Weekend Reads - Eye: A renaissance of vision

Weekend Reads - Eye: A renaissance of vision

From Gavin Francis's Adventures in Human Being, a fascinating and in-depth look into one of the things we take most for granted, our eyesight.

Posted on 30th May 2015 by Gavin Francis

Of all the things that have happened to me, I think the least important was having been blind.

James Joyce, as quoted by J. L. Borges

My office in Edinburgh has a large, east-facing window, and for most of the year I examine my patients in natural light. The exception is when a patient complains of a deterioration in their sight, and I want to look inside their eyes with an ophthalmoscope. Then it’s necessary to close the blinds and feel my way in the darkness, hands outstretched, back towards the chair where the patient sits. The ophthalmoscope fires a beam of light through a small aperture, I place it close against my own eye then move within millimetres of the patient’s. There are few examinations more intimate: my cheek often brushes theirs, and usually both of us, through politeness, end up holding our breath.

It’s an unsettling experience, projecting an image of someone’s inner eye so neatly into your own, retina examining retina through the intermediary of the lens. It can be disorientating too: gazing down the axis of the beam is like looking up into the night sky with an eyeglass. If the central retinal vein is blocked, the resultant scarlet haemorrhages are described in the textbooks as ‘stormy sunset appearance’. I sometimes see pale retinal spots caused by diabetes, and they’re reminiscent of cumulus clouds. In patients with high blood pressure the branching, silvered shine on the retinal arteries resembles jagged forks of lightning. The first time I looked into the curved vault of a patient’s eyeball I was reminded of those medieval diagrams that showed the heavens as an upturned bowl.

Ancient Greek opinion was that vision was possible because of a divine fire within the eye – the lens was a kind of transmitter that beamed energy into the world. The flashing reflections in eyes seen by firelight seemed to confirm this theory, held by the Greek poet and philosopher Empedocles as long as two and a half thousand years ago. Part way through a series of metaphors comparing the eye with the moon and sun, he wrote: ‘As when a man, about to go forth, prepares a light and kindles a blaze of flaming fire ... just so the Fire primeval once lay hid in the round pupil of the eye’.

Two centuries later Plato thought the same, though Aristotle, who believed that light was unique in obeying the same laws whether in heaven or earth, began to question the theory – if our eyes themselves clothe the world with light, why can we not see in the dark? In the thirteenth century the English philosopher Roger Bacon hedged his bets: the soul reaches out from the lens in a projection which ‘ennobles’ our environment, but that environment projects itself back into the eyes.

By the seventeenth century, classical perspectives on vision were giving way. Astronomers, whose very business was the elucidation and understanding of light, were peering into the eye in order to better comprehend the stars. The astronomer-mystic Johannes Kepler was the first to write about how an image of the world was projected upside down and back to front onto the retina. When Isaac Newton was working out the motion of the planets around the sun he embarked on dramatic experiments to test the reliability of his own vision. Inserting a long blunt needle (a ‘bodkin’) into his own eye socket between the bone and the eyeball, he described how wiggling it around distorted his vision. Understanding didn’t progress a great deal from Newton until the twentieth century, when quantum theory and the relativity theories of Einstein began again transforming our understanding of how light works.

If you are sitting reading this in the sunshine, the photons reaching your retina were born, just eight and a half minutes ago, through nuclear fusion in the core of the sun. Five minutes ago they were streaking past the orbit of Mercury, two and a half minutes ago they outran Venus. Those not intercepted by the earth will pass the orbit of Mars in about four minutes’ time, and Saturn in just over an hour. After this journey across space, and in unchanging time (because, as Einstein figured out, moving at the speed of light brings time to a standstill), the sun’s white light envelops the world around us and breaks into a multicoloured scatter. That scatter is funnelled by the cornea and the lens of the eye before tumbling onto the safety net of the retina. The energy of that impact causes proteins within the net to bend, starting a chain reaction, which, if enough proteins twist, leads to the firing of a single retinal nerve, and the perception of a single scintilla of light.

We can taste what’s in our mouths, touch what’s within our reach, smell within hundreds of metres and hear within tens of miles. But it’s only through our vision that we are in communication with the sun and stars.

Jorge Luis Borges's The Book of Imaginary Beings was first published two years after its author succumbed to the ‘slow nightfall’ of blindness, which he had been suffering since birth through a combination of cataracts and retinal detachments. I couldn’t have looked into Borges’s eyes with an ophthalmoscope: the vault of his retina was collapsing, and clouds of cataract forming in his lens would have obscured the view.

The Book of Imaginary Beings sets aside a whole page to the discussion of ‘Animals in the Form of Spheres’. The greatest of these, Borges believed, was the earth itself, which was thought to be a living being by thinkers as distinguished and diverse as Plato, Giordano Bruno and Kepler himself. Borges quotes Kepler’s vision of the earth as a vast orb ‘whose whalelike breathing, changing with sleep and wakefulness, produces the ebb and flow of the sea’, and describes the sphere as the simplest, the most beautiful, the most harmonious of forms, because every point on its surface is equidistant from its centre. The grief Borges felt at the loss of his sight surfaces fleetingly when he points out that the spherical shape of the earth recalls the human eye – ‘the noblest organ in the body’ – as if our eyes are themselves celestial bodies in miniature.

I was taught ophthalmology by a gifted surgeon with the exotically syncretic name of Hector Chawla. He delighted in pointing out that although ophthalmologists call the eyeball a ‘globe’, it is not in fact shaped like a planet, but more like a deep brandy glass. Its stem, the optic nerve, has its foot deep in the darker recesses of the brain, while the scoop of its bowl is silvered in light-sensitive nerve fibres – the retina. In Chawla’s handouts the lens, iris and cornea were like a cap placed over a glass.

For many medical practitioners, ophthalmology seems as wrapped in mystery as alchemy, but Chawla told us how to examine the eye in clear, no-nonsense language: ‘Ophthalmology tends to be thought of as a blend of mysticism and the application of drops four times a day,’ he said; ‘although the eye is happiest when shut, it has to open to be of any use.’ Like Newton or Kepler he used astronomical metaphors to explain the functions of the eye: ‘Parallel rays of light from infinity focus on the macula without effort, like a convex lens which concentrates the sun into charring a piece of paper.’ To assess the depth of the chamber at the front of the eye, he advised us to carry out the ‘eclipse test’: shining a torch onto the iris from the side to reveal its convexity, just as the curvature of the moon is revealed by the lateral rays of the sun.

Borges inherited his wealth and patrician sensibility from his mother, but his love of literature, and his blindness, came from his father and paternal grandmother. Ophthalmologists struggle to agree on the cause of the Borges family’s blindness, but it seems likely that glaucoma – a pathological increase in the pressure of the fluids inside the eye – was a prelude to the cataracts that overtook them.

Shakespeare, wrote Borges, was not quite accurate in describing the world of the blind as dark: his vision was obscured not by blackness, but by roiling mists of green light. He preferred Milton’s greater subtlety; Milton, who ruined his eyes writing anti-monarchist pamphlets and whose ‘dark world and wide’ conveyed the way the blind are obliged to move tentatively, hands outstretched. Borges identified too with the way Milton composed poetry, holding it in his memory – as Borges was later obliged to – ‘forty or fifty hendecasyllables’ at a time, and dictating them to visitors as they called by. It was a bitter irony that the year in which Borges took up his position as the director of Argentina’s National Library was also the year he lost his sight. He found himself wandering a labyrinth of a million books, but unable to read.

Photographs of Borges show him with a transcendent squint, as if one eye were watching the world, while the other bore witness to events on the astral plain. As his vision faded he lost his perception of colours at different rates. Red was the first to go, and was the most strongly mourned – his essay ‘Blindness’ contains a roll call of the names by which it is known in some of the tongues he knew: ‘scharlach, scarlet, ecarlata, écarlate’. Blues and greens merged into one another, and only yellow ‘remained faithful’ to him. The yellows of gold haunted his dreams; half a century after visiting the tiger compound at Palermo zoo he wrote a collection of poems called The Gold of Tigers grieving his lost sight, but elsewhere his writings suggest that he became reconciled to it. In his poem ‘A Blind Man’ he paraphrases Milton: ‘I repeat that I have lost only / the vainest superficialities of things.’

The onset of Borges’s own blindness could have unmade him, but though he experienced grief at the loss of his sight he fell rapturously into what he described as ‘that literature which exceeds the life of a man, and even generations of men’ – the literature of the English language. It was after he became blind that he embarked on a study of two of the roots of English: Anglo-Saxon and Old Norse. In his office at the National Library in Buenos Aires he’d gather students around him for sessions of reading the medieval classics of another continent: Beowulf; The Battle of Maldon; the Prose Eddas; the Volsunga Saga. ‘Each word was a kind of talisman we unearthed’, he wrote of the sessions with his students, ‘we became almost drunk’. Just as the constellations become visible only in darkness, it was through the slow nightfall of his blindness that it became clear to him how much literature he still had to explore.

One of my tutors at medical school tried to encourage me into a career as an ophthalmologist. He wasn’t an eye specialist himself – his field was the treatment of cancers in children. He told me that some of his patients had a survival rate of less than 50 per cent despite the best chemo and radiotherapy. He was compassionate, able, committed and enthusiastic, but when children died their parents’ need to blame someone meant that he was often sued. ‘Happens all the time,’ he told me once in his office, while half-reading another letter of litigation. ‘People get overwhelmed by grief. Now, about your career ... have you ever thought of Ophthalmology?’ I watched his expression as he tossed the letter to the side, exhaustion draining for a moment the colour from his face. ‘Imagine how wonderful it would be,’ he said, his face brightening, ‘to give your patients the gift of sight!’ Most ophthalmologists spend part of every week restoring sight through the removal of cataracts. ‘Think how grateful they would be,’ he added.

The word ‘cataract’ comes from the Greek kataraktes, meaning ‘waterfall’ or ‘portcullis’ – a barrier that descends on the vision. Cataracts develop through an opacification in the lens, and they have been treated surgically for at least two thousand years. Instructions or instruments for slicing the cornea and displacing the clouded lens away from the line of sight have been unearthed by archaeologists and historians in India, China and Greece. The removal of the lens restores only a partial, blurry kind of sight, but in the seventeenth century this displacement of the lens (‘couching’) had become a fairly common operation in the West. In 1722 a Frenchman named St Yves managed to fully remove a cataract, rather than just displace it deeper into the eyeball. It took only a couple of minor modifications to develop the cataract surgery that we know today.

The operation once required extraordinary self-control on the part of the patient, who had to hold his or her head and eye steady through terrible, piercing pain, as the globe of the eye was sliced open and the lens gouged out. Thanks to anaesthetic drops and paralysing agents that’s no longer necessary; when I went to watch a colleague perform cataract surgery I saw the patient lie back with ease, looking up into the theatre lights as if stargazing. ‘What do you see?’ I asked her as she was preparing to have her eye cut open. ‘Just patterns,’ she said, ‘just moving light and shadow. It’s rather beautiful.’

After numbing the eye with drops, my colleague placed little retractors of rounded wire under her eyelids to spring them apart. Ophthalmologists have to be among the most dextrous of surgeons – shaky hands can’t manage the subtle movements required to manipulate the lens. A tiny knife, shaped like a trowel only a couple of millimetres wide, sliced an entry wound into the edge of the cornea, then the space between the cornea and the lens was suffused with a synthetic jelly to maintain its pressure. Another wound was made at a separate point on the circumference of the cornea in order to introduce an instrument for manipulating the cataract, then a ‘phacoemulsifier’ was inserted into the first incision: it pulsed jets of fluid in and out of itself forty thousand times a second. The vibrating shock of that fluid broke up the portcullis of the cataract, simultaneously sucking the debris away. Tiny pieces of the remaining cortex were vacuumed up, and the eye left lens-less for a few moments while the surgeon prepared a replacement.

Artificial lenses can be customised according to the patient’s optical prescription; they may wake up not only with their vision restored but with little need for spectacles. The lenses are of thin and flexible silicone or acrylic,* held in place behind the iris with little struts that eliminate the need for sutures. The surgeon folded the malleable new lens in half, as if rolling a calzone pizza, and inserted it through one of the incisions. Once it was in position he released his hold on the forceps and the struts sprang into position. The cataract had been removed and the lens replaced, and the whole procedure had taken just six or seven minutes. The incision was so small that no stitches were needed to close it.

For Borges, sight was a transient blessing: he always knew that one day it would be withdrawn; when it was gone he turned to literature for consolation. We’ll never know what revolutions in perspective he could have described for us if his sight had been restored.

I’ve often asked my own patients how it felt to have their vision restored to them by cataract surgery: ‘lovely’, ‘marvellous’, ‘incredible’, they often say; ‘the colours are so beautiful again’. Wanting to understand more, I turned to a book on the subject by John Berger, who had his cataracts removed in 2010.

Berger has spent his life thinking about seeing. Here is his description of lying on grass looking up at a tree, from an essay published in 1960, when he was thirty-four: ‘The image of the pattern of the leaves remains for a moment before it fades, imprinted on your retina, but now deep red, the colour of the darkest rhododendron. When you re-open your eyes the light is so brilliant that you have the sensation of it breaking against you in waves.’ And this is from an essay published in his 1980 collection About Looking: ‘Shelf of a field, green, within easy reach, the grass on it not yet high, papered with blue sky through which yellow has grown to make pure green, the surface colour of what the basin of the world contains.’ In 1972 he had collaborated with four others – Sven Blomberg, Chris Fox, Michael Dibb and Richard Hollis – to produce a new kind of book, an extraordinary fusion of literature and visual art: Ways of Seeing. Berger’s aim was to challenge his readers’ perceptions of the images that surround us: a seminal work that redefined art criticism.

My copy of Berger’s Cataract has William Blake’s famous maxim printed on the back cover: ‘If the doors of perception were cleansed every thing would appear to man as it is, infinite.’* One of the first changes the author notes after his surgery is the newness of everything, the quality of ‘firstness’ that has been bestowed on the world, as if all its surfaces had been dewed with light. The second is how much blue there is, even in colours such as magenta, grey and green – blue that had hitherto been deflected by the opacities in the lens. This blueness restores his sense of distance, ‘as if the sky remembers its rendezvous with the other colours of the earth’, and just as a kilometre has been elongated, so has a centimetre. As a fish is in its element immersed in water, he perceives that as human beings we are immersed in the element of light. He compares cataracts to forgetfulness, the removal of them as a kind of ‘visual renaissance’ that takes him back to the first colours he registered as a child. Whites strike him as purer, blacks strike him as heavier, their essential natures reborn through a baptism of light.

The words in Berger’s essay are accompanied by cartoons drawn by the Turkish illustrator Selçuk Demirel. The picture to accompany the last page but one is of a couple standing side by side with their arms around each other’s shoulders, watching the night sky, while the taller figure points out a star or a planet. But both the figures’ heads have been drawn as eyeballs, as have the celestial bodies that hover over them – the sun and stars that generate light have metamorphosed into the organs for receiving it. Like Borges’s great spheres they gaze down at the figures on earth, out into the depths of space, or even forwards into the infinite literature we all still have to explore.

One spring, I was invited by John Berger to his home in France. I had written to ask about a book he wrote in the 1960s, A Fortunate Man – The Story of a Country Doctor, and about his unique perspective on vision. When we met we discussed light and darkness, sightlessness and vision, and how Borges felt simultaneously liberated and impris- oned by his blindness.

He mentioned the episode, recounted in his book Here Is Where We Meet, in which he describes a visit to Borges’s grave in Geneva. Borges was led to Geneva as an adolescent by his father, who was attracted to the city by the fame of its ophthalmologists. It was 1914, and as war overwhelmed Europe the Borges family became trapped. The young Borges grew to love Geneva and, according to a story recounted by Berger, lost his virginity there to a prostitute (he suspected his father of being another of her clients). In 1986 he returned to the city to die. His companion on that final journey was Maria Kodama, his new wife, and one of the young women who’d taken his arm and helped him to blindly navigate the labyrinth of books in the National Library of Buenos Aires.

The gravestone where Berger went to pay his respects had been chosen by Kodama. It was deeply etched with a line from the Anglo-Saxon poem The Battle of Maldon: ‘And Ne Forhtedon Na’ – Be Not Afraid. The text curved beneath a relief taken from the Lindisfarne gravestone, of Norse warriors arriving by sea. On the reverse side there was a phrase in Old Norse from one of the couple’s favourite sagas, the Volsunga Saga, which the pair had once translated together: ‘He takes the sword Gram and lays it naked between them.’

Berger found the grave adorned not with flowers, but a plant in a wickerwork basket. He identified it as evergreen box: ‘In the villages of the Haute-Savoie’, he explains in the book, ‘one dips a sprig of this plant into holy water to sprinkle blessings for the last time on the corpse of the loved one laid out on the bed.’

After paying his respects, he realised that he had no flowers or plants to leave at the graveside, so offered instead one of Borges’s own flower poems: ‘O endless rose, intimate, without limit / Which the Lord will finally show to my dead eyes.’ Borges knew both light and darkness, blindness and vision, and that there are more ways to connect with the infinite than through sight.

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Adventures in Human Being - Wellcome (Hardback)

Adventures in Human Being - Wellcome (Hardback)

Gavin Francis

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