Visual Symptoms

I've suffered from migraines with aura (including visual disturbances like blind spots and flashing lights) for quite a few years now, and one thing I've noticed is that even when I haven't had a migraine for ages, I still get these weird "floater" type things, but they're not floaters. They're little blobs/shards of light that suddenly appear in my vision, and they sort of look like when you look at a lightbulb for a second or the sun reflecting off a car and you get a blind spot for a short while. It's usually just one at a time, and are more visible for a split second when I blink. If I blink rapidly, they're really easy to see. They're also easier to see against lighter backgrounds, like the sky. They don't move around in my vision; they stay in one place and can last from 10 seconds to 30 minutes even, but they're usually around 10-20 seconds. Then they just sort of dissolve away and that's that. Sometimes I get them when I do a short burst of exercise, like running up the stairs or standing up quite quickly or something. Sometimes they're smaller and other times they're big. They don't completely block anything behind them. For example, I can still fully see words on a screen, they just sort of sit over the top of them but I can see through them. They're a bit distracting but not too annoying. Some days I get them quite regularly, other days I go hours without having (or at least noticing) one. I was just worried that they were something more serious. I went to have my eyes tested a couple of months ago to get glasses and the optician said my eyes were very healthy but I had a slight astigmatism in my left eye so I have glasses to wear for concentration tasks like using a computer and reading. I also noticed they come very regularly while I'm having a migraine after the aura period, and when I've recently had a migraine.