Abstract:
An apparatus for shipping, storing, and viewing a cornea comprising a container having a viewing window in a container base, an inner sidewall, and a corneal basket arranged within said container base. The corneal basket is in contact with said inner sidewall and adapted to support a corneoscleral disc by including more than one corneal support rod and more than one disc support surface and a lid that sealingly engages with the container.

Description:
RELATED APPLICATION 
     This application claims the benefit of priority of U.S. Provisional Application No. 61/187,919 filed Jun. 17, 2009, the disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The technical field of this invention is related to devices and methods that improve cornea preservation. 
     BACKGROUND OF THE INVENTION 
     Each of the applications, patents, and papers cited in this application and in as well as each document or reference cited in each of the applications, patents, and papers (including during the prosecution of each issued patent; “application cited documents”), and each of the PCT and foreign applications or patents corresponding to and/or claiming priority from any of these applications and patents, and each of the documents cited or referenced in each of the application cited documents, are hereby expressly incorporated herein. 
     The cornea is the transparent structure that forms the anterior one sixth of the outer coat of the eye and is responsible for more than two thirds of its refractive power. The cornea consists of several layers, including the epithelium, stroma, and single-celled endothelium. The endothelium is the most posterior layer, interfacing with the aqueous humor of the anterior chamber of the eye. Corneal clarity is dependent on a relatively dehydrated state. The endothelium plays a key role in maintaining dehydration by both preventing aqueous humor from entering the cornea and by pumping fluid from the corneal stroma into the anterior chamber. Corneal endothelial cells do not replicate. When destroyed by disease or surgery, the remaining cells enlarge and spread out to cover the posterior corneal surface, thus decreasing the cell density (cell count). Corneas with extremely low endothelial cell densities can no longer maintain a dehydrated state. The corneas may decompensate, swell, and become cloudy over time, with an associated loss of visual acuity. 
     Cornea transplants are used to improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. The most common indication in this category is pseudophakic bullous keratopathy, followed by keratoconus, corneal degeneration, keratoglobus and dystrophy, as well as scarring due to keratitis and trauma. Donor corneas provide the source material for the transplants. Since the health of the cornea at the time of surgery has an impact upon outcomes, it is critical that the cornea container used to store the cornea from the time that it is harvested from the donor eye globe to the point at which it is used in surgery maintains the cornea in an optimal state of health. This need has become even more imperative as LASIK surgery, which renders donor corneas unsuitable for transplant, has become widely accepted in society. Thus, there is a shrinking source of donor corneas and less opportunity to be selective among donated corneas, putting even more importance on the capability of the cornea container to maintain optimal cornea health. 
     Once removed from the donor, corneas are placed in a cornea container, which is filled with preservation medium and delivered to an eye bank. The eye bank stores the cornea, performs quality assessments by way of slit lamp and specular microscopy, and delivers the cornea to a surgical location. The cornea container should allow the technician that harvests the cornea to easily deposit the cornea into the container, facilitate quality assessments, and make it easy for those performing surgery to easily remove the cornea from the storage container. Unfortunately, cornea containers that are used, or have been conceived, are suboptimal. 
     The earliest storage containers merely placed the cornea in a vial filled with preservation medium. However, there was no control over the position of the cornea, causing problems that included trapping the endothelium in a position that cut it off from the surrounding medium, allowing the epithelium to make contact with the walls of the vial, letting gas bubbles contact the cornea, and preventing lack of controlled positioning for specular microscopy and slit lamp evaluation. Although it was easy to deposit the cornea into the vial, the ability to easily retrieve the cornea was difficult. 
     The vial container was improved by attaching the cornea to the lid with a suture in order to allow easier removal of the cornea. But attaching the cornea to the suture required more handling of the cornea by those retrieving them from the donor. It still allowed the endothelium to become trapped in a position that cut it off from the surrounding medium, allowed the epithelium to make contact with the walls of the vial, let gas bubbles contact the cornea, and prevented lack of controlled positioning for specular microscopy and slit lamp evaluation. 
     In an attempt to overcome some of the problems of attaching a cornea to a suture, U.S. Pat. No. 4,695,536 describes a cornea container that retains the cornea in a fixed position within a medium vial. A steel wire is attached to the lid. An alligator clip is attached to the opposite end of the wire. The person retrieving the cornea attaches the sclera (the tough white opaque tissue that surrounds the cornea) to the alligator clip and carefully attaches the lid so the epithelium comes to reside upon a plurality of dividers that reside in the body of the cornea container. Although this configuration resolves some of the positioning problems of the suture approach, such as preventing the endothelium from being cut off from its media supply, the epithelium is forced to be in direct contact with the dividers that reside in the vial. Direct physical contact between the dividers and the epithelium can cutoff media access, affecting the health of the cells that comprise the epithelium, and can physically damage the epithelium as it is dragged across the dividers when the cornea is removed for surgical implantation. Also, the technician is required to transfer the cornea from forceps to the retaining clip in a manner that prevents damage to the cornea. That process can add contaminants to the container as the technician is likely to place their gloved hands directly upon the alligator clip to open it during the process rather than find a clever way to actuate the alligator clip with a sterile tool. Touching a component that resides within the container, even with gloves, is not good practice because bioburden level is dependent on what the technician&#39;s gloves have contacted previously and is also impacted by the skill level of the technician. Thus, the process of using this storage container increases contamination risk and is highly dependent on the skill and patience of the technician. Manipulation of the tissue by the technician may also damage the non-regenerating endothelium. Also, there is no geometry to prevent gas from contacting the cornea as the container is shipped, subjecting the cornea to potential damage in transit. 
     U.S. Pat. No. 4,844,242 also attempts to prevent the cornea endothelium from becoming trapped face down in a medium vial by orienting the cornea in a fixed position within the retaining lugs of a support ring. However, the harvesting process currently used to obtain donated corneas often leads to corneas of various diameters and rarely results in a completely circular excision. The apparatus &#39;242 does not easily accommodate corneas of various diameters, or those that are not circular, since the support ring and the retaining lugs only allow about a 12% variation in cornea diameter before extra trimming is required. The more the cornea is handled for trimming, the more potential problems arise. For example, twisting, stretching, additional contact with forceps, and extra cutting increase the chances of damage to the tissue, particularly at its edges and on the endothelial cell surface. Furthermore, the outcome can vary from technician to technician since cutting the corneas to match the limited diameters accepted by the apparatus of &#39;242 requires patience, time, and a high level of skill. In general, those obtaining donor corneas desire the least amount of preparation and exposure to the environment necessary before the cornea is placed into its medium storage container. Moreover, the act of using forceps to press the cornea into the retaining lugs of the support ring can inflict further damage to the cornea. Still another problem with the apparatus of &#39;242 is that gas in the container has the potential to make contact with the cornea during shipping, and can even become trapped in direct contact with the endothelium depending on the orientation of the container. 
     For the reasons described, the US market has avoided the use of the free floating vial, and rejected sutured lids attached to a vial, as well as devices described in patents &#39;536 and &#39;242. Instead, the US standard is a cornea container that allows gravity to position the cornea in a basket that holds the cornea in a fixed location within the container. Throughout, we refer to the cornea container which has come to be the industry standard as a “conventional container”. The conventional cornea container includes a corneal basket to hold the cornea. It has completely dominated the US market since at least the late 1980&#39;s. The conventional container achieves its popularity because it is so easy to place the cornea into the container&#39;s corneal basket and remove it from the container&#39;s corneal basket with forceps. Just placing the lid on the container automatically fixes the position of the cornea, the cornea is positioned for examination by slit lamp and specular microscopy, and the process is not highly dependent on the skill level of the technician. 
     In use, a technician merely drops the cornea, epithelial side down, into the medium filled container. The cornea gravitates to reside upon a corneal basket, formed of a group of prongs emanating from the base of the container that are arranged in a circular pattern. The corneoscleral disc resides upon the prongs in a position such that the plane in which the sclera resides in is generally parallel to the top and the bottom of the container. This allows examination of the cornea by slit lamp and/or specular microscopy. The lid is designed so that a portion of it functions as a viewing window. No matter the orientation of the container, the cornea is kept from falling out of the basket by the viewing window, which is typically only about 0.05 inches from the sclera. A relieved area in the lid acts as a gas trap and occupies the perimeter of the viewing window, controlling the location of gas within the container. A similar gas trap is present in the container. The cornea basket is positioned away from the container walls, allowing gas to move from the lid to the bottom of the container without contacting the corneoscleral disc as the conventional container is inverted. 
     The conventional cornea container was introduced by Coopervision Inc, Irvine Calif. The basket included eight prongs that rose from the bottom of the container. The corneoscleral disc resided in contact with the prongs. The container left room for improvement however. The basket design included prongs which obstructed the ability for slit lamp observation of the epithelium. Around the late 1980&#39;s, Bausch &amp; Lomb entered the market with a conventional cornea container that allowed slit lamp observation. Their product is called the Independent Corneal Viewing Chamber™, and it came to dominate the US market. 
     Although the conventional cornea container has many advantages over any other proposed or previously tried cornea container, we have discovered that the design acts to limit cornea health. One problem, detailed within, is that the design of the corneal basket impedes the effective use of preservation medium within the container and as a result is suboptimal for maintaining corneal health. The other problem is that the lid design allows the sclera to become suctioned to it, thereby cutting off solute movement to the endothelium, and in some cases, even trapping gas against the endothelium. 
     A review of conventional container basket geometry helps clarify the problem of effective use of preservation medium within the container. When the cornea resides in the Coopervision cornea container, the prongs only provide a small open area between medium residing within the corneal basket and that outside of the corneal basket. The cross-sectional area of open space (about 0.69 in 2 ) for medium communication is exceeded by that of cross-sectional space occupied by prongs. There is only about 38% of the corneal basket open for preservation medium communication. The distance between prongs is also limited to about 0.1 inch, which acts to trap gas that may form during medium temperature increases as will be explained later. An additional problem exists with the width of the prongs, as measured from the inner diameter to the outer diameter of their basket arrangement. The width of the corneoscleral disc support section is virtually maintained constant from the base of the prong to the point of disc contact (i.e. along the height). That adds further resistance to medium communication. For example, the Coopervision prongs have a width of about 0.4 inches. 
     The same problems exist in Bausch &amp; Lomb&#39;s Independent Corneal Viewing Chamber™, which will be detailed further within. 
     SUMMARY OF THE INVENTION 
     The present invention is a novel cornea container that can improve the health of corneas, as determined by quantitative specular microscope analysis of the human corneal epithelium with respect to endothelial cell shape and corneal thickness. Accordingly, it is an object of the present invention to provide improved conventional corneal containers that overcome the problems of conventional corneal containers in order to provide superior cornea health. 
     In one aspect of the present invention, projections emanate from the lid to prevent the cornea from becoming suctioned against the lid. 
     In another aspect of the present invention, a corneal basket comprised of a plurality of prongs and disc support surfaces allows the area between the disc support surfaces and the container base to have an open area greater than 38%, and more preferably at least 50%, to allow improved movement of solutes residing within the preservation medium. 
     In another aspect of the present invention, the corneal basket includes upper and lower disc support surfaces to allow a greater range of cornea sizes to reside in the container. The corneal basket is structured to allow the area between the upper disc support surfaces and the container base to have an open area greater than 38%, and more preferably at least 50%, to allow improved movement of solutes residing within the preservation medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a cross-sectional perspective view of the conventional Independent Corneal Viewing Chamber™. 
         FIG. 1B  shows a top view of the conventional Independent Corneal Viewing Chamber™. 
         FIG. 1C  shows a cross-sectional view of the conventional Independent Corneal Viewing Chamber™ with a cornea residing in it. 
         FIG. 1D  shows an illustrative embodiment of the present invention in which a prong  14 A includes a wider section and a narrower section. 
         FIG. 2A  shows a cross-section of a perspective view of an illustrative embodiment of the present invention which can increase the cross-sectional area for solute movement to the endothelium while preventing the corneoscleral disc from contacting the lid. 
         FIG. 2B  shows a perspective view of the lid including three lid projections which emanate from lid underside. 
         FIG. 3A  shows a cross-section of the perspective view of another illustrative embodiment of the present invention. Cornea storage container is shown with lid attached to container base. First lid projections and second lid projections emanate from lid. 
         FIG. 3B  shows corneoscleral disc residing upon corneal basket at a first position well beyond the focal length of a specular microscope. 
         FIG. 3C  shows cornea container inverted so that endothelium of corneoscleral disc resides in a second position and can be examined by specular microscopy. Second lid projections act to keep corneoscleral disc from becoming suctioned to lid. 
         FIG. 4  shows a perspective view of how a band(s) of material can circle first lid projections to prevent the cornea from slipping past first lid projections when it departs from corneal basket. In this illustrative depiction, retaining band bridges the gap between first lid projections. 
         FIG. 5  shows a cross-section of a perspective view of an illustrative embodiment demonstrating how cornea retaining posts, as structure attached to or integral to corneal basket, can achieve the purpose of guiding corneas to the lid when the viewing container is inverted to place the cornea in a second position, and back to prongs when the viewing chamber is in the normal upright position where the cornea resides in a first position. 
         FIG. 6  is a cross-section of a perspective view of an illustrative embodiment of the present invention in which the traditional corneal basket has been altered in such a manner that allows more exposure of the cornea to preservation medium. Modified cornea basket includes medium access windows. 
         FIG. 7A  is a top perspective view indicating how use of a prong connecting ring can prevent the corneoscleral disc from falling from the corneal basket in order to create far superior communication between inner preservation medium and outer preservation medium. 
         FIG. 7B  is a cross sectional view showing how cornea basket windows allow a large gap for the inner preservation medium to interact with the outer preservation medium. 
         FIG. 8A  shows an illustrative embodiment of the present invention disclosing corneal basket that minimizes contact with the cornea and greatly improves cornea access to bulk preservation medium. 
         FIG. 8B  shows cross-sectional view A-A of the illustrative embodiment of  FIG. 8A  with corneoscleral disc residing within it. Cornea retention posts can interact with lid to retain cornea in a desired position. 
         FIG. 9  is a cross sectional perspective view of an illustrative embodiment of an adaptation to the embodiment of  FIG. 8A  in the event there is concern about the cornea falling past the corneal basket when it is placed into the cornea container. Corneal basket includes optional lower retaining ring and optional upper retaining ring. 
         FIG. 10A  is perspective view of another embodiment of the present invention with the lid removed for clarity. Corneal basket includes a first disc support surface residing at a height above second disc support surface. 
         FIG. 10B  is a cross sectional view of  FIG. 10A  with the lid attached. 
         FIG. 11  shows a cross-section of the embodiment used to gather the data and information presented in Example 1 and Example 2. 
         FIG. 12  shows a top view of the devices and results described in Example 2. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The container that corneas reside in during transport and during storage at eye banks is often referred to as a corneal storage container, viewing chamber, and/or storage and viewing chamber. Thus, herein the words, or any combination of the words chamber, container, storage container, and viewing chamber mean the device that holds a cornea and preservation medium. Herein, bulk preservation medium also means the same thing as storage medium and preservation fluid. Herein the words, or any combination of words cornea, corneal, corneoscleral disc, disc, corneal tissue, or donor tissue mean the tissue that is harvested, stored, shipped and/or transplanted. 
     To help define the problems present in the conventional cornea containers, an assessment of Bausch &amp; Lomb&#39;s Independent Corneal Viewing Chamber™ follows, aided by  FIG. 1A ,  FIG. 1B , and  FIG. 1C .  FIG. 1A  shows a perspective view of a cross-section of container  5  of the Independent Corneal Viewing Chamber™. The lid is not shown in order to clearly show the area in which the corneoscleral disc resides. Corneal basket  8  resides within container  5  and is attached to container base  11 , which forms the bottom of container  5 . Container base  11  includes a container viewing window  12  and corneal basket  8  occupies the perimeter of container viewing window  12 . Corneal basket  8  includes twelve prongs  14  arranged in a radial (i.e. circular) manner upon which the cornea resides. Each prong  14  has a disc support surface  17  which is a beveled area that intends to generally conform to the cornea curvature, a flat section  20 , and two cornea retention fingers  23  that rise from flat section  20  of each prong  14 . Also, each prong  14  is attached to container base  11 . In use, the cornea is oriented epithelium side towards container base  11  and typically makes physical contact with each disc support surface  17 . The minimum distance between prongs  14 , as best shown in the top view of  FIG. 1B , is about 0.05 inches. Note that the distance between two adjacent prongs is measured as the shortest path between prongs. Throughout this specification, we refer to “open area” and “closed area.” Open area is defined herein as the sum of the distance between adjacent disc support surfaces times the distance between the disc support surfaces to the container base. When the distance between support surfaces is referred to, it is the shortest linear distance between support surfaces. Thus, the open area is a measure of the ability for preservation medium to move to the volume of space beneath the cornea. 
     In use, prongs  14  act to surround a volume of preservation medium (inside preservation medium  15 ). Prongs  14  separate inside preservation medium  15  from outside preservation medium  16 . Thus, as best shown in  FIG. 1C , when a corneoscleral disc  25  resides upon prongs  14 , preservation medium residing within corneal basket  8 , (i.e. inside preservation medium  15 ) is blocked from communication with outside preservation medium  16  by corneoscleral disc  25  and by prongs  14 . Thus, inside preservation medium  15  can only communicate with outside preservation medium  16  by way of the “open area” below each support surface upon which the disc resides. In the Independent Corneal Viewing Chamber™, the cumulative open area is about 0.342 in 2 . Thus, about 0.342 in 2  of area is available for inside preservation medium  15  to interact with outside preservation medium  16 , while about 0.616 in 2  is closed area blocked by prongs  14 . Prongs  14  block more cross-sectional area between inside preservation medium  15  and outside preservation medium  16  than the open area provides. Thus, in use corneal basket  8  the amount of open area relative to the cumulative open area and closed area is only about 36%. Thus, only about 36% is open for liquid contact between inside preservation medium  15  and outside preservation medium  16 . 
     Herein, we will demonstrate that improvements to corneal health can result from increasing the cross-sectional area for inside preservation medium  15  to interact with outside preservation medium  16 . One approach is to merely alter the traditional Corneal Viewing Chamber™ design to increase the open area such as by eliminating prongs or increasing the distance between prongs. Other embodiments that improve upon the traditional design will be shown herein. 
     Also, interaction between inside medium and outside medium is further impeded by conventional container prong design, which includes a substantially uniform distance, past which preservation medium must travel for interaction between the inside preservation fluid and the outside preservation fluid. The standard uniform distance is best shown in  FIG. 1C  and is about 0.144. A superior prong design would retain the conventional geometry at the disc support surface and diminish said distance along the length of the prong between the disc support surface and the container base. 
       FIG. 1D  shows a preferred embodiment of the present invention in which prong  14 A includes a first width  19 A which exceeds second width  21 A. Preferably, second width  21 A is generally uniform from the transition at first width  19 A to container base  11 A. Preferably, second width  21 A is less than about 0.144 inches, more preferably less than 0.1 inch, and even more preferably less than about 0.06 inches. If structural strength is a concern, one or more prongs can allow second width  21 A to exceed that of other prongs  14 A, so long as at least the majority of prongs should integrate the narrower shape. 
     In conventional corneal basket design, the distance between prongs creates another problem. Preservation medium is often stored at 4° C. As medium temperature rises, which is often the case, its gas carrying capacity is reduced. Microbubbles form and rise. The microbubbles that form within the traditional corneal basket cannot easily escape because the limited distance between prongs causes surface tension barriers that will direct the bubbles to the epithelium side of the corneoscleral disc. This is another problem with the design of traditional cornea baskets. To ensure such problems don&#39;t exist, preferred minimum distance between disc support surfaces is 0.125 inches and more preferably 0.25 inches. 
     The epithelium is not the only area of the cornea that is impeded from access to the preservation medium. The endothelium is also, as best shown in  FIG. 1C . Corneoscleral disc  25  is shown residing within corneal basket  8 . A distance of about 0.05 inches exists between prongs  14  and lid  28 . This distance is intended to allow a gap for movement of preservation medium to and from the endothelium. In actual use, when the sclera makes contact with the lid, as may be the case when the container is placed upside down, corneas have a potential to stick to the lid surface by suction. This can prevent preservation medium from accessing the endothelium of the cornea which can damage the tissue by limiting solute delivery, trapping waste products, and/or trapping gas against the endothelium. Furthermore, even if the cornea is not in contact with the lid, the total cross-sectional area by which medium can access the endothelium is quite limited as can be seen in  FIG. 1C . This problem exists because conventional containers maintain the endothelium within the focal length of specular microscopes, even throughout transit and storage. The total cross-sectional area available for solute transport to the endothelium is typically the cross-sectional area between the cornea retention fingers of the prongs (this is best case since in use the cornea sclera can often block this area of mass transfer) plus the cross-sectional area from the top of the prongs to the lid, which cumulatively about 0.091 in 2 . 
     In yet another problem with the device, the prongs are designed to make contact with the sclera, but no attempt is made to minimize contact. Thus, the physical area of the sclera that can be in contact with the prongs is typically the cumulative surface area of the disc support surface which is about 0.054 in 2 . Physical contact can act to block mass transfer at the point of corneoscleral contact, further damaging tissue. 
       FIG. 2A  shows a cross-section of a perspective view of an illustrative embodiment of the present invention which can increase the cross-sectional area for solute movement to the endothelium while preventing the sclera from contacting the lid. Corneal viewing chamber  30  includes lid  32  which is attached to container base  33  in a liquid tight manner. O-ring  36  resides between lid  32  and container base  33 , providing a liquid tight seal of the contents when in use. Lid  32  includes lid viewing window  38 , which acts to allow specular microscopy of the corneal endothelium. The bottom of container base  33  is formed by container bottom  34 , which includes container viewing window  39 , which acts to allow slit lamp examination of the corneal epithelium. Preferably, like conventional containers, container viewing window  39  resides in a second plane above the lowest plane of container bottom  34  to form container gas trap  35  and to prevent container viewing window  39  from being scratched. Container bottom  34  includes a corneal basket  40 , which is a group of prongs  42  arranged in a radial pattern about the perimeter of container viewing window  39 . Prongs  42  include disc support surface  44 , which is an area upon which the corneoscleral disc is intended to reside. In this case, disc support surface  44  is the beveled area. The diameter of the circular prong arrangement is structured to hold corneas of various sizes. The range of cornea sizes is dependent on how they are excised from the eye globe, and whether or not the donor is an adult. Preferably, donated corneas can thus range in size from diameter of about 12 mm to about 23 mm. More preferably, the prongs are arranged to accept corneas with diameters from about 15 mm to 22 mm. 
     Lid  32  includes lid gas trap  46 , which is a relieved area about the perimeter of lid viewing window  38 . Lid gas trap  46  acts to trap gas in a location such that it does not encounter the cornea during transit. The depth of lid gas trap  46  is the difference between the lower plane in which lid viewing window  38  resides and the upper plane of the inside surface  37  of lid  32 . Lid projections  48  emanate from lid underside  37 , which is the surface of lid  32  that faces corneal basket  40 . Lid projections  48  act to prevent the corneoscleral disc from attaching, or suctioning, to lid underside  37  during transit, handling, or specular microscopy viewing. To accomplish this objective, any number of lid projections  48  can emanate from lid  32 . For example, just one lid projection  48  can prevent the periphery of the cornea from becoming suctioned to the lid. The use of three lid projections  48  allows the cornea to be retained a uniform distance from the lid, thereby allowing a uniform cross-sectional area for solute transport even if the cornea container is positioned upside down during shipping. This can also retain the sclera in a plane generally parallel to lid viewing window  38  and container viewing window  39 . Since corneas are often removed from the donor in a manner that renders them non-circular, more lid projections  48  can help ensure that the periphery of the cornea makes contact with at least three projections. In the preferred embodiment, as seen more clearly in  FIG. 2B  which shows a perspective view of lid  32  removed from the container base, three lid projections  48  emanate from lid underside  37  of lid  32 . Although the lid projections can be any shape, in the preferred embodiment the lid projections  48  are rectangular in shape and oriented with the long edge directed towards a common center point. The common center point preferably is center axis  41  of corneal basket  40  (see  FIG. 2A ). Thus, lid projections  48  are preferably arranged in a radial pattern about lid viewing window  38  to allow maximum assessment of the endothelium by specular microscopy. The lid projections  48  should be of sufficient diameter or width and/or length to interface with the dimensions of the corneal basket. Thus, if the corneal basket is designed to hold corneas of 15 mm at a minimum, as preferred in the above description, the narrowest diameter of the lid projections, as measured by the diameter closest to the axis would be slightly less than 15 mm, for example 13 mm, in order to ensure the sclera of a corneoscleral disc with a 15 mm diameter contacts a lid projection. The greatest diameter of the lid projections should slightly exceed the expected diameter of the donated tissue. For example, in the case of an expected 23 mm cornea tissue, the outer diameter of lid projections  48  would be at least about 24 mm. Then, in this example, the length of each lid projection  48  would be about 5.5 mm [i.e. (24 mm-13 mm)/2]. The width of each lid projection  48  should be narrow, so that medium access to the endothelium is not inhibited. Preferably, the width is less than about 1 mm. 
     If lid projections are just to break suction, a preferred distance is greater than about 0.02 inches. However, as the lid projections extend further from the lid there is an increase in cross-sectional area available for solute movement to the endothelium of the cornea as the distance between the sclera and the lid increases. If the lid projections are structured to maximize cross-sectional area for solute movement, they preferably do not extend a distance from the lid that prohibits specular microscopy. Thus, in a preferred embodiment for improved endothelium health, the lid projections place the entire endothelium in view of the specular microscope while maximizing the cross-sectional area for solute movement to the endothelium. Thus, the distance that the lid viewing window resides from the specular microscope lens, the thickness of the lid viewing window, the distance that lid projections emanate from the lid and the curvature of the cornea should be considered. For example, assuming that the specular microscope could focus at a maximum distance of 0.47 inches beyond the outside surface of the lid at the region of the lid viewing window, and assuming the furthest distance that the endothelium resides from the plane of the sclera is about 0.15 inches, and assuming the material thickness of the lid viewing window is about 0.06 inches, then lid projections should emanate a maximum distance of about 0.26 inches in order to maximize solute access to the endothelium while retaining the ability to assess the entire endothelium by specular microscopy. The length of the prongs of the corneal basket should be adjusted according to the distance that the lid projections emanate from the lid. At the point where the lid is secured in a liquid tight manner to the container base, a gap between the lid projections and the corneal basket exists and is preferably about 0.05 to 0.1 inches. 
     One of the limits of conventional cornea containers is that the cornea is always positioned within the focal distance of a specular microscope, even when the cornea is not being examined by specular microscopy. That has the effect of limiting bulk preservation medium from access to the cornea endothelium during transit and storage.  FIG. 3A ,  FIG. 3B , and  FIG. 3C  show views of an illustrative embodiment that, unlike conventional containers, allows the cornea to reside at a distance far beyond the focal length of a specular microscope during transit and storage, while retaining the ability to assess the cornea by specular microscopy. In this manner, bulk medium has greater access to the endothelium of the cornea during transit and storage. In essence, the cornea container is configured to allow the cornea to reside in either of two positions by the use of gravity. The cornea can reside in either a first position, in which the cornea resides upon a corneal basket that is at a distance far beyond that of the specular microscope focal length, or a second position in which the cornea resides within the focal length of the specular microscope. 
     In the cross-section of the perspective view of  FIG. 3A , cornea container  49  is shown with lid  50  attached to container base  51 , the bottom of container base  51  is formed by container bottom  52 . First lid projections  54  and second lid projections  56  emanate from lid underside  53  of lid  50 . In  FIG. 3B , corneoscleral disc  58  is shown residing upon corneal basket  60  at a distance well beyond the focal length of a specular microscope. Thus, relative to the illustrative embodiment of  FIG. 2A  and  FIG. 2B , an even more expansive open area is available for delivery of solutes and removal of waste from the endothelium. The increase in open area can be attained by increasing the distance from the top of the prongs to the lid beyond 0.05 inches and more preferably beyond 0.20 inches. Another element of the configuration is that features are present that ensure the cornea remains capable of being positioned epithelial side down upon the corneal basket. First lid projections  54  have the purpose of retaining corneoscleral disc  58  in a position so that it can return to its resting position upon corneal basket  60  after cornea viewing chamber  49  is inverted during shipping or specular microscopy. First lid projections  54  reside equal to or a small distance outside the diameter of corneal basket  60  such that when cornea container  49  is inverted for specular microscopy, first lid projections  54  do not obstruct the path of corneoscleral disc  58  as it moves towards lid viewing window  62  and comes to reside upon second lid projection(s)  56 . Design considerations for second lid projections  56  are as previously described. A preferred embodiment utilizes at least three first lid projections, oriented in a circular pattern about the corneal basket, to ensure the cornea is capable of moving to the center portion of the lid viewing window and returning to the corneal basket. More first lid projections can be used, but be aware that the open area should exceed 36%, and more preferably exceed 50%. As shown in  FIG. 3C , cornea viewing chamber  49  has been inverted so that cornea  58  can be examined by specular microscopy. Second lid projections  56  act to keep cornea  58  from becoming suctioned to lid  50 . The number of second lid projections  56 , and the distance that second lid projections  56  emanate from lid  50  are intended to keep the sclera of cornea  58  from making complete peripheral contact with lid  50 . Although only one second lid projection is needed to prevent suction from occurring, three second lid projections are preferred to make it very likely the sclera makes contact with at least one projection in order to prevent suctioning. Skilled artisans will recognize that sclera may not be circular, as the shape is determined by the skill and patience of the person removing the donated cornea from the eye globe. The distance that the second lid projections emanate from the lid need only be about 0.020 inch to prevent suction. However, as is typically the case, the cornea container can become inverted during transport. Thus, extending the distance between the second lid projections and the lid viewing window to the maximum distance that allows specular microscopy, as described previously, ensures maximum solute movement to the endothelium during transport. To minimize the potential for the cornea to invert its position when the cornea container is inverted during transport or specular microscopy, the distance from the corneal basket location upon which the cornea resides to the second lid projections should be less than the diameter of a typical cornea. In this manner, the cornea has little chance of rotating to a position in which the epithelium side is oriented towards the lid. Thus, with the range of donor corneas at a diameter generally between about 12 mm and 23 mm, and typical diameters in the range of about 15 to 22 mm, a distance of between 15 mm and 22 mm is preferred, and more preferably about 15 mm to eliminate the potential for most donor corneas to become inverted. 
     When there is a concern that the corneoscleral disc can rotate into a position that allows it to slip through first lid projections, more first lid projections can be added. Alternatively, a band(s) of material can circle the first lid projections to prevent the cornea from slipping past the first lid projections as shown in the cross-section of the perspective view of  FIG. 4 . Retaining band  66  bridges the gap between first lid projections  54 . Although more than one retaining band  66  can be present, in the preferred embodiments the volume of space that the band(s) displace is minimized to maximize the area for solute movement in the media. Again, as described previously, open area should exceed 36%, and more preferably 50%. Thus, as shown, one retaining band  66  is present and is located at a distance about halfway between corneal basket  60  and second lid projections  64 . Retaining band  66  need not completely circle first lid projections  54  so long as the open space is less than the diameter of a corneoscleral disc in order to prevent the disc from falling to a location at which it cannot return to the corneal basket. 
     Guiding corneas to the lid when the viewing container is inverted need not only be accomplished by first projections emanating from the lid. Structure attached to, or integral to, the corneal basket can achieve that purpose.  FIG. 5  shows a cross-sectional view of an illustrative embodiment of this approach. The lid is not shown for clarity. Corneal basket  74  emanates from container base  70  and includes cornea retaining posts  72  which emanate from corneal basket  74 . Alternatively they may emanate from container base  70 . Preferably, at least three cornea retaining posts  72  are present and they are equally spaced about corneal basket  74 , reaching nearly to the lid or the lid projections, so that the cornea does not escape the confines of cornea retaining posts  72 . 
     The barriers that conventional corneal baskets present to medium communication have been described in  FIG. 1A ,  FIG. 1B ,  FIG. 1C  and associated text. Referring again to  FIG. 1B  for example, inside preservation medium  15  is in limited communication with outside preservation medium  16 . We have discovered that this conventional corneal basket design is diminishing the health of the cornea. Thus, an objective of this invention is to reduce or eliminate the barriers to communication of preservation medium residing in the area below the corneoscleral disc (i.e. inside preservation medium) and preservation medium outside the area below the corneoscleral disc (i.e. outside preservation medium). We have already disclosed preferred modifications that retain the traditional use of prongs that are continuous from the container base to the disc support surface. Embodiments that deviate from the traditional use of prongs are now disclosed. 
     One type of modification to the conventional basket is to provide more open area by making at least one window through the corneal basket. Thus, this approach breaks with the traditional approach in which all prongs emanate from the container base and are a continuous structure between the disc support surface and the container base.  FIG. 6  is a cross-sectional view of an illustrative embodiment of the present invention in which the traditional corneal basket has been altered in such a manner to allow open area. For clarity, the lid has been removed. As shown, unlike the conventional cornea storage container, not all prongs make contact with the container base. Modified corneal basket  76  includes modified prongs  78  configured with disc contact surfaces  75  that act to hold a cornea in a planar position. Preferably at least one, more preferably all but one, and ideally all of modified prongs  78  terminate without direct contact with container base  84 . Modified prongs  78  are joined together by prong connection ring  80 . Support posts  82 , which can optionally be an extension of one or more prongs  78 , mate modified corneal basket  76  to container base  84 . One or more support posts  82  can be relied upon. Although modified corneal basket  76  is shown mated to container base  84 , it can attach to any surface within container base bottom  85  such as inner container wall  81 . In the event that modified corneal basket  76  is attached to inner container wall  81 , the outer diameter of corneal basket  76  is preferably not directly in contact with inner container wall  81  so that gas can move between modified corneal basket  76  and inner container wall  81  when the position of the corneal storage chamber is inverted. A distance of at least 0.1 inch is preferred. Modified corneal basket  76  increases the open area for communication of preservation medium directly below the corneoscleral disc (previously referred to as “inner preservation medium”) with the preservation medium not directly under the corneoscleral disc (previously referred to as “outer preservation medium”). Preferably the open area is greater than 38%, and more preferably at least 50%, of the open plus closed area. In essence, a medium access window is formed below the corneal basket. In this depiction, medium access window  86  is bounded on the sides by post  82 , on the top by modified prongs  78  and prong connection ring  80 , and on the bottom by container bottom  84 . In this embodiment, easy deposit and retrieval of the cornea afforded by the conventional container is retained, while at least the epithelium of the cornea is provided with much improved access to preservation medium. Also, prong connection ring  80  allows the number of prongs  78  of modified corneal basket  76  to be reduced relative to conventional cornea baskets, since it can be located in any manner necessary to prevent the corneoscleral disc from falling between prongs  78  or below modified corneal basket  76 . In the preferred embodiment, at least three prongs  78 , and more preferably six prongs  78  are present. Preferably, disc support surfaces  75  of prongs  78  are capable of holding corneas in the range of about 15 mm to 22 mm. The container lid is preferably structured with lid protrusions as described previously. Distances that the cornea can reside from the lid can range to that within the focal length of a specular microscope throughout transit or can be increased by the use of first projections about the modified corneal basket as previously described. 
     Another way to improve the conventional corneal basket is to widen the space between prongs, or eliminate prongs, while ensuring that the corneoscleral disc does not fall to the bottom of the container. The conventional corneal basket relies on prongs that are closely spaced together to prevent this event.  FIG. 7A  shows an illustrative embodiment indicating how use of a prong connecting ring can prevent the corneoscleral disc from falling from the corneal basket in order to create far superior communication between inner preservation medium and outer preservation medium. Modified cornea basket  202  resides within container base  200 . Prong connecting ring  206  is adjoined to prongs  204 . Prong connecting ring  206  acts to reduce the number of prongs needed relative to the conventional cornea basket because prong connecting ring  206  will make contact with the sclera if there is an attempt to place the corneoscleral disc onto the prongs in a manner that would allow it to otherwise fall to the bottom of container base  200 . Preferably three prongs are present. Whatever number is used, care should be taken to ensure that at least 38%, and more preferably at least 50%, open area exists. 
     As shown in the cross-sectional view of  FIG. 7B , cornea basket windows  208  can allow a large open area for the inner preservation medium to interact with the outer preservation medium. Preferably, prong connecting ring  206  resides in a plane below that of disc support surface  210  so that the corneoscleral disc does not make contact with prong connecting ring  206 . In this case, prong connecting ring  206  resides in plane  203  which is below plane  201  in which disc support surface  210  resides. Thus, preferably prong connecting ring  206  does not make physical contact with the corneoscleral disc during use. When creating connecting ring  206 , care should be taken to ensure that at least 38%, and more preferably at least 50%, open area exists. 
     In yet another embodiment of the present invention, a unique configuration for a corneal basket that minimizes contact with the cornea and can greatly exceed the 38% open area of the conventional cornea container by allowing open area to be up to 100% is disclosed.  FIG. 8A  shows a perspective view of an illustrative embodiment of the present invention in which the lid has been removed for clarity.  FIG. 8B  shows cross-section A-A of  FIG. 8A  when the lid is attached. Corneal basket  88  is attached to inner sidewall  90  of container base  92 . Skilled artisans will recognize that there are numerous options for attaching corneal basket  88  to inner sidewall  90  in order to retain it in a fixed position. In the preferred embodiment, corneal basket  88  is designed to hold the cornea such that the endothelium is oriented towards the lid. The distance between the furthest section of the endothelium is such that it does not exceed the focal length of a standard specular microscope as previously described. Corneal basket  88  is structured to allow the endothelium relatively unrestricted access to preservation medium and unimpeded slit lamp view of the epithelium, via container viewing window  96 . The sclera of the cornea resides upon disc support surfaces  112 , which are in essence the ends of cornea support rods  94 . Four disc support surfaces are shown to aid the description of the cross-sectional view, but preferably, at least three disc support surfaces are present, each at the same distance from the specular microscopy window so that the cornea periphery resides in a plane parallel to the lid viewing window. Each disc support surface is preferably oriented in a circular pattern at uniform intervals about the cornea. Preferably, as with all of the embodiments of this invention, the cumulative surface area of the disc support surface that make physical contact with the cornea is less than that of a conventional corneal basket, or at least less than about 0.054 in 2 . For example, when three cornea support rods  94  with a diameter of 0.04 inches are present, the amount of contact with the cornea is far less than that of traditional corneal baskets. Cornea retention posts  114  are preferably oriented in a vertical direction relative to the plane at which the cornea resides and act to keep the cornea from moving sideways, thereby keeping the cornea centered in corneal basket  88 . The distance between disc support surfaces  112  is structured to prevent the cornea from falling through corneal basket  88  and to minimize the potential for contact with the cornea itself as opposed to the sclera. In a preferred embodiment, the distance between cornea retention posts is structured to accommodate corneoscleral discs in the size range of about 15 mm to about 22 mm. 
     The primary seal is provided by o-ring  100 , which resides in o-ring gland  102  of container base  92 . O-ring  100  is compressed by container base  92 . A secondary seal is created as lid seal projection  108  makes physical contact with lid  106 . Lid viewing window  110  allows specular microscopy. Cornea retention posts  114  can interact with lid  106  to trap cornea  98  in a desired position. In a preferred position the endothelium of cornea  98  is within focal length of a specular microscope. In this case, lid projections  107  are integrated into lid  106  to prevent the cornea from becoming stuck to lid  106 . Preferably, cornea retention posts  114  should terminate with less than about a 0.1 inch gap, and even more preferably less than about a 0.05 inch gap, from the adjacent portion of lid  106  (in this case lid projections  107 ) to keep the cornea from moving out of corneal basket  88 . Centering rods  116  act to mate cornea retention posts  114  to basket retaining ring  118  and act to locate disc support surfaces  112  in a desired position relative to lid  106 . Centering rods  116  serve to ensure that the sclera does not move into the region below lid gas trap  122  in order to prevent, or greatly minimize, the possibility of gas contact with the endothelium. Thus, centering rods  116  preferably place all cornea retention posts  114  in a position such that they are never directly below lid gas trap  122 . Although only one centering rod  116  can be present, at least three are preferred in order to provide stability throughout transit. Also, centering rods  116  can be in any position relative to disc support surface  112 , centering rods  116  are preferred position equal to or below the height of disc support surface  112  so that centering rods  116  do not wick gas to the area above cornea  98  when the cornea container is inverted. 
     To eliminate the possibility of the cornea falling past the corneal basket when it is placed into the cornea container, one or more retaining rings can be added to the corneal basket to prevent that event.  FIG. 9  shows an illustrative embodiment of such an adaptation with two retaining rings to demonstrate various options for their location. Corneal basket  88 A includes lower retaining ring  89 . Lower retaining ring  89  is positioned below disc support surface  112 A to avoid continuous contact with a corneoscleral disc and act to prevent a cornea from falling between disc support surfaces  112 A. Spars  113  connect retaining ring  89  to disc support surfaces  112 A. Although only one spar  113  is needed, three are preferred to provide stability. An alternative and/or second retaining ring location is shown by upper retaining ring  91 , which is positioned to prevent the cornea from falling between disc support surfaces  112 A (and/or lower ring  89 ) and container inner sidewall  93 . In a preferred arrangement, upper ring  91  resides at or about the diameter of cornea retention posts  114 . Regardless of the geometric structure of this embodiment, it is preferred that at least 38%, and more preferably at least 50%, open area exists. 
       FIG. 10A  and  FIG. 10B  show an example of an illustrative embodiment of a cornea container that integrates a corneal basket structured to improve preservation medium access to the epithelium while accommodating a wider range of cornea tissue sizes in a manner that exercises superior control over the position of the actual cornea portion of the tissue. In  FIG. 10A  the lid has been removed to show cornea basket  126 .  FIG. 10B  shows a cross-sectional view with the lid attached. In this depiction, corneal basket  126  includes upper disc support surfaces  128  residing at a height above lower disc support surfaces  130 . Upper disc support surfaces  130  act to make contact with larger donor corneas than the donor corneas that will make contact with lower disc support surfaces  130 . Although not required, lower retaining ring  132  and/or upper retaining ring  134  can be present to assist the technician in placing the cornea into corneal basket  126 . Preferably, upper retaining ring  134  is positioned so that it does not make contact with the corneoscleral disc during transit or storage. Lower spars  136  attach lower retaining ring  132  to lower cornea support rods  138 . Lower cornea retention posts  140  mate lower cornea support rods  138  to upper cornea support rods  142 . Upper cornea retention posts  144  mate to centering rods  146 . Centering rods  146  attach to basket retaining ring  148 . Centering rods need not be present at each upper cornea retention post. Thus, some of the upper retention posts can simply terminate without connecting to the basket retaining ring. Lid  150  includes lid projections  152 . Lid projections  152  are optional, but preferred to prevent the donor tissue from sticking to lid  152  and to place the corneas at maximum specular microscope focal length for best endothelium access to preservation medium. O-ring  154  makes a liquid tight seal of lid  150  to container base  156 . Basket retaining ring  148  is prevented from moving lower by container base shelf  158  and basket retaining ring  148  is prevented from moving upward by lid  150 . To prevent medium from getting to o-ring  154 , lid seal  161  squeezes corneal basket retaining ring  148  and acts as a redundant seal. Although eight upper and eight lower disc support surfaces are shown, a more preferred embodiment has least three upper and three lower disc support surfaces. 
     When configuring the embodiment described above and shown in  FIG. 10A  and  FIG. 10B , care should be taken to ensure that basket geometry allows at least 38%, and more preferably at least 50%, open area as determined from the upper disc support surface to the container base to ensure that a large cornea that comes to reside upon the upper disc support surface attains superior solute movement beneath the cornea. 
     Material selection for any embodiment includes a wide array of materials typically present in any class 1 medical device. Preferably, for lower cost, the parts are injection molded. In the preferred embodiments, the material for the lid and container is clear PET, or any other non cytotoxic material that has relatively similar low carbon dioxide transmission and is not damaged or discolored by gamma irradiation. Low carbon dioxide transmission is beneficial as it acts to minimize pH shifts during storage when the medium includes a sodium bicarbonate buffer. When using an o-ring to create a seal between the lid and container, it is best to select non cytotoxic material compliant with gamma irradiation. Skilled artisans will recognize that there are numerous other options for material selection. 
     Skilled artisans will recognize that various features of the embodiments illustrated within can be mixed and matched to form a wide variety of configurations that attain the objective of improving cornea health. 
     EXAMPLES 
     Example 1 
     The Effect of Altering Cornea Container Geometry on Corneal Health as Determined by Quantitative Specular Microscope Analysis 
     The aim of quantitative specular microscopic analysis is to assign values to endothelial cells that can provide a measure of their functional status or health of the human cornea. One of the parameters of quantitative specular microscopic analysis is determining the shape of the corneal endothelial cell. In a perfect cornea, endothelial cells demonstrate a perfect 6-sided hexagonal cell. This 6-sided configuration allows for the cell to function optimally. The normal human corneal endothelium is a monolayer of uniformly sized cells with a predominately hexagonal shape. Human corneal endothelial cells that demonstrate great variability in shape or hexagonality are considered to be under physiological stress and abnormal. Corneas that exhibit increased swelling during storage are also considered to be under physiological stress. 
     Maintenance of corneal deturgescence during corneal storage at 2-8° C. is determined by the barrier function of both the corneal endothelium and the epithelium. The corneal epithelium plays a major role in maintaining a barrier function which prevents the corneal tissue from swelling by preventing fluid into the cornea. Loss of the corneal epithelium during storage greatly increases the swelling of the corneal stroma. Until recently, the importance of the corneal epithelium has not been fully understood. Maintaining all layers of the corneal are equally important and is a goal in optimizing corneal storage at low temperatures. 
     Increased swelling causes the formation of corneal folds from the thickening of the normal corneal stroma. These folds have a detrimental effect on the corneal endothelium. Increased hydration also increases corneal folds, which contribute to endothelial cell loss. Corneal swelling, if great enough, can also cause cell death to the corneal keratocytes. This increased hydration also causes irregular spacing of the collagen fibrils of the cornea, reducing optical clarity of the cornea. Increased corneal hydration reduces corneal quality, and length of time the cornea can be stored. Therefore, it is of the utmost importance to maintain the corneal epithelium as well as the endothelium. 
     The functional status of the endothelium and sustained corneal deturgescence during corneal storage are of great clinical importance and contribute primarily to the success of the surgical outcome. 
     Quantitative specular microscopic analysis of the human corneal endothelium with respect to endothelial cell shape and corneal thickness evaluations were conducted in order to assess the impact of altering viewing container geometry on corneal health. 
     Cornea containers were constructed in accordance with the present invention as described in the text related to the embodiment depicted in  FIG. 10A  and  FIG. 10B  with various dimensions identified in  FIG. 11 . 
     Human corneas were stored in identical preservation medium, either in the apparatus of the present invention or Independent Corneal Viewing Chamber™. Corneas were stored at 2-8° C. for 14 days. Pre storage and 14 day post storage central corneal thickness measurements and endothelial cell photographs were obtained for each cornea with a Konan Eyebank KeratoAnalyzer (Konan Medical Corporation, Fair Lawn, N.J.). 
     Table 1 and Table 2 show a summary of the results. 
     
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 HUMAN CORNEAL ENDOTHELIAL CELL HEXAGONALITY 
               
               
                 (PERCENT OF HEXAGONAL ENDOTHELIAL CELLS) 
               
             
          
           
               
                   
                   
                   
                 Percent 
               
               
                   
                 PRE % 
                 14 Days % 
                 change in mean 
               
               
                 APPARATUS 
                 Hexogonality 
                 Hexogonality 
                 hexagonality 
               
               
                   
               
               
                 Present invention 
                 61.71 ± 6.74% 
                 60.27 ± 5.83% 
                 −2.33% 
               
               
                 Independent Corneal 
                 60.55 ± 7.40% 
                 57.91 ± 6.66% 
                 −4.36% 
               
               
                 Viewing 
               
               
                 Chamber ™ 
               
               
                   
               
             
          
         
       
     
     The data of TABLE 1 show the ability of the apparatus of the present invention to improve cornea health by demonstrating a 46.56% increase in mean endothelial cell hexagonality as compared to the Independent Corneal Viewing Chamber™ (i.e. −2.33% divided by −4.36%) after 14 days storage at 2-8° C. 
     
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 HUMAN CORNEAL THICKNESS EVALUATION 
               
             
          
           
               
                   
                   
                   
                 Percent change 
               
               
                   
                   
                   
                 in mean corneal 
               
               
                 APPARATUS 
                 PRE μm 
                 14 Days μm 
                 thickness 
               
               
                   
               
               
                 Present invention 
                 540.80 ± 23.99 
                 511.80 ± 21.19 
                 −5.36% 
               
               
                 Independent Corneal 
                 541.20 ± 26.51 
                 518.40 ± 23.32 
                 −4.21% 
               
               
                 Viewing 
               
               
                 Chamber ™ 
               
               
                   
               
             
          
         
       
     
     The data of TABLE 2 show the ability of the apparatus of the present invention to improve cornea health by demonstrating a 27.3% decrease in cornea thickness relative to the Independent Corneal Viewing Chamber™ (i.e. −5.36% divided by −4.21%). 
     Example 2 
     The ability for dye to disperse within a cornea container of the present invention, constructed as described in Example 1, was compared to that of an Independent Corneal Viewing Chamber™. Cornea container devices resided upon a stationary surface with their lids removed and the container base of each device was filled with water. Then, trypan blue was dispensed into each device in proximity of the center of corneal basket in the area where the cornea would reside. Photographs were taken. The photograph of  FIG. 12  shows a typical example of the pattern of trypan blue dye dispersion in each apparatus. As clearly shown in  FIG. 12 , trypan blue easily dispersed throughout cornea container  300  (i.e. the apparatus of the present invention). To the contrary, the majority of trypan blue remained trapped in the corneal basket of Independent Corneal Viewing Chamber™  301 , with a relatively small amount moving into the surrounding liquid in a poorly distributed pattern forced by the small gap between prongs  302 . This indicates the superior ability of the apparatus of the present invention to distribute solutes to and from the cornea. For example, lactate from the endothelium of corneas in the Independent Corneal Viewing Chamber™ has to overcome the barrier of the traditional corneal basket to dilute into the surrounding medium. 
     Those skilled in the art will recognize that numerous modifications can be made thereof without departing from the spirit. Therefore, it is not intended to limit the breadth of the invention to the embodiments illustrated and described. Rather, the scope of the invention is to be interpreted by the appended claims and their equivalents.