Sacks & Sue

Reading Sacks’ article, I became acutely aware of my own eyes and the distance between them. An artist is taught that they should leave one eyes-length between the two. While I have long been privy to the notion that the eyes of prey are typically set farther apart than predators, It never occurred to me that this would effect their 3D perception. After regaining stereoscopic vision, Sue became more aggressive (predatory?) on the road—should we then equate the monoscopy caused by strabismus with defensiveness? I am curious, now, about vision in arachnids and other insects with more than two eyes. The media tends to portray an insect’s visual field as a blurry honeycomb of tiny images. It strikes me that there is more than likely a significant overlap in what each oculus sees. Would we humans be filled with the same wonder that Sue experienced were we to suddenly sprout extra eyes?

We are conditioned to assume that eyes are automatically situated on the horizontal plane. That a small difference in the vertical alignment of Sue’s eyes prevented her from experiencing the world as I do completely blew my mind. Under other circumstances I might go off on society’s “normalization” of stereoscopic vision—who’s to say that our way is the right way?— but the fact that alternatives become physically and mentally taxing over time proves my zeal misplaced.

Sacks’ childhood experiments with hyperstereoscopes and pseudoscopes prompted a frantic web search for examples of their effects and an irrepressible urge to build my own from paper towel rolls. It seems that hyper-stereo 3D, where the two perspectives (or eyes) converge at a sizable angle, has become a go-to format for video game designers looking to push boundaries. I’m less likely to emulate his other experience with stereoscopic deprivation, but the fact that one’s entire perceptual framework can shift based on the size of a room confirms that the brain is more responsible for our visual experience than our eyes.

Even after hearing Sue’s account I have a hard time grasping how one could function only using one eye at a time, especially with nearby objects. When I hold my phone right in front of my face I get completely different images from my right and left eyes. The effect of opening one after the other is almost jarring. Would Sue subconsciously favor one eye over the other in all close-up situations to avoid this effect? What if, in a deliberate attempt to trip up her visual stimuli, Sue rapidly alternated the eye she was using to focus? Like most of Sacks’ work, this story leaves me wishing I was able to meet and interact directly with his subject.

Side Note: I know that I, and many of my friends have a hard time working through “Magic Eye” illusions. I was surprised that such a frustrating game is used as proof of stereoscopic sight. Perhaps I’m just jealous.