Adventures in Achromatopsia

The Island of the Colour-blind was given to me by a friend who was himself red-green colour-blind. This discovery, early in our relationship, illuminated several of his quirks: a terrible dress sense, a preference for Dürer engravings over Impressionist sunsets, a comment made on an early date that our shirts ‘matched’ (I was in damson, he was in scarlet – the two shades of red clashed horribly). As a biologist, I thought I knew about colour-blindness, but this wonderfully weird book gave me a whole new perspective on the phenomenon.

The author, Dr Oliver Sacks, is an eminent neurologist with an impressive list of bestselling books to his name. The most famous of these is the memorably titled The Man Who Mistook His Wife for a Hat, in which I discovered ‘visual agnosia’ – the complete failure to recognize familiar objects or people – and felt suddenly grateful that my own friend merely mistook his reds and his greens. Dr Sacks has investigated and documented neurological oddities throughout his career, up to and including his own recent loss of one eye to ocular cancer in the acutely personal The Mind’s Eye. His writing style is scholarly, humane and highly accessible: The New York Times has called him ‘a kind of poet laureate of contemporary medicine’. Indeed, the medical mystery tour recounted in The Island of the Colour-blind (1997) is probably his most poetic offering. Dr Sacks begins his tale by describing how the visual migraines he experienced in childhood left him with an abiding interest in colour perception. He also sustained an omnivorous passion for biology in general and for island biogeography in particular: ‘Islands have always fascinated me; perhaps they fascinate everyone . . . special places, remote and mysterious, intensely attractive, yet frightening too.’ These various interests converged in adulthood when he met two colour-blind patients: one who had lost his colour vision in an accident and another who was born without it. Completely achromatic vision, ‘achromatopsia’, is seriously disabling, and as rare as red-green colour-blindness is common. So Sacks was intrigued to discover that a tenth of the entire population on the tiny Pacific island of Pingelap was achromatopic. How did these people cope with their condition? How had their culture adapted to accommodate it? Not content with merely reading up on the subject, Oliver Sacks travelled 7,000 miles to find out, having roped in an American ophthalmologist and an achromatopic physiologist from Norway for a scientific expedition rather akin to those of his Victorian heroes, Darwin and Humboldt. The answers proved to be complex, reaching beyond neurology to encompass genetics, history and anthropology. Sacks and his colleagues examined the colour-blind people of Pingelap, distributed visual aids and tried to dispel some of the folk myths surrounding maskun (Pingelapese for ‘not-see’), which included the fear that it progresses to total blindness and the belief that it is caused by mystic curses. In fact, the aetiology is a dramatic genetic bottleneck dating back to 1775, when the atoll’s population was slashed to just twenty by a devastating typhoon. Intensive inbreeding saved the community but also brought out the genetic disorder. Tiny, isolated islands like Pingelap, Sacks emphasizes, live very much ‘on the edge’, both physically and genetically. Typhoons are still a danger and the population still remains at a barely sustainable few hundred. It exists on the edge of stability and the edge of survival. Pingelap’s story of natural disaster and dogged renewal is told without drama, in the author’s habitual tone of pragmatic humanism. It is probably no accident that he moves on from Pingelap to describe the abject colonial history of neighbouring Pohnpei, where successive invaders brought infectious diseases, religious crusades and oppressive regimes that decimated the native islanders as effectively as any act of nature. Pohnpei is much larger than Pingelap and it harbours many immigrant communities from nearby atolls. The Pingelapese enclaves on Pohnpei are insular and geographically isolated, something that may have ensured their survival through a troubled recent history, but that also prevented out-breeding. Here, as on their native soil, the Pingelapese show a high rate of maskun. Leaving the island of Pohnpei, The Island of the Colour-blind takes a left turn and concludes with a separate episode on the islands of Guam and Rota, linked to the first purely by geography. Dr Sacks defends the book’s idiosyncratic structure in his preface:

I went to Micronesia as a neurologist, or neuroanthropologist, intent on seeing how individuals and communities responded to unusual endemic conditions – a hereditary total colourblindness on Pingelap and Pohnpei; a progressive, fatal neurodegenerative disorder on Guam and Rota. But I also found myself riveted by the cultural life and history of these islands. . . If seeing patients, visiting archaeological sites, wandering in rain forests, snorkelling in the reefs, at first seem to bear no relation to each other, they then fused into a single unpartitionable experience, a total immersion in island life.

It is in this spirit that one must read the book: as an idiosyncratic hybrid of travelogue, scientific monograph and detective tale, given coherence and propelled by the author’s eclectic interests. He describes the islanders’ diet, religion and prevailing attitude towards the disabled with nuanced sympathy. He waxes lyrical about night-fishing and snorkelling, and remarks delightedly on hearing his first cephalopod creation myth on Pohnpei. His sophisticated medical writing often contrasts sharply with a childlike enthusiasm for story-telling. ‘The first draft of what I write’, Sacks has admitted, ‘can be monstrously hyperbolic: I rely on editing.’ It can also, it seems, be monstrously erratic, and his editor has wisely collected the footnotes for this book into 65 pages of endnotes. I am seldom tolerant of copious footnotes, finding them distracting and self-indulgent; here, however, they are quite engrossing, being by turns scholarly, personal and just plain bizarre. They certainly disrupt the text, but you may not want to miss them. ‘My footnotes are my Prozac,’ Sacks once told an interviewer, ‘I love writing them.’ Since the story itself is a mere 200 pages long, the best approach may be to read it twice: once straight through, and then again complete with all the antidepressant asides. Throughout The Island of the Colour-blind, an odd, yet engaging, authorial personality is apparent. For a man much lauded as a scientific communicator, Oliver Sacks is famously shy and socially uneasy – it has been suggested that he has Asperger’s syndrome, a suggestion that he himself has met with ambivalence. Certainly, he seems to operate with an unusual directness of mind. Upon hearing that a sea cucumber found off Pingelap may be edible, he immediately sinks his teeth into it (‘I found it impossible to get through the leathery integument – it was like trying to eat an old, weathered shoe’). At several points on his journey, he falls into serious physical peril: a near crash-landing in a light aircraft and a violent storm in a tiny boat. Both are recorded with detached curiosity, as indeed is the potentially alarming experience of sampling Pohnpei’s local drug, sakau. ‘I tried to get up, but found I could not . . . “Excellent!” I thought, the neurologist in me aroused. “I have read of this, and now I am experiencing it. Lack of light touch, lack of proprioception – this must be what deafferentation feels like.”’ This experimental attitude to drugs may seem less surprising when it is put in context, for Sacks has admitted to amphetamine addiction as a young man. The habit lasted several years; then one day, while high, he decided to write books instead and quit the amphetamines overnight. If there is any truth in the Asperger’s theory, it clearly does not preclude compassion: Dr Sacks has been accused of parading his neurologically afflicted patients as a sort of freak show, but although their outlandish conditions may invite this attitude, his interest in them seems at least as humane as it is academic. In The Man Who Mistook His Wife for a Hat, he explains, ‘I feel myself a naturalist and physician both; and that I am equally interested in diseases and people.’ Thus, on the interminable flight from America to Pingelap, he talks to a military nurse, a Christian missionary and a Spam importer, reporting their contrasting views with journalistic zeal (albeit reserving a certain disapproval for the ‘South Seas Spam baron’). When Oliver Sacks visited my local bookshop last year to promote a new book, the queue for autographs stretched right around the building. ‘How nice to see this one again,’ he commented when I presented him with The Island of the Colour-blind. He meant, of course, that it made a change from signing the hundredth copy of The Mind’s Eye, but his phrasing made me reflect on his recurring theme of sensory perception, and on his own newly diminished power of sight. He could not, in fact, see the book very well with his one remaining eye: the signature was angular and choppy. Then I remembered the words of John Hull, who writes about becoming blind in his memoir Touching the Rock: ‘when I say I am pleased to see you, what I mean is that I am pleased to meet you, pleased to be with you, glad to be in your presence . . . There is an intimate connection between seeing and knowing.’ Indeed there is, and it is in this wider sense that Dr Sacks allows his readers to glimpse the Island of the Colour-blind for themselves.

Extract from Slightly Foxed Issue 37 © Catherine Merrick 2013