Oliver Sacks’ books are impressive and this one is no exception. He’s always willing to go that extra mile in trying to understand the experience of people who are confronted with all kinds of neurological anomalies. One of my favourite Oliver Sacks quotes is very truthful and at the same time marvelously reveals his curious and compassionate attitude towards his patients.
In this book Oliver Sacks delves deeper into the phenomena of alexia (loss of the ability to read), posterior cortical atrophy, aphasia (inability to speak), prosopagnosia (face or object blindness), stereo blindness (inability to see depth), his own experience with eye cancer and unilateral blindness and finally various accounts of complete blindness and mental imagery. I am intrigued by all of those conditions and the very diverse ways of neurological adaptation to them. Especially the gift of mental imagery based on visual memories and input from other senses some blind people develop, allowing them to do all sorts of unexpected things, is very inspiring. I personally on the other hand only have first hand experience with stereo blindness making this a rather biased review towards that topic. It is also in this book that he tells us the story of how he met Susan Barry and how they marveled at her discovery of stereo vision later in life which is discussed in more detail in her own book ‘Fixing my gaze’. For many strabismic people, including myself, the book ‘Fixing my gaze’ was a turning point in their lives and propelled them into a stereo frenzy. Aside from Susan Barry’s journey from zero to stereo, the chapter also describes Sacks his own experience as a ‘stereophile’ joining the NY stereoscopic society and experiences of various other people losing and gaining stereopsis and how it affected them. One of these stories confirms everything I’ve learned so far from many earlier readings but nonetheless it still didn’t fail to amaze me.
One has to lose the use of an eye for a substantial period to find how life is altered in its absence. Paul Romano, a sixty-eight-year-old retired pediatric ophthalmologist, recounted his own story in the Binocular Vision & Strabismus Quarterly. He had suffered a massive ocular hemorrhage, which caused him to lose nearly all sight in one eye. After a single day of monocular vision, he noted, “I see items but I often don’t recognize them: I have lost my physical localization memory.… My office is a mess.… Now that I have been reduced to a two-dimensional world I don’t know where anything is.”
The next day he wrote, “Things are not the same at all monocularly as they were binocularly.… Cutting meat on the plate—it is difficult to see fat and gristle that you want to cut away.… I just don’t recognize it as fat and gristle when it only has two dimensions.” After almost a month, though Dr. Romano was becoming less clumsy, he still had a sense of great loss:
Although driving at normal speed replaces the loss of depth perception with motion stereopsis, I have lost my spatial orientation. There is no longer the feeling I used to have of knowing exactly where I am in space and the world. North was over here before—now I don’t know where it is.… I am sure my dead reckoning is gone.
His conclusion, after thirty-five days, was that “even though I adapt better to monocularity every day, I can’t see spending the rest of my life in this way.… Binocular stereoscopic depth perception is not just a visual phenomenon. It is a way of life.… Life in a two-dimensional world is very different from that in a three-dimensional world and very inferior.” As the weeks passed, Dr. Romano became more at home in his monocular world, but it was with enormous relief that, after nine months, he finally recovered his stereo vision.
A reoccurring theme in all things neuroscience is the importance of stimulation and experience which is especially relevant in figuring out treatments such as Vision Therapy for neurological conditions.
“Our face cells (neurons used to recognize faces), already present at birth, need experience to develop fully. It is similar to many other capacities. From stereo vision to linguistic powers, some predisposition or potential is built in genetically but requires stimulation, practice, environmental richness and nourishment if it is to develop fully. Natural selection may bring about the initial predisposition but experience and experiential selection are needed to bring our cognitive and perceptual capacities to their full realization.”
Speaking of which… I recently listened to ‘The woman who changed her brain’ by Barbara Arrowsmith Young who developed and tested many cognitive exercises to treat herself and thousands of others with severe neurological deficits and learning disabilities. Her book and program of brain exercises are wonderful examples of what neuroplastic treatment can offer if only educators and doctors start learning about them!