A corneal punch comprising a base unit having a first annular mating surface surrounding a well in which a donor cornea may be located, and a separate guide unit including an inner annular guide shaft and an outer locating ring connected to the guide shaft and having a second annular mating surface. The formulation is based on a combination of safe organic enzymes and catalysts by utilizing natural microbal action to break down carbohydrate forming cell walls by consuming and digesting the offending fungus spores, mycotoxins, bacteria and other biological pathogens on contact. Each CAM entry line may include a selection line for enabling the CAM entry line for writing andor reading and an entry output for indicating matching to a search key. The width is between about 25 mm and 50 mm. The result of a TEST READ operation is compared with a NORMAL READ operation of a memory cell.