How much can each method correct?

Treatment limits

What can be treated depends greatly on the biomechanical strength, shape and thickness of the cornea. We need to assess all of these carefully, because we can’t generalize: every eye is different. In some eyes, it’s possible to safely laser 10 diopters of myopia. In other eyes, the limit might be just 5 dioptres. In fact, some eyes might not be suitable for laser refractive surgery at all. The boundaries here are fluid.

Experience of the surgeon

The safest decision depends to a large extent also on the experience of the surgeon.

Why can we treat more than other laser centers?

We cannot. But we know the limits very very well and our research is moving the entire field forward: our institute is heavily involved in corneal biomechanics research and is one of the world leaders in this field. What this means is that we have a deep understanding of not only the risks, but also the benefits of reshaping the cornea. The limits of refractive laser surgery are individual, but in general, the excimer laser can be used for myopia to about -11 D, hyperopia to +5 D and astigmatism to 8 D.

In 2019, our work on transPRK in very high myopia was elected best work out of submissions from 120 countries at ESCRS, the European meeting in our field. Based on research performed in our group between 2014 and 2019, we managed to perform PRK up to 12 diopters while keeping the postoperative inflammation very low.


-11 Diopters


+5 Diopters


8 Diopters

Why transPRK is "better" than SMILE and Femto-LASIK.

Which method is best for me?

We will discuss this issue with you after a thorough pre-investigation. We care about your cornea; its strength, and its stability for years to come. Although many options can be good options, we care about giving you the best option possible.

In general, we believe that surface treatment with transPRK, is an excellent choice. Why? The main reason is that it leaves a biomechanically stronger cornea than a Femto-LASIK and even SMILE and is therefore always our first choice in the following patient groups:

  • Patients with a rather thin cornea
  • Patients at risk of getting hit at the eye sometime (police officers, people practicing martial arts)
  • Women with an immanent desire for children (see cornea and pregnancy) – one of the research areas of the ELZA
  • Patients with hypothyroidism, also one of our active research areas

The ELZA Institute