I have used mono-vision contacts for many years. can it stop working? distance vision seems hazy and prescription has been changed twice in 6 mos.

Should still work: Monovision should continue to work unless something else is going on. It is possible that you have very early cataracts, which can cause changes in prescription.

Yes: Your prescription may have changed yet again . Have your eye reexamined by an ophthalmologist also to make sure there isn't something else going on.

Yes: As you become older you may be less happy with mono vision as you may lose more of your ability to focus.