Five minus one is four.
He has only four senses, and they have all sharpened drastically since he lost his sight. He can hear a pin drop across a crowded room. He can feel his way around a keyboard with his hands, and around a room with his cane, which has become an extension of his hands. He can easily pick out a single scent from among hundreds of mingled smells. He never thought much about his sense of taste before the accident; now when he walks down the street and tastes the air around him, he realizes how strong that sense can be.
Five minus one is black.
When the blackness swallowed him, it stole a part of his soul that he can never get back. Even if by some miracle he one day regains his sight, he will never be able to forget the blackness.
Five minus one is black and blue.
Because even after six years without sight, he still bumps into things about fourteen times a day.
Five minus one plus one drink too many is a night of wallowing in self pity.
He has had more of those nights than he cares to admit.
Five minus one is four.
His four remaining senses are heightened to an intoxicating degree when he's around her. He savors the memories of the first time he heard her voice, the first time he smelled her perfume, the first time he felt her hand on his arm, guiding him, and the first time he tasted her lips.
Four plus Annie is infinitely more than he could have ever dreamed, because he doesn't need his sight to see the world through her eyes.