Getting laser eye surgery? Here’s what you need to consider

In the Middle Ages, «beryl» was used as an umbrella term for clear crystals. A lens cut from the material was called a «brill». And two smoothed down lenses? «Brille», the German word for «glasses». The first proper pair of glasses, made of cut crystals, was created in the 13th century. It was invented by Italian monks, whose work required a lot of reading. Even before then, however, people with poor eyesight found help in the form of so-called reading stones. These were crescent-shaped rock crystal or quartz lenses, which enlarged letters when held over the text.

These days, there’s a much easier way to compensate for visual deficits such as short- or long-sightedness: wearing glasses or contact lenses. And there are even more options out there for near-sighted children.

Alternatively, you could go down the laser surgery route. There are essentially three different laser eye surgery methods: transPRK, Femto LASIK and SMILE (small incision lenticule extraction). Each laser method involves reshaping the cornea to compensate for your eyes’ refractive error. That means laser surgery doesn’t address the cause of your long- or short-sightedness (your eyeball being too long or too short). Instead, it adjusts the optics to a certain distance and corrects the dioptres.

In this video, Dr Farhad Hafezi from the ELZA Eye Institute in Dietikon clearly explains how these three refractive surgeries differ. You’ll find English subtitles for the video by clicking the gear icon. But which laser method is best? Without going for an eye examination first, there’s no one-size-fits-all answer to this. Your choice of surgery will strongly depend on your own cornea – especially its strength, thickness and mechanical function.

According to Dr. Hafezi, however, modern transPRK offers some advantages. In comparison to other methods, he says, it’s gentler and safer. Rather than cutting a lamella into the outer corneal layer as is done during LASIK surgery, or following the SMILE method of cutting a lenticule out of the cornea, transPRK works on the cornea without touching it. In my interview with eye expert Dr. Hafezi, I took a deep dive into the world of laser surgery:

If you get your eyes lasered, you’re basically having cosmetic surgery done, aren’t you?

Dr. Farhad Hafezi: «Errors in the refractive power of the eye aren’t caused by disease – they’re related to optics. So yes, more than 90 per cent of refractive laser eye surgeries are cosmetic, as most patients could correct their refractive error with glasses or contact lenses. At our institute, however, I also perform therapeutic refractive surgery on the eye in the case of corneal disease. An example of this might be keratoconus (editor’s note: a cone-shaped curvature of the cornea, which also becomes increasingly thin over time). Incidentally, it’s one of the most common causes of blindness in children.»

Are there statistics on which visual disorder is most commonly treated with laser surgery?

«Worldwide, and in Switzerland too, there are far more people with short-sightedness than long-sightedness. As for how many people in this country undergo laser eye surgery, the figures are just estimates. From experience in my practice, however, I can tell you that it’s usually younger people up to their early 30s who come to me. Then there’s a second peak between ages 40 and 50.»

Can over-60s get laser eye surgery? Or is there an age limit?

«There’s no age limit. I’ve also done laser surgery on patients who were in their 80s. However, these people weren’t having cosmetic procedures. They were patients with corneal diseases, and I was giving them medical treatment. When it comes to this type of reconstructive laser surgery, the ELZA Institute is one of maybe 15-20 institutes in Europe that performs complex surgeries like this on a regular basis.»

I’m short-sighted myself, and a few years back, I read that as long as you’re getting along fine with glasses and/or contact lenses, there’s no reason to get laser surgery. Is that still the case?

«The question of whether or not to operate is always answered on a case-by-case basis. You can definitely stick with contact lenses or glasses if that system has been working for you for years. What many contact lens users aren’t aware of, however, is that laser refractive surgery is about as safe as wearing contacts. A study has demonstrated as much.»

In your experience, what are the most common reasons that drive people to get laser eye surgery?

«I can think of two main reasons: sport and the discomfort of wearing contact lenses. Patients old enough to need reading glasses don’t want to wear varifocals or classic reading glasses. And then there are people affected by contact lens intolerance. After many years of wearing contacts, their eyes are often so dry that they can only keep them in for a few hours a day.»

Why do eyes that have tolerated contact lenses for years suddenly become too dry for them?

«Even the very best of contact lenses are considered a foreign object by the human body. The contact lens needs fluid in order to float. Over the years, this irritates the entire surface of the eye, including the goblet cells (glands) that produce mucins (the major component of mucus). Over time, you end up with dry eyes – regardless of whether you wear hard or soft contact lenses. Individual resistance to developing dry eyes varies widely from person to person. While some tolerate 20 years of contact-lens wear without issue, others have severe difficulty with them after just two to three years.»

Eye laser technology has changed drastically since the first excimer laser was used in 1986. In the video linked above, you argue in favour of the transPRK method – that’s the modern, refined version of laser surgery from the 1980s – as long as the patient fulfils the criteria. If the advantages of transPRK outweigh those of other treatments, why is a method like Femto LASIK still available?

«The video simplifies things a bit – that’s the nature of video. On the whole, all three methods are very safe. But relatively speaking, transPRK is that little bit safer because it doesn’t involve cutting the cornea. For certain indications, Femto LASIK is clearly the preferred method. Let’s say, for patients with a severe refractive error with or without astigmatism, as was the case with me. But for many people, all three methods are safe.»

What’s the most feared side effect of modern transPRK?

«The healing process is slower with transPRK than with LASIK, but it can be managed extremely well. It’s important for patients to work together with their doctor in the first few months, for example, by always coming in for follow-up visits.»

Do you think the technologies involved in laser refractive surgery will evolve in such a way that you’ll consider, say, SMILE, the most suitable treatment?

«It’s important to mention up front that the ELZA Institute offers all three procedures. Aside from this, many surgeons naturally tend towards the method they use most, and the one they have the most experience with.These days, we have two outstanding methods in transPRK and Femto LASIK, covering the entire spectrum of the surgery. Like transPRK, the third method, SMILE, provides solid corneal biomechanics after a surgery. This makes it less biomechanically intrusive than LASIK. By the way, we were the first in the world to demonstrate this, alongside Germany’s Walter Sekundo. It’s crazy how much the technology has changed – and made a sharp turn back towards the original therapy, transPRK. For healthy eyes, there won’t be much new in the way of technologies. What we don’t yet have a perfect solution for, however, is the gradual vision loss associated with old age.»

Can short-sighted people with age-related vision issues get laser surgery to completely eliminate the need for glasses?

«Even laser eye surgery obviously can’t halt the ageing process. But up to a certain dioptre, we can give a patient as much freedom from wearing glasses as possible. There’s no perfect technological solution as yet, so a trick is required: monovision. This involves each eye being treated differently during laser surgery. One eye is lasered to a dioptre that’s three quarters (or lower) than the dioptre of the other. As a result, one eye becomes responsible for seeing into the distance, the other for close-up vision. Beforehand, we can use lenses to see if the treatment is suitable for the patient. Age-related decline in vision can be treated relatively well, but you do need to live with some compromises. You shouldn’t expect to have the same long-, mid- or close-range vision that you did when you were 20. That’s impossible. Take me, for example. I’m 55, and after undergoing my own LASIK monovision surgery, I can still tackle about 95 per cent of everyday situations without needing reading glasses.»

How do you take away people’s fear of lasers? I imagine people get incredibly anxious.

«A lot of people have already gone through the decision-making process to have surgery by the time they contact us. These patients have less anxiety. However, at the ELZA Institute, we also carry out laser surgery on a number of people with corneal diseases such as keratoconus, who’ve been told elsewhere that they can’t be helped. When they initially hear that improving their condition is doable, they’re surprised and need some time. They take the information home with them – sometimes it takes months or even years for them to make up their minds.The surgeons’ experience helps a lot, of course.»

Why do ophthalmologists often wear glasses themselves?

That’s a misconception. The ASCRS (American Society for Cataract and Refractive Surgery) has been surveying surgeons on this for years. As part of a poll, surgeons were asked whether they had refractive errors and whether they’d undergone laser surgery. More than half of those eligible said they’d had the operation. That’s much higher than among the general population.»