US20020091401A1 - Automatic surgical device for cutting a cornea - Google Patents

Abstract

A surgical device for cutting substantially across a cornea of an eye of a patient, the device including a positioning ring structured to be temporarily attached to a portion of the eye surrounding the cornea to be cut, and defining an aperture sized to receive and expose the cornea to be cut. The surgical device further includes a cutting head assembly structured to be guided and driven over an upper surface of the positioning ring in a generally arcuate path, and having a cutting element positioned therein and structured to oscillate laterally to facilitate smooth and effective cutting of the cornea. The cutting head assembly is structured to be detachably coupled to the positioning ring while simultaneously permitting movement of the cutting head assembly relative to the positioning ring along the generally arcuate path.

Description

Claim of Priority
• The present application is a Continuation application of previously filed, now pending application having Ser. No. 08/840,430 which was filed on Apr. 29, 1997, which is a Continuation-In-Part of U.S. patent application having Ser. No. 08/598,180 filed Feb. 7, 1996, also incorporated herein by reference, which matured into U.S. Pat. No. 5,624,456 on Apr. 29, 1997.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0002]
• The present invention relates to a medical apparatus used during the performance of eye surgery. In particular, the present invention is directed towards an automatic surgical device for cutting the cornea of a patient's eye and creating a hinged flap of corneal tissue. More particularly, the automatic surgical device of this invention includes a cutting head assembly which is specifically structured to move across the patient's eye along a generally arcuate path, and further, is readily usable on both eyes of the patient.[0003]
• 2. Description of the Related Art[0004]
• The eye works on a principle very similar to that of a camera and is illustrated generally in FIG. 1. The iris I, or colored portion of the eye about the pupil P, functions like a shutter to regulate the amount of light admitted to the interior of the eye. The cornea C or clear window of the eye, and the lens L, which is located behind the pupil, serve to focus the light rays from an object being viewed onto the retina R at the back of the eye. The retina then transmits the image of the object viewed to the brain via the optic nerve, O. Normally, these light rays will be focused exactly on the retina, see dashed lines in FIGS. 2 and 3, which permits the distant object to be seen distinctly and clearly. Deviations from the WA normal shape of the corneal surface, however, produce errors of refraction in the visual process so that the eye becomes unable to focus the image of the distant object on the retina. As one example, illustrated in FIG. 2, hyperopia or “farsightedness” is an error of refraction in which the light rays from a distant it object are brought to focus at a point behind the retina, as indicated by the solid lines. As another example, illustrated in FIG. 3, myopia or “nearsightedness” is an error of refraction in which the light rays from a distant object are brought to focus in front of the retina, as indicated by the solid lines, such that when the rays reach the retina, R, they become divergent, forming a circle of diffusion and consequently, a blurred image.[0005]
• Until about twenty years ago, such refractive errors could only be treated with eyeglasses or contact lens, both of which have well known disadvantages for the user. As one example, a patient having a large degree of refractive error will commonly be prescribed to wear a very thick and cumbersome pair of glasses, which the patient should wear at all times to correct his/her extremely poor vision. As another example, contact lenses, which are designed to fit directly over the cornea, can be difficult to insert and remove, and in any event, must be carefully cleaned and cared for. Even then, contact lenses may at times irritate the eyes of those patients who can wear them.[0006]
• Consequently, in the last several years, research has been directed to surgical operations to change the refractive condition of the eye. Several methods and special instruments have been designed for performing this kind of surgery. One such technique was keratomileusis, developed by Dr. Jose Barraquer of Colombia in 1949, which required a precise reshaping of the cornea. The goal of corneal reshaping is to modify the curvature of the cornea, i.e., either to flatten or increase its curvature depending on the patient's condition, with the desired result being that light rays passing through the cornea will then be refracted to converge directly onto the retina. Keratomileusis was extremely difficult to perform because it required cutting the cornea to separate and remove a thin layer or section of corneal tissue from a patient's eye, termed the corneal cap, precise lathing of it into a new shape, and then replacing it and suturing it back onto the patient's cornea.[0007]
• Keratomileusis has been abandoned in recent years to eliminate the requirement of lathing the corneal tissue and suturing it back into place. Automated Lamellar Keratectomy (ALK) is another surgical technique which developed as an outgrowth of keratomileusis, wherein the eye is first numbed by a drop of anesthetic, and then a suction ring is placed on the eye to carefully position the cornea (termed “centration” in the art) for being cut by a very fine microsurgical instrument known as a microkeratome. The microkeratome is generally a blade carrying device that must be manually pushed or mechanically driven in a cutting path across the suction ring simultaneous with the motorized movement of the cutting element, which movement is transverse to the direction of the cutting path. For treating myopia pursuant to ALK procedures, the microkeratome is typically used to first cut into the cornea so as to raise a thin layer of the anterior cornea of between 100-200 microns in depth and about 7 millimeters in diameter. Next, the microkeratome is then used to make a second pass over the cornea to resect or remove a smaller part of the cornea, generally about 4 to 6 millimeters in diameter, which is then discarded. The anterior corneal cap which was cut away with the first pass of the microkeratome is then put back into its original position, without suturing, for healing to occur. The desired result of this procedure is that the cornea will have a new curvature because of the resected tissue, which provides a new refracting surface to correct the patient's original myopic condition. To correct hyperopia under ALK however, the microkeratome is typically used to make a single deep pass over the cornea. The cut layers are put back into their original position, without any removal of any other tissue. Because of the depth of the cut, the intraocular pressure within the eye causes a steepening of the cornea to again, provide a new refracting surface which hopefully will correct the patient's original hyperopic condition.[0008]
• In recent years, it has been learned that in using the microkeratome to cut and separate a thin layer of the cornea, termed the anterior corneal cap, it is highly undesirable to completely separate this cap from the rest of the cornea. First, the corneal cap has been lost in some instances which is calamitous because the anterior segment of the eye must then be completely reconstructed. Second, it is also now known that following the reshaping of the cornea, the corneal cap should be carefully and precisely aligned back into its original position on the cornea; failure to do so may result in astigmatism or some unbeknownst refractive error. Consequently, it is now understood that the microkeratome should not sever the cap from the eye but instead, should leave a portion connected or “hinged” to the eye, thereby forming a raised layer of corneal tissue hinged to the eye, known as a corneal flap F, illustrated in FIG. 4. A significant problem however, is that presently known microkeratome devices do not readily permit the formation of a corneal flap, F. Instead, known microkeratomes involve a degree of guesswork for determining where on the eye to stop cutting movement of the microkeratome across the cornea so as to form the corneal flap. Further, there are multiple issues that a surgeon needs to consider in corneal flap construction, the three most important factors being: flap thickness, flap size and hinge size.[0009]
• Another advance has been made in more recent years in surgical procedures to correct refractive errors of the eye, namely, the introduction of laser procedures to accomplish the reshaping of the cornea. One such procedure, known as Laser Intrastromal Keratomileusis, (LASIK), is currently considered optimal because it allows sculpting of the cornea without damaging adjacent tissues. Moreover, with the aid of computers, the laser can be programmed by a surgeon to precisely control the amount of tissue removed, and significantly, to permit more options for the reshaping of the cornea. Under LASIK procedures, the eye is still typically positioned within a suction ring and a microkeratome is typically used to cut into the cornea so as to raise a thin layer of the cornea. As described, it is now preferred that a corneal flap be formed. Significantly, it has been determined that the corneal flap should have a depth of no less than 130 microns and no more than 160 microns to yield optimal results. It should be borne in mind that achieving this result during surgery requires an extremely precise instrument as one micron is a unit of length equal to one thousandth of a millimeter. During laser surgery, the flap of corneal tissue is then gently pushed aside to expose and permit reshaping of the cornea by the laser. Consequently, the microkeratome is less frequently used to reshape the cornea, as occurred under ALK procedures, but is still used to cut into and to raise a thin layer of corneal tissue. A significant problem however, is that presently known microkeratome devices do not offer the degree of precision currently needed to properly and consistently form a corneal flap, instead of a corneal cap, let alone a corneal flap having a dimension within the range of currently desirable depth and a vastly improved smooth cut. Further, it has been determined that a larger diameter of the eye should be presented, as much as 8 to 10 millimeters, for corneal reshaping by the laser. This is because the laser can now be used to re-shape the corneal surface about a perimeter of the eye rather than at the center, which is believed to result in more accurate correction of refractive errors. Doing so however, requires that a sufficiently large diameter of the eye be presented and exposed, which is not possible to achieve with known microkeratome devices. For example, known suction rings for positioning the eye during surgery would likely require a greatly expanded frame, and that that frame be located lower on and about the girth of the eyeball, in order to expose a greater portion thereof. Such an assembly would likely be very difficult to employ given the physical space limitations of the eye socket.[0010]
• Finally, known microkeratome devices typically cut across the cornea in a linear direction along a horizontal plane. That is, known microkeratome devices typically cut across the cornea in a direction starting from the side of the eye near the temple, proceeding horizontally across the face towards the nose. As a result, even if such microkeratomes were able to be effectively used to construct a corneal flap, let alone one of the currently desired more precise dimensions, the hinged portion of the corneal flap would be oriented at right angles to the natural blinking action of the patient, which is in the vertical plane. It is believed that it would be most optimal to construct a corneal flap having a hinged portion which is oriented to correspond with the natural blinking action of the patient in the vertical plane. It is however, believed that known microkeratomes cannot move linearly in a vertical plane because of the restrictions presented by the size of the eye socket formed by the cheek and brow bones of the human skull.[0011]
• Thus, there is a need for an improved automated microkeratome which automatically and consistently permits the formation of a corneal flap, and which allows for even more precise construction of the corneal flap so as to result in a flap thickness of no less than 130 microns and no more than 160 microns, and a flap size between 8 and 10 millimeters in diameter. There is also a need for an improved automated microkeratome which more smoothly cuts across the cornea in forming the corneal flap so as to permit it to be precisely aligned back into its original position on the cornea following the reshaping of the cornea. Ideally, any such improved automated microkeratome will also permit construction of the corneal flap in such a way that the hinged portion of the flap will be oriented to correspond the natural blinking of the eye.[0012]
SUMMARY OF THE INVENTION
• The present invention is designed to satisfy the needs in the art and is directed towards a new and improved automatic surgical device known as a microkeratome. The improved microkeratome of the present invention is adapted to cut and raise a thin layer of the cornea of a patient's eye and to create a hinged flap of corneal tissue. The present invention is seen to comprise means for retaining and positioning the eye on which surgery is to be performed, a cutting head assembly including a cutting element positioned therein for cutting the cornea of the eye, and a coupling member for detachably coupling the retaining and positioning means and cutting head assembly while permitting movement of the cutting head assembly relative to the retaining and positioning means along a generally arcuate path.[0013]
• In the preferred embodiment, the retaining and positioning means comprise a positioning ring having means for temporary attachment to a portion of the eye surrounding the cornea to be cut, and which expose and present the cornea for cutting. The positioning ring includes guide means thereon, preferably disposed on an upper surface thereof and extending in a generally arcuate path.[0014]
• The cutting head assembly of the present invention is structured and disposed to be at least partially received in the guide means of the retaining and positioning means and to be driven substantially but not completely over the cornea of the eye so as to cut the cornea and form a corneal flap. The cutting head assembly is also structured and disposed to be guided by the guide means on the retaining and positioning means along a generally arcuate path during movement of the assembly thereacross. The cutting head assembly is seen to comprise a main housing which carries a cutting element positioned therein and disposed for cutting and raising the corneal flap. In the preferred embodiment, the cutting head assembly includes a flap receiving gap formed within an undersurface thereof forward of the cutting element for protectively receiving the corneal flap of tissue formed by the forward movement of the cutting head assembly. Further, the cutting head assembly is structured and disposed to be movably coupled to the positioning ring by way of a coupling member which detachably couples the cutting head assembly and the positioning ring and yet, permits movement of the cutting head assembly relative to the positioning ring along a generally arcuate path. The present invention further comprises driving means for driving the cutting head assembly over the retaining and positioning means, and in the preferred embodiment, includes stop means, which are structured and disposed to limit movement of the cutting head assembly across the retaining and positioning means. The stop means may be formed on the cutting head assembly and may be structured and disposed to engagingly abut the guide means of the retaining and positioning means so as to limit further movement of the cutting head assembly at a point before the cutting element has passed completely over the cornea of the eye, thereby forming a corneal flap on the eye undergoing surgery. In the preferred embodiment, the drive means are operably connected to the cutting head assembly at a top surface thereof and are capable of stopping and reversing the direction of movement of the cutting head assembly once the stop means have prevented movement of the cutting head assembly in a first direction across the retaining and positioning means.[0015]
• A primary object of the present invention is to provide an improved automated surgical device, for cutting and raising a thin layer of tissue from the cornea of an eye undergoing surgery, without completely severing the layer from the cornea of the eye, thereby creating a corneal flap.[0016]
• Another primary object of the present invention is to provide an improved automated surgical device which forms a corneal flap wherein the hinged portion of the flap is oriented so as to cooperate with the blinking of the eye, and thereby, assist proper repositioning and alignment of the corneal flap on the cornea following surgery.[0017]
• It is also an object of the present invention to provide an improved automated surgical device which permits a surgeon to more precisely and consistently construct a corneal flap and to obtain a flap thickness of not less than 130 microns and not more than 160 microns.[0018]
• A feature of the present invention is that it permits a surgeon to expose a diameter of the cornea which is between 8 to 10 millimeters, and ideally about 9.5 millimeters, so as to permit the construction of a relatively large diameter flap size which is preferable in reshaping a cornea utilizing laser procedures.[0019]
• Another object of the present invention is to provide an improved automated surgical device which more smoothly cuts across the cornea in forming the corneal flap so as to permit the flap to be more precisely aligned back into its original position on the cornea following the reshaping of the cornea.[0020]
• A further object of the present invention is to provide an improved automated surgical device which can be readily used on either a patient's left or right eye.[0021]
• Still another object of the present invention is to provide an improved automated surgical device having a center of gravity during operation which is substantially centered over the patient's eye.[0022]
• An additional object of the present invention is to provide an improved automated surgical device which exposes and permits cutting of a larger diameter across the eye without a greatly expanded assembly for positioning the eye.[0023]
• Yet another object of the present invention is to provide an improved automated surgical device which as a result of its arcuate path of travel, facilitates the formation of a larger diameter cut to the cornea, without having to locate the assembly positioning the eye to a lower position about the eye.[0024]
BRIEF DESCRIPTION OF THE DRAWINGS
• For a fuller understanding of the nature of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:[0025]
• FIG. 1 is a schematic illustration of a horizontal section of the eye;[0026]
• FIG. 2 is a schematic illustration of a hyperopic eye wherein refracted rays converge at a point behind the retina;[0027]
• FIG. 3 is a schematic illustration of a myopic eye wherein refracted rays converge at a point which is short of the retina;[0028]
• FIG. 4 is schematic illustration of a cornea of an eye wherein a corneal flap has been created.[0029]
• FIG. 5-A is a perspective view of an embodiment of the retaining and positioning means according to the present invention, namely a positioning ring;[0030]
• FIG. 5-B is an exploded perspective view of a preferred embodiment of the retaining and positioning means according to the present invention, which include a positioning ring having guide means and a toothed track;[0031]
• FIG. 5-C is a cross sectional view of the retaining and positioning means shown in FIG. 5-B;[0032]
• FIG. 6 is an exploded perspective view of the cutting head assembly according and the coupling member according to the At present invention;[0033]
• FIG. 7 is a side view of the present invention in assembled form and in position on a patient's cornea;[0034]
• FIG. 8 is a partial cross sectional view of the present invention in assembled form and in position on a patient's cornea;[0035]
• FIGS.[0036]9-A,9-B and9-C are partial, cross sectional views taken along the plane of the arrowed lines9-9 of FIG. 8, and illustrating sequential views during the cutting of the cornea in which:
• FIG. 9-A illustrates the cutting head assembly in an initial position in contacting relation with the positioning ring and the guide means thereon;[0037]
• FIG. 9-B illustrates the cutting head assembly moving through an intermediate position where cutting of the cornea occurs;[0038]
• FIG. 9-C illustrates the cutting head assembly in a movement stopped position wherein the abutting or stop means are in contacting relation with the guide means of the positioning ring;[0039]
• [0040]12FIG. 10-A is a front schematic illustration of the present invention in use on both a patient's left and right eyes and illustrating the cutting head assembly in the initial position;
• FIG. 10-B is also a front schematic illustration of the present invention in use on both a patient's left and right eyes and depicting the cutting head assembly in the movement stopped position, wherein a corneal flap has been formed with the resulting hinged portion being oriented so as to cooperate with the blinking of the eye following surgery; and[0041]
• FIG. 11 is an isolated perspective view of the drive means illustrating the operation and interconnection of the worm, worm gear, and oscillating shaft.[0042]
• Like reference numerals refer to like parts throughout the several views of the drawings.[0043]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• Illustrated throughout the drawings, the present invention is a mechanical apparatus used in the performance of surgery on the eye, and is generally indicated as[0044]10 in FIGS.10-A and10-B. More specifically, the invention is directed towards an automatic surgical device, known as a microkeratome, to be utilized on an eye which is about to undergo surgery to correct refractive errors of the eye such as hyperopia, myopia or astigmatism. The improved microkeratome of the present invention is structured to cut substantially but not completely across the cornea of a patient's eye so as to raise a thin layer thereof and create a hinged flap of corneal tissue. The hinged portion of corneal tissue created by the present invention is also oriented so as to cooperate with the blinking of the eye following surgery.
• Referring now to FIGS.[0045]5-A,5-B, and5-C, thedevice10 includesmeans30 for retaining and positioning the eye on which surgery is to be performed. The retaining and positioning means30, which may be made of high grade stainless steel, preferably comprise apositioning ring32 having anaperture33 formed therein. Theaperture33 is sized to permit the cornea C, of the eye to pass therethrough and be exposed, as depicted in FIG. 5-C. In the preferred embodiment, and as illustrated in the drawings,positioning ring32 is defined by a generally tear-drop shape, which is readily suited for accommodating the movement of a cutting head assembly,50, discussed below, along an arcuate path, and further, which is structured and disposed to present the cornea so that a diameter of generally about 8 to 10 millimeters may be cut. Thepositioning ring32 could, however, be formed to have another shape and still function for the intended purpose.
• Positioning[0046]ring32 further includes means for being temporarily attached to a portion of the eye surrounding the cornea on which surgery is to be performed. Ideally, the temporary attachment means include suctioning means. For example, positioningring32 preferably includes aconnection member37, which as illustrated in FIG. 5-C, is in fluid communication with an undersurface ofpositioning ring32.Connection member37 is adapted to be interconnected with a vacuum hose (not shown) which in turn may be connected to a vacuum means (also not shown) such that when suction occurs, the undersurface ofpositioning ring32 forms a seal about and is retained about the cornea portion of the eye which is about to undergo surgery. Further, the structure ofpositioning ring32, accompanied by the suctioning, acts to properly position the cornea C, for surgery and to maintain the position during surgery as well. Typically, a vacuum of about 25 inches of Hg at sea level will be used.
• The retaining and positioning means[0047]30 further include guide means or aguide assembly40 formed thereon. Guide means40 may be formed directly on thepositioning ring32, so as to be integral therewith, or may be operably connected thereto as a separate element. In any event however, the guide means40 will be disposed onpositioning ring32 so as to guide and facilitate movement of the cuttinghead assembly50, discussed below, during the surgical cutting of the cornea. Referring to FIGS.5-A and5-C, in the preferred embodiment, guide means40 are seen to comprise achannel member41,42, which extends along a length of at least one side ofpositioning ring32 and preferably, on an upper surface ofpositioning ring32. It will also be appreciated from the drawings that channelmember41,42 extends acrossring32 in an arcuate or semi-circular path. As depicted in FIG. 5-A,channel member41 may comprise an elongated, generally “C” shaped structure or even an inverted “L” shaped structure, which is operably connected to an upper surface ofring32, such as designated bynumeral34. As illustrated in FIGS.5-B and5-C however, in the most preferredembodiment channel member42 is formed by the interconnection of two separate elements, namely, an upwardly and arcuately extendingsidewall36 formed onpositioning ring32, and atoothed track43 which is interconnected withsidewall36. Still referring to FIG. 5-C, in the most preferred embodiment, positioningring32 is seen to include the upwardly and arcuately extendingsidewall36 having aridge38 formed on an upper surface thereof, and extending partially if not completely along, at least one side ofpositioning ring32. Further, in this preferred embodiment, thetoothed track43 is structured to be operably connected toridge38 by way of mating structure. For example, the mating structure can be in the form of a receiving groove disposed on the undersurface oftoothed track43, and/or by way of conventionally knownfasteners39′ such as screws, rivets, etc. which may pass throughpositioning ring32 atapertures39 and extend intotoothed track43. As further illustrated in FIG. 5-C,toothed track43 is seen to include alip43′ which is sized and dimensioned to protrude beyond the vertical plane formed bysidewall36. Thus, guide means40 in the form of a generally “C” shapedchannel member42 is comprised by the combined structure ofsidewall36 andtoothed track43, havinglip43′. With respect to the embodiment shown in FIG. 5-A, it is contemplated that a toothed track may also be mounted to an upper surface ofpositioning ring32 or to an upper surface ofchannel member41. It will be appreciated thattoothed track43 cooperates with the drive means80 (see FIGS. 7 and 11) so as to drive the cuttinghead assembly50 acrosspositioning ring32, as more fully discussed below.
• In a preferred embodiment, the guide means[0048]40 further comprise a rigidupstanding member44 disposed on the retaining and positioning means30, and generally opposite thetoothed track43. As will again be appreciated from the drawings, in the preferred embodiment, whereinpositioning ring32 is of a tear-drop shape, rigidupstanding member44 comprises apost member45 securely connected to positioningring32 on an upper surface thereof at or near atip35 thereof. From the explanation which follows, it will become clear thatchannel member42 and rigidupstanding member44 permit the cuttinghead assembly50 of the invention, in a preferred embodiment, to become effectively guided and securely received on the it positioningring32 in two places while still permitting cuttinghead assembly50 to be smoothly and slidably moved overpositioning ring32 along a generally arcuate path, by way of a pivoting motion about rigidupstanding member44. Of course, the positioning ring could be formed to include another channel member, such as41,42, which extends along a length of the other side ofpositioning ring32, also preferably, on an upper surface thereof, so as to also permit the cuttinghead assembly50 of the invention to become effectively guided and securely received on thepositioning ring32 in two places while still permitting the cuttinghead assembly50 to be smoothly and slidably moved overpositioning ring32 along a generally arcuate path.
• Referring now to FIG. 6, the present invention is seen to include a cutting[0049]head assembly50. A primary purpose of the cuttinghead assembly50 is to house a cuttingelement70, see FIG. 8, with a cutting surface operatively exposed therefrom. As such, upon the cuttinghead assembly50, with the cuttingelement70, being moved across the cornea retained withinpositioning ring32, the cornea may be precisely cut by cuttingelement70. To accomplish this, cuttinghead assembly50 includes amain housing51 containing the cuttingelement70. Additionally, included in themain housing51 is anaperture58 structured and disposed to permit drive means80 to be operably connected thereto (see FIGS. 7 and 11) and to thereby drive the cuttinghead assembly50 acrosspositioning ring32 in order to effectively cut the cornea. Further, as the cuttinghead assembly50 must be driven in a smooth and controlled manner across the cornea,housing51 includes tracking means60 which are structured and disposed for mating communication with and tracking withinchannel member42, ofpositioning ring32, in order to precisely guide the cuttinghead assembly50, and therefore the cuttingelement70, along the defined arcuate path. Finally, as a significant feature of the present invention is to cut a portion of the cornea without completely severing it, abutting or stop means65 are provided, which serve the purpose of limiting and preferably, completely stopping the movement of the cuttinghead assembly50 from cutting completely across the cornea, that is, before the assembly has passed completely over the cornea. The abutting or stop means are preferably disposed on themain housing51. These features will be discussed in more detail below.
• Still referring to FIG. 6, the preferred embodiment of the present invention is also seen to include a[0050]coupling member90. While the cuttinghead assembly50 might be directly and yet movably engaged with thepositioning ring32 for performing an operation on the eye, preferably, acoupling member90 is utilized as part of the invention, which is structured and disposed to movably couple the cuttinghead assembly50 to thepositioning ring32 while simultaneously permitting movement of the cuttinghead assembly50 relative topositioning ring32. As illustrated in FIG. 6,coupling member90 comprises two segments: a) a retainingsegment92 and b) apivot segment95. The retainingsegment92 is structured and disposed to be fitted onto atop wall surface56′ ofmain housing51 and may include downwardly depending flanges91,93 to snugly receive and grip a portion ofhousing51 therebetween. The retainingsegment92 also includes anaperture94 formed therein to correspond toaperture58 ofhousing51. As such,aperture94 is sized and configured to allow passage of the driving shaft of the driving means80 (shown in FIGS. 7 and 11) therethrough and intoaperture58 of thehousing51. Thus, in assembled form,coupling member90 is securely yet removably coupled tohead assembly50 as a result of the engagement of the driving means80 with thehousing51 through retainingsegment92. Turning to thepivot segment95 ofcoupling member90, it is structured and disposed to be coupled to rigidupstanding member44 ofpositioning ring32 and to permit couplingmember90, and accordingly, the cuttinghead assembly50 connected thereto, to pivotally move aboutpost member45. Preferably,pivot segment95 includes abushing97 having a bore96 formed therein, which is sized to receive a substantial height ofpost member45, thereby captivating it therein. Further, in the preferred embodiment, thepivot segment95 includes maintaining means46, see FIG. 5-C, for maintaining rigidupstanding member44 withinbushing97 and engagement means98 for maintainingbushing97 over rigidupstanding member44. Referring now to FIGS.5-B and5-C, the maintaining means46 preferably include anenlarged head47 on rigidupstanding member44, and anannular recess48 or taper about the neck section ofupstanding member44. As illustrated in FIG. 6, the engagement means98 preferably comprise a threaded shaft which passes through a sidewall ofbushing97 and can be selectively moved into engagement withupstanding member44 by rotatinghandle99 and causing a tip thereof to extend into theannular recess48, thereby preventing removal of thepivot segment95 from theupstanding member44, when surgery is to take place. It will be therefore be appreciated that in assembled form, the engagement means98 and maintaining means46 cooperate to permit couplingmember90 and cuttinghead assembly50 to rotate aboutupstanding member44 while preventingbushing97 from sliding up and off ofupstanding member44. It will also be appreciated that in assembled form,upstanding member44 acts as additional guide means for enabling the cuttinghead assembly50 to be driven along an arcuate path in a smooth and controlled manner across positioningring32 and thus, the cornea C.
• Referring back to FIG. 6, as well as to FIGS. 7 and 8, the cutting[0051]head assembly50 as well as its operation will now be described in more detail. As previously recited, the cuttinghead assembly50 comprises themain housing51 which includes atop surface56′, a bottom wall, and a surroundingsidewall structure53 defining afront end face52, and an oppositely disposedrear end face54. Because during surgery, the cuttinghead assembly50 is driven acrosspositioning ring32 along an arcuate path, front end face52 preferably defines a tapered nose to cooperate with the arcuate path ofchannel member42. Also as previously recited, the main housing is structured to contain the cuttingelement70 and operatively expose a cutting surface thereof. In the preferred embodiment, the cuttinghead assembly50 as well as the cuttingelement70, are structured and disposed to permit a diameter of the cornea of generally about 8 to 10 millimeters to be cut, and ideally, about 9.5 millimeters. Although the cuttingelement70 may be formed integrally withmain housing51, in the preferred embodiment themain housing51 includes aninterior chamber88, see FIG. 8, structured to receive and maintain anindependent cutting element70 in a cutting position. Most preferably, the cuttingelement70 is disposed within themain housing51 at about 20 to 30 degrees from the horizontal plane. Also, a cuttingopening56 is formed at a bottom ofhousing51 so as to expose a cutting surface of cuttingelement70, see FIG. 8. In the preferred embodiment, cuttingelement70 comprises a blade having a sharpenedcutting edge71, the cutting tip of which is preferably formed to have an angle of approximately and generally between 5 to 10 degrees from the horizontal axis of the blade, and further, the blade itself is operably connected to yet removable from, ablade holder72.Blade holder72 is operably connected to the drive means80, see FIG. 11, connected tohousing51 throughaperture58, and drive means80 impart an oscillating movement causingblade holder72 andblade71 to move back and forth generally between opposite walls of the surroundingsidewall structure53 ofhousing51. Accordingly, theinterior chamber88 withinhousing51 will be sized to receive the cutting element orblade70 andblade holder72 and to permit the oscillating cutting movement of same withinhousing51.
• Additionally, in order to permit a used cutting[0052]element70 to be removed and replaced,housing51 includes access means55. Although the access means55 may include an exterior slot or like access, in the preferred embodiment, and as illustrated in FIG. 8, access means55 at least partially form bottom wall ofhousing51 nearrear end face54, and ideally, comprise adoor member57 which is hingedly connected to the surroundingsidewall structure53 atrear end face54.Door member57 is movable between a closed operative position for surgery and an open position for permitting a used or contaminated cuttingelement70 to be removed from thehousing51 and replaced with a new or sterile cutting element.Door member57 may be selectively maintained in the closed position by conventionally known fasteners as depicted in FIG. 8. It will be appreciated from FIG. 8 thatdoor member57 does not completely bridge the cuttingelement70. It is believed that this structure is sturdier and less fragile than the structure of known microkeratomes, which are prone to being bent if, when the cutting element is inserted, it is not properly aligned within the microkeratome.
• Also, in the preferred embodiment,[0053]housing51 of cuttinghead assembly50 will include depth adjusting means75 for adjusting the depth at which cuttingelement70 cuts into the cornea. As illustrated in FIG. 8, the depth adjusting means75 are preferably disposed at the front end face52 ofmain housing51 and form at least a portion of the bottom wall ofhousing51 nearfront end face52. Preferably, the depth adjusting means75 comprise aseparate nose segment76, which is structured to be securely, yet removably interconnected withhousing51 by way of a conventionally knownfasteners74 such as a screw, a bolt, etc. Preferably, thenose segment76 comprises anengagement segment77 and a variabledepth plate member78.Engagement segment77 preferably includes aterminal end79 which is formed to define an inverted “V” shape, and preferably extends across the width of thenose segment76. This structure is sized and configured to be received and to nest within a corresponding void, also shaped like an inverted “V”, formed withinhousing51 on and between oppositely disposedsidewall structures53, adjacentfront end face52. It will be appreciated that this structure permits a highly stable nesting or dwelling ofterminal end79 withinhousing51 even as the cuttinghead assembly50 is moved along an arcuate path overpositioning ring32. Further, as illustrated, variabledepth plate member78 is preferably integral withengagement segment77 and is disposed substantially in the horizontal plane. Variabledepth plate member78, has a depth depicted as “H” in FIG. 8, which is a dimension pre-selected by the surgeon to correspond the desired depth of the cut to be made into the cornea. A significant feature of the present invention is to provide a plurality ofnose segments76, each including aplate member78 having a differently dimensioned depth “H”. It will be appreciated from FIG. 8 that there is an inverse relationship between the depth ofplate member78 and the depth of the cut to the cornea as the cuttinghead assembly50 proceeds forward during surgery in the direction of the arrow “A” and pushes down on the cornea. For example, aplate member78 having a larger depth “H”, will shield more of the blade'scutting edge71 whereas aplate member78 having a smaller depth “H” will expose more of area above the blade's cutting edge. It will thus be recognized that the cuttinghead assembly50 is designed to be interchangeable with differently sized depth adjusting means75 so as to precisely meet the needs of the patient undergoing surgery. Ideally, the present invention will offer two differentlysized nose segments76, namely one sized for 130 microns and another for 160 microns which are currently the most desirable depths for cutting into the cornea and exposing same for reshaping.
• As has been described,[0054]housing51 of cuttinghead assembly50 also includes tracking means60. Referring to FIG. 6, tracking means60, which in the preferred embodiment are disposed on a lower peripheral zone ofhousing51, are structured for mating communication with and tracking withinchannel member42, see FIG. 5-C, ofpositioning ring32. For example, tracking means60 may comprise an outwardly extending flange disposed on a side of thehousing51, along the lower edge thereof, and may take the form of a continuous flange about thehousing51, or alternatively a plurality of pin members disposed thereabout. In the preferred embodiment however, the tracking means60 are disposed on the depth adjusting means75 and are integral with and planar to the variabledepth plate member78 in the form of aflange62, see FIG. 6. Preferably,flange62 extends out beyond the periphery defined by surroundingsidewall53 ofhousing51 in generally perpendicular relation thereto. Further, although the cuttinghead assembly50 is designed to receivenose segments76 having variabledepth plate members78,flange62 which extends therefrom is of a uniform height so as to correspond and effect mating communication with and tracking withinchannel member42, ofpositioning ring32. Althoughflange62 could extend only from one side of thehousing51, in the preferred embodiment,flange62 is disposed on each side of variabledepth plate member78, thereby facilitating use of the present invention on either a patient's left or right eye.
• Also as previously recited, the[0055]main housing51 includes abutting or stop means65 which serve the purpose of limiting and preferably stopping, the forward movement of cuttinghead assembly50 acrosspositioning ring32. In the preferred embodiment, stop means65 are formed generally at rear end face54 on surroundingsidewall structure53 and are seen to comprise ashoulder66 formed at the juncture betweensidewall structure53 and rear end face54 of thehousing51, which shoulder is sized to be too large to pass within thechannel member42 of the guide means40, thereby preventing any further forward motion of thehead assembly50 acrosspositioning ring32. When abutting engagement occurs betweenshoulder66 andchannel member42, by way oflip43′, the driving means80 can be stopped and then reversed to permit movement of the cuttinghead assembly50 in the opposite direction. As has been described, it has been determined in recent years that in performing surgery on the cornea, the layers of the cornea which are cut should not be completely severed. A unique feature of the cuttinghead assembly50 and of thisinvention10 is that the cutting of the cornea results in the formation of a corneal flap F, as illustrated in FIG. 4, which is also safely preserved by theassembly50. To preserve the corneal flap F,housing51 includes aflap receiving gap59 formed withinhousing51. As illustrated in FIG. 6 and more clearly in FIG. 8,flap receiving gap59 is disposed generally near the front end face52 ofhousing51 and more particularly, is defined by a gap formed just forward of the blade'scutting edge71 and just rearward of variabledepth plate member78. Thus,flap receiving gap59 is disposed on an undersurface ofhousing51 and extends upwardly and intohousing51. Ideally,flap receiving gap59 extends through theopposite sidewall structure53 ofhousing51.
• Referring now to FIGS.[0056]9-A,9-B and9-C, the cutting head assembly is illustrated in sequential positions during its movement in a cutting path over the cornea being treated. As a preliminary step in the cutting the cornea, FIG. 9-A depicts a) the retaining and positioning means30, and b) the cuttinghead assembly50 coupled as previously described by couplingmember90, as the tracking means60 of thehead assembly50 have been initially matingly connected to the guide means40 ofpositioning ring32. More specifically, it is seen in FIG. 9-A that first, a front end offlange62 has been matingly received inchannel member42 of retainingring32 and also, that theworm gear120 is alignedly received ontoothed track43 ofpositioning ring32. Turning to FIG. 9-B, the cuttinghead assembly50 has moved into position across the positioning ring and cutting of the cornea C is taking place. FIG. 9-C illustrates the cuttinghead assembly50 in a position wherein the stop means65 are contactingchannel member42 of thepositioning ring32, to limit and preferably, prevent any further forward motion of the assembly. It will also be clear from FIG. 9-C that in this stopped position, the cuttingelement70 has not moved completely across the cornea C, but rather has cut a portion of the cornea up until this point, creating a corneal flap which is left attached to the cornea as designated by the area marked “F” which is shown in the FIG. 9-C. Moreover, as illustrated in FIG. 8, the corneal flap created has been directed by the forward movement of the assembly, upwardly and intoflap receiving gap59 ofhousing51 to be preserved and kept clear of cuttingelement70. Once the assembly has been stopped as in FIG. 9-C, the drive means80 can be reversed to permit movement of the cuttinghead assembly50 in the opposite direction, which does not result in any further cutting of the cornea, but rather, in the safe removal of the corneal flap F out offlap receiving gap59 ofhousing51. Thus, whenhead assembly50 returns through to a position analogous to that shown in FIG. 9-A, the head assembly can be disconnected from the retaining means30. The corneal flap F can then be maneuvered so as to permit the cornea to be reshaped, preferably by way of a laser surgical procedure. Once the surgery has been completed, the corneal flap is returned to a covering relation over cornea.
• Another unique feature of the present invention is not only that a corneal flap can be created, but significantly, that the corneal flap is positioned in such a way that the blinking of the eye will not improperly position the corneal flap on the cornea following surgery. Referring now to FIGS.[0057]10-A and10B, the invention is schematically illustrated on both a patient's left and right eyes. As depicted in FIG. 10-A, reference points of the work environment can be equated with the position of some numerals on the face of a clock. Thus, in FIG. 10-A, it will be noted that with respect to the patient's left eye, the cuttinghead assembly50 in the initial position is preferably disposed at a generally five o'clock position. With respect to the patient's right eye, the cuttinghead assembly50 in the initial position is preferably disposed at a generally seven o'clock position. Turning now to FIG. 10-B, the cuttinghead assembly50 is shown to have moved towards a position generally aligned with the twelve o'clock position, wherein the stop means65 are in abutting engagement withchannel member42 of thepositioning ring32, such that any further forward motion of the assembly is prevented. It will thus be appreciated that regardless of whether the surgical procedure is being performed on a patient's left or right eye, the cuttinghead assembly50 is preferably aligned generally with a twelve o'clock position. It will also be appreciated from FIG. 10-B that the resulting corneal flap F, remains attached to the cornea at an upper region thereof. Consequently, following the surgical procedure to reshape the cornea, the orientation of the corneal flap will be in generally the same direction as the natural blinking action. That is, it is believed that the downward blinking motion of the patient will tend to stroke the corneal flap down and thereby assist with maintaining the corneal flap in proper re-position on the cornea so as to avoid the development of astigmatism.
• Referring now to FIG. 11, the present invention includes drive means[0058]80 both: a) for driving the cuttinghead assembly50 across the previously described eyeball retaining and positioning means30; and b) for causing the cuttingelement70 to oscillate back and forth withinhousing51. The driving means preferably include amotor100, preferably electrically operated and most preferably, a micromotor capable of operating at a constant and uniform speed, regardless of the load. Specifically, under normal circumstances the natural resistance encountered by the cutting head assembly, as it is driven over the cornea, would result in an increased resistance in the winding of the micromotor, which would tend to cause a voltage drop and therefore a drop in speed. While some known systems attempt to avoid excessive drops in speed by incorporating an overpowered motor to keep losses below a 10% slow down, themotor100 of the present invention is preferably equipped to monitor current flowing therethrough, such as using an op amp, and utilize that information to control the applied voltage and maintain the constant speed. This monitoring and compensation, sometimes referred to as I R compensation, thereby permits a conventional, regulated12 V supply to be used with a DC motor in order to maintain the effective constant speed of travel over the eye.
• Referring now to FIGS. 8 and 11, the driving means[0059]80 further include agear box81 into which a motormain drive shaft101 extends. From thegear box81, and specifically concentrically through anengagement hub110 as shown in FIGS. 7 and 8, a cutting assembly main drive shaft operatively extends. The cutting assembly main drive shaft comprises two primary sections, namely: a) a threaded drive screw or “worm”115 shown in FIG. 11, which is an intermediate section that extends through theengagement hub110; and b) anoscillation shaft130, also shown in FIG. 11, and which is the inner most section and extends through theworm115.
• Turning first to the[0060]engagement hub110, shown in FIG. 8, it is an outer most section that preferably extends downwardly from thegear box81 and is structured to be matingly, and preferably threadingly engaged within the threadedaperture58 formed in themain housing51. As such, theengagement hub110 functions to secure the drive means80 to the cuttinghead assembly50. Further, it will be recognized that the drive means80 are thereby permitted to enter the cuttinghead assembly50 through atop surface56′ and are thus, generally vertically disposed. It is believed that this feature results in less interference with the surgical field and facilitates finer handling by the surgeon than is offered by conventionally known microkeratomes. Specifically, known microkeratomes have typically provided for horizontally disposed drive means, which resulted in the surgeon having to handle a cord of the driving means, which if not held properly could cause drag on the operation of the microkeratome and/or result in a different pressure being applied to the microkeratome. Moreover, the structure of the present invention maintains its center of gravity substantially over the center of the eye, unlike old systems, thereby providing increased balance and ensuring that the cutting head assembly does not inadvertently tip away from the surface of the eye during use.
• As illustrated in FIG. 8, the oscillation shaft also extends from the[0061]gear box81. Turning now to FIG. 11, theoscillation shaft130, which extends into thehousing51 through itsaperture58, is preferably an independent element that extends concentrically through and protrudes from both ends of theworm115. Theoscillation shaft130, which is preferably structured to freely rotate relative to theworm115 includes anupper drive portion132 which may be welded ontoshaft130 but which is in any event, drivingly engaged with amain drive gear102 secured to the motormain drive shaft101. Accordingly, rotation of the motormain drive shaft101 results in corresponding rotation of theoscillation shaft130. Further, protruding off center from anopposite end134 of theoscillation shaft130 is anoscillation pin135. Theoscillation pin135, which is preferably downwardly biased to maintain engagement pressure on the cuttingelement70 is structured to extend into aslot72′ formed in an upper surface of theblade holder72. As such, upon axial rotation of theoscillation shaft130, theoscillation pin135 rotates a predetermined radius off center and alternatingly engages opposite side edges of theslot72′ of theblade holder72 to result in alternating, oscillating movement of theblade holder72 and the cuttingelement70 held thereby.
• The[0062]oscillating shaft130 further includes asecondary drive portion133. Thesecondary drive portion133 is drivingly connected with a firstinterior drive gear103 contained within thegear box81. The firstinterior drive gear103 is connected with and drivingly secured to aninterior drive shaft104, which preferably includes a secondinterior drive gear105 disposed thereon in spaced apart relation from the firstinterior drive gear103. As such, upon rotation of theoscillation shaft130, the secondinterior drive gear105 also rotates.
• Drivingly connected with the second[0063]interior drive gear105 and structured to extend from an interior of thegear box81, concentrically through theengagement hub110, is the threaded drive screw or “worm”115. Theworm115, which extends up into thegear box81 includes adrive head116 which engages the secondinterior drive gear105. As a result, upon rotation of theinterior drive shaft104, theworm115 correspondingly rotates within thehousing51 of the cuttinghead assembly50. Further, rotatably disposed within thehousing51, in operative engagement with theworm115, is aworm gear120. Theworm gear120 preferably includes an increase diametercentral portion122 having a plurality of drive recesses formed about a perimeter thereof and structured to engage the exterior threaded surface of theworm115 such that thecentral portion122, and accordingly theentire worm gear120, rotates about a horizontal axis as a result of the rotation of theworm115 about a vertical axis. It is noted that the screw-like threaded surface of theworm115 enables theworm115 to rotate without moving vertically and successively engage the drive recesses on theworm gear120 to effect rotation thereof. Extending from at least one, but preferably both vertical faces of thecentral portion122 of theworm gear120 is apropulsion shaft125. Thepropulsion shaft125, which comprises additional tracking means, is structured to protrude from thesidewall structure53 of themain housing51 and engage thetoothed track43 on thepositioning ring32 such that upon rotation of theworm gear120, and accordingly rotation of thepropulsion shaft125, thepropulsion shaft125 rides along thetoothed track43 and drives the cuttinghead assembly50 across thepositioning ring32 smoothly and at a steady and defined pace. Furthermore, it is seen that by reversing the rotational direction of theinterior drive shaft101 within thegear box81, the direction of rotation of theworm115 and therefore theworm gear120 are reversed to effectuate reverse driven movement of the cuttinghead assembly50 over the positioninghead32. Also, so as to facilitate movement overtoothed track43 and the arcuate path thereof, it is preferred that thepropulsion shaft125 portion of theworm gear120 include a helical gear configuration or plurality of angled ridges to permit more effective alignment with thecurved toothed track43 and movement thereover.
• Referring once again to the[0064]motor100, it is preferred that it be controlled by a foot pedal or like actuation means. In the case of a foot pedal, it is preferred that it be a dual function foot pedal such that one side will function to drive the motormain drive gear101, and therefore the cuttinghead assembly50 in a forward direction, and the second side will drive them in a reverse direction. Further, the system may be set to a manual mode whereby a doctor must affirmatively reverse the direction of movement, or an “auto-reverse” mode wherein upon the cuttinghead assembly50 traveling its maximum distance it automatically reverses direction. In either case, however, themotor100 will preferably be equipped with a sensor to detect an abrupt current increase. Specifically, when the cuttinghead assembly50 reaches the stop means65 and further forward movement is either partially or completely resisted, an abrupt current increase will occur in themotor100. That abrupt current increase, once detected, can signal either the power to shut off, or the reverse movement to commence, depending upon a doctor's desired setting.
• Finally, it will be appreciated that the present invention can be utilized on both eyes of the patient. Specifically, as[0065]worm gear120 runs throughhousing51 and juts out of the opposite surroundingsidewall structure53 ofhousing51, the cutting head assembly is ready to use on the opposite eye of a patient. In order to accomplish this, and due to the symmetric shape of the cuttinghead assembly50, the drive means80 need only be removed from thehousing51 and thus,coupling member90, whereupon, it can be re-oriented 180 degrees for use with the opposite eye of a patient.
• Since many modifications, variations and changes in detail can be made to the described preferred embodiment of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.[0066]
• Now that the invention has been described,[0067]

Claims (34)

What is claimed is:

1. A method for cutting a cornea portion of an eye comprising the steps of:

temporarily maintaining the eye in an immobile, cornea exposed orientation, and

driving a cutting element across the cornea along an arcuate path from a lower region of the cornea to an upper region of the cornea so as to at least partially cut the cornea and such that normal, post-operative blinking of the eye results to substantially advance healing of the eye.

2. A method for cutting a cornea portion of an eye as recited inclaim 1 further including a step of defining said arcuate path along the cornea prior to driving said cutting element therealong.

3. A method for cutting a cornea portion of an eye comprising the steps of:

temporarily maintaining the eye in an immobile, cornea exposed orientation, and

driving a cutting element across the cornea so as to at least partially cut the cornea and so as to define a generally horizontally disposed corneal flap at an upper region of said cornea.

4. A method for cutting a cornea portion of an eye as recited inclaim 3 further including a step of defining an arcuate path along the cornea and driving said cutting element along said arcuate path.

5. A method for cutting a cornea portion of each of a patient's eyes comprising the steps of:

temporarily and selectively maintaining each of the patient's eyes in an immobile, cornea exposed orientation, and

driving a cutting element across the cornea of each eye so as to at least partially cut the cornea of each eye and so as to define a corneal flap remaining attached at a hinge on an upper region of said cornea of each eye, with said hinge being disposed in generally transverse relation to a direction of normal, post-operative blinking of each of the eyes.

6. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut; said positioning ring defining an aperture;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) a cutting head assembly including a cutting element for cutting the cornea; and

d) said cutting head assembly structured to move over said positioning ring along said generally arcuate path defined by said guide assembly.

7. A surgical device as recited inclaim 6 wherein said cutting path defined by said guide assembly terminates at an upper portion of the cornea of both the patient's left and right eye.

8. A surgical device as recited inclaim 6 wherein said cutting head assembly is structured for automated movement over said positioning ring.

9. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut; said positioning ring defining an aperture;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) said guide assembly including at least a post member structured to define an axis of rotation for said generally arcuate path;

d) a cutting head assembly including a cutting element for cutting the cornea; and

e) said cutting head assembly structured to be at least temporarily operatively coupled to said post member and to move over said positioning ring along said generally arcuate path.

10. A surgical device as recited inclaim 9 further including a coupling member structured and disposed to detachably couple said cutting head assembly to at least said post member and to permit movement of said cutting head assembly relative to said positioning ring along said generally arcuate path.

11. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut; said positioning ring defining an aperture;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) said guide assembly including at least a post member disposed on said positioning ring and structured to define an axis of rotation for said generally arcuate path;

d) a cutting head assembly including a cutting element for cutting the cornea; and

e) said cutting head assembly at least temporarily operatively coupled to said post member and structured to move over said positioning ring along said generally arcuate path.

12. A surgical device as recited inclaim 11 wherein said post member is disposed over the patient's eye on said positioning ring.

13. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a positioning assembly structured to position the cornea of the eye in an exposed, cuttable orientation; and

a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly structured to move over the cornea along a cutting path which terminates in generally aligned relation with a direction of normal postoperative blinking of the eye.

14. A surgical device as recited inclaim 13 wherein said cutting path which terminates in generally aligned relation with the direction of normal post-operative blinking of the eye is defined by a generally arcuate path.

15. A surgical device as recited inclaim 13 wherein said cutting path terminates at an upper portion of the cornea of both the patient's left and right eye.

16. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a positioning assembly structured to position the cornea of the eye in an exposed, cuttable orientation; and

a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly structured to move over and cut the cornea and to define a corneal flap secured at generally an upper region of the eye.

17. A surgical device for selectively cutting across a cornea of each of the eyes of a patient, said device comprising:

a positioning assembly structured to selectively and at least temporarily position the cornea of each of the eyes in an exposed, cuttable orientation;

a cutting head assembly including a cutting element for cutting the cornea; and

said cutting head assembly and said positioning ring being cooperatively structured with one another so as to selectively move said cutting head assembly over the cornea of each of the eyes along a cutting path which terminates in generally aligned relation with a direction of normal post-operative blinking of each of the eyes.

18. A surgical device as recited inclaim 17 wherein said cutting path which terminates in generally aligned relation with the direction of normal post-operative blinking of the eye is defined by a generally arcuate path.

19. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut; said positioning ring defining an aperture;

b) said positioning ring including a guide assembly defining a cutting path which terminates in generally aligned relation to a direction of normal post-operative blinking of the eye;

c) a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly being structured and disposed to be driven across said positioning ring along said cutting path defined by said guide assembly; and

d) a drive assembly operably connected to said cutting head assembly for causing movement of said cutting head assembly across said positioning ring and for causing oscillating movement of said cutting element.

20. A surgical device for selectively cutting across a cornea of each eye of a patient, said device comprising:

a) a positioning ring having means for selectively and at least temporary attachment to a portion of the eye surrounding the cornea to be cut; said positioning ring defining an aperture;

b) said positioning ring including a guide assembly defining a cutting path which terminates in generally aligned relation to a direction of normal post-operative blinking of the eye;

c) said guide assembly including at least a post member structured to define an axis of said cutting path; and

d) a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly being operatively coupled to said post member and structured and disposed to be selectively driven across said positioning ring along said cutting path which terminates generally in aligned relation with said direction of normal post-operative blinking of each of the eyes.

21. A surgical device as recited inclaim 20 wherein said guide assembly further comprises a guide track.

22. A method for cutting a cornea portion of a either eye comprising the steps of:

selecting an eye whose cornea is to be cut,

identifying whether the selected eye is a left eye or a right eye;

temporarily maintaining the selected eye in an immobile, cornea exposed orientation,

positioning a cutting element on the selected eye in accordance with whether the selected eye is a left or right eye,

driving a cutting element forward across the cornea along an arcuate path which, at least partially as a result of the positioning of the cutting element, is from a lower region of the cornea to an upper region of the cornea and at least partially cuts the cornea to define a generally horizontally disposed corneal flap at an upper region of said cornea.

23. A method for cutting a cornea portion of an eye comprising the steps of:

temporarily maintaining the eye in an immobile, cornea exposed orientation,

moving a cutting element across the cornea from a lower region of the cornea towards an upper region of the cornea,

cutting the cornea with the cutting element at least during a portion of its movement so as to define a corneal flap,

stopping the cutting element in the upper region of the cornea prior to complete severing of the corneal flap, and

removing the cutting element from engaging relation with the cornea while the corneal flap remains connected to the cornea at a generally horizontal segment in the upper region of the cornea.

24. A method for cutting a cornea portion of an eye comprising the steps of:

temporarily maintaining the eye in an immobile, cornea exposed orientation utilizing a positioning ring,

driving a cutting element over the positioning ring across the cornea so as to at least partially cut the cornea and so as to define a generally horizontally disposed corneal flap at an upper region of said cornea, and

removing the cutting element from a cornea engaging relation with the positioning ring.

25. A method for cutting a cornea portion of an eye comprising the steps of:

positioning a cutting element on a positioning ring structured to at least temporarily maintain the eye in an immobile, cornea exposed orientation,

driving a cutting element over the positioning ring so as to at least partially cut the cornea and so as to define a generally horizontally disposed corneal flap at an upper region of said cornea, and

removing the cutting element from the positioning ring.

26. The method ofclaim 25 wherein removing the cutting element from the positioning ring further comprises removing the cutting element from the positioning ring while maintaining the positioning ring in engaging relation with the eye.

27. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) a cutting head assembly including a cutting element for cutting the cornea; and

d) said cutting head assembly and said positioning ring being structured to operably associated with one another such that said cutting head assembly moves over said positioning ring along said generally arcuate path defined by said guide assembly from generally a lower region of the cornea to an upper region of the cornea of either a left eye or right eye.

28. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut as a result of a vacuum;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) a cutting head assembly including a cutting element for cutting the cornea;

d) said cutting head assembly structured to move over said positioning ring along said generally arcuate path defined by said guide assembly; and

e) said cutting head assembly structured to be removed from said positioning ring without interrupting said vacuum.

29. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) said guide assembly including at least a post member structured to define an axis of rotation for said generally arcuate path;

d) a cutting head assembly including a cutting element for cutting the cornea;

e) said cutting head assembly structured to be selectively coupled to said post member in an orientation corresponding a left eye or a right eye, and to move over said positioning ring along said generally arcuate path.

30. A surgical device for cutting across a cornea of an eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut by a vacuum;

b) said positioning ring including a guide assembly defining a generally arcuate path;

c) said guide assembly including at least a post member structured to define an axis of rotation for said generally arcuate path;

d) a cutting head assembly including a cutting element for cutting the cornea; and

e) said cutting head assembly structured to be removably coupled to said post member without interruption of said vacuum at said positioning ring and to move over said positioning ring along said generally arcuate path.

31. A surgical device for cutting across a cornea of either eye of a patient, said device comprising:

a positioning assembly structured to position the cornea of either eye in an exposed, cuttable orientation; and

a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly structured to move over the positioning assembly and cut the cornea of the selected eye to define a corneal flap secured at generally an upper region of the eye in generally aligned relation with a direction of normal post-operative blinking of the selected eye.

32. A surgical device for cutting across a cornea of either eye of a patient, said device comprising:

a) a positioning ring structured to be at least temporarily attached to a portion of the eye surrounding the cornea to be cut;

b) said positioning ring including a guide assembly, said guide assembly structured to define a cutting path which terminates at an upper portion of the cornea in generally aligned relation to a direction of normal post-operative blinking of either of the eyes on which said positioning ring is disposed;

c) a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly being structured to be driven across said positioning ring along said cutting path defined by said guide assembly towards said upper portion of the cornea of the eye on which said positioning ring is disposed; and

d) a drive assembly operably connected to said cutting head assembly for causing movement of said cutting head assembly across said positioning ring and for causing oscillating movement of said cutting element.

33. A surgical device for selectively cutting across a cornea of each eye of a patient, said device comprising:

a) a positioning ring structured to be selectively and at least temporary attached to a portion of the eye surrounding the cornea to be cut by a vacuum;

b) said positioning ring including a vacuum port through which said vacuum is applied;

c) said positioning ring further including a guide assembly defining a cutting path which terminates in generally aligned relation to a direction of normal post-operative blinking of the eye;

d) said guide assembly including at least a post member independent from said vacuum port and structured to define an axis of said cutting path; and

e) a cutting head assembly including a cutting element for cutting the cornea, said cutting head assembly being operatively coupled to said post member and structured and disposed to be selectively driven across said positioning ring along said cutting path which terminates generally in aligned relation with said direction of normal post-operative blinking of each of the eyes.

34. The surgical device ofclaim 33 wherein said cutting head assembly is removably coupled to said post member.

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