Abstract:
A beveled tip, wide-angle illuminator is disclosed, one embodiment comprising: a light source for providing a light beam; an optical cable, optically coupled to the light source for receiving and transmitting the light beam; a handpiece, operably coupled to the optical cable to receive the light beam; an optical fiber, operably coupled to the handpiece, wherein the optical fiber is optically coupled to the optical cable to receive and transmit the light beam; an optical element, optically coupled to a distal end of the optical fiber, for receiving the light beam and scattering the light beam to illuminate a surgical field, wherein the optical element comprises a beveled sapphire; and a beveled cannula, operably coupled to the handpiece, for housing and directing the optical fiber and the optical element. The optical element can be a small-gauge, diffusive sapphire element having a polished distal surface co-incident with the distal end of the cannula and a light refracting hemispherical surface facing the optical fiber.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Patent Application No. 60/983,677 filed Oct. 30, 2007. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to surgical instrumentation. In particular, the present invention relates to surgical instruments for illuminating an area during eye surgery. Even more particularly, the present invention relates to a beveled tip, small gauge, wide-angle illuminator for illumination of a surgical field. 
       BACKGROUND OF THE INVENTION 
       [0003]    In ophthalmic surgery, and in particular in vitreo-retinal surgery, it is desirable to use a wide-angle surgical microscope system to view as large a portion of the retina as possible. Wide-angle objective lenses for such microscopic systems exist, but they require a wider illumination field than that provided by the cone of illumination of a typical fiber-optic probe. As a result, various technologies have been developed to increase the beam spreading of the relatively incoherent light provided by a fiber-optic illuminator. These known wide-angle illuminators can thus illuminate a larger portion of the retina as required by current wide-angle surgical microscope systems. Currently existing wide-angle illuminators, however, display several disadvantages. 
         [0004]    One disadvantage exhibited by some prior art small gauge, wide-angle illuminators for ophthalmic surgery is that they are not able to provide a high luminous flux and high peak luminous intensity. Typically in these probes, wide angle beam spreading is achieved without sufficient intensity to permit a surgeon a clear and bright view of the surgical field. 
         [0005]    Another disadvantage of currently available wide-angle illuminators is glare. Glare results when the source of the illumination is small and bright, and the user (e.g., an ophthalmic surgeon) has a direct line of sight to the small bright illumination source. Glare is unwanted stray radiation that provides no useful illumination, and either distracts an observer or obscures an object under observation. Glare can be corrected for in current wide-angle illuminators, but typically only by reducing the total illumination light flux, which reduces the amount of light available for observation by the surgeon. For example, the “bullet probe” manufactured by Alcon Laboratories, Inc., of Fort Worth, Tex., achieves wide-angle illumination by using a bullet-shaped fiber having a surface diffusive finish to scatter light emanating from the distal end of an optical fiber. To reduce glare, the bullet probe can use a geometric shield, which reduces the illumination angle by reducing the overall available light flux. 
         [0006]    A further disadvantage of typical prior art wide-angle illuminators is that they are expensive to produce, a cost which is passed along to the surgeon and ultimately to the patient. As a result, prior art illuminators are typically not disposable and will require periodic maintenance and sterilization between surgical procedures. 
         [0007]    Therefore, a need exists for a variable-intensity, wide-angle illuminator that can reduce or eliminate the problems of low luminous flux, low peak luminous intensity, glare, cost, efficiency and other problems associated with prior art wide-angle illuminators. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The embodiments of the beveled tip, wide-angle surgical illuminator of the present invention substantially meet these needs and others. One embodiment of this invention is a small-gauge, beveled tip, wide-angle illumination surgical system comprising: a light source for providing a light beam; an optical cable, optically coupled to the light source for receiving and transmitting the light beam; a handpiece, operably coupled to the optical cable to receive the light beam; an optical fiber, operably coupled to the handpiece, wherein the optical fiber is optically coupled to the optical cable to receive and transmit the light beam; an optical element, optically coupled to a distal end of the optical fiber, for receiving the light beam and scattering the light beam to illuminate a surgical field, wherein the optical element comprises a beveled sapphire; and a beveled cannula, operably coupled to the handpiece, for housing and directing the optical fiber and the optical element. 
         [0009]    The optical element can be a small-gauge, optical-grade diffusive sapphire element having a polished flat circular surface co-incident with the distal end of the cannula and a light refracting hemispherical surface facing the optical fiber. The distal end of the cannula and the flat distal surface of the optical element can be beveled at a predetermined angle from the normal plane to the longitudinal axis of the cannula, as shown in  FIGS. 2 and 3 . The optical element can be sized, for example, for housing within a 19, 20 or 25 gauge cannula (e.g., about 0.75 mm to about 0.4 mm diameter optical element). Further, the cannula and the handpiece can be fabricated from biocompatible materials. The optical cable can comprise a first optical connector operably coupled to the light source and a second optical connector operably coupled to the handpiece (to optically couple the optical cable to the optical fiber housed within the handpiece and cannula). These connectors can be SMA optical fiber connectors. The optical element, optical fiber and optical cable (i.e., the optical fibers within the optical cable) should be of a compatible gauge so as to transmit the light beam from the light source to the surgical field. For example, all three elements could be of equal gauge. 
         [0010]    Other embodiments of the present invention can include a method for wide-angle illumination of a surgical field using a beveled tip, wide-angle illuminator in accordance with the teachings of this invention, and a surgical handpiece embodiment of the beveled tip, wide-angle illuminator of the present invention for use in ophthalmic surgery. Embodiments of this invention can be implemented as a handpiece connected to a cannula, or other housing, including a fiber optic cable terminating in a diffusive optical element. Further, embodiments of this invention can be incorporated within a surgical machine or system for use in ophthalmic or other surgery. Other uses for a beveled tip, wide-angle illuminator designed in accordance with the teachings of this invention will be known to those having skill in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0011]    A more complete understanding of the present invention and the advantages thereof may be acquired by referring to the following description, taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features and wherein: 
           [0012]      FIG. 1  is a simplified diagram of one embodiment of a system for variable, wide-angle illumination in accordance with the teachings of this invention; 
           [0013]      FIG. 2  is a more detailed diagram of a stem housing an embodiment of a diffusive optical element for wide-angle illumination in accordance with the teachings of this invention; 
           [0014]      FIG. 3  is a diagram illustrating the use of an embodiment of a wide-angle illuminator of the present invention for ophthalmic surgery; and 
           [0015]      FIG. 4  is a diagram illustrating an embodiment of an adjusting means  40  in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Preferred embodiments of the present invention are illustrated in the FIGURES, like numerals being used to refer to like and corresponding parts of the various drawings. 
         [0017]    The various embodiments of the present invention provide for a small gauge (e.g., 19, 20, or 25 gauge) optical fiber based endo-illuminator device for use in surgical procedures, such as in vitreo-retinal/posterior segment surgery. Embodiments of this invention can comprise a handpiece, such as the Alcon-Grieshaber Revolution-DSP™ handpiece sold by Alcon Laboratories, Inc., Fort Worth, Tex., connected to a small gauge cannula (e.g., 19, 20, or 25 gauge). The inner dimension of the cannula can be used to house one, or a plurality of, optical fibers terminating at a diffusive optical element in accordance with the teachings of this invention. Embodiments of the wide-angle illuminator can be configured for use in the general field of ophthalmic surgery. However, it is contemplated and it will be realized by those skilled in the art that the scope of the present invention is not limited to opthalmology, but may be applied generally to other areas of surgery where wide-angle illumination may be desired. 
         [0018]    An embodiment of the beveled tip, wide-angle illuminator of this invention can comprise a light diffusive optical element fabricated of optical-grade sapphire, and a stem and a handpiece fabricated from biocompatible materials. Some embodiments can be made of polymeric materials such that the invasive portion of the wide-angle illuminator is a disposable surgical item. Unlike the prior art, each embodiment of the beveled tip, wide-angle illuminator of this invention can provide high optical transmission/high brightness with low optical losses and reduced glare. Embodiments of this invention fabricated from biocompatible polymeric materials can be integrated into a low cost, articulated handpiece mechanism, such that these embodiments can comprise an inexpensive disposable illuminator instrument. 
         [0019]      FIG. 1  is a simplified diagram of a surgical system  2  comprising a handpiece  10  for delivering a beam of relatively incoherent light from a light source  12  through cable  14  to a stem  16 . Cable  14  can be any gauge fiber optic cable as known in the art, but is preferably a cable having 19, 20, or 25 gauge fiber. Further, cable  14  can comprise a single optical fiber or a plurality of optical fibers optically coupled to receive and transmit light from light source  12  to stem  16  through handpiece  10 . Stem  16  is configured to house a diffusive optical element  20  at the distal end of stem  16 , as is more clearly illustrated in  FIG. 2 . Coupling system  32  can comprise an optical fiber connector at each end of cable  14  to optically couple light source  12  to optical element  20  within handpiece  10 , as discussed more fully below. 
         [0020]      FIG. 2  is a magnified view of the distal end of stem  16 . Stem  16  is shown housing fiber  22  and optical element  20 . Stem  16  and optical element  20  are beveled at a predetermined angle θ from the normal plane to the longitudinal axis of stem  16 . Optical element  20  is optically coupled to fiber  22 , which is optically coupled to fiber optic cable  14 . In some embodiments, fiber optic cable  14  can extend through the handpiece  10  and is optically coupled directly to optical element  20 . For these embodiments, fiber  22  is not used. When implemented within handpiece  10 , fiber  22  is of a gauge compatible with the gauge of fiber optic cable  14 , such that it can receive and transmit light from fiber optic cable  14 . Handpiece  10  can be any surgical handpiece as known in the art, such as the Revolution-DSP™ handpiece sold by Alcon Laboratories, Inc. of Fort Worth, Tex. Light source  12  can be a xenon light source, a halogen light source, or any other light source capable of delivering incoherent light through a fiber optic cable, as will be known to those having skill in the art. Stem  16  can be a small gauge cannula, preferably on the order of 19, 20, or 25 gauge, as known to those having skill in the art. Stem  16  can be stainless steel or a suitable biocompatible polymer (e.g., PEEK, polyimide, etc.) as known to those in the art. 
         [0021]    The fiber optic cable  14  or fiber  22  housed within the stem  16  is operably coupled to the handpiece  10 . Light source  12  can be optically coupled to handpiece  10  (i.e., to fiber  22 ) using, for example, standard SMA (Scale Manufacturers Association) optical fiber connectors at the proximal ends of fiber optic cable  14 . This allows for the efficient coupling of light from the light source  12  through fiber optic cable  14  to the handpiece  10  and finally emanating from optical element  20  at the distal end of the stem  16 . Light source  12  may comprise filters, as known to those skilled in the art, to reduce the damaging thermal effects of absorbed infrared radiation originating at the light source. The light source  12  filter(s) can be used to selectively illuminate a surgical field with different colors of light, such as to excite a surgical dye. 
         [0022]    Fiber(s)  22  (and/or  14 , depending on the embodiment) is/are terminated by optically coupling to optical element  20 . Fiber  22  and optical element  20  can be optically coupled through direct contact. Optical element  20  can be an optical grade sapphire diffuser having a beveled semi-hemispherical shape. Optical element  20  can comprise a distal polished flat surface  25  at the distal end of stem  16  (i.e., facing out towards a surgical field) and a hemispherical surface  26  facing the distal end of fiber  22 . The distal surface  25  of optical element  20  and the distal end of stem  16  are beveled at a predetermined angle θ from the normal plane to the longitudinal axis of stem  16 . This predetermined angle θ can range up to about 45 degrees. Optical element  20  is sized for housing within stem  16  (e.g., a 19 to 30 gauge cannula). For example, optical element  20  can have a diameter of about 0.75 mm to about 0.4 mm. The flat surface  25  of optical element  20  can be co-incident with the open aperture at the distal end of stem  16 . 
         [0023]    Embodiments of the beveled tip, wide-angle illuminator of the present invention can be produced by removing a beveled section from the stem  16  and optical element  20 . One method of fabrication can comprise locating a positioning pin inside stem  16  and then press fitting a sapphire ball optical element  20  inside the distal end of stem  16  so that it rests against the positioning pin. Optical grade adhesive can be used to bond the optical element  20  securely to stem  16  (such as in the embodiment of  FIG. 2 ). A grinder, such as an angled grinder, can be used to grind away a desired beveled portion of the stem  16 /optical element  20  assembly. 
         [0024]    Alternatively, optical element  20  can be slip-fit into stem  16  and locked in place within stem  16  by a side roller to cause the distal end of stem  16  to roll over the edge of the distal surface  25  of optical element  20 . A subsequent angled grinding step can be performed to bevel the stem  16 /optical element  20  assembly to create an embodiment such as shown in  FIG. 3 . Optical grade adhesive can be used in any embodiment of the present invention to any spaces between the optical element  20  and stem  16  to prevent fluid entry into the space between the optical fiber  22  and optical element  20 . 
         [0025]    As shown in  FIGS. 2 and 3 , optical element  20  comprises a smooth semi-hemispherical sapphire. Optical element  20  can be a commercially available sapphire element known to those having skill in the art. The optical element  20 , optically coupled to the distal end of the light carrying fiber  22 , is housed inside stem  16 . Stem  16  is itself operably coupled to the handpiece  10 , which can be either a re-usable or a disposable handpiece  10 . 
         [0026]      FIG. 4  illustrates the use of one embodiment of the beveled tip, wide-angle illuminator of this invention in an ophthalmic surgery. In operation, handpiece  10  delivers a beam of incoherent light through stem  16  (via fiber optic cable  14  and/or optical fiber  22 ) and through optical element  20  to illuminate a retina  28  of an eye  30 . The collimated light delivered through handpiece  10  to optical element  20  is generated by light source  12  and delivered to illuminate the retina  28  by means of fiber optic cable  14  and coupling system  32 . Optical element  20  spreads the light beam delivered from light source  12  over as large an area of the retina as, for example, a microscopic wide-angle objective lens permits a surgeon to see. The embodiments of the wide-angle illuminator of this invention can provide illumination angles up to about 160 degrees. 
         [0027]      FIGS. 5   a - 5   d ,  6  and  7  illustrate calculated results of the effect of bevel angle on relative flux and luminous intensity for a beveled tip, wide-angle illuminator in accordance with the present invention. As can be seen from these FIGUREs, increasing the magnitude of the optical element  20  bevel angle results in increased flux, decreased glare towards a user (surgeon) and increased luminous intensity in the a direction away from the surgeon. 
         [0028]    The embodiments of the beveled tip, wide-angle illuminator of this invention provide several advantages over the prior art, such as maximizing light transmission, a high angular spread (about 85-92 degrees FWHM angular bandwidth in saline solution), a high luminous flux (e.g., about 15-18 lumens for a 23 gauge probe) with an illuminator (light source  12 ) such as the Alcon High Brightness Illuminator, manufactured by Alcon Laboratories, Inc., of Irvine, Calif., a high peak luminous intensity, elimination of glare in the direction of the surgeon, and more light emitted in a direction away from the surgeon and onto a surgical field. 
         [0029]    A traditional fiber-optic illuminator with a polished face will produce an included illumination angle that is a function of the numerical aperture (“NA”) of the fiber. NA defines the acceptance angle of entrance of the light from the light source into the fiber optic cable. Commonly, the fiber used for ophthalmic illumination applications has a typical NA of 0.5. This provides a calculated acceptance angle of 60 degrees in vacuo. Wide-angle viewing systems commonly used by ophthalmic surgeons typically have a viewing angle requirement greater than about 100 degrees in vivo. Thus, conventional fiber optic illuminators cannot provide a lighted field that matches the viewing system angle of visibility. The embodiments of the variable-intensity, wide-angle illuminator of this invention can provide an angle of illumination in excess of about 160 degrees (i.e., a range of illumination angles up to about 160 degrees). 
         [0030]    Although the present invention has been described in detail herein with reference to the illustrated embodiments, it should be understood that the description is by way of example only and is not to be construed in a limiting sense. It is to be further understood, therefore, that numerous changes in the details of the embodiments of this invention and additional embodiments of this invention will be apparent to, and may be made by, persons of ordinary skill in the art having reference to this description. It is contemplated that all such changes and additional embodiments are within the spirit and true scope of this invention as claimed below. Thus, while the present invention has been described in particular reference to the general area of ophthalmic surgery, the teachings contained herein apply equally wherever it is desirous to provide wide-angle illumination, and where contact with a transparent fluid might normally interfere with the ability to obtain wide-angle illumination.