Yes, working in the dark does hurt your eyes. Because people depend on a cell named cone cell to see things clearly, however, the cell functions under the condition of ample light. In the dark, the function of the cone cell is greatly restrained, so people cannot see things clearly. Under such circumstance, eyes adjust themselves with the ciliary muscle. Over a long period of time, the adjustment of ciliary muscle becomes stronger, which could lead to the spasm of the ciliary muscle, then you will feel an ache in your eyes, worse still, it even causes ocular hyperemia. Therefore, do not work in the dark as far as possible because it hurts your eyes much and you may become myopic.