If my misaligned eyes had been straight and looked at the same object, then neurons carrying information from each eye would have delivered the same input to binocular neurons in my visual cortex. Since my eyes were not straight and saw different things, the binocular neurons in my brain received conflicting input. This situation set up a competition between my two eyes, and for each neuron, one or the other eye won out. Each neuron in my brain now responded to input from only one eye. My brain was wired in a way that prevented sterovision. While reading in college about “critical periods” in vision development, I had to conclude that it was too late for my vision to change. Yet, much more recent scientific research indicates that the adult brain may be more “plastic,” or capable of rewiring, than previously realized.
— Susan R. Barry, Fixing my Gaze
I went to the eye center early, before my fifth therapy session, to have a prism film applied to the right lens of my glasses. The prism corrects the misalignment to a limited degree, so I still must make an effort to fuse the double vision on my own. It’s a crutch of sorts, bringing images into a zone that deters my ingrained tendency to suppress the vision in one eye. Because of this, things usually look chaotic when I put on these glasses because they force my perceptions to deal with the lack of fusion. During therapy we had a bit of a breakthrough when Mary Ellen at last identified the precise configuration of prisms that seemed to provide for me vision that was fully singular. Pow. Suddenly I had a non-jumbled picture before me, without regard to head position or directional glance. But as appealing as that sounds, wearing this configuration of corrective lenses would do nothing to reverse the underlying brain-eye disorder. So the emphasis remains on integrated therapy, including a new pattern of exercises I do with a metronome. When I tried my first metronome task, I thought, “I don’t think I’ll ever be able to do this.” I kept at it, and when I noticed the first shade of progress, I experienced a startling shift in mindset— “I’m wrong. This is possible. For too long I’ve told myself that I can’t do things.” This awareness has now become the standard when a new exercise seems difficult. I don’t trust that initial feeling of insurmountability. Instead, I begin to anticipate some indication of partial success, and then I accept that daily practice will turn the tide. In other cases, the exercises have seemed too easy. I’ve learned to tell myself that there must be various kinds of neuron activity necessary to the overall brain rewiring. Easy or hard probably has nothing to do with it. At the sixth session, the “breakthrough” prism-set didn’t work at first, but then everything sort of snapped into place after a delay. I had noticed this phenomenon before when using the “crutch glasses.” Clearly there is more to this than getting a new pair of spectacles. It’s more like acquiring a new wiring diagram for my gray matter, synapse by synapse.