After he is dismissed from the British intelligence agency ("the Circus"), retired spy George Smiley (Gary Oldman) changes his glasses.
This shot serves a structural purpose. It cues us to recognize that every shot in which we see Smiley with his old, orange-colored glasses will be a flashback. In turn, when we see Smiley wear the black glasses, we will know we are in the present. Yet the film's flashbacks could probably survive the exclusion of this device; it is clear enough, most of the time, when Smiley is remembering his years in the Circus and when he is in the present, investigating who the mole (an infiltrator in the agency) might be. For this reason, the glasses motif equally serves, I think, to create two different kinds of emotional frames. Smiley, in the present, looks back at the life and friends he once knew (even as he rather coldly performs his investigation into the identity of the mole). He regrets that his most meaningful friendship (with the agency's chief, Control, played by John Hurt) ended in suspicion of duplicity. By contrast, in the flashbacks, Smiley's orange glasses blend in with the orange and brown hues of the film's meticulous set design, fully rendering the character's feelings as part and parcel of the Circus itself. Few films have so beautifully rendered what it feels like to be wrested away from the institutions and colleagues through which one has defined one's life.