The harm of children playing with cell phones for a long time is mainly reflected in the following aspects: cause visual fatigue, cause refractive error, induce dry eye, etc.. 1. cause visual fatigue: due to the small screen of the cell phone, if the child plays with the cell phone for a long time, especially one-time play with the cell phone time is too long, long time close staring at the cell phone screen, easy to cause visual fatigue, thus appearing eye soreness, eye dryness, blurred vision and other manifestations. 2. Causes refractive error: children playing with cell phones for a long time leads to eye fatigue for a long time, resulting in long time ciliary muscle over-adjustment of the eyes, which is easy to cause vision loss, resulting in nearsightedness, astigmatism, amblyopia and other refractive error problems. 3. induced dry eye: children play with cell phones for a long time, due to long time staring at the screen, vision over-concentration, easy to induce dry eye, resulting in insufficient tear secretion. It can be seen that children playing with cell phones for a long time is more harmful, it is recommended that parents strictly control the time of their children watching cell phones, when there is an adverse reaction, they should seek medical attention in a timely manner.