I decided that I'm no longer going to use the Oz position, but instead focus on o1 and o2. They seem far more effective and I notice the results are much greater the next day.
Yesterday I was quite frustrated because my eyes were exhausted as a result of not being able to diverge sufficiently. Combine that with the fact that my suppression is way down, I had some really annoying diplopia. But Monday and a few days before that I had the anode on the Oz position. I had been using that position because I had heard about researchers giving anodal stimulation on that region to help people gain stereopsis. But it doesn't really make sense to do that. The brain is split in two hemispheres. You want to stimulate the visual cortex on the two different hemispheres which are located on each side of the head.
Yesterday I went back to the original o1 and o2 positions that I've already had quite a bit of success with. This time I didn't split the anode. I used two anodes and two cathodes since my Chattanooga device has dual channels. One anode on the o2 with its cathode crossing to the left side of the neck with the other anode on o1 with its cathode crossing to the right side of the neck, creating an 'X'.
I could tell the difference in the anode placement almost immediately, and certainly during the day today. I just noticed much less fatigue. It's a lot easier to point my eyes at the same spot in space. I'm a lot less irritable today, despite the fact that I didn't sleep too much--on a side note, try to do tDCS preferably several hours before you sleep--they don't call it transcranial direct current stimulation for nothing. It's stimulating.
What tDCS seems to do is boost the amount of energy that the visual system has. I'd talked about the concept of energy in the visual system in entries long ago, and how for vision therapy success, strategies are often implemented to conserve energy in order to make fusion easier. The idea is that your visual system has a finite amount of energy which can be used for different functions like accommodation, fusion, movement, vergence, and so on. One way to conserve energy is by cutting down on the amount of compensation the visual system has to make by correcting any kind of refractive errors with contact lenses. One of the things that my vision therapist wanted me to do was use prism glasses to compensate for hypertropia that I had so the vision system could put more of its energy into fusion. The idea was energy conservation.
When I've done a good tDCS session, it seems there's more energy available for the visual system. It's much easier to fuse, and point my eyes at things so tasks which would ordinarily be exhausting aren't as exhausting. Today I'm not nearly as exhausted I was yesterday. I believe it's a result of the change in anode positioning. Yesterday when playing XCOM after my exercises I noticed more depth than ever. It was pretty badass. I was noticing depth in places where I don't normally notice it as well. Whenever I experience new levels of depth I get excited because it's so stimulating. And it's going to get stronger than this, possibly a lot stronger. So it was a good way to end a frustrating day.