The Adventure of the Golden Pince-Nez

A murder was committed at the old professor Coram's house. His secretary Smith was killed while the professor was still in bed. Coram would have been the first suspect if it was not for the fact that he was an invalid who could not move. Inspector Hopkins got to a dead end in the investigation so he reached out for help from Watson and Holmes. The only evidence they found was a pince-nez. Can this be enough for them to solve the case? "The Adventure of the Golden Pince-Nez" is a part of "The Return of Sherlock Holmes".