My friend is seeing waves of colors out of the corner of his eye it is just on his right side wht could this b

he wasn't looking at any bright light or anything like that he said it just happens randomlyMy friend is seeing waves of colors out of the corner of his eye it is just on his right side wht could this b
A dust particle could cause it, or even an eye muscle spasm. Whatever it is he should go to the eye doctor as soon as possible.
I get something similar to that when I get migraines. I get them maybe once or twice a year. If he's getting them frequently, I might go to a doctor.
He needs to check with both his family doctor and an eye doctor.
There are some things like seizures and psychotic episodes that may be preceded by visualization of things that aren't really there. Sometimes smells or tastes.
With any luck, it's just an eye problem.