Understanding the different types of Laser Eye Surgery

There are several different types of laser eye surgery. The various terms used to describe each one can be confusing though. In this article we will discuss the difference between LASIK and LASEK, Presbymax, Blended Vision, as well as SMILE and some of the reasons why one may be preferred to another.

Laser eye surgery commonly corrects short-sightedness (myopia), long-sightedness (hypermetropia), astigmatism and reading vision problems (presbyopia). The technique used to correct the conditions above are all different but are achieved through the use of a laser which reshapes the surface of the cornea and adjusts the focus of the eye.

Upon your initial consultation you will have various diagnostic tests carried out to determine suitability for the laser procedure and which type of procedure is best suited to you:

LASIK eye surgery

This is one of the safest and most commonly performed surgical procedures worldwide with 90% of patients being suitable.

The procedure starts with an anaesthetic drop being put into the eye to numb the surface. The next step involves creating a thin microscopic flap in the surface of the cornea and then re-shaping the cornea underneath this in order to change its power and accurately focus light. All of this is completely painless and takes less than 5 minutes for each eye.

The main advantages of LASIK are that both the laser eye surgery procedure and recovery are painless and that most patients experience fantastic vision after only a few hours meaning that a fast return to work and play is possible.

LASIK is the most common form of laser eye surgery carried out in the world today. It’s estimated that there have been over 50 million procedures carried out worldwide. In many developed countries up to one in thirty of the general population of all ages have already had this procedure carried out.

At OCL Vision, all of our LASIK (and advanced surface) procedures are wavefront treatments with 7 dimensional eye tracking which means that the laser will be programmed to give you the best quality of vision possible.

Our laser eye surgeon Mr Ali Mearza explaining the different types of laser eye surgery.

LASIK stands for Laser-Assisted In-situ Keratomileusis. In order to better understand what this involves it’s helpful to break this down a little further:

Laser: At OCL Vision 2 lasers are used ensuring that we always carry out bladeless surgery. The first laser is a femtosecond laser which is programmed to make the flap as thin and small as safely possible using the lowest amounts of energy without compromising on precision or safety. We will read about the second laser below
Assisted: Many people believe that the lasers do it all. We pride ourselves on having the most up to date, fastest and precise technology for laser eye surgery in London. However, despite this, your surgeon is the main determining factor of a safe outcome. The reason for this is not only down to how the lasers are programmed but also because there are manual components of surgery and the surgeon’s skill and experience play an important part in ensuring that everything is carried out to perfection
In-situ: This literally means ‘in its place’ which just means that the steps explained above and below occur in the cornea which is the clear natural watch crystal of the front surface of the eye
Keratomileusis: This means re-shaping and is carried out by a second laser. This laser is called an ‘excimer’ laser which stands for ‘excited dimer’. This explains the process by which electricity is able to combine with two gasses (argon and fluoride) inside the laser and create light energy of a very specific ultraviolet wavelength which allows for extremely precise reshaping. This is a cold laser and thus contrary to popular belief there is absolutely no heat nor burning involved in modern laser eye surgery

LASEK eye surgery

This is an alternative to the LASIK procedure and a better choice for patients who have thinner corneas. LASEK stands for laser-assisted subepithelial keratectomy. It is one of a collection of procedures that we term advanced surface laser ablation.

All of these surface procedures involve reshaping the cornea without creating a flap. In order to do this, the surface layer of cells on the cornea (the epithelium) is disrupted either manually or with a laser and must regrow. For this reason, although the procedure is painless, the recovery is painful for 2-3 days and the vision is blurry for the first week, taking a few weeks to get to the 20/20 or 6/6 vision level or better. We give you anaesthetic drops and painkillers to go home with, in order to minimise any discomfort.

We tend to only recommend a surface procedure when we feel that LASIK is not advisable; for example in thin or irregular corneas and around 10% of the laser vision correction procedures that we carry out are surface advanced surface laser ablation procedures. In higher prescriptions, we use the anti-scarring agent MMC (mitomycin C) to reduce the chance of haze following the procedure.

Once this procedure is finished, a bandage contact lens will be inserted to aid the healing process, which is a slower visual recovery than the Lasik procedure. The bandage contact lens will be removed between 3-5 days after surgery with vision improving noticeably for weeks after the treatment.

Presbymax eye surgery

This is a procedure available only on the Schwind Amaris 1050RS laser platform. This procedure extends the depth of focus in the non-dominant eye by precisely adjusting the optics of the eye. This extended range of focus creates a smoother transition between the distance and near vision for a complete range of focus.

Presbymax treats presbyopia, also known as ‘reading vision’. The following conditions can also be corrected at the same time: myopia (short-sightedness), hypermetropia (long-sightedness), and astigmatism (irregular eye shape).

Not all patients are suitable to have Presbymax and the best treatment will be determined by your in-depth examination and discussion with your individual surgeon.

Laser Blended Vision

This is a procedure offered to presbyopic patients where the dominant eye is corrected for distance vision and the non-dominant eye corrected for reading/near vision.

This is because, if both eyes are corrected for distance vision, the near vision would remain a problem. Instead, our eye surgeons adjust the dominant eye for distance vision and the non-dominant eye for reading and near vision. This treatment is called blended vision.

This is a reversible procedure – the near distance eye can simply be fully corrected for perfect distance vision in the rare case of intolerance to blended vision. This results in a great quality of vision throughout the day. Blended Vision is performed either by LASIK or LASEK, again dependent on the suitability for the procedure.

SMILE TM (Zeiss) eye surgery

SMILE TM (Zeiss) stands for Small Incision Lenticule Extraction.

It is the newest form of laser eye surgery and involves using only one laser to create a lens within the cornea which is then dissected and removed. Some people are drawn to the fact that it does not require creating a flap in the cornea and that it is new.

However, the fact that it is new means that certain safety features which are present in LASIK are not yet available with SMILE. Safety features for LASIK such as pupil tracking, centration control and astigmatism control do not exist with SMILE.

SmartSight™ laser eye surgery

SmartSight™ is the latest innovation in laser eye surgery. It uses lenticule extraction in the same way as SMILE™, but has additional safety features such as advanced pupil tracking and astigmatism software.

OCL Vision is currently the only UK clinic to offer this pioneering surgery. The team at OCL were handpicked by Schwind (the manufacturer of the laser) to be the flagship bearer of this technology in the UK.