It's not clear what causes AWS, but doctors are trying to better understand it. They do know that AWS isn't a problem with your eyes, a hallucination, or a mental or neurological illness.
Researchers believe unusual electrical activity in the brain causes abnormal blood flow to the parts of the brain that process your environment and experience visual perception. This unusual electrical activity may be the result of several causes.
One study found that 33 percent of people who experienced AWS had infections. Both head trauma and migraines were tied to 6 percent of AWS episodes. But more than half of AWS cases had no known cause.
Although more research is needed, migraine is considered the leading cause for AWS in adults. Infection is considered the primary cause for AWS in children.
Other possible causes include: