Patent Description:
<FIG> is an image that illustrates an example of a perspective view of a conventional ophthalmic operating microscope system with a wide-angle viewing attachment that includes a non-sterile inverter <NUM> and imaging lens housing <NUM> removably attached to the non-sterile inverter <NUM>, in addition to their associated fixturing. A conventional ophthalmic operating microscope is used by surgeons and assistants for improved visualization during many surgical procedures involving the eye and orbital structures. The conventional opthalmic opreating microscope is typically a stereoscopic microscope with a working distance in a range from about <NUM> to about <NUM>, and a magnification range from about 5x to about 25x. In specific procedures involving the retina, ocular fundus, and areas of the vitreos humor, an additional set of optics is generally used to view these structures through the limited aperture of the pupil. The optic that makes it possible to view the posterior structures through the pupil is a wide-angle lens which must be positioned very close to the eye and is characterized by having a very high diopter. When the additional optics are supported by and attached to the microscope it can be referred to as a wide-angle viewing attachment. The combination of the viewing attachment and the operating microscope together can be referred to as a conventional posterior ophthalmic operating microscope system. One example of such a conventional posterior ophthalmic operating microscope system <NUM> is the Haag-Streit Erect Indirect Binocular Ophthalmic System (EIBOS®) (originally developed by Moeller-Wedel, a division of the Haag-Streit Group). The imaging lens housing <NUM> (with lens) is positioned proximal to the eye of the surgical patient and creates an inverted virtual image of the fundus. The non-sterile inverter <NUM>, typically consisting of a series of prisms, mirrors and lenses, is used to reinvert the image to an orientation representative of the surgical field, which is viewed through the oculars <NUM>. This non-sterile inverter <NUM> may be positioned between the microscope <NUM> body and the oculars <NUM>, or in the case of the system <NUM> (<FIG>) is integrated into the viewing attachment between the imaging lens housing <NUM> and the microscope objective <NUM>. <CIT> discloses a sterilizable drape apparatus for enclosing an ophthalmoscopic lens housing projecting form a surgical microscope.

Due to the delicate opto-mechanical construction of the conventional microscope system <NUM>, the non-sterile inverter <NUM> cannot be sterilized in a practical manner (e.g. with steam autoclave). Thus, conventional sterile covers have been developed (e.g. silicone cover <NUM> in <FIG>) to separate the sterile surgical field from the non-sterile inverter <NUM> and microscope system <NUM>. <FIG> depicts the non-sterile inverter <NUM> secured within the silicone cover <NUM> and with the imaging lens housing <NUM> secured outside the silicone cover <NUM>. After performing surgery using the conventional microscope system <NUM>, the inventors of the present invention recognized that the system <NUM> requires disassembly prior to sterilization. Such disassembly involves several steps including removal of knobs <NUM>, detaching the imaging lens housing <NUM> from the non-sterile inverter <NUM>, removing the non-sterile inverter <NUM> from the silicone cover <NUM> and subsequently sterilizing (e.g. steam autoclave) the knob <NUM>, imaging lens housing <NUM> and silicone cover <NUM> before reassembling the system <NUM>. Additionally, although some conventional systems offer a disposable imaging lens and housing <NUM>, the inventors noticed that sterilization would still require disassembling and sterilization of the knobs <NUM> and silicone cover <NUM> before reassembling the microscope system. The inventors of the present invention realized that these conventional systems involve reprocessing time that is costly, the component of the systems are susceptible to degradation such as coating failure and mineral deposits on the optical surface, while the silicone cover <NUM> can wear out due to repeated use and high/low temperature cycles.

In order to overcome the above noted drawbacks of conventional microscope systems and conventional silicone covers, the inventors of the present invention developed the sterile cover discussed herein. The invention is defined by claims <NUM>, <NUM> and <NUM>. In one embodiment, the inventors of the present invention recognized that a disposable sterile cover could be designed which integrated the imaging lens housing, so that the non-sterile inverter <NUM> and a disposable imaging lens could be secured within the disposable sterile cover. In an embodiment, the disposable imaging lens is sterile. After performing eye surgery, the sterile cover, knobs and imaging lens could then be conveniently disposed and no disassembly and sterilization of the microscope system components would be required. Instead, the sterile cover and imaging lens would just need to be replaced with another sterile cover and imaging lens. The inventors of the present invention even developed a design feature to ensure that each sterile cover is used only once, to prevent reuse. The inventors of the present invention also recognized that the sterile cover could include integrated knobs so that separate knobs would not need to be detached and sterilized.

In a first embodiment, an apparatus is provided including a sterile cover. The sterile cover includes a first portion that defines a first cavity such that the first portion is configured to secure a non-sterile inverter of a microscope within the first cavity. The sterile cover also includes a second portion integral with the first portion. The second portion defines a second cavity continuous with the first cavity. The second portion is configured to secure an imaging lens of the microscope within the second cavity.

In a second embodiment, a method is provided for using the microscope including an apparatus. The method includes securing a first sterile cover of the apparatus over the non-sterile inverter of the microscope such that the non-sterile inverter is secured in a first portion of the first sterile cover and the imaging lens is in a second portion of the first sterile cover. The non-sterile inverter and imaging lens are aligned along an optical axis. The method further includes performing eye surgery using the non-sterile inverter and the imaging lens within the first sterile cover. The method further includes removing and/or destruction (for prevention of reuse) of the first sterile cover from the non-sterile inverter of the microscope. The method further includes disposing the first sterile cover and the imaging lens secured in the second portion of the first sterile cover. The method further includes securing a second sterile cover over the non-sterile inverter of the microscope such that the non-sterile inverter is secured in the first portion of the second sterile cover and the imaging lens is secured in the second portion of the second sterile cover such that the non-sterile inverter and imaging lens are aligned along an optical axis.

In a third embodiment, a molding or casting method is provided for forming an apparatus. The method includes providing a mold with a cavity defined by the sterile cover of the apparatus. The method further includes providing a liquid material into the mold. The method further includes curing the liquid material into a solid material. The method further includes removing the solid material defining the sterile cover from the mold.

Still other aspects, features, and advantages are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the invention. Other embodiments are also capable of other and different features and advantages, and its several details can be modified in various obvious respects, all without departing from the scope of the invention, as defined by the claims. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which:.

A method and apparatus are described for providing a sterile cover for a non-contact fundus viewing device. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope are approximations, the numerical values set forth in specific non-limiting examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements at the time of this writing. Furthermore, unless otherwise clear from the context, a numerical value presented herein has an implied precision given by the least significant digit. Thus, a value <NUM> implies a value from <NUM> to <NUM>. The term "about" is used to indicate a broader range centered on the given value, and unless otherwise clear from the context implies a broader range around the least significant digit, such as "about <NUM>" implies a range from <NUM> to <NUM>. If the least significant digit is unclear, then the term "about" implies a factor of two, e.g., "about X" implies a value in the range from <NUM>. 5X to 2X, for example, about <NUM> implies a value in a range from <NUM> to <NUM>. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of "less than <NUM>" for a positive only parameter can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of <NUM>, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than <NUM>, e.g., <NUM> to <NUM>.

Some embodiments of the invention are described below in the context of sterile covers for viewing devices, specifically microscopes. However, the invention is not limited to this context. In other embodiments, the invention can be employed in the context of handheld sterile observation instruments/tools, e.g. a cover for a microscope or any other attachments for the microscope.

For purposes of this description, the term "cover" means an element or component that is used to provide a sterile barrier between a sterile surgical field being viewed by a viewing device and one or more non-sterile components of the viewing device (e.g. non-sterile inverter <NUM>).

<FIG> are schematic diagrams that illustrate example views of an apparatus <NUM> including a sterile cover <NUM>, according to an embodiment. In an embodiment, the sterile cover <NUM> includes a first portion <NUM> that is configured to secure the non-sterile inverter <NUM> within a first cavity <NUM> defined by the first portion <NUM>. Additionally, in an embodiment, the sterile cover <NUM> includes a second portion <NUM> that is configured to secure an imaging lens <NUM> of the microscope within a second cavity <NUM> defined by the second portion <NUM>. In an embodiment, the first cavity <NUM> is continuous with the second cavity <NUM>. For purposes of this description, "continuous" means that the first cavity <NUM> and the second cavity <NUM> form one collective cavity of the sterile cover <NUM> and/or there is no boundary between the first cavity <NUM> and the second cavity <NUM>. In an example embodiment, the first cavity <NUM> has a larger volume than the second cavity <NUM>. In still other embodiments, the first portion <NUM> and first cavity <NUM> take a rectangular and/or an elongated oval shape whereas the second portion <NUM> and second cavity <NUM> take a cylindrical and/or conical section shape. In an example embodiment, the first cavity <NUM> has a height of about <NUM> millimeters (mm) or in a range from about <NUM> to about <NUM> (e.g. where the height is measured along the Z axis depicted in <FIG>). In another example embodiment, the first cavity <NUM> has a width of about <NUM> or in a range from about <NUM> to about <NUM> (e.g. where the width is measured along the X axis depicted in <FIG>). In another example embodiment, the first cavity <NUM> has a depth of about <NUM> or in a range from about <NUM> to about <NUM> (e.g. where the depth is measured along the Y axis depicted in <FIG>). In another example embodiment, the second cavity <NUM> has a height of about <NUM> or in a range from about <NUM> to about <NUM>, a width of about <NUM> or in a range from about <NUM> to about <NUM> and a depth of about <NUM> or in a range from about <NUM> to about <NUM>. In one example embodiment, the second cavity <NUM> is a cylindrical cavity or a conical section cavity. In an example embodiment, the height, width and/or depth of the second cavity <NUM> are measured along similar X, Y, Z axes (<FIG>) as the first cavity <NUM>.

In an embodiment, the sterile cover <NUM> is made from a semi-rigid material. For purposes of this description, "semi-rigid material" means a material with a value of a parameter within one or more ranges. In one embodiment, the parameter is flexural modulus and the value of the parameter is greater than <NUM> Megapascal (MPa) and/or in a range between about <NUM> MPa and about <NUM> Mpa and/or in a range between about <NUM> MPa and about <NUM> MPa. In yet another embodiment, the parameter is flexural strength and the value of the parameter is about <NUM> MPa and/or in a range from about <NUM> MPa to about <NUM> MPa. In another embodiment, the sterile cover <NUM> is made from a semi-rigid molded plastic material. In still another embodiment, the sterile cover <NUM> is made from a disposable material and/or a sterilizable material. For purposes of this description, "sterilizable material" is a material which maintains its functional properties (e.g. semi-rigid material properties, tear strip properties, etc.) after sterilizing said material. In yet another embodiment, the lens <NUM> is also made from the sterilizable material. In an example embodiment, the material used to form the sterile cover <NUM> and/or the lens <NUM> and/or the semi-rigid material and/or the sterilizable material includes one or more of Polypropylene (PP), High-density polyethylene (HDPE), Low-density polyethylene (LDPE), Polyethylene (PE), Polyethylene terephthalate (PET), medical-grade Silicone/Rubbers, sterilizable material, recyclable material, non-allergenic material and/or bio-compatible material.

<FIG> is a schematic diagram that illustrates an example of a side view of the non-sterile inverter <NUM> of <FIG> and the sterile cover <NUM> of <FIG>, according to an embodiment. <FIG> is a schematic diagram that illustrates an example of a side view of the non-sterile inverter <NUM> secured within the sterile cover <NUM> of <FIG>, according to an embodiment. To position the non-sterile inverter <NUM> into the sterile cover <NUM>, a base of the non-sterile inverter <NUM> is slid into an opening at a top of the sterile cover <NUM> and pushed until a lower aperture <NUM> (<FIG>) of the non-sterile inverter <NUM> engages a tapered lip <NUM> adjacent a base of the first portion <NUM> of the sterile cover <NUM>. As also depicted in <FIG>, in an embodiment, the sterile cover <NUM> defines one or more openings <NUM> to receive knobs <NUM> of the non-sterile inverter <NUM>. However, in other embodiments, one or more knobs are positioned at the location of the openings <NUM> and are integral and/or made from the same material as the sterile cover <NUM>. In an example embodiment, as depicted in <FIG>, a modified knob <NUM> is provided that features a snap feature to receive the knob <NUM> in the opening <NUM> of the cover <NUM>. In another example embodiment, the modified knob <NUM> is threadably received in the opening <NUM> of the cover <NUM> (e.g. external threads on the knob <NUM> engage internal threads in the opening <NUM>). In this embodiment, once received, the modified one or more knobs <NUM> become permanently retained within the sterile cover <NUM> for purpose of adjusting the inverter <NUM>. This advantageously allows the user to dispose of the sterile cover <NUM> and the modified one or more knobs <NUM> as one piece and/or advantageously discourages the reuse/sterilization of the knobs <NUM>.

<FIG> are images that illustrate example cross-sectional views of the non-sterile inverter <NUM> secured within the sterile cover <NUM> of <FIG>, according to an embodiment. In an embodiment, <FIG> depicts that the first portion <NUM> of the sterile cover <NUM> includes a structural feature, such as a snap clip <NUM> configured to engage the non-sterile inverter <NUM> to secure the non-sterile inverter <NUM> along a first axis <NUM> (Z axis) defined by an optical axis <NUM> (<FIG>) of the non-sterile inverter <NUM> and imaging lens <NUM>. The optical axis <NUM> is defined in the frame of reference of the sterile cover <NUM>. As previously discussed, the non-sterile inverter <NUM> is positioned within the sterile cover <NUM> by inserting the base of the non-sterile inverter <NUM> through an opening in a top of the sterile cover <NUM>. As the top of the non-sterile inverter <NUM> passes the top of the sterile cover <NUM>, the snap clip <NUM> deflects outward and then inward to secure over the top of the non-sterile inverter <NUM>. This advantageously secures the non-sterile inverter <NUM> within the first cavity <NUM> and specifically prevents movement of the non-sterile inverter <NUM> along the first axis <NUM>.

In some embodiments a plurality of snap clips <NUM> are provided (e.g. spaced apart) along a perimeter of the top of the sterile cover (e.g. as shown in <FIG>). In other embodiments, structures other than a snap clip can be used at the top of the sterile cover <NUM> to secure the non-sterile inverter <NUM> along the first axis <NUM>. <FIG> depict other embodiments of securement structures <NUM>', <NUM>", <NUM>"' that can be employed instead of the snap clip <NUM>, in order to secure the non-sterile inverter <NUM> in the sterile cover <NUM> along the first axis <NUM>. In some embodiments, the securement structures <NUM>', <NUM>", <NUM>‴ can be of any length, number and/or can be contiguous around the entire perimeter of the sterile cover <NUM>. In an example embodiment, any one of the securement structures depicted in any of <FIG> can be used around the perimeter (e.g. spaced apart) of the sterile cover <NUM>. In one example embodiment, a combination of different securement structures depicted in any of <FIG> can be used around the perimeter. The inventors recognized that one advantage including a combination of different securement structures is that it is easier to implement in a molded part in regards to the parting line of the mold.

In another embodiment, as shown in <FIG> the first portion <NUM> of the sterile cover <NUM> includes a lip <NUM> configured to engage a lower aperture <NUM> of the non-sterile inverter <NUM>. In one embodiment, the lip <NUM> engages the lower aperture <NUM> to secure the non-sterile inverter <NUM> along a second axis <NUM> (Y axis) and a third axis <NUM> (X axis) which are both orthogonal to the first axis <NUM> oriented in a direction from the first portion <NUM> to the second portion <NUM>. In an example embodiment, the lip <NUM> and the lower aperture <NUM> are circular and/or oval shaped where an inner diameter of the lower aperture <NUM> is greater than an outer diameter of the tapered lip <NUM>. In an example embodiment, the inner diameter of the lower aperture <NUM> is about <NUM> or in a range from about <NUM> to about <NUM> and the outer diameter of the tapered lip <NUM> is about <NUM> or in a range from about <NUM> to about <NUM>. In some embodiments, the values of the inner diameter of the lower aperture <NUM> and/or the outer diameter of the tapered lip <NUM> can differ based on the viewing device (e.g. Haag-Streit has released a few versions of the EIBOS® inverter). In one example embodiment, the values of the inner diameter of the lower aperture <NUM> and the outer diameter of the tapered lip <NUM> are based on the EIBOS® <NUM> inverter and/or any future releases from Haag-Streit. In one embodiment, the lip <NUM> is a tapered lip, e.g. a taper which was designed such that the top of the lip <NUM> has sufficient clearance between the outer diameter of the tapered lip <NUM> and the inner diameter of the lower aperture <NUM>. In an example embodiment, as the non-sterile inverter <NUM> gets lowered into the sterile cover <NUM>, this clearance as a result of the taper restricts the movement to a maximum (e.g. about <NUM>) in each direction (e.g. <NUM> outer diameter of the lip <NUM> and <NUM> inner diameter of the lower aperture <NUM>). In another embodiment, an outward taper <NUM> is defined in the second portion <NUM> of the sterile cover <NUM> for moldability. In still other embodiments, the lip <NUM> is non-tapered.

In another embodiment, as depicted in <FIG>, the second portion <NUM> of the sterile cover <NUM> includes an interference fit <NUM> configured to engage the imaging lens <NUM> to secure the imaging lens <NUM> along the first axis <NUM>, the second axis <NUM> and the third axis <NUM>. In an example embodiment, the imaging lens <NUM> is one or more of a wide angle imaging lens used for a microscope, such as an ophthalmic operating microscope. In an example embodiment, the imaging lens <NUM> is a single lens, or system of multiple lenses. In an example embodiment, the imaging lens <NUM> has a combined diopter number of about <NUM> to <NUM> diopters designed to image the retina onto a virtual image plane situated above the upper apex of the imaging lens. In an example embodiment, the imaging lens <NUM> is a single biconvex lens with aspheric surfaces, injection molded out of Polymethyl methacrylate (PMMA). In still other example embodiments, the imaging lens <NUM> is made from other lens materials such as optically clear plastics or ceramics. In an example embodiment, the plastics might include one or more of Polycarbonate, Polystyrene, or co-polymers, while ceramics might include one or more of glass, silica, or quartz. In still other example embodiments, the imaging lens <NUM> is formed using one or more manufactuing methods such asComputer Numerical Control (CNC) machining (single point diamond turning), pressing, grinding, 3D printing and other additive manufacturing techniques In an example embodiment, the interference fit <NUM> is achieved based on the lens <NUM> having an outer diameter of about <NUM> or in a range from about <NUM> to about <NUM> and secured along the outward taper <NUM> where the inner diameter of the sterile cover <NUM> is about <NUM>-<NUM> smaller than the outer diameter of the lens <NUM>. In one embodiment, the interference fit <NUM> includes a groove at a specific location on the interior wall of the second portion <NUM> and the outer diameter of the lens is sized to fall into the groove. In one embodiment, the groove is located so that the lens is positioned a certain distance (e.g. about <NUM> or in a range from about <NUM> to about <NUM>) away from the lower face of the inverters lower aperature <NUM>. In yet another embodiment, the optimal position is the position to allow for the range of focusing necessary to view all sections of the ocular fundus (e.g. in a range from about <NUM> to about <NUM>, depending on the imaging lens <NUM>).

In another embodiment, as depicted in <FIG>, the first portion <NUM> of the sterile cover <NUM> includes a pair of ribs <NUM> spaced apart along the second axis <NUM> orthogonal to the first axis <NUM> and the ribs <NUM> placed parallel to the plane formed by the first axis <NUM> and second axis <NUM>. In an embodiment, the ribs <NUM> have a length that is extruded vertically along the first axis <NUM> and spaced on opposite sides of the non-sterile inverter <NUM>. In an embodiment, the pair of ribs <NUM> are configured to engage the non-sterile inverter <NUM> to secure the non-sterile inverter <NUM> within the first cavity <NUM> along the second axis <NUM>. In an example embodiment, a thickness of each rib <NUM> is sized to have a thickness along the second axis <NUM> so that an inner distance <NUM> (<FIG>) of the first portion <NUM> between pair of ribs <NUM> is based on an outer distance of the non-sterile inverter <NUM> along the second axis <NUM>. In an example embodiment, the thickness of each rib <NUM> is sized so that the inner distance <NUM> of the first portion <NUM> between the pair of ribs <NUM> is about equal (e.g. within ±<NUM>%) of the outer distance of the non-sterile inverter <NUM> along the second axis <NUM>. This arrangement can be contrasted with <FIG> where a sterile cover <NUM>' is shown without the ribs <NUM> and thus the non-sterile inverter <NUM> is free to shift along the second axis <NUM>. In some embodiments only one pair of ribs <NUM> are provided in the sterile cover <NUM>. In other embodiments, a plurality of pairs of ribs <NUM> are provided (e.g. spaced apart) along the sterile cover <NUM> (e.g. <FIG> showing spaced apart ribs <NUM> along the first portion <NUM>). In other embodiments, other structures other than ribs can be used in the first portion <NUM> to secure the non-sterile inverter <NUM> along the second axis <NUM>. In some embodiments, structures other than ribs <NUM> could be employed along the first portion <NUM> such as blisters/bumps, step feature, contiguous circumferential smooth lip, and/or secondary attachments (e.g. slide-in pieces, tape/rubber placed on interior wall).

The various structural features of the sterile cover <NUM> advantageously secure the non-sterile inverter <NUM> and imaging lens <NUM> in one or more directions (e.g. snap clip <NUM> secures the non-sterile inverter <NUM> along the first axis <NUM>; tapered lip <NUM> secures the non-sterile inverter <NUM> along the second axis <NUM> and third axis <NUM>; ribs <NUM> secure the non-sterile inverter <NUM> along the second axis <NUM> and interference fit <NUM> secures the lens <NUM> along the axes <NUM>, <NUM>, <NUM>). This advantageously ensures that concentricity (e.g. optical axis <NUM> in <FIG>) and correct focus position between the imaging lens <NUM> and non-sterile inverter <NUM> is achieved (e.g. the non-sterile inverter <NUM> and lens <NUM> are centered along the second axis <NUM> and third axis <NUM> and spaced apart along the axis <NUM> based on the focal length of the lens <NUM>). This is advantageously achieved upon securing the non-sterile inverter <NUM> within the sterile cover <NUM> and engaging the lower aperture <NUM> at the tapered lip <NUM>.

<FIG> are images that illustrate example cross-sectional views of the non-sterile inverter <NUM> secured within the sterile cover <NUM> along the line A-A in <FIG>, according to an embodiment. <FIG> is a schematic diagram that illustrates an example side view of a sterile cover <NUM>, according to an embodiment. In an embodiment, <FIG> depicts that the first portion <NUM> defines an inward taper <NUM> from an intermediate portion to the lip <NUM>. In an example embodiment, the inward taper <NUM> has a convergence angle of about <NUM> degrees (or in a range from about <NUM> degrees to about <NUM> degrees) and/or is defined based on an inner distance of the first cavity <NUM> being reduced from about <NUM> (or in a range from about <NUM> to about <NUM>) to about <NUM> (or in a range from about <NUM> to about <NUM>) adjacent to the lip <NUM>. In another embodiment, the first portion <NUM> of the sterile cover <NUM> defines a gap <NUM> by a termination of the rib <NUM> , where the gap <NUM> is a consequence of molding a part. In an example embodiment, the height at which the rib <NUM> ends is a design feature that defines the gap <NUM> and the mechanism to prevent reuse of the sterile cover <NUM> discussed below. The gap <NUM> is provided so that the thickness of the sterile cover <NUM> is smaller adjacent to the gap <NUM> than the thickness of the rib <NUM>. This advantageously facilitates the placement and use of the mechanism to prevent reuse of the sterile cover (e.g. permanently break the sterile cover <NUM> adjacent to the gap <NUM>, since it is easier to break the sterile cover <NUM> at the reduced thickness region adjacent to the gap <NUM>).

<FIG> are schematic diagrams that illustrate example views of a sterile cover <NUM> with a tab <NUM>, according to an embodiment and in accordance with the present claimed invention. In an embodiment, the tab <NUM> is provided along the first portion <NUM> of the sterile cover <NUM>. In one embodiment, the tab <NUM> is provided to disengage the first portion <NUM> from the non-sterile inverter <NUM> and/or prevent reuse of the sterile cover <NUM>. In one embodiment, the first portion <NUM> includes the snap feature <NUM> configured to engage the non-sterile inverter <NUM> to secure the non-sterile inverter <NUM> along the first axis <NUM>. In an embodiment, the tab <NUM> is provided to permanently disengage the snap feature <NUM> from the non-sterile inverter <NUM> to facilitate removal of the non-sterile inverter <NUM> from the sterile cover <NUM> along the first axis <NUM>. In an embodiment, the rib <NUM> is provided along a first segment <NUM> (<FIG>) of the first portion <NUM>. In an example embodiment, a first thickness of the first segment <NUM> (e.g. about <NUM> plus a thickness of the rib <NUM>) varies from a larger thickness (e.g. about <NUM>) adjacent a top of the rib <NUM> to a smaller thickness (e.g. about <NUM>) adjacent a bottom of the rib <NUM>. In one embodiment, the tapered first thickness of the first segment <NUM> is due to the tapered thickness of the rib <NUM> from a top of the rib <NUM> to a bottom of the rib <NUM>. In an embodiment, the tab <NUM> is provided along a second segment <NUM> (e.g. adjacent the gap <NUM> of <FIG>) of the first portion <NUM> of the sterile cover <NUM> with a second thickness (e.g. about <NUM>) that is less than the first thickness (e.g. about <NUM> plus the thickness of the rib <NUM>) of the first segment <NUM>.

In one example embodiment, the second thickness varies from a larger thickness (e.g. about <NUM>) to a smaller thickness (e.g. about <NUM>. <NUM>) adjacent a pre-scored line <NUM>. In yet another embodiment, the second segment <NUM> of the first portion <NUM> of the sterile cover <NUM> includes the pre-scored line <NUM> that projects into the first portion <NUM> parallel to a plane defined by the second axis <NUM> and third axis <NUM>. In an example embodiment, the pre-scored line <NUM> leaves a material thickness of about <NUM> or in a range from about <NUM> to about <NUM>. In an embodiment the pre-scored line <NUM> extends an entire length of the side of the sterile cover <NUM>. In still other embodiments, the pre-scored line <NUM> extends only a portion of the length of the side of the sterile cover <NUM> and/or around the entire sterile cover <NUM>. Additionally, in yet another embodiment, the second segment <NUM> of the first portion <NUM> includes a notch <NUM> oriented in a direction orthogonal to the pre-scored line <NUM> (e.g. third axis <NUM>). In an example embodiment, the notch <NUM> has a depth in a range from about <NUM> to about <NUM>. The pre-scored line <NUM> and/or notch <NUM> advantageously make it easier to sever and/or break the first portion <NUM> with the tab <NUM>. In some embodiments, the pre-scored line <NUM> can vary in depth and can include complete perforation in some areas and variable depth in other areas.

<FIG> are schematic diagrams that illustrate example views of sterile covers <NUM>', <NUM>", <NUM>'", <NUM>"" with a tab, according to various an embodiment. In an embodiment, the tabs of the sterile covers of <FIG> are variations on the tab <NUM> of <FIG>. In an embodiment, the tabs have one or more similar characteristics (e.g. define an opening that has sufficient dimensions for a user to insert their fingers/hand as shown in <FIG> and <FIG> or define a handle with sufficient dimensions for a user to grasp the handle with their fingers/hand as shown in <FIG>). In one embodiment, the tab <NUM>' of <FIG> does not feature an opening to grab the tab but rather features a pair of wings for the user to grab. In another embodiment, the tab <NUM>" of <FIG> is an extension of the first portion <NUM> of the sterile cover <NUM> and defines an opening which the user can grab. In yet another embodiment, the tab <NUM>‴ of <FIG> is similar to the tab <NUM>" but is angled relative to the first portion <NUM> of the sterile cover <NUM>. In yet another embodiment, the tab <NUM>"" of <FIG> is similar to the tab <NUM>" of <FIG> with the exception that an opening of the tab has a different shape than the tab <NUM>" (e.g. arcuate shape around the perimeter of the opening). In one example embodiment, in contrast with the opening defining the tab <NUM>" of <FIG> (e.g. circular or oval shape around the perimeter of the opening) the opening defining the tab <NUM>"" of <FIG> includes a first portion <NUM> that is flat and a second portion <NUM> that is arcuate. In another example embodiment, the opening defining the tab <NUM>"" is shaped to be easily grabbed by a hand of a user such that a base surface of the hand (e.g. palm) engages the flat portion of the opening and a top surface of the hand (e.g. adjacent the knuckles) faces the second arcuate portion. In an example embodiment the first portion <NUM> has a length of about <NUM> or in a range from about <NUM> to about <NUM> and the second portion <NUM> is separated from the first portion <NUM> by a distance <NUM> of about <NUM>. Although tabs are provided in each embodiment of <FIG>, any structure that can be used and physically actuated by a user to separate the snap feature <NUM> from the non-sterile inverter <NUM> and/or to prevent reuse of the sterile cover and/or the permanently break the sterile cover can be used in the present invention. In an example embodiment, other possibilities of a separation line include but are not limited to imbedded wire/string and a blade/zipper wedge.

<FIG> is a flowchart that illustrates an example of a method <NUM> for using the sterile cover <NUM> of <FIG> with a viewing device such as a microscope, according to an embodiment. In an embodiment, step <NUM> includes removing a preassembled first sterile cover <NUM> from a sterile packaging, where the preassembled first sterile cover <NUM> includes the imaging lens <NUM> pre-secured (e.g. before step <NUM>) within the second portion <NUM> of the sterile cover <NUM>. In one embodiment, in step <NUM> a first sterile cover <NUM> is secured over the non-sterile inverter <NUM> of the viewing device so that the non-sterile inverter <NUM> and imaging lens <NUM> (e.g. secured within the second portion <NUM> of the sterile cover <NUM> before step <NUM>) are secured or positioned within the first sterile cover <NUM>. In an embodiment, in step <NUM>, a base of the non-sterile inverter <NUM> is inserted within an opening at a top of the sterile cover <NUM>. Since the base of the non-sterile inverter <NUM> has a smaller dimension than an opening at the top of the sterile cover <NUM>, the base of the non-sterile inverter <NUM> can be inserted within the top of the sterile cover <NUM>. In this embodiment, in step <NUM>, the non-sterile inverter <NUM> is continuously moved into the first sterile cover <NUM> until the lower aperture <NUM> of the non-sterile inverter <NUM> engages the tapered lip <NUM> of the first sterile cover <NUM> (<FIG>) and/or the snap features <NUM> deflected outward then inward and engage the top of the non-sterile inverter <NUM> (<FIG>). In this embodiment, the first sterile cover <NUM> already includes the lens <NUM> secured within the second portion <NUM> with the interference fit <NUM>. After step <NUM> is performed, the non-sterile inverter <NUM> and lens <NUM> are concentrically positioned and in proper focal position with respect to each other.

In step <NUM>, a medical procedure is performed with the microscope (e.g. eye surgery is performed on a subject). In an embodiment, in step <NUM>, the sterile cover <NUM> and non-sterile inverter <NUM> are rotated from a first position (e.g. where the optical axis <NUM> is aligned with axis <NUM>) to a second position (e.g. where the optical axis <NUM> is aligned with the axis <NUM>). The microscope is then used to perform eye surgery on the patient. In one embodiment, during various stages of the eye surgery, the sterile cover <NUM> and non-sterile inverter <NUM> can be rotated from the first position to the second position, to provide free access to the eye for the surgeon and/or to image anterior anatomy of the eye.

In step <NUM>, the tab <NUM> is pulled along the first portion <NUM> of the sterile cover <NUM>. In one embodiment, in step <NUM>, the tab <NUM> is pulled to detach the first portion <NUM> and snap clip <NUM> from the non-sterile inverter <NUM> , to ease the removal of the non-sterile inverter <NUM> from the sterile cover <NUM>. In another embodiment, in step <NUM> the tab <NUM> is pulled to permanently break the first portion <NUM> (e.g. along the line <NUM>) to prevent reuse of the sterile cover <NUM>.

In step <NUM>, the first sterile cover <NUM> is removed from the non-sterile inverter <NUM>. In an embodiment, in step <NUM>, after performing step <NUM> the snap cover <NUM> has disengaged the top of the non-sterile inverter <NUM> and thus the first sterile cover <NUM> can be easily slid off the non-sterile inverter <NUM>. In step <NUM>, the first sterile cover <NUM> (and lens <NUM> within the second portion <NUM>) is disposed.

In an embodiment, after step <NUM> the method proceeds to block <NUM> where it is determined whether further medial procedures (e.g. surgery) need to be performed with the microscope. In one embodiment, in block <NUM> it is determined whether additional surgery needs to be performed (e.g. with additional patients). In still another embodiment, in block <NUM> it is determined whether a newly sterilized field is required. If the determination in block <NUM> is in the affirmative, the method proceeds to step <NUM>. If the determination in block <NUM> is in the negative, the method ends.

In one embodiment, in step <NUM> for a newly sterilized field (e.g. new patient requiring a newly sterilized field), a second sterile cover <NUM> is positioned over the non-sterile inverter <NUM> in a similar manner as the first sterile cover <NUM> was positioned over the non-sterile inverter <NUM> in step <NUM>. This advantageously involves only one step to prepare the microscope for the next eye surgery instead of the numerous sterilization and disassembly steps involved in the conventional microscope systems and covers. In an embodiment, the method then restarts with step <NUM> for each additional procedure where it is determined in block <NUM> that a newly sterilized field is required. If this determination in block <NUM> is affirmative, the method continues from step <NUM> back to steps <NUM>, <NUM>, <NUM>, <NUM> and block <NUM>, which are repeated with new sterile cover. If this determination in block <NUM> is negative, the method ends.

<FIG> is a flowchart that illustrates an example of a molding method <NUM> for forming the sterile cover <NUM> of <FIG>, according to an embodiment. In step <NUM>, a mold is provided with a cavity defined by the sterile cover <NUM>. In an embodiment, the mold includes core elements based on gaps in the sterile cover <NUM>, such as the gap <NUM> (<FIG>). In another embodiment, the cavity of the mold includes angles to form the sterile cover <NUM> including a draft angle <NUM> (<FIG>) which is used to define the width of the ribs <NUM>. In an example embodiment, the draft angle <NUM> is about <NUM> degrees or in a range from about <NUM> degrees to about <NUM> degrees.

In step <NUM>, a liquid material is provided into the mold. In an embodiment, the liquid material is a gamma stable, semi-rigid thermoplastic material. In an embodiment, in step <NUM>, the liquid material is cured into a solid material. In one embodiment, in step <NUM> the mold is closed which takes a certain time period (e.g. about <NUM>-<NUM> seconds). In another embodiment, in step <NUM> the liquid material is injected into the mold, over a certain time period (e.g. about <NUM>-<NUM> seconds). In an example embodiment, a mold temperature (e.g. for PP material) is in a range from about <NUM> degrees Fahrenheit (F) to about <NUM> degrees F. In another embodiment, a temperature of the liquid material (e.g. PP material) at injection is in a range from about <NUM> degrees F to about <NUM> degrees F. C = <NUM>/<NUM> × (F-<NUM>).

In step <NUM>, the cured material is removed from the mold and defines the sterile cover <NUM>. In an example embodiment, in step <NUM> various steps are performed over certain time periods such as pack and hold (e.g. about <NUM>-<NUM> seconds); part cooling (e.g. about <NUM>-<NUM> seconds); screw return (e.g. about <NUM>-<NUM> seconds); mold opening (e.g. about <NUM> second) and ejection (e.g. about <NUM> second). In still another embodiment, a step is also performed to assemble the cover and the lens (e.g. securing the lens within the sterile cover with the interference fit) and/or placing the assembled cover in a sterilized packaging. In an embodiment, the sterile cover <NUM> is then used such as in the method <NUM>. In another embodiment, multiple sterile covers are formed using the method <NUM> so that multiple sterile covers can be used during the method <NUM>.

Although <FIG> depicts a flowchart of one method (e.g. molding) for forming the sterile cover <NUM>, the embodiments of the present invention encompasses any method that can be used to form the sterile cover <NUM>. In one example embodiment, the embodiments of the present invention include a method for forming the sterile cover <NUM> using additive manufacturing techniques. In this example embodiment, the method includes generating a data file with information indicating the shape and/or contours of the sterile cover <NUM>. In this example embodiment, the data file is then used by the additive manufacturing machine to produce the sterile cover <NUM>. In an embodiment, a 3D-printer (e.g. stereolithography 3D printer) may be used to produce the sterile cover <NUM>, in stacked two-dimensional layers. In one example embodiment, the sterile cover <NUM> is produced in the stacked two-dimensional layers using an optical beam (e.g. laser, such as a CNC controlled ultraviolet laser) to cure a photopolymer resin into a solid plastic with one of more characteristics of the sterile cover <NUM> discussed herein (e.g. material properties, dimensions, etc.).

Claim 1:
An apparatus (<NUM>) comprising:
a sterile cover (<NUM>) including;
a first portion (<NUM>) that defines a first cavity (<NUM>) such that the first portion (<NUM>) is configured to secure a non-sterile inverter (<NUM>) of a wide angle viewing attachment for a microscope within the first cavity (<NUM>),
a second portion (<NUM>) integral with the first portion (<NUM>), said second portion (<NUM>) defines a second cavity (<NUM>) continuous with the first cavity (<NUM>), said second portion (<NUM>) configured to secure an imaging lens (<NUM>) of the wide angle viewing attachment for the microscope within the second cavity (<NUM>); and
a tab (<NUM>) provided along the first portion (<NUM>), wherein the tab (<NUM>) is provided to disengage the first portion (<NUM>) from the non-sterile inverter (<NUM>) and prevent reuse of the sterile cover (<NUM>).