Contact lenses stand for seeing clearly without others noticing the help. A lost or slipping lens is traditionally read as a blurred view of a situation you thought you understood.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.