Aura (more brain lightening)

When I got on the BART train this morning and tried to start reading my book I realized I was having a "fortification spectrum" event again -- I couldn't see the type on the page, or directly in front of me. Lasted from Lafayette until I sat down at my desk in Oakland, about 20 minutes, and changed from a tight arc in the center of my vision slowly expanding and moving as if toward me on the left side of my vision. I believe that is similar to the previous times I've noted this type of event. There is not pain or other physical symptom as this is occuring, and it remains when I close either or both eyes. Although the visual symptom is now gone I feel slight light-headedness and disorientation and fatigue and sensitive, and it was difficult to recall what a coworker was just talking to me about. Now (30 min after visual effect) slight pressure, like sinus headache, is noticeable at my right temple. A little frightening as weird experiences go, given there's no pain or ache or twitch.