HEALTH / Laser surgery: do the ayes have it?: It's not for the squeamish, but it takes 15 seconds and could be a cure for myopia. Annabel Ferriman on the pros and cons of PRK

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IT IS difficult to open a newspaper these days without seeing an advertisement for a mysterious and apparently miraculous procedure, known as PRK. Although the name sounds like a type of peanut, it is actually a laser surgery technique which can seemingly correct defective eyesight in just 15 seconds.

Only a visit to Lourdes or attendance at a Billy Graham rally can rival PRK for immediate action. In less than a minute, you are cured; you can throw away your glasses and see. For those people who find glasses heavy, restrictive or bothersome, these promises are seductive. But, at the same time, surgical procedures on the eyes evoke deep-seated fears. In many minds, eye operations conjure up visions of torture or the horrors of King Lear.

So what brave souls volunteer for PRK, or photo-refractive keratectomy, to give it its full name - an operation in which a microscopic layer of tissue is shaved off the front of the cornea? Does it hurt and does it work? Moreover, is it worth shelling out about pounds 1,300, the usual cost of the operation, just to avoid wearing glasses? After all, most people who use them hardly notice that they have them on.

The operation is not available on the NHS, except in a few places, such as St Thomas's Hospital, London, where clinical trials are being held. Although one centre in London only charges pounds 400 for the procedure, most places ask more than pounds 1,000.

There is no shortage of volunteers, according to the 15 or so centres which now offer PRK. More than 5,000 patients have undergone the procedure since it was first carried out in this country in 1989. These guinea-pigs, for that is essentially what they are, opt for the treatment for a variety of reasons; to satisfy vanity or the need for freedom; because they want to swim or water-ski without glasses, or not to have to search for them first thing in the morning.

Margaret Rodgers wore spectacles for 71 years. At the age of 79, she decided she had had enough. Her glasses were spoiling her golf, because they became smeared in the rain. Seeing an advertisement for PRK in a newspaper, she wrote off for details. 'I did not reveal my age in my first letter, but just asked if there was an upper age limit. When they replied that there wasn't, I wrote again, confessing that I was 79. But I added that, as I intended to live until I was 100, over 20 years of improved sight would be a bonus.'

The surgeon agreed that she was fit enough for surgery and that her prescription made her suitable for the new operation. She was short- sighted, but not exceptionally so, which meant that surgery was likely to produce good results.

So at the age of 80, Mrs Rodgers became the oldest woman in the country to undergo the procedure. She was delighted with the result. Only five days after the operation, she was able to drive the 50 miles for a check-up with her surgeon in St Albans, with only her re-shaped cornea between her and the windscreen. Six months later, she had the second eye done.

'It gives you a sense of freedom, not having to put glasses on as soon as you wake up. And it is a great advantage not having to wear them for golf,' says Mrs Rodgers, who lives in Danbury, Essex, and is the over-80s female golf champion of Great Britain.

The demands of sport were among the reasons why Rachel Mabbutt, a 29-year-old radiographer from Wigston, Leicester, decided to have the operation. Last year, the Bupa Hospital, Leicester, where she works, bought a laser machine used in the procedure and offered the operation free to anyone who was willing to speak about the experience afterwards to doctors, opticians, patients or anyone who might want to know. Rachel was one of those who volunteered.

'I took up water-skiing two years ago, and found it difficult to learn because I could not wear my contact lenses in case one fell in the water,' Rachel says. 'I have now had both eyes done, and it is terrific. I don't have any problems water-skiing and being able to see the scenery while skiing on Lake Windermere is an advantage.'

But what is involved in the operation itself and how does it work? Both PRK, and the more old-fashioned radial keratotomy, which was developed by the Japanese, but widely performed by the Russians, correct short sight by altering the shape of the cornea. In a perfect eye, light comes to a focus exactly on the retina at the back of the eye, giving a crisp image. But in people who are short-sighted, the cornea is too thick and bulgy, so that the light comes to a focus in front of the retina, producing a blur.

Both operations flatten the cornea slightly, to bring the light to a focus at the correct point, but they do it in different ways. In laser surgery, which is done under local anaesthetic, surgeons first remove the epithelium, or outer tissue of the eye, and then use the laser machine to shave away a layer of cells no thicker than a human hair at the front of the cornea. Healing takes about three months as the epithelium gradually grows back.

In radial keratotomy, done under a general anaesthetic, the surgeon makes eight radial micro-incisions round the edge of the cornea, each cut running from the centre to the periphery. As they heal, the cornea flattens slightly, because the periphery is relaxed. Although this operation has been around longer, arriving in Britain in the early Eighties, it has been overtaken in popularity by the more recent laser procedure and relatively few places offer it.

While the laser operation does not hurt, patients can experience quite intense pain in the following 24-48 hours. 'It was child's play, having the operation,' says Mrs Rodgers, who had the surgery performed at the private Corneal Laser Centre, Clatterbridge Hospital, Chester, for pounds 1,300.

'I was not really looking forward to it but I didn't feel anything. Before I saw the surgeon, I was given drops in the eye, every five minutes for 20 minutes. I then lay back in something like a dentist's chair and looked at the light above.

'The surgeon said I should listen to the man standing next to me, counting up to 20. I could tell the surgeon was doing something, but I could not feel what he was doing. This chap counted up to 11 and that was it. They warned me that I would feel some pain that night and they gave me some pills before I left.

'I was staying at a nearby hotel with other patients having the operation, so the dining room was full of these one-eyed people. Halfway through dinner, the pain was so bad that I had to take a pill and go to bed. But by the next morning, the pain had gone. The eye was a bit sore and itchy, but that was all.'

Mrs Rodgers returned home to Essex that day, then had check-ups two days later in London and two days after that in St Albans.

Some patients suffer worse pain than Mrs Rodgers, but others have less, depending on such things as the amount of pain relief they are given, pain thresholds and what they have been led to expect. One patient said: 'I was crawling up the wall with the pain; I can never remember experiencing such agony.'

So is the pain worth it? Does the procedure work, and what are the possible side-effects or complications? For patients with moderate or mild myopia, the results are considered highly predictable. Deviations from normal vision are measured in dioptres with normal vision being zero and moderate myopia being classified as up to six dioptres. (About 10 million people in Britain are short-sighted and about nine out of 10 of them have a deviation of less than five dioptres.) In patients with prescriptions worse than minus six, surgery is less successful.

It is also important to stress that the operation cannot halt the normal ageing process. As people grow older, the lens of the eye (which is behind the cornea) loses its ability to change shape and focus. Consequently, although people who are given laser treatment get improved long-sight, they often have to wear glasses for reading, because their short sight may be made worse.

According to Professor John Marshall, of St Thomas's Hospital, who pioneered advanced laser surgery techniques in Britain, there are several complications that can arise. 'The individual may have disturbances in night vision. They may see halos or radiating lines from sources of light, such as street lamps. Most myopes (people with short sight) would have that problem anyway but surgery can make it worse. If the laser cut is off centre, some individuals may have problems with double vision. In those cases, patients may have to wear contact lenses, until we can re-operate on them. Some have also experienced a haze or loss of transparency in the cornea. Again, in those cases we have re-operated on them to put it right.'

Given that the operation carries a risk of complication, albeit a small one, and given that it is not cheap or pain-free, why has laser surgery for short sight taken off in such a big way? 'I believe that the word laser has a little magic about it, which attracts patients,' says Philip Starr, an ophthalmic surgeon at the London Eye Clinic, who was one of the first surgeons in Britain to perform both radial keratotomy and PRK. 'There are also strong commercial pressures encouraging surgeons to perform laser surgery.

'When a clinic buys a laser machine, it costs about pounds 300,000 and it needs to re-coup its investment. Clinics can advertise their services and, as we all know, advertising works. The instruments for radial keratotomy cost only pounds 2,000- pounds 3,000, so there is not the same pressure to operate.'

Mr Starr believes that patients should realise that PRK is still considered an experimental procedure by the College of Ophthalmologists, which insists that the results of all cases are collected and monitored.

He advises anyone considering surgery to ask themselves whether they really need it and to consider all the implications before deciding. 'You cannot give 100 per cent guarantees to anyone,' he says.

(Photograph omitted)