Close eyes and see

Semir Zeki finds the inspirational and impenetrable in books on vision.

Georgina Kleege is a novelist and essayist who suffered from macular degeneration at an unusually early age and became blind at 11. Well not quite, for she is partially sighted and can make out a great deal with her peripheral vision. She belongs therefore in the twilight world, not necessarily blind in a casual encounter and yet set apart from the great majority of sighted people by her disability. And herein lies the value of her book, for apart from being an important medical document of considerable interest to ophthalmologists and brain specialists, it is also a human document, the story of all those who belong but also do not belong, the common ingredient that allows those with insight to dissect society and describe it with greater clarity, sensitivity and knowledge.

It is quite extraordinary that it should take a partially sighted person to understand better than most fully sighted people, including perhaps many specialists in vision, how the brain constructs the visual world. "The sighted," she says, "can be so touchingly naive about vision. They apparently believe that the brain can stay out of it", that the visual process works "like a fax machine". Not so for Kleege, who experiences almost hourly - at an art gallery, in a street, during a social encounter - how the brain "can process the incomplete" and construct the visual world. Thus completed, the visual world may not be that of normally sighted people, but it is no less wonderful for that, indeed perhaps more so because of the exhilaration of seeing and using details to which the sighted are indifferent - it is so common to them - and of knowing what the brain can do. An eminent (and sighted) art historian recently said that I was "daft" to have written that an artist like Michelangelo, who left three-fifths of his sculptures unfinished, did so almost deliberately,though perhaps unconsciously, leaving it to the brain of the spectator to complete the sculpture, an idea that also forms the basis of the recent exhibition in Vienna on the finished and unfinished work of Cezanne. I doubt that Kleege, whose brain has to undertake that task of completion continuously, would think me "daft". For her, "Ad Reinhardt's flat planes of colour... vibrate with ghosts of form. Mark Rothko's exquisite colours bleed beyond their frames, staining the wall and the air around them." She would understand better than most what Schopenhauer meant when he said that "something, and indeed the ultimate thing, must be left over for the mind (the brain) to do."

Kleege was not blind from birth. She had a considerable period of visual apprenticeship between birth and the onset of macular atrophy. Medically, the interest of the book lies in the demonstration of how stable and able the visual brain becomes once visually instructed after birth, how much it can use its early instruction and how much it forgets. Kleege, whose parents were artists, draws what she "knows", not what she "sees" - though I doubt the distinction is that clear, since she knows what she has seen. But she has quite forgotten what "eye contact", that all-important medium for social interaction, is. She has moreover, put her early visual apprenticeship to good use by educating other parts of her brain to negotiate what her failed vision is no longer able to do.

The directions she gives to people mystify them because they are too topographical; they depend upon aspects of the surroundings which "sighted people are apparently oblivious to". She relies on expectations and calculates probabilities, precisely what we all do, except that she does it for what appears to us to be mundane visual tasks. Her vision, in short,differs from ours in degree, not in kind. But that difference gives her insights that the normally sighted might find surprising. Her visual disability has allowed her, moreover, to penetrate the mysteries of vision with remarkable acumen.

That she is sighted and not sighted makes her an insider who is also an outsider. She tries at first to camouflage her disability, to pretend to others at least, but also occasionally to herself, that she is normal, and hence acceptable to them. But her affliction nevertheless makes her more sensitive to all that is around her; she actually sees much more than sighted people do. In daily conversation, in the cinema and in literature, she discerns details and nuances to which most are impervious; above all, she is sensitive to the prejudice against blindness, often conveyed in veiled terms. That prejudice, commonly the product of ignorance and insensitivity rather than malice, nevertheless has the disturbing effect of making lesser people of the blind. This book does much to show how misguided we all are in supposing that those who are blind or partially so feel or sense less than we do. Well-meaning people would no doubt be horrified if they knew of the devastating effect that the casual thoughtless comment and conduct can have. Or would they, one wonders? Do doctors who speak loudly of the beautifully deformed retinal vessels within earshot of a patient anxious about her future treat her as anything more than a useful object for medical demonstration? And does the anonymous man in the museum who tells her to stand back to appreciate a Matisse care to learn that the person addressed is struggling hard, but without complaint, to see what he, normal that he is, sees so effortlessly?

But Kleege does not condemn. She tolerates because she understands the source of this prejudice, which is the common source of all prejudice - ignorance. Finally she rebels against dissimulation, and against denying the undeniable, imposed upon her not by her condition, but by the way in which society perceives that condition. Her conversion comes while rehearsing the role of Annie Sullivan, that formidable lady who tutored Helen Keller, in The Miracle Worker. She has a resentment against Keller, who was deaf and blind and yet never complained, while Kleege is struggling, both with herself and with her society. We can only be grateful for that struggle, and marvel at its outcome.

Kleege's description is all the more powerful for being brief, dignified and matter of fact. She does not complain or ask for either pity or help. Yet one cannot but be aroused and disturbed by the pathos of many moments described in this book. These moments were experienced with dignity and silence. But that they should have been recorded at all shows her sensitivity to them; they are silently wounding even if the indignity inflicted is borne with courage. This marvellous book, written in simple and compelling prose, is required reading not only for those interested in blindness, but also for ophthalmologists, vision scientists and philosophers. As a human document, its interest is much wider, for it portrays not only how a genetic defect leads to estrangement and alienation but also how a determined person can rise above these disadvantages, and indeed turn them into advantages.

If Kleege's book is easy to read, Shimon Edelman's book is the exact opposite, and I doubt that, even in spite of its attractive title, there are many even in the world of visual science who would be able to understand much of what it says. This is not a criticism but a statement of fact, and it is indeed good to know that there are still those who will stray from the current craze for publishing coffee-table books with a short half-life - embellished with encomiastic "advance praise" on their dust jackets, often in breach of the Description of Goods Act - and concentrate instead on books with a long shelf life. Even so, I think it is a pity that Edelman has not made a greater effort to reach a wider public, for he addresses an extremely interesting, if hugely difficult theme - how the brain represents the shapes in the world. He believes that the representation is actually veridical, a view I do not share but which merits careful study. Much of the book is computational in nature, thus putting it well beyond the reach of any but the most hard-core computational neurobiologists of vision.

Edelman does, however, describe the experimental evidence, from animal physiology, from human mapping studies and from psychophysics, in favour of his view. That description is, unfortunately, too selective and leaves out of account much that has been learned in neurophysiology, neuroanatomy and human brain studies. Edelman believes in terminal areas, and for him the terminal area for shape recognition is located in the inferior convolutions of the temporal lobe. While this may well turn out to be so, it is nevertheless a view that will be disputed by many who will have been impressed by the anatomical evidence that there is no terminal area in the cortex, in that all areas send and receive, that there are massive interconnections between the temporal lobe and other areas of the brain, visual and non-visual, and by the clinical evidence showing the complexities of shape perception not touched upon here. His view, he tells us, is philosophical and it therefore seems appropriate to remind ourselves of what Schopenhauer once said of representation: that it is "an exceedingly complicated physiological process in the brain of an animal, the result of which is the consciousness of a picture there". I doubt that anyone can improve on that today. I nevertheless hope that Edelman's interesting and original view, described in this book, will be given the serious consideration that it merits in the circles for which the book is obviously intended.

Semir Zeki is professor of neurobiology, University College London.