I get the squiggly lines too, and the little dots. but that's not due to any drug, it's one of 2 things:

1. occular migraines. this is actually the same process of a migraine, but it happens in your eye. there's no pain though, so don't let the "migraine" part fool you.

2. a small area of your eye is damaged and the little dots or lines are blind-spots. if it's a solid black line then yes, it's truly a BLIND spot, but blind-spots can also just mean that an area is damaged enough to make it blurry or like looking through a gell.