I found this article yesterday and thought I'd share. It should give you an idea what a migraine with aura looks/feels like. I currently have about 2 of these a month these days for the last few years.
It is sometimes difficult to explain this symptom, but this is a pretty good illustration by the Mayo Clinic.
In about half of my aural migraines, I lose between 20-30% of my center of vision. (I can only see 70% of the visual field and only at the periphery) In the other half of my migraines with aura, I lose between 10% and 95% (Twice with a 95% loss) of my vision at the periphery. (I can only see in the center of my field of vision)
For me, these are the most dangerous migraines as they have typically hit when I'm driving, power tools, etc. The key to these migraines is that when they come on, you MUST get your medication ASAP! On several occasions these have hit when I was away from my medication. I drove 30 miles one day with one of the more severe periphery losses--I wouldn't recommend it!
I would probably recommend medical attention for these types of migraines, but I have rarely sought help. With my sheer number of migraines, I've learned to work through these. One of these migraines with aura signals for me that my day is over. Within an hour of one of these hitting, I am hit with the most severe head pain I have ever had. 2 hours after that, my nose starts bleeding and continues for hours. 24 hours after the aura hits, I cannot concentrate nor function normally.
These aural migraines usually take 2-3 doses of my Imitrex over the course of 24 hours. This is why I recommend medical attention. If you aren't familiar or experienced with migraines or self-treatment, I wouldn't recommend going it alone.