I have this too. When it happened in one eye, I spoke to my optician who sent me to the eye hospital for checking. When it happened in the other eye, I thought I knew what it was and ignored it, thus earning a dressing down from the optician who said I should have had it checked in case it was more serious.
My PVD symptoms consist of flashes of light in the corners of my eyes sometimes when it's dark, a bit like a car headlight going past. Also, black 'blobs' floating in front of my eyes, not very big but quite a few. I really don't notice them now, my brain filters them out although they are there if I look for them.
I'm told it's age related, the brain soon learns to ignore them, but when it happens suddenly, it should always be checked. My eyesight is still very good, I only need reading glasses and, until I saw this thread, had completely forgotten about it.