Depending on the edition of the novel Silas Marner that you are currently using you will find that not every copy is the same. In chapter 3 of Silas Marner (the Enotes version) places the setting of the novel at the red house. The focus of our online version of chapter 3 is Squire Cass, who is the most revered man in Raveloe, and the introduction of his two sons, Dunstan and Godfrey.
The central theme of this chapter is the description of the Cass family, the dysfunctional nature of the brothers, and the fear that Godfrey may be following the steps of his younger but much good-for-nothing brother, Dunstan.
Additionally, this chapter serves as the preamble to what is to come, which is that Dunstan will steal Silas's gold and create the central conflict of the story. You can read the chapter by clicking on this links to our eNotes edition.
However, if you move further to chapter V on Enotes you will find the allusion to Sila's short-sightedness which begins with
He reached his door in much satisfaction that his errand was done; he opened it, and to his short-sighted eyes everything remained as he had left it, except that the fire sent out a welcome increase of heat.
Here, his short-sighted nature is what prevents Silas to realize that the footprints of Dunstan Cass are already marked on the floor. It is also Silas's tendency to be short-sighted as a whole (a person who does not look beyond his immediate real) what made Silas miss out in many chances of getting to really know the people around him. If he had been more open and willing to literally open his eyes at his reality he would have not become so isolated, thus rendering himself as a potential victim of someone like Dunstan. Hence, the short-sightedness of Silas Marner can be seen as foreshadowing of what will happen next (when he realizes that the money is gone), and as a metaphor that explains Silas's behavior as someone who merely sees what he wants to see and does not expand his horizons for fear of getting hurt.