Abstract:
An instrument for use in ophthalmic surgery, includes an elongated body portion having one end formed with an engagement member for insertion through an incision into the anterior chamber of the eye for retracting the iris. A fixation member is slidably secured to the body portion for positioning and fixing the body portion in place. The body portion is made of a flexible polymeric material having a hue which contrasts a hue of the iris, at least along an area starting from the engagement member to at least half the length of the body portion.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally refers to a surgical instrument for use in ophthalmic surgery, and in particular to an iris retractor for use in eye surgery of a living being for retraction of the iris. 
     Iris retractors are known which generally include an elongated body portion with a substantially hook-shaped end for retracting the iris, and a fixation member slidably mounted on the body portion for securing the iris retractor in place when the body portion is inserted with its hook-shaped end into the anterior chamber through a suitable incision made in the cornea. 
     It is well known that adequate dilatation of the pupil of the eye is essential during e.g. cataract surgery. In particular, for removal of a cataract, the surgical procedure in the posterior section as well as anterior section of the eye requires a sufficiently large and constant viewing range for the surgeon. Generally, the dilatation of the pupil is effected through administration of pharmaceuticals. However, on occasions, the use of pharmaceuticals is insufficient to attain the desired dilatation so that the use of surgical instruments for retracting the iris is proposed, e.g. application of one or more suitably spaced iris retractors which attach to the iris to pull it outwardly for enlarging the opening of the pupil. The individual iris retractors are inserted into the anterior chamber of the eye through an incision in the cornea and suitably fixed in tight manner by the fixation member at the outer contour of the eye. After surgery, the iris retractor is released from the iris and withdrawn from the anterior chamber of the eye. 
     European Pat. No. 0 653 197 describes an iris retractor for use in the ophthalmic surgery, with the iris retractor having a body portion formed at one end with a hook-shaped engagement member for insertion into the anterior chamber of the eye and withdrawal of the iris. A plate-shaped fixation member is slidably mounted to the body portion to hold the body portion in place in the region of the transition area from the cornea to the sclera. 
     U.S. Pat. No. 5,716,328 describes an iris retractor which includes an elongated body portion for insertion through an incision in the eye to retract the iris, with the body portion including two parallel shafts secured to each other along a common longitudinal edge wherein each shaft has at least one end formed with a hook-shaped member. The shafts of the body portion are so joined together that the hook-shaped members diverge from the longitudinal edge downward at an angle to one another to exhibit a Λ-shaped configuration, and exhibit parallel shanks which are spaced from each other at a distance, the dimension of which depends on the angle between the hook-shaped members. 
     In both these conventional iris retractors, the individual body portion has a length of about 5 mm to 8 mm and is made of a flexible polymeric material with a diameter of about 0.15 mm to 0.20 mm, whereas the hook-shaped engagement member has a length of about 1.0 mm to 1.5 mm. 
     The use of such iris retractors for ophthalmic surgery in the anterior or posterior eye sections suffers, however, shortcomings as far as recognition is concerned. As a result of their relatively small size, the surgeon has oftentimes great difficulty to see the individual iris retractors during the process of inserting the retractors into the anterior chamber and attaching the retractors to the iris or removing them from the eye. This may potentially adversely affect the surgery. 
     SUMMARY OF THE INVENTION 
     It is thus an object of the present invention to provide an improved iris retractor, obviating the afore-stated drawbacks. 
     In particular, it is an object of the present invention to provide an improved iris retractor which is easily recognizable during surgical procedure and subsequent withdrawal so as to enable the surgeon to clearly and reliably determine the disposition of the iris retractor. 
     These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing an elongated body portion having one end formed with an engagement member for insertion through an incision into the anterior chamber of the eye for retracting the iris, and a fixation member slidably secured to the body portion for positioning and fixing the body portion in place, wherein the body portion is made of a flexible polymeric material having a hue which contrasts a hue of the iris, at least along an area starting from the engagement member to at least half the length of the body portion. 
     Through the provision of an iris retractor according to the present invention, the surgeon can easily ascertain the individual iris retractors when inserted in the eye and spaced around the iris, and can reliably withdraw the single iris retractors from the eye after surgery. Thus, the position of an iris retractor can be visually established without any problems, essentially eliminating the risk that the iris retractor inadvertently contacts the iris or other parts of the eye during the process of introducing or removing the retractors into or from the eye. 
     According to another feature of the present invention, the body portion may be made of a flexible polymeric filament of circular or elliptic cross section, having a homogenous hue which contrasts the hue of the iris. Suitably, the body portion may have a cross section which is colored homogenously in red, glaring red, brown, black, deep black, yellow and white. 
     According to another feature of the present invention, the fixation member may be made of a caoutchouc mixture, e.g. a silicone caoutchouc mass, which exhibits a glaring and visually distinct hue. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The above and other objects, features and advantages of the present invention will be more readily apparent upon reading the following description of a preferred exemplified embodiment of the invention with reference to the accompanying drawing, in which: 
     FIG. 1 is an enlarged schematic illustration of the forward eye section of a living being, illustrating one region of the iris being retracted by an iris retractor according to the present invention; 
     FIG. 2 is an enlarged, schematic plan view of a portion of the eye, showing by way of example a partial retraction of the iris at two locations by means of a first type of iris retractor; 
     FIG. 3 is an enlarged, schematic plan view of a portion of the eye, showing by way of example a partial retraction of the iris at a random location by means of a second type of iris retractor; 
     FIG. 4 is an enlarged side view of the iris retractor of FIG. 2, comprised of body portion and fixation member; 
     FIG. 5 is a top view of the iris retractor of FIG. 4; 
     FIG. 6 is a cross sectional view of the body portion of the iris retractor, taken along the line VI—VI in FIG. 5; 
     FIG. 6A is a cross sectional view of a modified body portion of the iris retractor of FIG. 2; 
     FIG. 7 is an enlarged side view of the iris retractor of FIG. 3, comprised of body portion and fixation member; 
     FIG. 8 is a top view of the iris retractor of FIG. 7; and 
     FIG. 9 is a cross sectional view of the body portion of the iris retractor, taken along the line IX—IX in FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals. 
     Turning now to the drawing, and in particular to FIG. 1, there is shown an enlarged schematic illustration of the forward eye section of a living being, generally designated by reference numeral  10  and including the anterior chamber, designated in its entirety by reference character V, the lens  1  (ocular) with the ciliary bodies  4  and zonule fibers  4 . 1 , the pupil  2 , the iris generally designated by reference numeral  3  and including both circular areas 3.1 and 3.2, the cornea  5 , and the sclera  6 . For a surgical procedure in the anterior eye section as well as in the posterior eye section, the provision of a greatest possible and constant viewing field for the surgeon (ophthalmologist) is a prerequisite for a successful procedure. To accomplish a desired viewing field, an iris retractor, generally designated by reference numeral  15  is inserted in a first phase into the anterior chamber V through an incision  8  in a transition  7  between the cornea  5  and the sclera  6 . After engaging behind the circular area 3.2 of the iris  3 , the circular area 3.2 is pulled outwards in the direction of arrow Z. The iris retractor  15  is held in proper position at the transition  7  by a fixation member  20  which is mounted on the iris retractor  15  for displacement in longitudinal direction. The fixation member  20  is suitably elastically deformable and provided with an arcuate seat surface  21  to substantially conform to the transition  7 . 
     FIG. 2 shows an enlarged, schematic plan view of a portion of the eye, showing by way of example a partial retraction of the iris  3  by two iris retractors  15  which are held in proper position by the fixation members  20  at the transition  7  between the cornea  5  and the sclera  6 . The configuration of the iris retractor  15  is shown in more detail in FIGS. 4 and 5, with FIG. 4 depicting a side view of the iris retractor  15 , and with FIG. 5 depicting a top view thereof. The iris retractor  15  includes a body portion in the form of an elongate, slightly curved, shaft  17  having one end which is bent over once in a hairpin-like manner to provide a hook-shaped engagement member  18  having a shank  19  in parallel relation to the shaft  17  at formation of a gap  16 . The fixation member  20 , mounted on the shaft  17  for displacement in direction of double arrow X is configured, for example, as a circular disk having two spaced-apart bores  22  for passage of the shaft  17 . The bores  22  are so arranged relative to one another that the flexible fixation member  20  can be shifted along the shaft  17 , when squeezed together, and is held in place at a desired location, when releasing the fixation member  20 , whereby the arcuate seat surface  21 , formed by the fixation member  20 , rests at the transition  7  of the eye  10  with the iris  3  being retracted in a manner shown in FIG.  1 . As shown in FIG. 6, the shaft  17  may have a circular cross section, or, as shown in FIG. 6A, an elliptic cross section. 
     Turning now to FIG. 3, there is shown another type of iris retractor  15  for partial retraction of the iris  3 , which differs from the iris retractor of FIG. 4 in that the body portion is comprised of two substantially elongated shafts  17  which extend parallel to one another and are suitably joined together, e.g. by an adhesive, along a longitudinal edge  14 , as shown in FIG.  9 . The shafts  17  have a generally circular cross section and terminate in engagement members  18  which exhibit a hook-shaped configuration, by bending over once the ends of the shafts  17 , and have shanks  19  which extends parallel to the shafts  17  at a distance  16 , as shown in particular in FIGS. 7 and 8. The hook-shaped engagement members  18  are arranged at an acute angle to one another to exhibit a downwardly diverging substantially Λ-shaped configuration. A fixation member, such as fixation member  20 , is slipped over both shafts  17  for displacement in direction of double arrow X and is formed as circular disk with two spaced-apart bores  22  for allowing displacement of the fixation member  20  in longitudinal direction and securement of the fixation member  20  at a desired location. 
     In order to provide a surgeon, operating on the eye  10 , a tool to unmistakably see each iris retractor  15  during the surgical procedure, the body portion of the iris retractor  15  is made, at least from an area extending axially from the hook-shaped engagement members  18  to half the entire length of the body portion, preferably however over the entire length of the body portion, of a flexible polymeric material which has a hue that clearly contrasts the hue of the iris  3  at hand. A preferred example for the polymeric material includes a polyamide filament. According to another variation, the flexible polymeric material or polyamide filament may be provided in axial direction with an outer, circular ring shaped envelope of particles which has a color whose hue contrasts the color of the iris  3 . It is also within the scope of the present invention, to provide the flexible polymeric material or polyamide filament with a cross section that is homogenously colored in contrast to the hue of the iris  3 . 
     Also the fixation member  20  is suitably made of a caoutchouc mixture, e.g. silicone caoutchouc mass, exhibiting a glaring and visually distinct color. 
     Suitably, the body portion and the fixation element  20  of the iris retractor  15  has a flat, dull outer surface to avoid an undesired reflection. In the following, examples for the colored iris retractor  15  are provided in dependence to the hue of the iris  3  of the eye  10 : 
     a) For a hue of the iris  3  of: blue, bluish gray, green, green gray or a blend thereof, the color of the body portion should be: red, glaring red, brown, black or deep black. 
     b) For a hue of the iris  3  of: brown or dark mixed color, the color of the body portion should be: yellow or white. 
     It will be understood by persons skilled in the art that the above examples should not be considered exhaustive so that the present invention should not be limited thereto as other combinations are conceivable as well and thus within the scope of the present invention, so long as the iris retractor  15  is clearly and visibly contrasted from its background, i.e. from the hue of the iris  3 . For example, appropriate mixed colors of the flexible polymeric material for the body portion as well as for the fixation member  20  of caoutchouc mixture should be covered by the present invention. 
     While the invention has been illustrated and described as embodied in a iris retractor for use in surgical procedure on the eye of a living being, 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.