If you have HCRA - healthcare reimbursement account - you pay into that account with every paycheck. Spend the FULL amount before you leave! Buy glasses! Figure out a way to spend it ALL! I was given that advice last year - I left in July, so had about half of the planned 2015 amount "in the bank." I spent the full amount -- and the person who gave me the advice was right, IBM never came after me for the other half of the money. They must somehow account for the full amount at the beginning of the year.
Anyhow, if you have an HCRA - try to spend it all! (Nothing to lose here. If they did come after you, you still got the tax break on the expenses. If they do not come after you - and I think they will not - then that's gravy.)