LASIK vs LASEK vs ReLEx SMILE: Laser Eye Surgery Treatment Types

With so much jargon and a seemingly endless list of treatment types and brand names thrown around, many people can become overwhelmed by the prospect of Laser Eye Surgery. But the truth is, many of the confusing abbreviations you will come across are actually variations of the same three core treatments: PRK/LASEK, LASIK, and ReLEx SMILE.

So, what is the real difference between these three procedures? Let’s find out – but first, let’s have a recap on the basics of Laser Eye Surgery.

How Does Laser Eye Surgery Work?

Modern Laser Eye Surgery builds on previous refractive surgeries in its aim to correct common refractive errors such as myopia (short-sightedness), hyperopia (long-sightedness), astigmatism, and presbyopia. All of these procedures are based on the genius of Jose Barraquer, who first described the concept of reshaping the cornea in 1948.

The method 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 basis of the treatment is to change the shape of the cornea to effectively adjust the way light is refracted into the eye. This is achieved by removing a pre-determined area of corneal tissue using high-precision lasers. As a result, light is directed more effectively onto the retina (the photosensitive layer at the back of the eye), correcting the error and improving vision.

However, this can be achieved in several ways. The main difference between the three main Laser Eye Surgery procedures is the way in which the surgeon accesses the corneal tissue. So, with that in mind, let’s take a more detailed look at PRK/LASEK, LASIK, and ReLEx SMILE.

PRL/LASEK: The Surface Procedures

Commonly known as surface ablation or surface procedures, PRK and LASEK are the oldest Laser Eye Surgery techniques. In PRK – the original Laser Eye Surgery procedure – a femtosecond laser is used to completely remove an area of corneal epithelium. Once the treatment is complete, a soft contact lens is placed over the treatment area to protect the eye while the cells repopulate. This process typically takes around 4-5 days.

LASEK is a very similar procedure; however, rather than completely removing the epithelium, it’s loosened with an alcohol solution and pushed to one side. Following correction, the loosened epithelium is put back in its original position. Again, a contact lens is applied while a whole new layer of cells repopulates the surface area, aided by the original epithelial layer.

LASIK: The Most Common Procedure

LASIK (short for Laser-assisted In Situ Keratomileusis) was introduced in the 1990s, offering a less invasive method of laser vision correction. It built on the methods used in PRK/LASIK with the bonus of faster healing times and has since become the most common Laser Eye Surgery procedure.

In LASIK, rather than removing a whole area of epithelium, a high-precision laser is used to create a “flap” in the cornea. This corneal flap is then folded back, allowing the surgeon to use a second laser to remove the necessary amount of stromal tissue. Once this step is completed, the flap can simply be returned to its original position, where the eye immediately gets to work to seal the edges.

The rest of the epithelial layer is unaffected, so the recovery time is much faster than PRK or LASEK.

ReLEx SMILE: The Least Invasive Method

Refractive Lenticule Extraction, Small Incision Lenticule Extraction (understandably known more commonly as “ReLEx SMILE” or simply “SMILE”), is the latest innovation in Laser Eye Surgery. This minimally-invasive procedure involves creating a small incision on the surface of the cornea. While this technique was first described theoretically by Barraquer, with early development starting in 1996, it was the introduction of the VisuMax femtosecond laser that made SMILE a reality in 2008.

This state-of-the-art laser delivers a series of pulses, creating a tunnel from the surface of the eye to the stromal tissue beneath. The surgeon can then remove the necessary tissue through the keyhole incision – a process that takes only a matter of minutes.

The minimally-invasive nature of ReLEx SMILE further improves recovery times. Moreover, the procedure is suitable for a wider range of patients and is associated with a lower risk of post-operative side effects, such as dry eye.