This dream took place in another country, at some point I saw my reflection in a window or wall or mirror & my glasses (eyeglasses) were very tinted & would not transition back to clear (everything else was normal), I have photochromic (transition) lenses, this confused me, and so I started doing a reality check eventually I assume.
During my reality check I closed my eyes & I opened them again to see if anything changed, I remember being surprised that I did not accidentally wake up, so at this point I knew that it was a dream, and so it became a lucid dream.
John Jr's Blog 