Nystagmus is an involuntary, rhythmic, pendulum-like or skipping-like oscillation of the eyeballs. The main causes of nystagmus are early oculomotor dysplasia, such as having congenital cataracts that form nystagmus, and a family history of genetic predisposition, Down syndrome, brain injury, or lesions, such as inflammation, tumors, degeneration, trauma, and vascular disease of the brain, which may cause nystagmus. In addition, eye disease or eye dysfunction, degenerative changes in the optic nerve, severe astigmatism, highly myopic eyes, physical diseases, multi-site sclerosis, stroke, and severe ear inflammation can cause nystagmus. There are some poisonings that can also cause nystagmus, such as sedative poisoning, antipsychotic poisoning, bromide poisoning, etc. Alcoholism and albinism are also among the causes of nystagmus. Sometimes there is no clear cause for nystagmus, but it can also be influenced by mental and physical factors, such as stress, fatigue or tension.