Migraines can cause many problems and be manifested in many ways. Many people report visual disturbances or auras just before a Migraine is about to occur. This can be hours in advance or just before the head pain starts.
I have some auras, but primarily I have distubances in vision that can manifest as darkening of my vision, like a blanket being pulled over my eyes. The symptoms can also include trouble focusing, along with the typical spots or bright lights than many Migraine sufferers report.
As you have experienced, these visual distubances can be annoying and interfere with work and home life. Even though these auras can be short lived, they can make you stop and relax for a while until your vision clears.
Damn those complicated Migraines. As always, if you have any concerns with your health, go see your doctor today.