Eye strain is known to cause: fatigue, difficulty concentrating, headaches, dizziness, and slight nausea. Other symptoms include: eye pain, blurred vision, watery or dry eyes, sore neck, and photophobia (extreme sensitivity to light, an abnormal sensitivity to or intolerance of light, an abnormal fear of light.) Computer usage can also cause additional symptoms such as: difficulty focusing when looking from paper to monitor screen and afterimages when looking away from monitor screen. Symptoms usually begin to appear after extended computer use, reading, straining your eyes in dim lighting, or during activities that involve prolonged visual tasks.
I personally had never heard of this eye condition until I started having a difficulties when I studied for large amounts of time and used a computer. I thought I just needed reading classes or something, and when I went to get an eye exam the doctor told me I had "Asthenopia." I had no clue what the word meant so I looked it up and recognized a lot of the symptoms and thought is would be interesting to share.