I've been dealing with PVD's for about 10 years, off and on. My opthomologist (as well as my BIL who is a retinal surgeon) agreed - based on my symptoms, they said if I was a runner, they would tell me to switch to brisk walking and not to do kickboxing where you are hitting a bag and don't do downward facing dog or any other routine where my head is down for an extended period of time.
I still do Turbo Jam, barre work, pilates and yoga but I just watch what I'm doing and where my head is at
, making sure I'm not jumping around too much.
I remember the first time I had one...frightening, but I'm told they are quite common as you get older.
Good luck.