Why won't my beta eat?

I have one female beta in a 2 gallon tank. She's been fine for the 9 months I've had her. But now she hasn't eaten for a week. I give her food and she act like she doesn't even see it. She swims to one corner and sits at the top of the water, then...

eventually moves to another corner. I'm still putting food in the tank, but I wonder if she could be blind.

I thought I answered this?