The mystery of the frozen M-K medium.

Donor corneal material stored or transported in M-K medium can freeze easily if placed in an insulated environment, such as a styrofoam container, with ice that is colder than 0 degrees C. To assure proper maintenance of the recommended temperature of M-K medium of + 4 degrees C, the ice used should be allowed to stand at room temperature until it has a glistening, wet look to its surfaces. M-K medium already cooled to + 4 degrees C can be safely stored and maintained at + 4 degrees C in a well-insulated styrofoam container for approximately 24 hours if this type of glistening-wet, melting ice is used.