On average, workers and adolescents in modern cities spend over 45 hours every week staring at computer screens, playing video games, watching television, or interacting with smart phones. The U.S. National Institute of Occupational Safety and Health found that over 88% of office workers report eyestrain. A European study showed that 23% of Swedish schoolchildren experience eye fatigue due to playing video games excessively. This widespread use of visual displays increases stress on the eyes, which leads to a complex ophthalmic and psychophysical condition called computer vision syndrome (CVS). Symptoms of CVS include eye strain, sensitivity to glare, sore eyes, blurred vision, and neck and shoulder pain. CVS also causes mood swings, irritability, physical burnout, headaches, and a consequent decline in mental performance, motivation, and interpersonal efficacy.