You should see a doctor
immediately!!! Regardless of what answer I tell you, or what diagnosis you may have, facial swelling to that degree is something that will need to be treated by a physician, and will likely require at least antibiotics and possibly other interventions. Any time that you experience any change in your vision, you need to act immediately to make sure that you don't lose your eyesight for the rest of your life. No matter whether the infection is caused by your tooth, your sinuses, or any thing else, facial swelling should never affect your eyesight. Please, please visit a doctor immediately, with an emergency room visit likely being the best place to start first.
Now, this could be related to your sinuses. The sinuses are air filled (usually) spaces that fill some of the bones of our face and skull. When they become infected, the infection can track through the sinuses and even up into the tear ducts of the eye, which drain into the nose. These infections can then readily track to places that are even more important, and cause cause strokes and other serious complications in some cases. Please go to the emergency department immediately.