Monocular diplopia is a condition in which there is a slight double vision in one eye, but this double vision is improved in both eyes. Generally, this condition is related to astigmatism, which is a certain amount of astigmatism after the optometry, and it is more obvious at night. In adulthood, it is relatively stable, within 100 degrees of such a range of change, will not disappear on its own, so once the phenomenon of monocular double vision, especially at night is more serious, you need to go through the optometry and wear a pair of astigmatism glasses, you can improve the situation of diplopia. Especially at night when driving without glasses, it is easy to have some danger, so when there are obvious symptoms, it is still recommended to correct through glasses, because self-recovery is almost unlikely. There may also be uneven clouding of the lens or dislocation or semi-dislocation of the lens, which also cannot recover on its own and requires surgery. There may also be pupillary abnormalities, such as double pupils or partial pupillary defects.