After Drysdale tears up the note that Cratchit brought in, Cratchit sets his bell on the desk. A switch to the closeup shows him putting on his glasses with the bell clasped in his hand. Upon the switch back to the longer shot, he is shown putting on his glasses again, but with the bell still on the desk.
In Mr. Drysdale's dream sequence, when Mr. Drysdale starts to open his office door, Cratchit is wearing glasses. But when the shot changes to him entering the office, Cratchit is not wearing glasses.
After Drysdale rips off the employee's petition, the camera cuts to a close up of Cratchit, who puts a pair of glasses on. Next scene cuts to a two shot of Cratchit and Drysdale and Cratchit isn't wearing glasses.
Mr. Drysdale never accepts the collect call from Miss Jane but they continue the phone conversation as if he had.