My wife has had visual snow since she was a teen many years ago. Her 50 year old daughter also has it. Eye doctors as well as most Neurologists have NEVER heard of visual snow, which frustrates the heck out of my wife.
She also recently read that it's supposed to get better as you age - WRONG!
When she was younger she could drive at night. Now she is virtually night blind and in winter, is always home before dusk.
This is a case where the medical profession needs to realize that it is so rare that it doesn't need to be acted on, but made to be part of the education eye doctors receive.