If there is inflammation, trauma, or neurological disorder in any one of the six muscles which control the rotation of the eyeblaas, then the actions of the optic muscles will become very discordant, thus limiting the rotation of the eyes, and the images of the object seen by the two eyes can not locate in the same spot on the retina, which makes people see two same objects, making the double vision. There are some reasons to cause double vision, such as impotence or paralysis of the extraocular muscles, disturbance in the cranial nerves, strabismus when reading. In your case, it can be strabismus that make you get double vision, that is, you do not use your eyes in a correct way when you are reading. For example, you have habits of reading while lying in bed or placing your head on arms, making the optic muscles transformed. Therefore, you should get rid of these bad reading habits, and go to the doctor's for an eye examination, and usually the doctor will ask you to wear eyeglasses to help correct your vision.