I see the post is a few days old, but visual migraine symptoms I know only too well. You seem to be describing a Scintillating Scotoma, literally means a colorful blindspot. These type of migraines occur in the occipital lobe of the brain, also known as the visual cortex.
Each of our eyes are connected to the brain in a unique way that most people are unaware of. Half of each eye is connected to one brain half, the other half of each eye is connected to the other brain half.
In these types of migraine, the Scintillating Scotoma is located in the left or right visual field of "each" eye, but may be perceived as being just to the left or right. When you have another one, try closing both your eyes and seeing if it is in "each" eye. Most likely it is.
By now you have been to your GP, please let us know how it turned out. I got this type of migraine for years, often 2 times a week. The visual phase lasted 45 minutes each time, occasionally doubling for 90, and I never had headaches.
Post Edited (JungRulz) : 1/9/2014 4:19:57 PM (GMT-7)