There are many causes of diplopia, mostly due to ophthalmic diseases, central injuries and systemic diseases. Some diplopia is more difficult to prevent, some, such as acute common internal strabismus caused by diplopia, systemic diseases caused by diplopia can be prevented to a certain extent by reducing the time spent in close proximity to the eye, control the systemic systemic diseases. If the symptoms of diplopia appear, promptly seek medical attention, find the cause, and treat the cause and symptoms.