Eye strain, also called asthenopia, which is an ophthalmological condition. Eye strain can be a debilitating repetitive stress injury. So many symptoms company it: headaches, blurred vision, eye pain, tired and sore eyes. Well, it's true that eye strain can cause flashing lights. Because eye strain has a bad effect on sight. When the nerves that govern our eye movements feel fatigue, then the proper signals of images cannot reach our eyes in time. And if your eyes feel strain in a long time,the some basic eye problems will come into being. At that time, your eye disorders are much complex than ever. The best thing to prevent eye strain and keep eye health is correct bad habits and reduce contrast. I know a great site(ergonomics.about.com ) that offers details of eye strain included causes, symptoms and preventions.
Well, in my opinion, your fatigue can just lead to this situation in your eyes, such as flashing lights in your eyes. And generally speaking, when you are tired, it will just increase the eye pressure, and then affect your eyes, leading to some eye problems such as flashing lights. And if you have flashes of light, it can be an indicator of a serious eye problem that needs immediate treatment. In some serious cases, flashes accompanied by vision loss or by a large number of floaters, small specks, which appear in your line of vision and appear to float or dart from side to side. So you should pay more attention to it.
Eye strain often result of tired eyes. It cause by foucing something in a long time without rest. When you feel eye strain, it is possible to see flashing lights in front of eyesight. Besides, you may also feel dry eyes, eye pain. And your eyes may possible appear red. To release those symptoms, you can use warm compress on your eyes. Also, you shall close your eyes and have a good rest. Hope this can help you.