How Exactly Does Laser Eye Surgery Work?
Laser refractive surgery has been around for decades and has been successfully used to correct the vision of tens of millions of people around the world. Since its invention, Laser Eye Surgery has become the most popular elective procedure worldwide! Yet, many people are still unsure how the procedure actually works.
Being unsure how something works can make us more afraid of it. So, let’s clear this up once and for all and get to the bottom of how Laser Eye Surgery corrects common refractive errors. After all, knowledge often dispels fear!
A Brief History of Laser Eye Surgery
Laser Eye Surgery was introduced commercially in the late 1980s; however, the theory behind this popular procedure dates back much further. In 1948, Spanish ophthalmologist José Ignacio Barraquer Moner performed the precursor to Laser Refractive surgery as he sought a better alternative to external visual aids.
Barraquer Moner theorised that it was possible to correct refractive errors, such as myopia (short-sightedness), by changing the shape of the cornea (the transparent part at the front of the eye that covers the pupil and iris) itself. Of course, putting this theory into practice was more complicated. In the days before laser technology, this involved removing an area of corneal tissue from the eye, freezing it to allow it to be reshaped, and then reattaching it to the eye.
This procedure was successfully performed on thousands of patients in the 1960s and beyond; however, it wasn’t until the early-1990s that we started to see procedures that more closely resembled modern Laser Eye Surgery. This is when the invention of the excimer laser paved the way for the invention of LASIK as we know it today.
So, let’s take a closer look at how the three key Laser Eye Surgery procedures work.
What is Laser Eye Surgery?
Laser Eye Surgery is a kind of modern refractive surgery – that is, a procedure that corrects the focusing power of the eye. The treatment works on the basis that changing the shape of the cornea can adjust the way light is directed into the eye, correcting any existing refractive error. The same theory is used when determining the lens power required in glasses and contact lenses. Of course, Laser Eye Surgery takes this a step further, changing the shape of the eye itself.
The use of high-precision lasers allows trained surgeons to adjust the curvature of the cornea by removing a pre-determined area of corneal tissue. This allows light to be focused more effectively on the retina (the photosensitive layer at the back of the eye).
Our expert Laser Eye Surgeon, Mr Glenn Carp, explains more in the video below:
The first laser refractive surgery was performed in 1987, using a procedure known as Photorefractive Keratectomy (PRK) – which brings us to the different types of Laser Eye Surgery. While your research might have left you with the impression that there is an endless list of different Laser Eye Surgery procedures, there are really only three you need to know about: PRK/LASEK, LASIK, and ReLEx SMILE.
PRK and LASEK – The Surface Procedures
Surface procedures – also known as surface ablation – are the earliest forms of Laser Eye Surgery. They involve completely removing an area of corneal epithelium (a thin layer of tissue on the surface of the eye) using an excimer laser. This grants access to the stromal tissue beneath, allowing the surgeon to reshape the cornea.
In PRK, this layer of epithelium is removed and discarded. Following the procedure, a protective contact lens is placed over the exposed area of the eye. This protects the eye until the cells of the epithelium have repopulated – a process that typically takes a matter of days.
In LASEK, the removed area of epithelium is simply pushed to one side while the procedure is being performed. Once complete, the tissue can be put back in place, where it is once again covered with a protective contact lens.
While both PRK and LASEK are still considered extremely effective, they only account for around 5% of procedures performed today.
LASIK – The Most Common Procedure
The first LASIK procedure was performed in 1989 to correct the vision of a patient with myopia – and it remains the most popular Laser Eye Surgery procedure to this day. Unlike surface ablation procedures, LASIK doesn’t require the complete removal of the epithelium from the eye. Instead, a laser is used to create a ‘flap’ on the surface of the eye, allowing the surgeon to access the tissue beneath.
Once the surgeon has finished reshaping the cornea, this flap can simply be closed to cover the exposed area of the eye. At this point, suction holds the corneal flap in place, and the edges of the flap immediately begin to heal, removing the need for a protective contact lens. The less invasive nature of LASIK also means that healing times are significantly reduced when compared to PRK/LASEK.
ReLEx SMILE – The Least Invasive Method
The third and final Laser Eye Surgery procedure you need to know about is often referred to simply as SMILE. This relatively new technique, developed by our very own founder and expert surgeon, Professor Dan Reinstein, has only been around since 2008. In fact, London Vision Clinic was the first clinic in the UK to offer this innovative treatment.
ReLEx SMILE is a keyhole procedure that doesn’t require any of the corneal epithelium to be displaced. Instead, a small incision is made in the epithelium, through which a femtosecond laser is used to create a small tunnel from the surface of the eye to the corneal tissue beneath. The surgeon is then able to draw out the small amount of tissue required to reshape the cornea.
This innovative technique has helped to make Laser Eye Surgery an option for more people than ever before. It allows for the treatment of higher prescriptions and is often suitable for patients with thinner corneas or those who are prone to dry eyes!
While Laser Eye Surgery was initially only used to treat short-sightedness, it can now be used to effectively correct hyperopia (long-sightedness), astigmatism, and presbyopia, too!
If you’d like to find out more about Laser Eye Surgery, get in touch with one of our friendly clinic coordinators today. Alternatively, Book a Consultation to find out if you could be suitable for treatment.