When someone donates a cornea it is then sent to an EYE Bank and once arriving at the EYE Bank the Donor Tissue can be kept for up to 14 days before it must be transplanted to someone.
After 14 days the cornea can no longer be used but the good thing and not so good thing is that there is great demand for corneal transplants so most times the donor cornea only stays at the eye bank for 3 to 4 days.
So most times the cornea is transplanted long before it can no longer be stored and it's very rare for an eye bank to need to keep any corneas up to 14 days.