When strabismus begins in childhood, the brain learns to ignore the image from one eye just to avoid double vision. On the other hand, when strabismus begins in adulthood, the brain cannot just ignore one eye. In those cases, double vision can emerge and it can become quite unbearable. Patients might try closing one eye, tilting the head, prisms, "pirate" patches, even covering one eyeglass lens with fingernail polish or tape just to try to get rid of the double image.