the present invention, the liquid supply through aperture  68  may include a dissolving agent, as is known in the art, which assists in the surgical procedure. 
     In a preferred embodiment of the present invention, manipulator head  66  further includes a heating device  74 , juxtaposed with cryogenic tip  72 . Heating device  74 , which may include a miniature heating element known in the art, is preferably activated when cryogenic tip  72  is deactivated, to further expedite the release of the freeze-grip, thereby to further improve the efficiency of cryomanipulator  50 . Electric power to operate tip  74  is prefereably provided from an external power source (not shown in FIGS.  2  and  3 ), via electric conductors  60 . Activation and deactivation of heating device  74  is preferably controlled by the surgeon using a switch  65 , which is preferably located on body portion  52 . 
     As further shown in FIGS. 2 and 3, manipulator head  66  preferably further includes a surgical tip  70 , for example a nail-shaped blade mounted on sleeve  54 , which assists in manipulating the intraocular tissue and/or in guiding cryogenic tip  72  to a desired position. Surgical tip  70  can also be utilized to perform a given surgical function, for example cutting or breaking of the tissue in lens  20 . The shape and structure of surgical tip  70  is preferably designed in accordance with specific surgical requirements. For example, tip  70  may have a “fingernail” shape as shown in the drawings, a “can-opener” shape, a “pin” or any suitable shape as is known in the art. Additionally, the surface of surgical tip  70  may be coated within abrasive coating (not shown) such as a diamond-dust coating. 
     Reference is now made also to FIGS. 4 a  and  4   b  which schematically illustrate, respectively, a cross-sectional top view and a cross-sectional front view of one preferred variation of cryomanipulator  50 . In this preferred variation, conduits  58  include coaxial inner and outer conduits  84  and  82 , respectively, separated by a barrier  88 . Insulator layer  76  covers the entire external surface  86  of conduit  82 , except for an exposed region defining tip  72 . In the example shown in FIG. 4A, inner conduit  84  functions as an inlet for the cryogenic gas and outer conduit  82  functions as an outlet for the cryogenic gas. As shown in FIG. 4B, conductors  60  and liquid-supply/suction pipe  56  are both mounted above the conduits and pipe  56  is mounted below the conduits. 
     As shown particularly FIG. 4A, sleeve  54  is preferably mounted to body portion  52  using a bayonet structure including an outer connector  80  on sleeve  54  and an inner connector  78  on body portion  52 . This enables simple removal of sleeve  54 , e.g., for cleaning and/or for replacement by a different sleeve, or a different mounting configuration, as explained below with reference to FIGS. 6 and 7. 
     Reference is now briefly made to FIGS. 5A and 5B which schematically illustrate, respectively, a cross-sectional top view and a cross-sectional front view of another preferred variation of cryomanipulator  50 . In this preferred variation, conduits  58  include folded conduit segments  94  and  92 , having edges  96 . Segments  94  and  92  are preferably cast in insulating material  98  which covers the entire external surface of edges  96  except for the exposed region defining tip  72 . In the example shown in FIG. 5A, segment  94  functions as an inlet for the cryogenic gas segment  92  functions as an outlet for the cryogenic gas. As shown in FIG. 5B, conductors  60  and liquid-supply/suction pipe  56  are both mounted along conduit segments  92  and  94 . Preferably, conductors  60  are mounted above the segments and pipe  56  is mounted below the segments. 
     Reference is now made to FIGS. 6 and 7 which are schematic side view illustrations of two respective, preferred, mounting configurations of sleeve  54  on body portion  52 , using bayonet connectors  78  and  80 . In the configuration of FIG. 6, surgical tip  70  is situated above cryogenic tip  72  and the “air collector”-shaped aperture  68  is below tip  72 . The appropriate mounting configuration for sleeve  54  is preferably selected by the surgeon in accordance with other specific surgical tasks of manipulator head  66 . In other preferred embodiments of the present invention (not shown in the drawings), sleeve  54  may be replaced by different types of sleeves which are selected in accordance with specific surgical requirements. For example, the replacement sleeves may include sleeves having different types of surgical tips  70 , as described above. 
     As further shown in FIGS. 6 and 7, liquid-supply/suction pipe  56  preferably extends along conduits  58  only in body portion  52  and not in sleeve  54 , i.e., pipe  56  ends substantially in line with bayonet connectors  78  and  80 . Thus, in the liquid supply mode described above, the liquid supplied from pipe  56  is distributed substantially homogeneously around tip  72  at aperture  68 . This ensures that the supplied liquid covers the entire contact region  64 . 
     Reference is now made to FIG. 8 which schematically illustrates a preferred electrical circuit  100  for cryomanipulator  50 . Circuit  100  includes a cryogenic controller  104  and heater  74  which are preferably connected to a power supply  106  via activating switches  62  and  65 , respectively, and conductors  60 . Power supply  106  preferably includes a low voltage DC power supply such as a battery or an appropriate AC/DC converter/transformer. Cryogenic controller  104 , which preferably includes a valve (not shown) on conduits  58  (FIGS.  2 - 7 ), controls the supply of cryogenic gas to tip  72  via conduits  58 . The operation of heater  74  has been described above with reference to FIGS. 2 and 3. 
     Reference is now made to FIG. 9 which is a schematic isometric view illustrating a cataract removing system. The cataract removing system  202  includes a hand held cataract removing device (CRD)  204 , a motor  206  for powering the CRD  204 , a reservoir  212  for supplying a sterile physiological irrigation solution  213  to the cataract removing device  204 , a vacuum pump  208  for providing reduced pressure at the tip of the CRD  204  and a foot pedal  210  for controlling the action of the vacuum pump  208 . 
     The motor  206  is a variable speed electrical motor which is detachably connected to the CRD  204  by a flexible shaft  214  for supplying rotary power to the CRD  204 . The motor  206  also includes a suitable control cable (not shown for the sake of clarity of illustration) which connects the motor  206  with the CRD  204  to enable CRD  204  to control the rotation speed of the motor  206 . The motor  206  also includes the control circuits (not shown) for controlling the rotary speed of the motor  206 . 
     The reservoir  212  is connected by tubing  216  to the CRD  204  for supplying the sterile irrigation physiological solution  213  to the CRD  204 . The reservoir  212  can be a standard sterile infusion bag having tubing  216  built-in. The rate of flow of the irrigation solution  213  can be controlled gravitationally by adjusting the height of the reservoir  212  above the level of the CRD  204 . Alternatively, the rate of flow of the irrigation solution  213  can be controlled by other means of flow control such as the standard flow regulating constricting device which is usually built into standard commercially available infusion-bag tubing (not shown) or an adjustable speed peristaltic pump (not shown). 
     The vacuum pump  208  can be any suitable vacuum pump or other suitable device for providing reduced pressure. The vacuum pump  208  is connected to the CRD  204  by a tubing  218 . Alternatively, in cases where a centrally supplied vacuum is available tubing  218  can be suitably connected to the vacuum inlet, obviating the need for vacuum pump  218 . The tubing  218  can be any suitable flexible tubing that can operate under reduced pressure. Pump  218  is suitably connected to foot-pedal  210  which controls the vacuum pump  208 . 
     The CRD  204  includes a handle  220  and a disposable drilling unit  230  which is connectable to the handle  220 . 
     Reference is now made to FIGS. 10A,  10 B,  11  and  12  illustrating the structure of the handle  220  and the drilling unit  230  in detail. 
     FIG. 10A is a schematic isometric view illustrating the cataract removing device (CRD) of the cataract removing system of FIG.  9  and FIG. 10B is a schematic isometric view illustrating in detail the tip of the disposable drilling unit which is part of the CRD of FIG.  10 A. 
     The handle  220  is a rod-like handle having two hollow cylindrical passages  226  and two recesses  254  therewithin. The handle  220  also includes a rotatable coupler  228  which is suitably connected to the motor  206  by the flexible shaft  214 , which passes through the handle  220 . Thus, when the motor  206  is operating the rotatable coupler  228  is rotated by the flexible shaft  214 . The flexible shaft  214  can be structurally integrated within the handle  220  and directly connected to the coupler  228 . Alternatively, coupler  228  can be connected to a separate axle (not shown) which is detachably connected to the flexible shaft  214 . In the latter case the flexible shaft  214  can be detached from the handle  220  to facilitate the sterilization thereof. 
     The handle  220  also includes a controlling unit  224  (FIG. 10A) for manually controlling the speed of rotation of the motor  206 . The controlling unit  224  can be any suitable switch for enabling the starting and stopping of the motor  206  and for controlling the speed of rotation thereof. The handle  220  can be made of any suitable material which is sterilizable, such as a metal or a durable plastic. 
     FIG. 11 is a schematic top view of the CRD  204  of FIG. 10A illustrating the disposable drilling unit  230  assembled with the handle  220  of the CRD  204 . The drilling unit  230  is roughly Y shaped as best seen in FIG.  11 . As best seen in FIG. 10A, the drilling unit  230  has two hollow tubular members  240  at its end proximal to the handle  220 , and a middle part  241  which tapers at its end distal from the handle  220 , forming a distal shaft  242 . Each tubular member  240  has a notch  236  therein (FIG. 10A) and has a fluid conduit  256  (FIG. 11) passing therethrough. Each tubular member  240  also includes a sealing gasket  238  suitably mounted thereupon. Each of the sealing gaskets  238  abuts the middle part  241 . The fluid conduits  256  continuously taper within the middle part  241  (FIG. 11) extending therethrough to the tip of the distal shaft  242 , where they each end in an orifice  250  (FIG.  10 B). The drilling unit  230  also includes a drill axle  248  which passes through a cylindrical axle channel  249  (FIG.  12 ). The axle channel  249  extends through the middle part  241  and the distal shaft  242  of the drilling unit  230  and is positioned between the fluid conduits  256 . The drill axle  248  is connected to a drill blade  246  (FIG. 10B) and to a coupler  232 , thus forming a drill. The distal shaft  242  includes a guard lip  244  which extends under the drill blade  246  (FIG.  10 A). 
     It is noted that the CRD  204  is designed for disintegrating a lens or cataract of the eye which has been converted from its gel-like state into a solid-like state. The lens can be converted into a solid state by freezing it into an ice-like consistency by any suitable method of freezing, such as freeze-gripping by any of the embodiments of the cryomanipulator disclosed hereinabove. However, any other suitable method for converting the lens into a solid-like state can be used to enable the use of the CRD of the present invention. When the lens is frozen or in a solid-like state, the drill blade  246  of the drilling unit  230  can effectively break (disintegrate) the cataract. 
     It is also noted that the drilling unit  230  can be made of any suitable material. For example, the drilling unit  230  can preferably be made of sterilizable non-pyrogenic plastic. It is also noted that the axle  248  and the drill blade  246  can be made of any suitable material, such as surgical steel or stainless steel. 
     FIG. 12 is a schematic cross section of the disposable drilling unit of FIG. 11 along the line XII—XII illustrating two fluid conduits  256  passing within the drilling unit  230  It is noted that, although the two fluid conduits  256  passing within the drilling unit  230  are shown to be structurally similar to each other ( FIGS.  11  and  12 ), they can also be of different dimensions. For example, the part of one of the two fluid conduits  256  which passes within the distal shaft  242  may have a larger diameter than the corresponding part of the other fluid conduit  256 . Thus, the diameters of the orifices  250  which are shown to be equal in FIG. 10B, can also be of different dimensions. For example, the orifice  250  which is used for irrigation can have a larger diameter than the orifice  250  which is used for aspiration, mutatis mutandis. 
     Reference is now made to FIG. 13 is a schematic side view of the CRD  204  of FIG. 11 illustrating the disposable drilling unit  230  assembled with the handle  220  of the CRD  204 . Each of the tubes  216  and  218  includes a hollow adapter  222  suitably attached thereto. The adapter  222  of tubing  216  can be sealingly fitted into one of the passages  226  for providing irrigation fluid to one of the orifices  250  of the drilling unit  230  through one of the conduits  256 . The adapter  222  of tubing  218  can be sealingly fitted into the remaining passage  226  for providing reduced pressure at the distal shaft  242  of the drilling unit  230 , thus removing excess irrigation fluid by aspiration thereof at the second orifice  250  through the other conduit  256 . 
     The handle  220  also includes two spring and ball latches  252 . Each spring and ball latch  252  is attached within the handle  220  in such a way that the ball  237  of the spring and ball latch  252  slightly protrudes into the cylindrical space of the passage  226 . 
     The drilling unit  230  is connected to the handle  220  by inserting the tubular members  240  of the drilling unit  230  into the passages  226  of the handle  220  and pushing until the balls  237  of both spring and ball latches  252  lock within the notches  236  of the tubular members  240 . For removing the drilling unit  230  from the handle  220 , the drilling unit  230  and the handle  220  are pulled apart, disengaging the balls  237  from the notches  236 . 
     When the two tubular members are locked within the passages  226  by the spring and ball latches  252 , the couplers  228  and  232  are engaged so that when the coupler  228  is rotated by the axle  227 , the coupler  232  also rotates. The coupler  232  thus rotates the axle  248  and the drill blade  246  of the drilling unit  230 . Additionally, when the two tubular members are locked within the passages  226  by the spring and ball latches  252 , the sealing gaskets  238  are pressed against the surface of the handle  220  sealing the connection between the drilling unit  230  and the handle  220 . Thus, the sealing gaskets  238  prevent leakage of irrigation fluid from passages  226 . The sealing gasket  238  also prevents penetration of atmospheric air into the passage  226  connected to the tubing  218 , thus, preventing pressure equalization between the conduit  256  which is connected to the vacuum pump  208  and the air outside the CRD  204 . 
     The couplers  228  and  232  are conical in shape and can be made from any suitable material such as synthetic rubber or a similar resilient material. Thus, when the drilling unit  230  is latched within the handle  220 , the couplers  228  and  232  are slightly pressed one against the other and are thus mechanically coupled by friction. This arrangement has the advantage that if the drill blade  246  is accidentally stopped from rotating by contacting a hard object such as the cryomanipulator tip  72  or any other hard object, the breakage or twisting of the axle  248  is prevented since coupler  228  will slide against the static coupler  232 . 
     It is noted that, although the couplers  228  and  232  of the preferred embodiment of the present invention are shown as conical in shape and made of synthetic rubber, they can be made in other shapes and of other materials. For example, the couplers  228  and  232  can have a spherical shape or a hemispherical shape or any other shape suitable for rotatably coupling the couplers  228  and  232  together. If the couplers  228  and  232  are spherically or hemispherically shaped (not shown), they can be rotatingly engaged at a multiplicity of different angles, incontrast to conical couplers which can be effectively coupled at specific predetermined angles. Thus, spherically or hemispherically shaped couplers can have an advantage over conical couplers in implementations where the handle  220  needs to be couplable to different drilling units, each having a coupler that is oriented at a different angle to the coupler of the handle  220 . 
     Additionally, the method of coupling of the couplers  228  and  232  can be any suitable method of rotational coupling. For example the couplers  228  and  232  can be conical cogwheels or any other suitable type of cogwheels. 
     It is also noted that, the couplers  228  and  232  can be differently shaped and can be made of a different materials. For example, coupler  228  can be conical in shape and made of plastic and coupler  232  can be hemispherical in shape and made of synthetic rubber. It is also noted that, since the drilling unit  230  is disposable, the coupler  232  can be made of a material which is less durable than the coupler  228 . 
     When the CRD  204  is assembled for use in a cataract operation, the two hollow adapters  222  of the tubing  216  and  218  are inserted into the two passages  226  and the drilling unit  230  is assembled by inserting the tubular members  240  into the passages  226  and latching the drilling unit  230  in place as described hereinabove. The surgeon starts the operation of the vacuum pump  208  and adjusts the rate of flow of the sterile irrigation physiological solution  213  at the tip of the distal shaft  242  of the drilling unit  230 . The surgeon makes two small incisions at the sclero-corneal region of the eye. The incisions can be regular incisions or can be made using the “tunnel” technique. The tunnel technique is the prior art technique of forming a passage through the tissue of the sclero-corneal region of the eye to create a “self-sealing” passage into the eye. The surgeon then forms two tracts extending from the incisions through the anterior chamber of the eye to the anterior capsula. The surgeon then inserts a cryomanipulator through the first incision and first tract into the anterior chamber of the eye. The surgeon also inserts the distal shaft  242  of the drilling unit  230  of the CRD  204  through the second incision and second tract into the anterior chamber of the eye under visual control using a stereoscopic microscope. The surgeon further makes at least one opening in the anterior capsula of the lens. The opening is made before the insertion of the cryomanipulator and the CRD into the lens. 
     FIG. 14, to which reference is now made, is a schematic, side view, partly cross-sectional illustration of a human eye during cataract surgery, illustrating the cryomanipulator  50  and the CRD  204  positioned within the eye, in accordance with another preferred embodiment of the present invention. The surgeon inserts the cryogenic tip  72  of the cryomanipulator head into the lens and places the tip  72  in contact with the nucleus of the cataract at the region of contact  64 . The surgeon freeze-grips the nucleus with the cryomanipulator. The nucleus is at least partially frozen into a solid-like state by the cryomanipulator. 
     When the tip of the distal shaft  242  of the CRD  204  is correctly positioned relative to the frozen nucleus, the surgeon switches the motor  206  on by using the controlling unit  224  of the handle  220  and uses the controlling unit  224  for controlling the speed of rotation of the drill blade  246 . The surgeon uses the drill blade  246  to break (disintegrate) the frozen nucleus under visual control, while the nucleus is being held fixed to the tip  70  of the cryomanipulator  50 . The fragments of the cataract which are broken off by the drilling action of the drill blade  246  are continuously washed out by the irrigation physiological solution  213  which flows out of one of the orifices  250  and removed by aspiration through the other orifice  250 . The rate of aspiration can be controlled by the surgeon by using the foot pedal  210  which in turn, controls the reduced pressure created by the suction pump  208 . 
     It is noted that, in contrast to the use of an ultrasonic probe such as the “Phaco”, the area of the cataract which is being affected by the drill blade  246  is clearly visible during the operation. An additional advantage of the present invention is that the guard lip  244  at the tip of the distal shaft  242  protects the tissue directly underneath the drill blade  246  from being accidentally damaged if the distal shaft  242  is inadvertently moved downwards. An important feature of the guard lip  244  is that when the distal shaft  242  is advanced into the frozen tissue, the drill blade  246  drills a hole (not shown) in the tissue until the guard lip  244  touches the frozen tissue preventing further drilling in the initial drilling direction. In order to continue the drilling the surgeon must readjust the drilling direction to enable the guard lip  244  to be inserted into the initially drilled hole. Thus, the distal shaft  242  must be moved in a direction suitable for enabling the insertion of the guard lip  244  into the drilled hole, thus during the drilling of the nucleus the distal shaft is gradually moved away from the posterior capsula. This feature helps in protecting the posterior capsula from being accidentally damaged while the parts of the cataract adjacent to the posterior capsula are removed. After the cataract has been completely removed, an artificial lens can be introduced. The cryomanipulator and the distal shaft  242  of the drilling unit  230  are then taken out of the eye through the incisions. The surgeon disposes of the used drilling unit by pulling it out of the handle  220 . 
     It is further noted that, when the CRD  204  is assembled from the handle  220  and the drilling unit  230 , the distal shaft  242  is inclined at an angle relative to the handle  220 . A variety of different drilling units (not shown) can be made, each different drilling unit producing a different angle between the handle  220  and the distal shaft  242 , in the assembled CRD, so that the surgeon can select a drilling unit which is suitable for a specific operation or which is most convenient for him to operate. 
     Reference is now made to FIG. 15 which is an isometric view illustrating a CRD  260  in accordance with another preferred embodiment of the present invention having a drilling unit  270  in which one of the fluid conduits is positioned within the other fluid conduit. The CRD  260  can be used similarly to the CRD  204  in the cataract removing system of FIG.  9 . 
     The CRD  260  includes a hand held handle  262  and a disposable drilling unit  270 . The handle  262  includes two cylindrical cavities  266  therewithin. The handle  262  also includes two spring and ball latches  255  . The spring and ball latches  255  of the handle  262  are similar in construction and operation to the spring and ball latches  252  of the handle  220 . The handle  262  also includes a controlling unit  264  similar to the controlling unit  224  of the handle  220  of the CRD  204 . The handle  262  also includes a flexible shaft  214  and a coupler  228  as described in detail for the handle  220  of the CRD  204  and illustrated in FIG. 10A hereinabove. 
     The drilling unit  270  includes two cylindrical members  268  each having a notch  272  therein, for receiving the ball of the spring and ball latch  255  therewithin. The drilling unit  270  is assembled with the handle  262  as disclosed in detail hereinabove for the drilling unit  230  and the handle  220 , respectively. The drilling unit  270  further includes a middle part  281  and a distal shaft  283 . The drilling unit  270  also includes two flexible tubes  274  and  276  for providing irrigation fluid and reduced pressure to the distal shaft  283 , respectively. Each of the tubes  274  and  276  is connected to the distal shaft  283  at one end and to a hollow adapter  278  at the other end. 
     The hollow adapters  278  are connectable to the adapters  222  of the tubes  216  and  218 . The tubes  274  and  276  are secured to the middle part  281  of the drilling unit  270  by retainers  280 . The tubes  274  and  276  are connected to the tubing  216  and  218  of the cataract removing system  202  of FIG. 9 for supplying irrigation fluid and reduced pressure to the drilling unit  270  as disclosed in detail for the drilling unit  230  hereinabove. 
     Reference is now made to FIGS. 16-19. FIG. 16 is an exploded isometric view illustrating a part of the drilling unit  270  in detail. FIG. 17 is a schematic cross section of the distal shaft  283  of FIG. 16 taken along the lines XVII—XVII thereof. FIG. 18 is a schematic isometric view of the distal shaft  283  of the drilling unit  270  of FIG.  15 . FIG. 19 is a longitudinal cross-section of the distal shaft  283  of FIG. 17 taken along the lines XIX—XIX. 
     The distal shaft  283  of the drilling unit  270  of FIG. 16 includes a cylindrical tube  284  having one closed end  284 A (best seen in FIG. 19) which is attached to the middle part  281  of the drilling unit  270 . The tube  284  includes a guard lip  282  (best seen in FIG. 18) extending at its open end and having a similar function to the guard lip  244  of FIG.  10 B. The distal shaft  283  also includes a cylindrical tube  286  which is smaller in diameter than the cylindrical tube  284 . The cylindrical tube  286  is shorter than the tube  284  and has one closed end  286 A (FIG.  19 ). The tube  286  is positioned inside the tube  284  and attached thereto in such a manner that the longitudinal axes (not shown) of the tubes  284  and  286  do not coincide (FIG.  17 ). The distal shaft  283  further includes a cylindrical tube  288  which is smaller in diameter than tube  286  and is open at both ends (FIG.  19 ). The tube  288  is positioned within the tube  286  and attached thereto in such a manner that the longitudinal axis (not shown) of the tube  288  coincides with the longitudinal axis (not shown) of the tube  284  (FIG.  17 ). The tube  288  passes through the closed ends  284 A and  286 A of the tubes  284  and  286 , respectively, and is sealingly attached to the ends  284 A and  286 A (FIG.  19 ). Thus, the distal shaft  283  contains therewithin two separate fluid conduits  284 B and  286 B. 
     The distal shaft  283  also includes a drill axle  248  passing within the tube  288 . The drill axle  248  can freely rotate within the tube  288 . The drill axle  248  is connected to a drill blade  246  at one end and to a coupler  232  at the other end, thus forming a drill, as best seen in FIG.  19 . The tubes  274  and  276  are connected to the tubes  284  and  286  in such a way that the fluid conduit  284 B is continuous with the internal space  274 B of the tubing  274  and the fluid conduit  286  is continuous with the internal space  276 B of the tubing  276 . Thus, when the CRD  260  replaces the CRD  204  in the cataract removing system  201  of FIG. 9, irrigation fluid can be supplied to the fluid conduit  284 B by tubing  216  and reduced pressure can be supplied to fluid conduit  286 B by tubing  218 . Alternatively, irrigation fluid can be supplied to the fluid conduit  286 B by tubing  216  and reduced pressure can be supplied to fluid conduit  284 B by tubing  218  (not shown). 
     The CRD  260  is used in eye surgery for removing a cataract as disclosed in detail for the CRD  204  hereinabove. 
     Reference is now made to FIG. 20 illustrating a handle  290  having an internal power source and motor in accordance with a preferred embodiment of the present invention. 
     The handle  290  can be connected to the drilling unit  230  of FIG. 10A instead of the handle  220 . The handle  290  is similar to the handle  220  of FIG. 10A except that, instead of being connected to the external motor  206  of FIG. 9, the handle  290  includes an internal motor  300  suitably connected to an electrical power source  212  through a control unit  298 . The electrical power source  312  can be a suitable electrical battery, such as a disposable battery, a rechargeable battery or a power supply connected to the standard alternating current mains socket (not shown). A removable cover  314  enables the replacement of the power source  312 . The control unit  298  is connected to a controlling unit  296  for switching the motor  300  on and off and for controlling the speed of rotation of the motor  300 . The motor  300  is suitably connected to an axle  310  which is connected to a coupler  302  similar to the coupler  228  of the handle  220 . When the controlling unit  296  is switched on, the motor  300  rotates the axle  310  which rotates the coupler  228 . The handle  290  also includes two hollow cylindrical passages  306 , two recesses  304  and two spring and ball latches  308  similar to the passages  226 , the recesses  254  and the spring and ball latches  252  of handle  220 , respectively. The handle  290  is typically easier to manipulate than the handle  220  since it is not connected to a flexible shaft. 
     It is noted that, the handle  262  of the CRD  260  can also be replaced by a handle (not shown) which has an internal power source  312  such as a the battery of the handle  290  and cylindrical cavities which are identical to the cylindrical cavities  266  of the handle  262 . 
     It is also noted that, while the handles  220 ,  262  and  290  include spring and ball latches  252 ,  255  and  308 , respectively, any other suitable type of latch can be used. 
     It is further noted that, while the motor  206  of FIG. 9 is a variable speed electrical motor, any other type of suitable motor can be used to rotate the flexible shaft  214 . For example, the motor can be a pneumatic motor operated by a compressed-air supply. 
     It is yet further noted that, the flexible shaft  214  connected to the CRD  204  and  260  can also be encased within a flexible protective sleeve (not shown) which is detachably connected to the motor  206  at one end and to the handle of the CRD  204  or  260  at the other end. 
     It is still further noted that, while the vacuum pump  208  of FIG. 9 is controlled by the foot pedal  210 , the vacuum pump can also be controlled by any other suitably located controlling device. For example, the vacuum pump  208  can be controlled by a dial placed on the handle of the CRD  204  (not shown). Similarly, the starting, stopping and speed control of the motors  206  and  300  of FIGS. 9 and 20 can be performed using any suitably placed controlling device, such as a suitable foot pedal. 
     It is additionally noted that the drilling unit  270  of FIG. 15 can also be made in more than one variation, each variation having a different angle between the distal shaft  283  and the handle  262 , in the assembled CRD  260  as disclosed in detail for the CRD  204  hereinabove. The surgeon can thus select the most appropriate variation of the drilling unit  270  to be assembled with the handle  262 . 
     It is further noted that the distal shafts  242  and  283  have a length in the range of a few centimeters and a width approximately in the range of a few millimeters across their widest dimension. Preferably these dimensions are optimized to allow the insertion of the distal shafts  242  and  283  into the eye through the smallest possible incision while still having fluid conduits that have a sufficient diameter to allow efficient irrigation and removal by suction of irrigation fluid at the tip of the distal shafts  242  and  283 . 
     It is also noted that the vacuum pump  208  of the system for removing cataract can also include a liquid trap (not shown) for trapping the excess irrigation fluid which is aspired by the CRD  204  and  260  of FIGS. 9 and 15, respectively. 
     The present invention has been described above in conjunction with the specific application of intraocular surgery, particularly cataract surgery. It should be appreciated, however, that at least some aspects of the present invention may be applicable to other surgical procedures. 
     While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been thus far described. Rather, the scope of the present invention is limited only by the following claims.