I dreaded the first glance at objects around me. It was not that I feared to look upon things horrible, but that I grew aghast lest there be nothing to see.
When the narrator comes to realize that he is unbound and confined within something damp and hard, he refuses to open his eyes. For a few minutes, he just let his hand lie there as he tried to come up with an explanation for where he could possibly be. As the quote says above, he was not afraid that he would find something gruesome, but that he would find nothing, whether because there was nothing to be seen or because he could not actually see it. Finally, however, he can no longer suffer his imagination, so he opens his eyes to look at his surroundings. Much to his horror, his worst fear came true: he was in a room of pure darkness, which was what he truly dreaded to find.