Patent Application
20050078910
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 variable intensity, small gauge, wide-angle illuminator for illumination of a surgical field.
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.
One disadvantage exhibited by some prior art wide-angle illuminators for ophthalmic surgery is a matching of the light refracting index of the vitreous eye fluid to that of the light refracting surface of the lens of the illuminator that comes in contact with the vitreous eye fluid. Contact of the vitreous eye fluid with the light refracting surface of the light spreading lens of such prior art systems results in sub-optimal light refraction due to index switching caused by the vitreous eye fluid. U.S. Pat. No. 5,624,438, entitled “Retinal Wide-Angle Illuminator For Eye Surgery,” and issued to R. Scott Turner, provides a system for overcoming the effect of refractive index matching through the use of a high refractive-index step, mediated by the presence of an air-gap. The air-gap is presented between the distal end of an optical fiber and the light refracting surface of the illuminator lens. The light emanating from the optical wave guide (i.e., the optical fiber) will therefore undergo angular dispersion without any index switching that might be caused by contact with the vitreous eye fluid before it passes through the light refracting surface of the illuminator lens.
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.
A further disadvantage of typical prior art wide-angle illuminators is that they do not provide for varying the illumination angle and/or the intensity of the light source to adjust illumination for different conditions within the surgical field. Further still, prior art wide-angle surgical illuminators 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.
Therefore, a need exists for a variable-intensity, wide-angle illuminator that can reduce or eliminate the problems of refractive-index matching, glare, adjustable illumination properties, cost, efficiency and other problems associated with prior art wide-angle illuminators.
The embodiments of the variable-intensity, wide-angle surgical illuminator of the present invention substantially meet these needs and others. One embodiment of this invention is a small-gauge, 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 hemispherically shaped sapphire; and a 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, 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. For example, the optical element can be sized 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.
To enable some of the advantages of the embodiments of this invention, the optical fiber can be operably coupled to the handpiece to enable linear displacement of the optical fiber within the cannula. The sapphire optical element remains fixed relative to an open aperture of the cannula (i.e., co-incident with the open aperture edge). The handpiece can include a means, such as a push/pull mechanism, for adjusting the linear displacement of the optical fiber. Other adjusting means as known to those in the art can also be used. Adjusting the linear displacement of the optical fiber will change the distance between the optical element and the distal end of the optical fiber. When the optical fiber end is closest to the optical element, the light exiting the optical fiber end will be diffracted less before entering the optical element than when the optical fiber end is farther away from the optical element. Thus, by adjusting the linear displacement of the optical fiber (i.e., adjusting the distance between the optical fiber distal end and the optical element), the angle of illumination and the amount of illumination provided by the optical element from the light beam to illuminate the surgical field (e.g., the retina of an eye) can be adjusted by the surgeon. Embodiments of this invention can provide a range of illumination angles up to about 160 degrees (e.g., about 20 degrees to about 160 degrees).
Other embodiments of the present invention can include a method for wide-angle illumination of a surgical field using a variable-intensity, wide-angle illuminator in accordance with the teachings of this invention, and a surgical handpiece embodiment of the variable-intensity, 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 variable-intensity, wide-angle illuminator designed in accordance with the teachings of this invention will be known to those familiar with the art.
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:
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.
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 ophthalmology, but may be applied generally to other areas of surgery where wide-angle and/or variable illumination may be required.
An embodiment of the variable-intensity, 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 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 variable-intensity, wide-angle illuminator of this invention can provide high optical transmission/high brightness with low optical losses. 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.
The fiber optic cable 14 or fiber 22 housed within the stem 16 can be operably coupled to the handpiece 10, for example, via an adjusting means 40, as shown in
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, or through a variable intermediary air gap 24. The size of air gap 24 can be adjusted via adjusting means 40 of
As shown in
The greater refraction of the non-parallel light rays 30 when optical element 20 and fiber 22 are farther apart will cause some of the non-parallel light rays 30 to enter the refractive spherical surface 26 at steeper angles. The result will be a greater degree of refraction within optical element 20, and, consequently, a pattern of light 32 exiting from optical element 20 at a greater angle of illumination. Thus, the angle of illumination and the amount of illumination provided by optical element 20 to illuminate the surgical field (e.g., the retina 28 of an eye 30) can be easily adjusted by a surgeon by adjusting the linear displacement of optical fiber 22 (i.e., adjusting the distance between optical fiber 22 and optical element 20). In this way, a surgeon can adjust the amount of light spread over a surgical field as desired to optimize the viewing field while minimizing glare. The adjusting means 40 of handpiece 10 can be any adjusting means known to those familiar with the art.
In one embodiment of the variable-intensity, wide-angle illuminator of the present invention, a simple mechanical locking mechanism, as known to those skilled in the art, can permit the illumination angle (distance between optical element 20 and fiber 22) to be fixed, until released and/or re-adjusted by the user via the adjusting means 40. Thus, the pattern of light 32 emanating from the distal end of stem 16 will illuminate an area over a solid angle θ, the angle θ being continuously adjustable by a user (e.g., a surgeon) via the adjusting means 40 of handpiece 10.
An advantage of the optical element 20 and of the embodiments of the variable-intensity, wide-angle illuminator of this invention, is that an operator can continuously vary the intensity and angle of illumination of the pattern of light 32 exiting optical element 20 to optimize viewing conditions within the surgical field. The pattern of light 32 from optical element 20 can thus be focused and controlled as desired by the operator. The embodiments of the variable-intensity, wide-angle illuminator of the present invention are therefore operable to adjust the angle and intensity of the light provided by light source 12 to substantially cover the area of the surgical field desired by a surgeon.
The embodiments of the variable-intensity, wide-angle illuminator of this invention provide several advantages over the prior art, such as maximizing light transmission by eliminating the requirement of multiple transmitting, reflecting, or diffracting optical elements, all of which can present sources of further transmission loss between a light source 12 and a target area to be illuminated. Further, the embodiments of this invention have an inherently high light flux capacity and a variable illumination angle, which will permit the operator to tailor the angular illumination requirements for a specific surgical environment. Additionally, a variable illumination angle allows an operator to adjust the intensity of the illumination using both source intensity variations and angle of incidence variations to minimize glare and shadowing in the surgical field. By varying the angle of illumination on a specific portion of the surgical field, an operator, such as a surgeon, can get an improved perception of spatial awareness.
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).
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 and variable illumination, and where contact with a transparent fluid might normally interfere with the ability to obtain wide-angle illumination.
This application claims priority from U.S. Ser. No. 60/509,479 filed Oct. 8, 2003.
| Number | Date | Country | |
|---|---|---|---|
| 60509479 | Oct 2003 | US |
