In Part 1 we noted the visual distress that Wendy experiences when panoramically viewing. Her sense of seeing too much at one time, as she could when stopped at a traffic light and being consumed by all of the sights around her, can cause her to visually shut down. While some patients with intermittent exotropia find that the having one eye straight and one outward simultaneously is a visual advantage, as if watching a big screen TV with picture-in-picture mode, for others like Wendy this adds to visual confusion.
We tend to associate this type of visual confusion with vision at a distance, usually encountering it with patients who have intermittent exotropia of the divergence excess type. These patients can either space out or shut down in response to one eye drifting outward. The patients who have large visible drifts of one eye relative to the other tend to space out: when their mind is out their eye is out, and vice-versa. Those who have less cosmetically noticeable drifts typically encounter more visual confusion or distress. Yet there are patients like Wendy for whom the drift at near has consequences rarely spoken of in vision care literature. Again, Wendy describes it best:
Someone like Wendy can therefore have compromised distance visual function causing them to shut down in extrapersonal space, yet also have visual issues at near or within personal space. We might refer to this diagnostically as “basic, small angle intemittent exotropia”, and note that her near visual issues are consistent with a diagnosis of convergence insufficiency. In other words, Wendy is going into divergence excess mode with increasing frequency at distance, and is experiencing convergence insufficiency at near more frequently as well.
Although intuitively we might sense what it feels like to have either of these conditions, Wendy’s eloquent description gives us pause to realize that we really don’t know what it’s like until we experience it. Perhaps the best we can do is to identify with the effort that patients make consciously or subconsciously to modify their binocular vision, and the courage that it takes to probe the depths of emotions involved. We might conceive of this as yet another way, and a very intimate one, in which vision is the brain’s way of touching.