LASIK vs LASEK vs SMILE: What are the differences?

Starting your journey to Laser Eye Surgery can be a daunting prospect – one that isn’t helped by the jargon and acronyms thrown around when you start to look for information.

These unfamiliar words and terms can make it challenging to understand which treatment is right for you – but fear not, we’re here to explain the differences between three of the most common types of Laser Eye Surgery: LASIK, LASEK, and SMILE.

What is Laser Eye Surgery?

Laser Eye Surgery has been around for decades, and during this time, new, more effective techniques have been developed. Today, Laser Eye Surgery is the most common elective procedure carried out globally, and it has helped to correct the vision of millions of people around the world.

On the surface, all types of Laser Eye Surgery rely upon the same technique: using a laser to reshape the permanent corneal or stromal tissue that sits in the corneal bed. This allows us to make the stroma flatter or steeper to enable it to bend light more effectively into the retina; however, each technique involves accessing this tissue differently.


LASIK, or Laser-assisted in situ keratomileusis, is still the most common Laser Eye Surgery technique used today. This technique involves creating an ultra-thin, hinged flap in the cornea. A laser is then used to reshape the deeper corneal tissue to address the cause of the refractive error. This access can allow surgeons to treat a number of refractive errors, including short-sightedness (myopia), long-sightedness (hyperopia), astigmatism, and even the need for reading glasses (presbyopia).

Following laser correction, the flap is smoothed back in place, where it can begin to heal quickly on its own. As the eye is one of the fastest healing parts of the body, most people are back to work within 24 hours of the procedure!

LASIK was developed in the late-1980s and offered a faster, more efficient way to access the cornea and stroma. As a result, over 90% of our patients are suitable for LASIK treatment, and many of those patients can even be in and out of the surgical theatre within 15 minutes, ready to enjoy the benefits of their improved vision.


Before the introduction of LASIK changed the ‘norm’ of Laser Eye Surgery, LASEK (laser sub-epithelial keratomileusis) was King. This technique involves the complete removal of the epithelium (outer layer of the cornea) to completely reveal the area that requires treatment. Next, the removed area of epithelium is carefully pushed aside, ready to be replaced at the end of the procedure. The exposed area is then treated practically as in LASIK, using a laser to reshape the cornea. Once the epithelium is carefully replaced, a soft contact lens is placed on the eye to protect the tissue while it heals.

Also similar to LASIK, LASEK can be used to treat short-sightedness, long-sightedness, and astigmatism.

As LASEK involves the complete removal of an area of epithelium, more time is needed for the eye to heal. It can often take between 5-7 days for this to occur and for your vision to stabilise completely. This type of Laser Eye Surgery is becoming less common, thanks to the effectiveness of LASIK; however, it is sometimes necessary.

At our clinic, only a small percentage of patients will require LASEK surgery. This is most commonly due to the presence of pre-existing scars or surface irregularities on the surface of the retina or cornea, which are more effectively treated using LASEK. While this procedure is more invasive than other Laser Eye Surgery techniques, LASEK is still a safe option for those not suitable for other treatments.


SMILE (small incision lenticule extraction) – also called ReLEx (refractive lenticule extraction) SMILE – is the most recent development in Laser Eye Surgery techniques. SMILE’s introduction in 2011 revolutionised Laser Eye Surgery, thanks to its minimally invasive procedure.

SMILE allows surgeons to carry out laser surgery without removing any of the epithelium – an important step in LASIK and LASEK techniques. This is possible thanks to the invention of the state-of-the-art Carl Zeiss VisuMax laser (we are proud to be one of few clinics in the country with access to such innovative technology. The VisuMax laser is the only femtosecond laser that provides the precision needed to perform SMILE procedures.

This laser places a series of pulses within the cornea, forming bubbles less than 1/1000th the width of a human hair. These bubbles outline the tissue that needs removing and create a tiny connecting tunnel through which the tissue can be drawn out. Amazingly, SMILE procedures can be completed in as little as four minutes, with very little time needed for recovery. Due to the non-invasive nature of the SMILE technique, patients usually feel nothing during the procedure.

Furthermore, SMILE is often an option for patients who are told they are unsuitable for other types of Laser Eye Surgery. This includes patients with high prescriptions, drier eyes, and thinner corneas – all considerations that can make them unsuitable for LASIK treatment.

Which treatment is right for you?

Thanks to advances in technology and the unrivalled expertise and experience of our surgeons, we are able to treat 98% of patients who contact us at our Harley Street clinic.

We can advise on which type of Laser Eye Surgery is right for you. This can depend on a number of factors, including your prescription and lifestyle; however, our consultants are on hand to give you all the information you need and to determine whether Laser Eye Surgery is a suitable option.

If you would like to discover more, arrange a Suitability Call to find out if Laser Eye Surgery is a suitable option for you; or book a consultation at London Vision Clinic by calling 020 7224 1005 or filling out our online form