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Laser vision correction has been around for over 25 years and has changed many lives for the better. Two recent patients of mine stand out. One was wheelchair bound and due to his physical disability often dropped his glasses. He was then unable to pick them up, becoming functionally blind as a result. Fear of dropping them made him totally dependent on his helper. Laser vision correction gave him back his independence. Another patient, a professional chef, complained that his glasses would always steam up when he came out of his kitchen's large industrial refrigerator. Again laser vision correction changed everything. He wanted to see the food that he was preparing on the kitchen counter, when standing, without glasses. The laser treatment was aimed for precisely this focal distance and today he functions at a much higher level.

Individuals are interested in laser vision correction for many reasons including for sport, cosmesis and work, and usually start their decision making process by consulting with an expert to see if they are suitable candidates. There are several large laser companies in Israel including American Laser, Care Vision, Enaim, Hadassah Optical and Assuta. There are also several well known eye surgeons who work for one of these companies but who also consult privately in their own clinics. Whilst offering a more personal approach, they still have the benefit of the use of the advanced technologies employed by the commercial companies.

Performing laser vision correction is not especially difficult as opposed to other eye surgical procedures. What differentiates better laser surgeons is their experience and ability to select the correct candidates and to exclude unsuitable ones. The best surgeons also know how to make the procedure as easy as possible for the patient and to control postoperative healing to maximize the result.

Contrary to popular belief the selection process is not always a black and white issue. Whilst the majority of patients are excellent candidates and will achieve superb results, and a smaller proportion are definitely not suitable, there is a significant percentage that fall in to a grey area. Whether to recommend treatment depends very much on the demands and expectations of the patient together with the anatomical data of the patient's eyes. Talking to the candidate about their lifestyle and expectations is just as important as the clinical examination and data recording of the patient's prescription and vision. For instance a candidate with a very high prescription has an increased chance of requiring an enhancement treatment in the future. A demanding patient who doesn't understand this and is likely to complain bitterly that the treatment has failed, should the need arise, is a poor candidate. Another more tolerant patient with the same high prescription who merely wishes to reduce his dependence on glasses to a minimum would be more suitable. Some patients demand to be out of all glasses for ever including reading glasses, such as clerical workers. Others, such as taxi drivers, will be happy with just good distance vision and accept that readers may be required afterwards in certain situations. Someone who is unhappy with his vision when wearing glasses will probably be unhappy after his laser correction also and should be discouraged from laser treatment.

Laser vision correction solves patients' focusing problems by remolding the cornea. An eye is similar to a camera. The cornea, the transparent front of the eye in front of the pupil, is like the camera's lens and should, in an ideal situation, focus light accurately on the retina or film at the back of the eye. When this doesn't occur, glasses are required to compensate. The laser beam remolds the cornea, changes its curvature, and by doing so light rays are more accurately focused on the retina, giving a clear image.

Although there are many names used by the companies to describe apparently different laser techniques in today's competitive market, there are basically only two different ways of performing laser vision treatments. The laser beam can either be applied a) to the surface of the eye, or b) applied under the surface by initially creating a surface flap, raising it and exposing a deeper layer to the laser beam.

Surface treatments, called variously PRK, Lasek and Advance Surface Ablation (ASA) all have in common the initial removal of the surface skin layer (epithelium) with the laser applied to the exposed surface below. Treatment is very gentle, without any cutting of the cornea, but healing takes a few days as the epithelium regenerates, before functional vision is achieved. The first couple of days can be painful.

In contrast the flap technique, called, for example, Lasik, Super-Lasik, or Intralasik creates good vision within hours with minimal discomfort, but the upper layers of the cornea are cut to raise the flap. This means it is a more invasive procedure with a degree of controversy and uncertainty about its long term safety. The flap can be made either by a computerized oscillating blade with a machine called a microkeratome (Lasik) or a separate laser machine called a femtolaser (Intralasik). Whilst laser centers performing Intralasik (Enaim here in Israel) proclaim its greater safety, other companies using modern microkeratomes would argue that this is also controversial and just a marketing ploy to charge more.

There is no shortage of information on the internet about the pros and cons of the different techniques and it is worth reading up as much as possible before your consultation so that you can better understand which technique you are being offered and why.

Today's results are better than ever in terms of the quality of vision achieved and the safety of the procedure, which lead to greater patient satisfaction. There are a number of objective reasons for better results. Screening procedures by consulting doctors are better. There is better preoperative equipment for examining candidates, and we know better who to exclude. Also latest generation laser machines are equipped with two specific features that were not present on earlier generation machines. One is an eye tracker that is able to follow eye movements during treatments and constantly realign the laser direction to keep it central, in front of the pupil. Secondly, the laser applied to the cornea is dispersed over the cornea in a more sophisticated manner called a Wavefront pattern.

There are two main reasons why interested candidates look into laser vision correction but hesitate before going ahead. One is fear of an unsuccessful result and even going blind and the second a fear of the procedure itself.

The procedure itself is very easy and pain-free with most patients in the laser room for no more than 10-15 minutes. The laser application itself takes a matter of seconds, all performed under local anesthetic. To dismiss the idea of laser vision correction with all its benefits because of fear of this 10 minute procedure is a shame.

Regarding the issue of blindness (by which patients usually mean complete blackness in both eyes), I have never seen or heard of a patient going blind due to laser treatment anywhere in the world during the 10 years I have been involved in the field. Nevertheless the safety of laser vision correction, as it should be, is an ever present concern and patients have to sign a consent form confirming that they are aware of very small risks involved. A consulting doctor will not go into every event that can possibly happen during and after a laser procedure but almost never does any more than a pilot will warn passengers of the hundreds of reasons a plane can crash mid-flight but almost never does. He should, however, tailor the discussion to the specific patient before him.

So how safe is laser? Statistics will vary from center to center, are not the same for every patient, will vary according to which period is being assessed i.e. with older equipment or with newer generation equipment, and according to other variables. However one can say that the chance of experiencing significant damage to one's vision is much less than 1%, and probably much less than 0.1%.

Two other facts are also of general interest. The chance of developing a serious infection from contact lenses over all is much higher than from laser vision correction so the decision to undergo treatment is much easier for contact lens wearers. Secondly such is the safety record and success rate of laser today that the US army now pays for and encourages every combat soldier who is interested to have laser vision correction free of charge, including pilots who cost millions of dollars to train.

Laser eye surgeons may not perform heroic life-saving surgery, but together with support teams they improve quality of life to the great satisfaction of themselves and their patients.

Dr Andrew Fink MD FRCOphth (London)