Hello goten,
Welcome to the forums and welcome to TES. Here is your complementary http://images.uesp.net/c/c4/Fishystick.jpg
It's a bug that is tied to the "on self" effect, of the Fortify Magicka. Chain Spells were restudied, by some of us, last week. We experienced the same thing. I can only assume it is due to something in the latest patch. I don't know for sure. I am on the 360 and a PC gamer reported the same thing. This will also happen when Fort Mag is applied to other Custom Spells, with different spells applied, like Frost or Shock, with no damage to the player character. The effects, from adding the other spells, do not blind the player like the Fire Spells.
I feel your pain. It is almost impossible to track the target when this happens. Alas, there is no known fix. At least none that I have read, heard or come up with.