Hemingway contrasts light and dark to show the difference between this man and the young people around him, and uses his deafness as an image if his separation from the rest of the world. Near the end of the story, the author shows us the desperate emptiness of a life near finished without the fruit of its labor, and the aggravation of the old man's restless mind that cannot find peace. Throughout this story stark images of desperation show the old man's life at a point when he has realized the futility of life and finds himself the lonely object of scorn. The most obvious image used by Hemingway in this story is that of the contrast between light and dark. It is a refuge from the darkness of the night outside.
Darkness is a symbol of fear and loneliness.
The light symbolizes comfort and the company of others. There is hopelessness in the dark, while the light calms the nerves. Unfortunately for the old man, this light is an artificial one, and its peace is both temporary and incomplete. Maybe the old man hides in the shadows of the leaves because he recognizes the shortcoming of his refuge. Perhaps he is drawn to the shadows so that the darkness of his own age will not be so visible as it would be in the full force of the electric light.