ero ids ▁along ▁with ▁Im m unos upp ress ive ▁ther apy . ▁ ▁Cor ne al ▁button ▁storage ▁ ▁There ▁are ▁two ▁main ▁storage ▁methods ▁used ▁in ▁the ▁storage ▁of ▁the ▁cor ne al ▁button . ▁They ▁are ▁stored ▁using ▁a ▁hypoth erm ic ▁storage ▁method ▁or ▁an ▁organ ▁culture ▁method ▁in ▁a ▁t issue ▁culture ▁medium . ▁Cor ne al ▁buttons ▁cannot ▁be ▁reli ably ▁fro zen ▁as ▁a ▁storage ▁method . ▁ ▁Usually , ▁the ▁cor ne al ▁button ▁is ▁removed ▁from ▁the ▁entire ▁glo be ▁before ▁storage ▁as ▁this ▁extends ▁the ▁possible ▁storage ▁time . ▁ ▁The ▁hypoth erm ic ▁storage ▁method ▁was ▁first ▁introduced ▁in ▁ 1 9 7 4 ▁and ▁it ▁requires ▁no ▁complex ▁equipment . ▁It ▁is ▁stored ▁in ▁a ▁re fr iger ator , ▁usually ▁ 2 – 6   ° C , ▁in ▁commer cially ▁available ▁storage ▁solutions . ▁Fact ors ▁such ▁as ▁the ▁temperature , ▁maximal ▁storage ▁time , ▁exp iry ▁date , ▁etc . ▁should ▁be ▁maintained ▁according ▁to ▁the ▁storage ▁solution ▁manufact urer ’ s ▁recommend ations ▁and ▁can ▁vary ▁depending ▁on ▁the ▁solution . ▁Also , ▁provided ▁don or ▁screen ing ▁perm its ▁are ▁available , ▁the ▁cor ne al ▁t issue ▁can ▁be ▁used ▁immediately ▁after ▁leaving ▁storage ▁for ▁surg ery . ▁In spe ction ▁of ▁t issue ▁can ▁however ▁be ▁performed ▁in ▁a ▁closed ▁system ▁under ▁a ▁sl it ▁lamp ▁or ▁sec ular ▁mic ros cope . ▁ ▁The ▁organ ▁culture ▁method , ▁first ▁introduced ▁in ▁ 1