As with all apocalyptic or disaster stories the characters face obstacles that force them to face themselves first. The name of the game is always survival. The ethics involve personal versus community, wrong versus right considering circumstances (something that ethics claims should not be in play), sick versus healthy, children first, strong versus weak, and basically, just how far a character will go to survive (the literary "getting what one wants desperately").
In this novel, there are a series of conflicts and resolutions. With the drama focusing on blindness, we would consider that to be the cause, the reactive behavior following to be the effect. We no longer care–nor do the victims–what caused the blindness. In place of a fight or flight instinct (that may be a parallel story happening outside the walls of the mental institution storyworld) there is a fight or accept situation being asked daily. Food, leadership, sex; these are the main needs of the people and how they must act upon these needs is the question.
When a single group seeks control over the masses, the blindness, likely because they have not gotten used to it quite yet, is what stands as an obstacle between the moral and the immoral behaviors of both the bad guys and the good guys. The good guys are willing to sacrifice their valuables and then their women (this from almost all the guys and all the women) in order to eat since the bad guys have all the food and a gun. Life is still too precious to risk despite the filth and degradation the victims of first blindness, then incarcerations, now the bullying tactics of a clearly immoral group (NOTE: I question how'd these 20 blind men find each other and end up all in the same ward? Is it another case of mob mentality, or what is best for the group?).
When one crosses the line of accepted behavior, societal or personal, is it justified as a one-time deal? Is the future (survival) even considered or is the present the important impetus? What of the past, the deeds done that one would never have considered without the pressure of the situation–does one return to one's moral stance or has the line hardened to prevent return…
One cannot read this story without questioning one's own judgments in trying to imagine what one would do in similar circumstances–an easy armchair choice when it's not real.