Laser Eye Surgery treatment types
There are laser eye treatments then there are laser eye treatments.
What’s the difference I hear you ask? Well, on the surface, not much. But the thing is you can walk into one high street provider and find a long list of treatments, with names like UltraLASEK, Epi-LASEK, Epi-LASIK, Custom LASIK, and Zyoptix. Yet you could walk into another and see a completely different list, maybe with UltraLASEKplus and Wavefront LASIK on it. Or, even more confusingly, you could visit an independent clinic or hospital and find only a small selection of two or three.
So what’s going on here? Well, the fact is there are only three main types of refractive surgery: PRK/LASEK (surface ablation), LASIK, and ReLEx SMILE. Even that’s pushing it as PRK and LASEK are considered slight variations of the same technique, and it is not uncommon to find these treatments under slightly different names.
This means that understanding the different types of Laser Eye Surgery is actually pretty straight-forward. Each treatment is simply an improvement on the one that preceded it. Starting with PRK nearly 30 years ago, the knowledge, techniques, and technology have evolved over time, offering the marketing LASIK and ReLEx SMILE.
In fact all of these procedures are based on the genius of Jose Barraquer, who first described the concept of reshaping the cornea in 1948. The procedure he developed at that time was called keratomileusis and involved removing the top section of the cornea, which was then frozen and reshaped on a watchmaker’s lathe, before being sewn back onto the cornea.
The three main types of modern refractive surgery are all slightly different, but much more precise, versions of this technique. Let’s now take a look at them in the order of which they were first introduced.
PRK (Photorefractive Keratectomy)
First performed in 1988, PRK was the original vision correction procedure that used excimer lasers to reshape the corneal tissue much more accurately than could be done using a lathe, as in keratomileusis.
In PRK, the entire outer layer of cells (epithelium) is removed and an excimer laser is used to evaporate some tissue from the cornea. The eye subsequently regrows the skin layer but requires the patient to wear a soft contact lens for 3-5 days, extending the healing process.
There have since been a number of attempts to reduce the pain associated with PRK, such as LASEK, in which the skin layer is loosened and moved to one side and then repositioned at the end of the procedure. However, the epithelial cells are no longer viable and serve no function – numerous studies have shown that there is in fact no benefit to doing this.
LASIK (Laser-assisted In Situ Keratomileusis)
LASIK arrived on the scene quite quickly after PRK. The term LASIK was first used in 1990 and quickly became the most popular type of refractive surgery.
Taking inspiration from the pioneering keratomileusis procedure (the ‘K’ in LASIK stands for keratomileusis), LASIK combined the creation of a flap using a precision surgical instrument known as a microkeratome (the “in situ” part of the name), and the accuracy of the excimer laser (the “laser-assisted” part of the name). In the early 2000’s a further improvement was made when the microkeratome was replaced by an even more precise method of making a flap – a different type of laser called a femtosecond laser.
Using a femtosecond laser (or microkeratome), the surgeon makes a small, thin flap just below the epithelium as a little doorway to the tissue underneath. The surgeon then reshapes the permanent tissue and folds the flap back into place. As it’s only the edges of the flap that need to heal, the recovery time of LASIK is considerably less than that of PRK and LASEK.
ReLEx SMILE (Refractive Lenticule Extraction, Small Incision Lenticule Extraction)
ReLEx SMILE was first described theoretically by Barraquer, with early development starting in 1996, but it was the introduction of the VisuMax femtosecond laser that made SMILE a reality in 2008. Using state-of-the-art femtosecond technology, ReLEx SMILE transformed refractive surgery into a minimally-invasive key-hole procedure.
Using the laser, a series of pulses are made to create the outline of a lens-shape within the cornea together with an incredibly small tunnel that links this outline to the surface. The surgeon is then able to manually remove the lens-shaped piece of tissue through the tunnel, completing the procedure in just a few minutes.
Due to the technology and the fact that the surgeon doesn’t need to switch between instruments, SMILE surgery makes an improvement on the efficiency and comfort of LASIK. And as it is minimally-invasive, there is no flap to be worried about, it’s appropriate for a wider range of patients, and reduces the chances of post-surgery side-effects.
If you’d like to find out which Laser Eye treatment is for you, ask us in the comments below or book a consultation at our UK clinic based on Harley Street, London.