If you read in low light, Your eyes have to work harder to separate the words from the page, which strains your eye muscles. Consider this to be strenuous exercise for your eye muscles. So your eye muscles will ache. When your eyes are working this hard for a long period of time, the strain may cause a number of physical effects. Symptoms of eye strain include sore eyeballs, headaches, back and neck aches, drooping eyelids and blurred vision (kittle, 2008).