I think that one can pull much from the poem that Wiesel writes when his family enters Auschwitz- Birkenau. Consider the first stanza:
Never shall I forget that night,/ the first night in the camp/ which has turned my life into one long night,/ seven times cursed and seven times sealed.
The powerful image of how Eliezer's life has become "one long night," speaks to the suffering, pain, and dissolution that ends up becoming part of his narrative. Consider at this point of the poem, he becomes separated from his sister and his mother, never to see them again. The construction of "two lines" helps to enhance this "long night" in that a sense of personal loss becomes inescapable. If we extrapolate this, it only becomes in the darkness of the night when one becomes lost, unable to see or find others. It is in this mode that Eliezer's life ends up becoming "one long night," for the bonds that connect him to other people, his family, and even his belief in God end up becoming dissipated and severed as a result. There is a lack of sight that is a part of his experiences, namely because survival becomes the only foreseeable end. It is here where another example of how Eliezer's life has become "one long night" becomes more present.