Laser Eye Surgery: How Complex is the Procedure?

Generally speaking, treatments tend to only be as complex as the problem they’re designed to fix. For example, minor injuries like cuts and scrapes might only require a wash with an antibacterial solution and a plaster, whereas organ problems may well require invasive surgical interventions.

But in recent years, a number of treatments have flipped this theory on its head. Take Laser Eye Surgery, for example. Despite dealing with one of the most complex organs in the body – the eyes – and having a life-changing impact, Laser Eye Surgery is a surprisingly straightforward and minimally invasive procedure – at least after the testing and planning stage.

In this article, we take a look at each step of the Laser Eye Surgery procedure to establish the true complexity of this now-common elective treatment.

Correcting Refractive Errors

Laser Eye Surgery was invented around four decades ago with the development of  LASer Epithelial Keratomileusis – or LASEK. For the first time, technology enabled surgeons to adjust the shape of the cornea by hundredths of a millimetre to correct the way light enters the eye. Prior to this innovation, the vast majority of patients would rely on glasses, contact lenses, or risky invasive surgeries to improve their vision.

Today, Laser Eye Surgery can successfully correct all common refractive errors, including short-sightedness (myopia), long-sightedness (hyperopia), astigmatism, and even presbyopia.

All of these refractive errors occur when light is unable to enter the eye effectively. Our vision uses refraction – the bending of light as it passes through one object onto another – to send clear images to our brain. When working correctly, our eyes should refract light that bounces off of the objects around us to settle directly on the retina – the photosensitive layer of cells – at the back of the eye.

The cornea – the outermost, clear layer of the eye – is responsible for achieving this refraction. In the absence of a refractive error, light is focused at a single point on the retina which is then able to send electrical signals through the optic nerve to the brain; however, when the cornea is unable to focus the light correctly, we can experience blurred and distorted vision which is usually sensitive to different distances.

Myopia (Short-Sightedness)

Short-sightedness is the most common refractive error, worldwide. It occurs when the eyeball and/or the cornea is too steep. For example, in myopic eyes, the curve of the cornea may be more pronounced than in non-myopic eyes. As a result, light is focused in front of the retina instead of directly on it, causing blurred vision at long distances.

To correct myopia, the surgeon will remove a pre-determined area of corneal tissue to flatten the cornea and correct the way light is refracted onto the retina.

Hyperopia (Long-Sightedness)

In contrast, long-sightedness occurs when the eyeball is too short or the cornea is too flat. This causes light to be focused beyond the retina, causing blurred vision at close distances, such as when reading. To correct hyperopia, the surgeon will remove a small amount of tissue to make the cornea more curved, increasing the eye’s focusing power.


In healthy eyes, the cornea appears spherical, like a football, with even curves both horizontally and vertically. However, in astigmatic eyes, the cornea is closer in shape to a rugby ball – more flat across one of its axes. As a result, light is refracted in two points on the retia, causing blurred and distorted vision. Astigmatism can also co-occur with other types of refractive error.

To correct astigmatism, the surgeon will remove a portion of tissue to make the cornea more symmetrical.


And then there’s the natural stiffening of the lens in the eye that happens as we age, known as presbyopia. This causes the eyes to lose their focusing power, gradually increasing the need for reading glasses or multifocal lenses. To correct presbyopia, a slightly different approach to Laser Eye Surgery is used: PRESBYOND® Laser Blended Vision.

This technique works by correcting each eye in a slightly different way, creating a “blend zone”. This allows your brain to combine the two images from each eye to establish clear vision at all distances. Find out more about PRESBYOND® Laser Blended Vision here.

How Does it Work?

In all of these refractive errors, problems with the shape of the cornea, the zooming ability of the lens, or the length of the eye are to blame for the impaired vision.

Traditionally, external visual aids like glasses and contact lenses have been effective at correcting these refractive errors; however, they each possess their shortcomings – particularly when relied upon over the long term. So, how does Laser Eye Surgery work, and is it as complex as it sounds?

Laser Eye Surgery uses an excimer laser to reshape the cornea. This impressive piece of kit works by breaking down chemical bonds (it’s not hot like the lasers in sci-fi films!) in the cornea, allowing for the removal of a small area of tissue. While the laser itself is a rather complex, state-of-the-art technology, the procedure couldn’t be more straightforward for the patient. In fact, most procedures are completed in just a matter of minutes. Moreover, most patients will notice an immediate improvement in their vision!

Arguably, the most complicated part of your Laser Eye Surgery treatment is completed before you even head into the operating room. You see, each patient’s treatment needs to be carefully planned to create a bespoke treatment profile. This data is gathered at your screening appointment – where we are able to determine whether you are a suitable candidate for the procedure.

Your initial screening will involve a wide range of tests and examinations to ensure we have all the necessary data to create your tailored treatment plan. This is an extensive review of your eye health and refractive error that can take around 2-3 hours to complete.

All in all, Laser Eye Surgery might still seem like a futuristic and alien medical procedure, but the truth is, with the right preparation and the best technology, it really isn’t as complex as you might think.

If you’d like to learn more about what you can expect from Laser Eye Surgery at London Vision Clinic, get in touch with one of our friendly clinic coordinators. To find out if you’re suitable for treatment, Book a Consultation today.