Please explain the narrowness of vision, or short-sightedness, in characters portrayed by Jane Austen in Pride and Prejudice.
Narrowness of vision is defined by Longman's Dictionary as a narrow idea or attitude in which one's "way of looking at a situation is too limited and does not consider enough possibilities." While short-sightedness is similar but defined by Longman's as "not considering the possible effects in the future of something that seems good now."
Elizabeth believes Charlotte too short-sighted when she accepts Collins proposal (in fact, encourages his proposal). Elizabeth learns to have a different understanding once she sees Charlotte in her new home, married and free from her father's protection. Elizabeth sees a content Charlotte in Kent at Hunsford, yet gets no glimmering that she may herself had narrowness of vision.
[Though] evidently regretting that her visitors were to go, she did not seem to ask for compassion. Her home and her housekeeping, her parish and her poultry, and all their dependent concerns, had not yet lost their charms.
Earlier, Charlotte had warned Elizabeth against narrowness of vision when she tried to prompt Elizabeth to be civil and courteous toward Darcy so as not to offend a man of such great wealth and importance: why make an enemy of a powerful man? Later, Darcy sees that he was short-sighted about his reserve, pride and condescension when he hears in what terms and for what reasons Elizabeth refuses his marriage offer.
"You have said quite enough, madam. I perfectly comprehend your feelings, and have now only to be ashamed of what my own have been. Forgive me for having taken up so much of your time, and accept my best wishes for your health and happiness."
Austen's narrative couldn't have been told if it weren't for Mr. Bennet's narrowness of vision and short-sightedness in (1) expecting a male heir who would break the entail and restore Longbourn and wealth back to the Bennet family; (2) in abandoning the raising of his five daughters to their silly mother, since he has become disheartened over his failure to produce an heir; (3) in his folly in abandoning Lydia to the care of the (silly) Forsters in Brighton. Austen builds the whole story around this character flaw in Mr Bennet.
"You may well warn me against such an evil. Human nature is so prone to fall into it! No, Lizzy, let me once in my life feel how much I have been to blame. I am not afraid of being overpowered by the impression. It will pass away soon enough."