I think the main thing is make sure he has somewhere dark to go in his cage
They need a good sized house/hide that is dark inside. A good option is a shoebox with a tunnel or bendy bridge over the door. Cut the bottom out of the shoebox, keeping the lid as a lift-off roof, cut a hole for a door in the front and put the bendy bridge over. Also if you have deep substrate your hammy can burrow to be out of the light.