Laser Eye Surgery procedure: How complex is the treatment?

laser eye surgery equipment

In general, treatments are as complex as the problem they’re designed to fix.

Minor cuts and scrapes are easily managed with some antibacterial wash and a plaster. Gallstones are more serious and require medical intervention, but the procedure is pretty straightforward and routine. Brain injuries are incredibly complicated and challenging and need nothing less than an expert to perform risky open brain surgery.

But advancing knowledge and technology is turning this idea on its head. Many complex injuries and conditions which were once difficult if not impossible to treat can now be resolved with a mere injection or the click of a few buttons.

A good example of this is the treatment of refractive errors. Not too long ago it was unthinkable to be able to adjust the eye by hundredths of a millimeter and successfully mitigate any problems with vision. Yet now it’s a very real reality, and every day thousands of people wake up short or long sighted or with astigmatism and go to bed with perfect vision.

This leap forward in vision correction is thanks to the development of sophisticated laser technology. To understand how it works, we first need to understand what a refractive error actually is.

Error: light cannot focus correctly, please update your lens

Our vision works by means of ‘refraction’ — the bending of light as it passes through one object to another. Refraction is demonstrated using a transparent prism with three glass sides of different angles. As light rays enter the prism, they’re bent or ‘refracted’ and sent in different directions.

It’s this process of bending light rays that allow light to focus on one single point on the retina at the back of the eye. It’s then converted into electrical signals, sent through the optic nerve to the brain, and translated into the image we see. Whether you see a clear image or not depends on the health and functionality of your cornea and lens.

Common problems with this system are known as refractive errors. Short-sightedness or ‘myopia’ occurs when the eyeball is too long and/or the cornea has a more pronounced curve than a normal eye, therefore focusing power is too strong. This causes light from distant objects to focus in front of the retina rather than on it. To fix myopia, surgeons need to remove a small amount of tissue in order to flatten out the curve.

In longsightedness or ‘hyperopia’, the eyeball is usually too short or focusing power too weak, causing light to focus behind the retina rather than on its surface. Without the adequate length, the cornea needs to curve more to be able to direct light onto the retina.

In astigmatism, the lens is distorted and more like the back of a spoon than spherical like a ping pong ball. This causes light to refract into two focal points. To correct astigmatism, the cornea needs to be made more symmetrical.

And then there’s the natural stiffening of the lens in the eye that happens as we get older, known as presbyopia. In all these conditions, problems with the shape of the cornea, zooming ability of the lens, or the length of the eye are to blame for the impaired vision.


Traditionally, refractive errors are managed with external lenses like contacts and glasses. These are great to temporarily improve vision, but they are a far from ideal solutions. And so, refractive surgery was born. It works by reshaping the cornea and permanently changing the focal point of light so that your eyes operate like a normal, unaided pair.

It does this by using a tightly-focused beam of ultraviolet light to remove a tiny amount of tissue from the corneal bed. First, the laser is programmed according to data from the patient’s treatment profile.

Next, the surgeon makes a tiny flap in the surface of the cornea to access the tissue underneath the epithelium (the layer of skin on top of the cornea). After the flap is created, the laser makes an incredibly precise number of pulses into the target tissue. As soon as the flap is moved back, the cornea — one of the fastest healing parts of the body — instantly begins to heal itself and seal the edges shut.

All this is only possible thanks to the invention of the excimer laser — perhaps the most complex but most elegant part of Laser Eye Surgery. Having been first conceptualised by Einstein at the start of the 20th century, it wasn’t until 1960 that the first laser was built, however these lasers were ‘hot’ in that they would burn tissue. During the 1970s, the excimer laser was developed and was discovered to be a ‘cool’ laser, meaning it doesn’t heat up the surrounding area – as was first demonstrated by some IBM researchers using their turkey leftovers from Thanksgiving! Instead, its beam of ultraviolet light is absorbed by the immediate surface it contacts, resulting in the breakdown of molecular bonds in the material. With pulses half the width of a human hair, the technology can be used to make incredibly fine changes to the cornea and permanently correct refractive errors.”

For a procedure that can banish vision problems in less time than it takes to make dinner, Laser Eye Surgery is nothing short of impressive. If you’d like to find out more about the treatment or book a consultation at London Vision Clinic, send us a message or give us a call us on 020 7224 1005.