It may be time to get new glasses when:
-you see an old woman walking her dog while wearing a WWII war helmet only to drive a little closer and see that she is in fact wearing a sun visor.
-you see three volleyball type things in a field only to see that in fact they are birds....that move...and are alive.
-you have to roam the parking lot at work for 5 minutes because you can no longer spot your car (or is that memory loss??).
-you and your mother spend your time asking each other "can you see what it says? No, can you? I can't, you squint and figure it out, I give up."