If you use ipod touch too much, not only your eyes suffer strain and pain ,but also your skin are affected. If you go on like this, your eyes will be very easily to get nearsightedness and retinal problem, and accompany by the relevant and constipation, such as, headache, anemia, etc. It is mainly because there is strong radiation. So, we are often recommended to have a rest or look around in the distance after a period looking at the screen.
Yeah, most electric productions, like ipod touch, apple phones and so on, will have bad influence on your eyes. Because the screen will inflect the light resource directly into your eyes which may stimulate your eye nerves to make it tired easily because of the near distance. If you keep on using ipod touch for a long time without rest, you may get short sighted. Thus, you'd better keep notice of it.