<prompt> Which of the following is the longest acting ocular Beta blockerTimololBetaxololCaiololMetoprolol  <response>: Ref-KDT 6e p145 Betaxolol is a cardioselective Beta blocker useful in glaucoma.it is longer acting than timolol .another non selective Beta blocker used topically for the treatment of glaucoma is levobunolol. 