IELTS Academic Reading Practice Test 320

Almost anyone who has had an eye test has read letters from a chart on a wall. The procedure is so familiar that it seems always to have existed, yet it was devised by one physician in the Netherlands in the middle of the nineteenth century. Before his chart appeared, doctors could describe a patient's eyesight but could not measure it, and two specialists examining the same person might reach quite different conclusions. What ended the confusion was a printed sheet of letters of decreasing size, read aloud from a fixed distance.

Hermann Snellen was born in 1834 and studied medicine at the University of Utrecht, where he later became professor of ophthalmology. He remained in that city for the greater part of his career, treating diseases of the eye and teaching students, and he was not yet thirty when his letter chart was published in 1862. Snellen also wrote on glaucoma and on the surgery of the eyelids, but it is for the chart that he is remembered.

Snellen was not the first to print letters for the purpose. In 1843 the German physician Heinrich Küchler produced cards bearing letters of decreasing size, though his choice of letters was his own and they differed in difficulty. Eleven years later the Viennese ophthalmologist Eduard Jaeger published reading cards designed for testing near vision. His aim was chiefly to judge how well a patient could read at close range rather than to measure sight at a distance. Neither early system was truly standardised.

Snellen's own contribution lay in the design of the letters. He called them optotypes, and each was drawn inside a square divided into a grid of five by five. The height of a letter occupies five units and every stroke is one unit across, so the thickness of a stroke is one fifth of the letter's height. The optotypes stand in lines that shrink from top to bottom, and the sheet is read from a fixed distance. Because every letter obeyed the same rule, the smallest line a patient could manage became a measurement rather than an impression.

The result is expressed as a fraction. The upper figure gives the distance at which the test is carried out; the lower gives the distance at which a person with normal sight could read the same line. A patient who reads at six metres a line that a standard eye could read at twelve metres therefore has vision of 6/12, or half of normal. Countries that use feet record the same performance as 20/40, since twenty feet is roughly six metres. A score of 6/6, or 20/20, describes an average eye rather than a perfect one.

Because the chart required no apparatus and could be administered by anyone who could read, it was taken up by military medical boards and by school health services. Employers also began to use it, since a growing number of trades needed to know whether a worker's sight was adequate. The chart travelled with European medicine, and local editions were printed in many languages. Within a few decades a Snellen chart had become standard equipment in clinics, barracks and classrooms across Europe and North America.

Yet the chart has never been a perfectly consistent instrument. Snellen could not make every letter equally easy to identify: some letters proved easier to recognise than others, so a line containing them was slightly less demanding. The steps between the lines were irregular as well, and the number of letters on each line varied, which meant that a patient could guess or memorise a line and so raise a score. Recruits and schoolchildren, who saw the same chart year after year, sometimes recited a line they could not actually see.

Two further difficulties were practical. Many patients could not read the Latin alphabet at all, because they were young children, illiterate, or unused to European script. For them other charts were devised, among them a card showing a capital E in four orientations, known as the tumbling E. Another was the broken ring designed by the Swiss ophthalmologist Edmund Landolt, in which the patient simply says where the gap lies. Both are still in use today, and simple picture charts, in which a child names or matches shapes, were produced for the very young.

In 1976 two optometrists working in Melbourne, Ian Bailey and Jan Lovie, set out to remove these inconsistencies. Their chart keeps the ratio between lines constant, gives every line the same number of letters and scores each letter rather than each line as a whole. Because the steps are calculated on a logarithmic scale, the system became known as logMAR, short for the logarithm of the minimum angle of resolution. The design was later adopted for large clinical trials, where small differences in vision must be detected reliably.

Even the most carefully made chart, however, measures only one aspect of sight. It records how sharply the centre of the field of vision distinguishes black letters on a white background at a fixed distance. It says nothing about peripheral vision, about the ability to see low-contrast objects in dim light, or about how well someone copes in the ordinary visual world. For all that, the sheet of letters on the wall survives, because it is quick, cheap and understood by every eye specialist in the world.

A fracture is a break in a living material. Bone looks like stone, but it is a composite of flexible collagen fibres stiffened by crystals of calcium phosphate, and it is threaded with blood vessels and populated by cells that are constantly at work. Bone tissue is replaced throughout life: old bone is continually removed by one set of cells and new bone laid down by another, which is why a skeleton is never quite the same from one year to the next. Because of this, a broken bone does not simply scar over. In most healthy people the damaged tissue is replaced by new bone, and after a year or two an X-ray may show no sign that the bone was ever broken.

The repair begins within minutes. When a bone breaks, the vessels running through it are torn, and blood collects in the gap and beneath the surrounding membrane, forming a clot known as a haematoma. This is more than a plug. The clot holds the broken ends roughly in place and acts as a scaffold for the cells that follow, and the platelets inside it release signals that summon help. In the days that follow, inflammatory cells arrive to clear away dead bone fragments and any bacteria that have entered through a wound. A fracture with a good blood supply heals reliably; one without it may not heal at all.

Next, cells from the outer membrane of the bone and from the marrow multiply and migrate into the clot, and small blood vessels push in behind them. Fibroblasts lay down collagen, while cartilage-forming cells produce a soft, rubbery tissue that gradually replaces the clot. This 'soft callus' has little strength of its own, but it does something essential: it bridges the gap and holds the two ends together well enough for the next stage to begin. In an adult this phase takes a couple of weeks, and the limb is usually kept still while it lasts.

The soft callus is then converted into bone in a process called endochondral ossification. Blood vessels invade the cartilage, its cells die, and osteoblasts, the bone-forming cells, deposit mineral in their place. The result is woven bone, a crude material whose fibres run in all directions. It is not as strong as normal bone, but it is solid, and it unites the two fragments. Some new bone also forms directly from the periosteum, the membrane that wraps the outside of every bone. On an X-ray this hard callus appears as a bulge around the break, and it is the first sign that the fracture is mending.

The final stage, remodelling, is the slowest and the most impressive. Osteoclasts, cells that dissolve bone, remove the crude woven material, while osteoblasts lay down new bone in its place. The new tissue is arranged in sheets and cylinders aligned with the forces that pass through the limb, so that the healed section ends up as strong as the bone it replaced. Osteocytes, star-shaped cells embedded in the matrix, sense where the stress is greatest and help to direct the work. In a child remodelling may be finished within months; in an adult it can continue for several years, and the bone slowly resumes its original shape.

Repair can fail. Some bones have a notoriously poor blood supply: the scaphoid in the wrist, the neck of the femur and the lower end of the tibia are all sites where healing is unreliable, and a fracture there may never unite. Infection, movement at the broken ends and certain drugs, notably long courses of steroids, also hinder the process, as do diabetes and smoking, which narrow the vessels and reduce the delivery of oxygen. Where the gap is too large or the blood supply too poor, the bone may form a false joint instead, a condition that can leave a patient in pain for years.

Attempts to speed up or rescue the process are diverse. Low-intensity pulsed ultrasound, applied to the skin for twenty minutes a day, is used in some countries, though reviews of the evidence have reached conflicting conclusions. Electrical stimulation has a longer history and a modest evidence base. Bone morphogenetic proteins, growth factors that are normally present in tiny quantities during healing, can now be manufactured; they are used in some spinal operations, but they are expensive and can cause serious side effects. Researchers are also testing scaffolds printed to match the shape of a defect, stem cells taken from the patient's own marrow, and gene therapy designed to make repair cells produce more of the right signals.

Yet for all this activity, much of the control system remains unexplained. Biologists can describe the sequence of the repair but cannot yet say precisely how the body decides when to stop building callus and start remodelling, or why some people's cells respond so much better than others'. The next decade of research is likely to concentrate on those questions, since a treatment that helped the body do faster what it already does well would be more valuable than any artificial implant.

Few questions in medicine attract as much emotion as the legalisation of assisted dying. The phrase covers two arrangements: assisted suicide, in which a doctor supplies a lethal substance that the patient takes, and voluntary euthanasia, in which the doctor administers it. Several legislatures have now permitted one or both, among them Oregon, the Netherlands, Belgium, Canada and several Australian states. In this article I argue that the case for legalisation is stronger than the case against it, provided that any law is narrowly written and that decent palliative care is available alongside it.

The central argument is about self-determination. A competent adult who is dying should be allowed to decide when the end comes, because the alternative is to endure a decline that the person may find humiliating and pointless. The request is usually made not because the patient fears death but because the patient fears a particular kind of dying. Modern medicine can keep a body functioning long after the person has lost nearly everything that made life worth living. Moreover, a patient may already refuse treatment that will certainly end in death, and doctors must respect that decision even when they disagree with it. If the law accepts that a patient may choose to die by declining a ventilator or dialysis, it is hard to explain why the same patient may not ask for help when the dying process is slower and more distressing. Consistency, rather than compassion alone, is the strongest point in favour of reform.

Against this stands the risk to people who are not making a free choice. The elderly, the disabled and those who depend on others may ask to die because they fear becoming a burden rather than because they want to end their lives. Depression, which is common in serious illness, can distort judgement, and pain that seems uncontrollable at three in the morning may be manageable a week later. Opponents point out that safeguards are only as reliable as the doctors who apply them, and that pressure within a family can be subtle and invisible to any assessor. These are serious concerns, and I do not think they can be dismissed.

The most substantial of them is the fear of a slippery slope. The Netherlands and Belgium now permit euthanasia in circumstances that go well beyond what their legislators first debated. Belgium removed the age limit in 2014, allowing terminally ill children to request euthanasia with parental consent, and in both countries requests from people whose suffering is psychiatric rather than physical have been accepted. Some of these developments may be defensible, but they demonstrate that the boundaries of a law are not fixed by its original wording. Any statute must therefore define its limits precisely, so that widening them requires a deliberate decision by parliament rather than a gradual reinterpretation by doctors.

The quality of care for the dying is the point at which the two sides meet. Opponents argue that once assisted dying is available, governments will have less reason to fund hospices, and that the option will be offered most readily to those who cost the most to keep alive: the very old, the very ill and the poor. The argument is powerful, but it cuts both ways. If people ask to die because their pain is badly managed, or because they cannot get the help they need at home, the scandal is the failure of care, and the remedy is to provide it. It does not follow that the option should be withheld from those whose suffering cannot be relieved.

Designing such a law requires care. Eligibility should be limited to adults who are terminally ill, whose death within a defined period is expected, and who have the mental capacity to decide. Requests should be made more than once, in writing, with an interval between them, and the patient should be free to withdraw at any point. Two independent doctors should certify, one of whom should be trained to recognise depression. Every case should be reported to an independent body with the power to investigate. Doctors who object should never be obliged to take part, and no one should be offered assisted dying as a way of saving money.

What does the evidence from existing schemes show? The numbers remain small in jurisdictions with strict rules, and official reviews have not found the widespread abuse that opponents predicted. Opponents reply that the numbers are small partly because the laws are still restrictive, and that this is exactly how a gradual extension begins. The record, in other words, is encouraging but far from conclusive: reporting is imperfect, and the countries concerned have not been operating such laws for long enough to answer every objection.

Weighing these arguments, I come down in favour of legalisation — narrowly drawn, independently monitored and reviewed by parliament at fixed intervals — accompanied by a serious commitment to fund end-of-life care. The risks opponents describe are real, but they are risks of badly made law, and the alternative is to leave in place a prohibition that causes certain and sometimes terrible suffering. A society that refuses to discuss the details of dying is not protecting its weakest members; it is simply refusing to help them.