Some Eastern Catholic and Orthodox do reserve the Blessed Sacrament. [/quote:3qpwg6p6]
My understanding is that the Orthodox reserve it only to be given to the sick. They do not reserve it for the adoration of the faithful as in the Catholic Church. Also, it is not easy to reserve the Blessed Sacrament in the form of leavened bread for long. It will get hard like any other bread. That is not the case with wafers which are hard to start with.
Some Eastern Catholics reserve the Blessed Sacrament eg. the Maronite Church (using wafers) and others do not eg. the Coptic Catholic Church (using leavened bread).