Abstract:
The invention relates to a method and device for the treatment of glaucoma, though insertion of an implant into the lumen of the Schlemm&#39;s canal to realize proper drainage of the aqueous humor, which implant is brought into its position in the Schlemm&#39;s canal by means of a catheter having a distal and a proximate portion and provided with a number of pores through which a gaseous or fluid medium which comes from a pressure source can emerge during insertion of the catheter carrying the implant into the Schlemm&#39;s canal, and while the catheter is being inserted into the Schlemm&#39;s canal the gaseous or fluid medium is released under pressure thereby expanding the Schlemm&#39;s canal and the implant and upon releasing the implant at its determined location, the catheter can be withdrawn from the Schlemm&#39;s canal.

Description:
[0001]    The present invention relates in general to a method and a device for the treatment of glaucoma, and more specifically to a method whereby a tube-shaped implant is introduced into Schlemm&#39;s canal which has been exposed through a scleral incision and the implant placed at a target location in the Schlemm&#39;s canal. 
       BACKGROUND OF THE INVENTION 
       [0002]    In a healthy eye, the drainage of the circulating aqueous humor takes place in known manner, here not illustrated in detail, from the rear chamber to the front chamber and in the area of the irido-corneal angle (angulus irido-cornealis) drains via the trabecular meshwork into the lumen of the circular Schlemm&#39;s canal and from there reaches the blood stream via the episcleral vein system. In a pathological condition of the afflicted eye, and such obstructions as for example, a blocked Schlemm&#39;s canal, continuous drainage of the aqueous humor, which is generated by the epithelial layer of the ciliary body and renewed on an ongoing basis, is oftentimes no longer realized or is substantially reduced. Upon blockage of the Schlemm&#39;s canal, the eye&#39;s interior pressure can be elevated to such a level that the blood circulation of the optical nerve and its function is diminished which can lead to the eye disease known as glaucoma and can then lead to entire blindness in the afflicted eye. 
       PRIOR ART 
       [0003]    A device for the treatment of glaucoma is known from the publication U.S. 2003/0236484 A1, where the device includes a tube-shaped catheter having a proximal and a distal portion with an injection unit disposed at the proximal portion and a casing disposed at the distal portion and insertable with the distal portion through a scleral cut, into the lumen of the Schlemm&#39;s canal. Through an insertion motion, which takes place in circumferential direction, pressurized medium from the injection unit is injected from the distal point of the distal end portion, whereby as a result the casing is being expanded in a balloon-like manner. This device is developed for the local stretching of the circular Schlemm&#39;s canal. 
         [0004]    From the publications EP 0 898 947 A2 and EP 1 125 568 A2, a respective implant is known which is tube-shaped and made from flexible biocompatible material, which is inserted through a scleral incision in the Schlemm&#39;s canal of an eye, whereby the lumen of the circular Schlemm&#39;s canal is retained open in a local area of the approximately segment-shaped implant, in order to realize the natural drainage of the aqueous humor from the Schlemm&#39;s canal via the episcleral vein system. 
         [0005]    In order to effect a circular opening of the Schlemm&#39;s canal, the so-called circumferential dilation or canaloplasty method is also known, whereby the Schlemm&#39;s canal is being circularly stretched by means of an inserted micro-catheter and either simultaneously or subsequently injected with a high molecular visco-elastic medium by means of a so-called micro-screw. Afterwards, the micro-catheter is being removed and at the same time the Schlemm&#39;s canal stretched against the anterior chamber with means suitably placed inside the lumen, such that an extension of the trabecular tissue is realized with an increased permeability and an enhanced drainage of the aqueous humor. 
         [0006]    These techniques in the prior art have however the drawback in that they are mostly temporary in their effect. It would therefore be desirable and advantageous to provide an improved method to obviate prior art shortcomings and to provide a more permanent solution to the drainage problem. 
       SUMMARY OF THE INVENTION 
       [0007]    According to one aspect of the present invention, a method is provided as well as a device for carrying out the method, whereby a permanently controlled circulation of the aqueous humor is realized as well as the natural drainage of the aqueous humor from the anterior chamber via the trabecular tissue into the Schlemm&#39;s canal and from there, via the episcleral vein system, into the blood stream. 
         [0008]    Accordingly, the method for treatment of glaucoma includes the steps of providing an incision in the sclera and forming a scleral flap thereby exposing the Schlemm&#39;s canal for insertion of a tube-shaped implant into the exposed Schlemm&#39;s canal; sliding a tubular implant over an axial portion of a catheter; inserting the catheter with the implant into the lumen of the Schlemm&#39;s canal in a direction of a target site; expanding the Schlemm&#39;s canal and the implant by means of pressure application; releasing the implant at the target site from the catheter; and withdrawing the catheter from the lumen of the Schlemm&#39;s canal so that the implant returns to an original shape. 
         [0009]    In another aspect of the invention, the device for carrying out the afore-stated method includes a device for treatment of glaucoma which includes a catheter having proximal and distal portions; a tubular implant placed over the distal portion of the catheter for insertion into the Schlemm&#39;s canal in a direction of a target site, wherein the distal portion has spaced-apart bores in communication with an interior space of the catheter for injecting a medium under pressure at the target site to expand Schlemm&#39;s canal and the implant and thereby allow release of the implant from the catheter and allow withdrawal of the catheter, which then returns to an original shape. 
         [0010]    In a further aspect of the invention, the medium for applying pressure to expand the Schlemm&#39;s canal and the implant is a gaseous medium or a fluid medium. 
         [0011]    The present invention resolves prior art problems by providing natural drainage of the aqueous humor of an eye suffering form glaucoma and to restore and permanently maintain it in the foregoing manner such that the aqueous humor drains from the anterior chamber via the trabecular tissue into the Schlemm&#39;s canal which has been expanded either circumferentially or at a predetermined target location of the implant and from there the aqueous humor drains via the episcleral vein system into the blood stream, to thereby realize a reliable natural regulation of the eye inner pressure (intraocular pressure IOP). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0012]    Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which: 
           [0013]      FIG. 1  is a schematic frontal view of an eye showing Schlemm&#39;s canal partially exposed by a lamellar incision for insertion of a catheter and an implant disposed at the catheter according to the present invention; 
           [0014]      FIG. 2  is a detailed view of a portion of the eye on an enlarged scale showing the catheter with the implant disposed thereon inserted into the lumen of the Schlemm&#39;s canal; 
           [0015]      FIG. 3  is a front view on an enlarged scale of a first embodiment of the implant; 
           [0016]      FIG. 4  is a view of the cross section of the implant according to  FIG. 3  along section line A-A; 
           [0017]      FIG. 5  is a front view on an enlarged scale of a second embodiment of the implant; 
           [0018]      FIG. 6  is a view of the cross section of the implant of  FIG. 5  along section line B-B; 
           [0019]      FIG. 7  is a front view of the catheter with a proximal portion and a distal portion with the head piece disposed thereon; 
           [0020]      FIG. 8  is a variant of the head piece disposed at the distal end of the catheter. 
           [0021]      FIG. 9  is a front view of the catheter with the head piece and the implant according to  FIG. 3  disposed thereon; 
           [0022]      FIG. 10  is a view of the cross section of the catheter with the implant along the section line C-C as in  FIG. 9 ; 
           [0023]      FIG. 11  shows a variant on an enlarged scale of the oval ring shaped cross section of the implant; 
           [0024]      FIG. 12  is a top view of a third embodiment of the implant showing ring parts axially disposed and apart from each other at the connecting part; 
           [0025]      FIG. 13  shows an enlarged view designated by K of the ring part according to  FIG. 12  with the gap between the two ring members in closed position; 
           [0026]      FIG. 14  shows the ring part according to  FIG. 13  with the two ring members spread apart in direction of arrow X; 
           [0027]      FIG. 15  shows a further variant of the ring members in closed position; and 
           [0028]      FIG. 16  the ring part of  FIG. 15  with the two ring members spread apart in direction of arrow X. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]    Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals. 
         [0030]    Turning now to the drawing, and in particular for better understanding of the problems in connection with the glaucoma surgery, an eye is illustrated in  FIG. 1  in a schematic front view where Schlemm&#39;s canal is seen partially exposed by an incision in the sclera for insertion of an implant disposed at the catheter.  FIG. 2  shows a portion of the exposed Schlemm&#39;s canal on an enlarged scale as well as a portion of the catheter and together with the implant inserted into the lumen. 
         [0031]    In  FIG. 1  there is shown a front view of the eye  10  and the cornea  11  depicted in a schematic view, the iris  12 , the sclera  13 , the lens  14  with the pupil  14 ′ as well as the circular Schlemm&#39;s canal  20  in connection with the circumferentially distributing aqueous humor channel system  18  and small canal  19 . Furthermore,  FIG. 1  shows the generally known partially exposed Schlemm&#39;s canal  20  (sinus venosus sclerae) through the lamellar incision  17  of a size about 3 mm by 3 mm in the sclera  13  with opened scleral flap  15 . The scleral flap  15 , after severing an interior scleral part which is not shown here in detail, is held in open position for further surgical procedures. The incision  17  forms a scleral bed  16  (reservoir) in the sclera  13  which is connected by oppositely located openings  21  and  22  with the Schlemm&#39;s canal  20 . After insertion and local placement of the implant  35 , the scleral bed  16  is being filled with a highly viscous medium (high viscosity sodium hyaluronate). When the scleral flap  15  is turned down and sewn to the sclera  13 , the filled in medium prevents a connecting contact between the inner side  15 ′ of the scleral flap  15  with the inner side  16 ′ of the scleral bed  16 . 
         [0032]    A catheter  25  provided for the insertion and local release of the implant  35  is schematically illustrated in  FIG. 1 , where the implant  35  is seen slipped in axial direction over the catheter  25  (inserting instrument). For example, the catheter  25  together with the implant  35  is inserted through the first opening  21  according to arrow  24  into the lumen  23  of the circular Schlemm&#39;s canal  20 . After release of the implant  35 , the catheter is withdrawn according to direction of arrow  24 ′ relative to the released implant  35  form the lumen  23  of the Schlemm&#39;s canal  20 . 
         [0033]    The catheter  25  is made of an elongated tube as illustrated in  FIG. 1  and has a distal portion  28 , which is provided with a head piece  30 , and a proximal portion  27  adjacent the distal portion  28  in the same axial direction. The proximal portion  27  is on one end connected to a pressure source  45  by means that are not shown here in detail, in such a manner that upon insertion of the catheter  25  and upon the release of the implant  35 , a biologically suitable gaseous medium or a hydrophilic fluid is being injected in direction of arrow  46  essentially through the catheter  25  into the Schlemm&#39;s canal  20 . 
         [0034]    Upon the insertion into the Schlemm&#39;s canal  20  of the distal portion  28  with the implant  35  slipped axially tightly onto it, the inner wall of the Schlemm&#39;s canal  20 , with the wall of the implant  35  bearing against it becomes expanded, preferably slightly; then, due to the careful dosing of the injected medium and in the area of the distal head piece  30  Schlemm&#39;s canal becomes successively expanded in balloon-shaped manner, such that the distal portion  28  together with the implant  35  can be easily inserted into the Schlemm&#39;s canal and the implant  35  released at any chosen circumferential location, for example, at a locally afflicted site. 
         [0035]      FIG. 2  shows on an enlarged scale a portion of eye  10  with the lamellar incision  17  and opened scleral flap  15 , and for example, the distal portion  28  with the implant  35  disposed thereon, which has been inserted through a first opening  21  into the lumen  23  of the circular Schlemm&#39;s canal  20 . In this embodiment, the distal portion  28 , with the implant  35  has a length dimension not shown here in detail, extending form the first opening  21  along the circumference of the Schlemm&#39;s canal  20  to the oppositely located second opening  22 . 
         [0036]    As further shown in  FIG. 2 , the inserted distal portion  28  of the catheter  25  with the distal head piece  30  partially penetrating the second opening  22  such that the implant  35  can be released in the lumen  23  of the circular Schlemm&#39;s canal  20  and subsequently, the catheter  25 , with the distal portion  28  according to arrow  24 ′ relative to the released implant  35 , can be withdrawn from the Schlemm&#39;s canal  20 . For example, the so placed implant  35 , upon withdrawal of the catheter form the Schlemm&#39;s canal  20  in the area of opening  22 , may be held in place by means not shown here in detail, for example by pliers or forceps or similar. 
         [0037]    At this point it is noted that the implant  35  insertable into the lumen  23  of the Schlemm&#39;s canal  20  can extend (not shown here) for example to at least a quarter, a half, three quarter or completely circumferentially form the first opening  21  up to the second opening  22 . In a variant, which is not shown here, it is possible, that in a first phase, an approximately semi-circular, deformable segment of the implant  35  is inserted from the first opening  21 , and in a second phase, a further, semi-circular, deformable segment of the implant  35  is inserted from the opposite, second opening  22  into the lumen  23  of the Schlemm&#39;s canal  20 . By means of the inserted and released implant  35 , the inner wall  20 ′ of the Schlemm&#39;s canal  20  is being supported and the lumen  23  kept permanently open in order to realize drainage of the aqueous humor. 
         [0038]    Furthermore, by means of the catheter  25 , it is possible to insert and release an implant  35  which is curved approximately according to the radius of the Schlemm&#39;s canal  20  and is of chosen length for release at a predetermined site, for example at a locally afflicted site. 
         [0039]      FIG. 3  shows a first embodiment of the implant  35  made from an elongated flexible tube  36 . The implant  35  is of a configuration that includes a connecting part  35   b  continuously extending in axial direction along a longitudinal axis Z with a substantially circular-shaped cross sectional profile, and disposed thereon several ring members  35   c  spaced apart by recesses  35   a . The circular interior space  35   e  of the connecting part  35   b  flanked by the ring members  35   c , is constructed for receiving the tube-shaped distal portion  28  of the catheter  25 . 
         [0040]    The length L of the implant  35  corresponds either to the location of the afflicted site or corresponds to a distance extending from the first opening  21  to the second opening  22  of the circumference of the Schlemm&#39;s canal  20 . The circular Schlemm&#39;s canal  20  has a diameter approximately from 10.0 mm to 12.0 mm which is preferably determined prior to the surgical procedure for the respective eye  10 , and computed in dependence on the entire extension of the length L of the implant  35 . 
         [0041]      FIG. 4  illustrates the cross section of the circular ring-shaped implant  35  having an outer diameter D and an inner diameter D′ according to the section line A-A as per  FIG. 3 , showing the connection part  35   b  and ring member  35   c  bordering the circular interior  35   e . Each of the ring members  35   c , located at a distance from each other at the connection part  35   b , opposite the connection part  35   b , is separated by a slot-shaped gap  35   d . In a variant of this embodiment which is not shown here, it is also possible to configure the ring-shaped members  35   c  according to  FIG. 3 , alternatively as a non-separated ring member  35   c  (without the gap  35   d ) or with the slot-shaped gap  35   d . The axially extending recesses  35   a  that are separating the ring members  35   c  respectively have an opening angle W on the order between 280° to 290°. 
         [0042]      FIG. 5  shows an example of a second embodiment of an implant  35  made form a flexible elongated tube  36  and in the direction of longitudinal axis Z, two diametrically opposed connection parts  35   b  as well as several ring members  35   c  in direction of the longitudinal axis Z and distanced from each other by recesses  35   a . The recesses  35   a  each respectively connect to the interior  35   e  and are configured in rectangular shape in this embodiment. However, the recesses  35   a  can also be of an oval, elliptical, square or trapezoidal shape. The length L of the implant  35  according to  FIG. 5  is computed analog implant  35  as described in connection with  FIG. 3 . 
         [0043]      FIG. 6  shows the cross section of the profile of the circular ring-shaped implant  35  according to the section line B-B in  FIG. 5 , where the two connecting parts  35   b  are shown disposed diametrically opposite relative to each other and in direction of the longitudinal axis. In one of the connecting parts  35   b , the slot-shaped gap  35   d  oriented in direction of the longitudinal axis Z is shown in its original position and is shown by broken lines in a separated position. Furthermore, recesses  35   a  are shown circumferentially connected between each of the connecting parts  35   b  with the interior  35   e  of implant  35  by an opening angle W delimited between 90° and 105°. The two connecting parts that are disposed diametrically opposite each other are provided with a circular-shaped support surface  35   b ′ relative to the longitudinal axis Z ( FIG. 5 ). 
         [0044]    The tube-shaped implant  35  shown in  FIGS. 3 to 6  has an outer diameter D on the order of about 0.20 mm to 0.35 mm and an inner diameter D′ on the order of 0.15 mm to 0.25 mm. The maximal length L of the implant  35 , which extends circumferentially, for example form the first opening  21  to the opposite second opening  22  ( FIG. 1 ), is dependent upon the diameter of the Schlemm&#39;s canal  20 , which is about 10.0 mm to 12.0 mm. The implant  35  may have a length L that is adjusted for changes in the Schlemm&#39;s canal  20  due to locally diseased sites and inserted into the lumen  23  where it is placed at the target site. 
         [0045]    It should be noted that the implant  35  described in connection with  FIGS. 3 to 6  and  FIG. 11  is configured as an elongated tube made, for example, from biocompatible material, such as for example, plastic, stainless steel, special steel, as well as silver, gold platinum, nitinol or similar, preferably form biocompatible flexible material; for example, from polymeric material with thermic or mechanical shape memory effect. Implant  35  produced from flexible material with shape memory effect, especially an implant  35  that is of an approximately circular shape configured according to the Schlemm&#39;s canal  20 , which at room temperature of about 18° C. to 22° C. is slipped in linear form in axial direction onto the distal portion  28  of the catheter for insertion into the Schlemm&#39;s canal  20 , wherein at a body temperature of about 35° C. to 37° C., after release from the distal portion, the implant reverts to the circular form of and bearing against the lumen wall  23 ′. In a further variant, the implant  35  made form the elongated tube  36  is provided with a biologically active coating, for example a heparin coating. 
         [0046]      FIG. 7  illustrates the catheter  25  for use in the insertion of the implant  35  made from a flexible tube, respectively from a flexible mini canula and essentially includes the proximal portion  27  and the distal portion  28  disposed in the same axial direction. In a variant not shown here, the proximate portion  28  connected to the distal portion  28  is disposed laterally at the distal portion  28 . 
         [0047]    In the embodiment as shown in  FIG. 7 , the two tube-shaped portions  27  and  28  of the catheter having the same axial direction are removably connected to each other by means of a schematically illustrated coupling  26 . The bearing edge  26 ′ of the coupling  26  facing the distal portion  28 , as schematically shown in  FIG. 2 , acts as a border for the implant  35  which may be axially slipped over the distal portion  28 . The distal portion  28  has an outer diameter D″, which corresponds approximately to the inner diameter D′ ( FIG. 4 ,  6 ) of the slip-on implant  35 . The circular bearing edge  26 ′ of coupling  26  has an outer diameter equal to the outer diameter D of the implant  35 , 
         [0048]    The distal portion  28  of catheter  25 , as schematically illustrated in  FIG. 7 , starting from the coupling  26  including the distal head piece  30  is provided with bores  29  in circumferential as well as in axial direction which connect to the interior  32  of catheter  25 . The bores  29  which are essentially formed as pores acting as nozzles, for example, have a diameter of from 10 μm to 25 μm and are bored into the tube-shaped distal portion  28  by means of a known laser technology, preferably by means of an Excimer laser not shown here. Disposed at the front end of distal portion  28  and shown in a partial section view, is head piece  30  configured as a semi-circular cap. The head piece  30  is provided with at least one, but preferably several bores  31  across the surface and which act as injection nozzles and connect to the interior  32  of the catheter. The head piece  30  is preferably produced from light reflecting and biocompatible material or alternatively is coated with a light reflecting biocompatible film or similar. 
         [0049]      FIG. 8  shows another embodiment of the head piece  30  disposed at the front end of the distal portion  28 . A partial section view shows the head piece  30 , starting from the outer diameter of the distal portion  28  which is provided with bores  29 , tapering in direction of a front tip  33  and connected with the interior by means of bore  31  acting as a nozzle. 
         [0050]      FIG. 9  shows a partial section of the catheter  25  with the implant disposed at the distal portion  28 , and the proximate portion  27  with the coupling  26 , as well as the distal portion  28  with the bores  29  across the surface that connect to the interior  32 . Further are shown the ring members  35   c  arranged at a distance from each other and the recesses  35   a  provided on implant  35  according to  FIG. 3 . The implant has been slipped onto the distal portion  28  in axial direction where it fits tightly and bears against the bearing edge  26 ′ of coupling  26 . The bearing edge  26 ′ of the coupling  26  permits a locally exact insertion of the implant  35  at the target location in the Schlemm&#39;s canal  20 .  FIG. 9  shows the distal and proximal portions  27  and  28  and partially cut-away, the interior  32 . 
         [0051]      FIG. 10  shows the catheter  25  in diameter with the slipped on implant  35  according to the section line C-C in  FIG. 9 , with the circular ring-shaped ring member  35   c  provided with the slot-shaped gap  35   d , as well as the distal portion  28  of catheter  25  disposed co-axially in the interior  35   e  of the implant  35 . The ring-shaped members  35   c  permit the implant  35  to be expandable upon applying pressure by a pressure medium such that the catheter  25  can be removed after the implant  35  has been placed in the target location. Upon insertion into the lumen  23  of Schlemm&#39;s canal, the semi-circular portion of the ring members  35   c  of the implant  35  are bearing tightly against the outer diameter D″ of the distal portion  28 . To achieve the release of the implant  35  at the target location, each of the ring members  35   c , as schematically shown in  FIG. 10 , will be slightly bent outwardly at the gap as shown in broken lines relative to the interior  35   e  of the implant  35  in such a manner that, after placing the implant  25  at the target location, the expanded implant permits the withdrawal of the entire catheter  25  from the interior  35   e  according to arrow direction  24 ′. ( FIG. 1 ). Once the catheter  25  has been withdrawn, the implant  35  returns to its shape before it was expanded. 
         [0052]    For the insertion of the catheter  25  in the Schlemm&#39;s canal  20  in direction of arrow  24 , a hydrophilic medium from a pressure source is being injected under a low pre-pressure such that by means of the fluid emerging from the bores  29  of the distal portion  28  and in the area of the recesses  35   a  of the slipped on implant  35  as well as the area at the head piece  30  of the distal portion  28 , the lumen  23  of the Schlemm&#39;s canal becomes expanded in somewhat balloon-like manner ( FIG. 1 ). As soon as the distal portion  28  with the slipped on implant  35  has been inserted circumferentially into the Schlemm&#39;s canal  20  and has reached the target location or the end position ( FIG. 2 ), the initial pressure is increased such that the fluid emerging form the bores  29  of the inner wall of the web-shaped ring members  35   c  of implant  35 , widens the gap  35   d  of the ring members  35   c  ( FIG. 10 ) slightly, so that the catheter  25  with the distal portion  28  can be withdrawn form the Schlemm&#39;s canal in direction of arrow  24 ′ ( FIG. 1 ) relative to the released implant  35  and the ring-shaped members  35   c  of implant  35  return to their original shape after the catheter  25  has been withdrawn. 
         [0053]    In another embodiment not shown here in detail, the Schlemm&#39;s canal  20  can be expanded by means of the canaloplasty method and the distal portion  28  of the Schlemm&#39;s canal with the slipped-on implant  35  inserted into the lumen  23  to the predetermined target area. Subsequently, the expansion and release of the implant  35  is effected by pressurizing the distal portion  28  connected to the proximate portion  27  through the pressure source  45 , so that the fluid emerging form the bores  29  of the inner wall of the web-shaped ring members  35   c  of implant  35  slightly opens the gap  35   d  in order to effect withdrawal from the Schlemm&#39;s canal  20  in direction of arrow  24 ′ of the catheter  25  with the distal portion  28  relative to the expanded and released implant  35 . 
         [0054]    Advantageously, the head piece  30  disposed at the front end of the distal portion  28  is coated with a reflecting material or a reflecting film or similar such that upon insertion of the distal portion  28  together with the implant  35  or withdrawal of the distal portion  28  relative to the released implant  35  into the Schlemm&#39;s canal  20 , the reflecting head piece  30  is visually recognized and thus permits control of the distal portion&#39;s  28  respective position. For example, the head piece  30  is provided with a reflective fluorescence coating, whereby the reflection ceases within a millionth of a second after the light irradiation. Irradiation is carried out by means of a light source from a surgical microscope, not shown here. 
         [0055]      FIG. 11  shows a variant of the implant  35  on an enlarged scale according to section line B-B according to  FIG. 5 . As compared to the embodiment shown in  FIG. 6 , this implant  35  according to  FIG. 11  has an oval-shaped diameter, preferably configured as a double symmetrical ring-shaped oval, with two axes, X and Y extending orthogonal to the longitudinal axis Z. The implant  35  configured as a double symmetrical ring-shaped oval includes two connecting parts  35   b  located respectively at the smaller end of the oval and oriented in direction of the longitudinal axis Z ( FIG. 5 ). The connecting parts  35   b  each include a support or surface  35   b ′, wherein one of the connecting parts  35   b , at the axis Z is separated thereby forming a gap  35   d .  FIG. 11  also shows openings  35   a  with an opening angle W of between 90° and 105° at each of the longer sides of the oval which connect to the interior  35   e.    
         [0056]      FIG. 12  shows a top view of a third embodiment of the implant  35  made from the elongated flexible tube  36 . The implant  35  includes the connection part  35   b  which extends along the longitudinal axis Z and has a substantially circular cross section, as well as the ring parts  35   c  that are spaced apart by the recesses  35   a . The connection part  35   b  and the ring parts  35   c  having interior space  35   e  are constructed for receiving the tube-shaped distal portion  28  of catheter  25  ( FIG. 9 ). 
         [0057]    The ring parts  35   c  which are spaced apart by recesses  35   a  and disposed at tube  36  maybe also, as schematically illustrated in  FIG. 12 , disposed in grouped and in axial disposition of two or more ring parts  35   c  at any location at the implant  35 . 
         [0058]    In a variant to the first embodiment ( FIG. 3 ) of implant  35 , the ring parts  35   c  in the embodiment according to  FIG. 12  are formed by a first ring member  35   c ′ and a second ring member  35   c ″ which meet at a Z-shaped gap. The approximately semi-circular shaped ring members  35   c ′ and  35   c ″, in their basic position according to  FIG. 13 , form a detachable form-fitted connection which, in accordance with  FIG. 14 , can be spread apart according to arrow X. 
         [0059]      FIG. 13  shows an enlarged detail view of the ring part  35   c  as shown in  FIG. 12  and designated by circle K, with the two ring members  35   c ′ and  35   c ″ that are separated by an approximately Z-shaped gap  35   d  and the axially extending connecting part  35   b  showing the recesses  35   a . The first ring member  35   c ′ and its interior  35   e  are seen in a partial section view. The ring members  35   c ′ and  35  c″ separated by the Z-shaped gap  35   d , where they are facing each other, are each provided with a tongue  35   f  and  35   g  and show gaps  35   f  and  35   g ′. In the basic position according to  FIG. 13 , the first tongue  35   f  fits into gap  35   g ′ and tongue  35   g  fits into gap  35   f . When the ring members close, the two tongues  35   f  and  35   g  are sliding along each other in a relative motion perpendicular to the axis Z and in direction of arrow X along their side walls that are not shown here in detail. 
         [0060]      FIG. 15  shows an enlarged detail view of a further embodiment of the ring part  35   c  with the two ring members  35   c ′ and  35   c ″ separated by an approximately U-shaped gap  35   d  and the axially extending connecting part  35   b  showing the recesses  35   a . In this variant the first ring member  35   c ′ is provided with a tongue  35   f  and the second ring member  35   c ″ is provided with two tongues  35   g  with an approximately U-shaped slot  35   g ′ in-between. In the basic position according to  FIG. 16 , the tongue  35   f  of ring member  35   c ′ is form-fit into the U-shaped gap  35   g ′ in a relative motion perpendicular to the axis Z and in direction of arrow X, the two tongues  35   g  are sliding along tongue  35   f ′ into formfitting disposition. 
         [0061]    While the invention has been illustrated and described as embodied in a method and device for effecting the drainage of an eye, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. Further practical embodiments of catheter  25 , especially the portion  28  with the distal tip  30  and different configurations of the implant  35  for slipping onto the distal portion  28  are possible as well as further biocompatible materials for the respective elements, as well as for the coating and the light-reflecting foil are also possible. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. 
         [0062]    What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and their equivalents: