We the see the idea of nonexistence, or not wanting to exist in mainly two ways, Oskar "zipping up the sleeping bag of himself" and the distinction in his grandfather's apartment between Nothing and Something. This idea seems to be key, since when someone close to you is lost, they want to become nonexistent, and the lost one themselves are nonexistent.
my eyes are crummy
My eyes are crummy should be linked to nonexistence because due to the fact that she cannot see, she writes her entire life story without actually writing it. Her life story is a gigantic pile of blank pages, where her story should be. It is nonexistent, and will now never be existent.
The picture on page 60 shows Central Park as blanked out.
The concept of non existence or blankness connects to the idea that life is meaningless
The grandmother and the grandfather created nothing and something places for privacy and nonexistence. If you don't want to be seen they go to nothing places to get away from the world or just don't want to be seen. Nonexistence and privacy are linked together.