A variety of problems related to prolonged viewing of a computer or mobile screen. Short term effects include dry eyes, blurred vision, mild headaches and eye fatigue. Long term effects include migraines and visual epilepsy. Some solutions are to keep reflections and glare to a minimum and to provide a non-fluorescent, uniform light source. Special lamps are available that maintain the proper light around the monitor and generate light at much higher frequencies than regular light bulbs.
The 20-20-20 Rule
A worthwhile rule of thumb is 20-20-20: look into the distance at least 20 feet for 20 seconds after every 20 minutes of computer, tablet or smartphone use. See medical conditions