Common Questions About Laser Eye Treatment at London Vision Clinic

Lizzie - Laser Eye Surgery team member at London Vision Clinic

When toying with the idea of having Laser Eye Surgery, there will likely be a huge number of questions and concerns whizzing around your head. This is only natural – I mean, we all want to know as much as we can when it comes the to the health and safety of our eyes.

That’s why we’ve put together this guide: to answer all of the most common questions about Laser Eye Surgery in one place so that you can spend less time worrying and more time seeing clearly. So, let’s answer your questions!

Does Laser Eye Surgery hurt?

This is probably the first and most urgent question that will pop up when considering Laser Eye Surgery. Luckily, it is an easy one to answer: the procedure itself is virtually pain-free. As Laser Eye Surgery has developed, in many cases, the procedure has become less invasive.

With LASIK treatment, while you may experience a pressure sensation when the surgeon creates a flap in the cornea, most patients feel no pain. Nonetheless, you should expect to experience some slight discomfort and irritation for up to 24 hours following the procedure. Irritation may last for longer (up to a week) following PRK/LASEK treatment; however, during the healing phase, we provide pain relief medication and eye drops to reduce discomfort as much as possible.

Learn more about what to expect from Professor Dan Reinstein.

How long does laser eye treatment take?

One of the beauties of Laser Eye Surgery is just how little time it takes. In most cases, the operation is complete in just a matter of minutes, with the laser itself only active for a few seconds. Preparation for surgery on the day typically takes between 30 minutes to an hour. You should also plan for time in the recovery room immediately following your procedure.

Watch this video to learn more relating to this question.

How long is the waiting list to have Laser Eye Surgery at London Vision Clinic?

The waiting times to have Laser Eye Surgery here at London Vision Clinic can vary significantly depending on the time of year. Typically, you should expect to wait between 1 and 6 weeks, though the best way to find out the current waiting time is to contact one of our friendly Patient Care Coordinators.

Where do you perform the treatment?

Our clinic is located on the world-famous Harley Street in London, UK – this is where all of our Laser Eye Surgery treatments are performed. Harley Street has become known as the leading global hub of Laser Eye Surgery. It is also conveniently situated within easy reach of the London Underground, major bus routes and international airports.

What kind of laser is used for the procedure?

At London Vision Clinic, we have access to world-class Laser Eye Surgery technology – including the Carl Zeiss VisuMax laser. This laser is the latest and most accurate in the industry, providing clear advantages and benefits to our patients.

The ins and outs of laser technology can get a little complex, but there are a few things you should know when deciding on any treatment. The most important thing to know is that a high-quality laser can make a huge difference – but, finding a good Laser Eye surgeon with the experience and expertise in using that laser is just as critical to a successful treatment.

Four areas will determine the type of laser used for your treatment. These are:

  • Spot size
  • Eye tracking
  • Treatment time
  • Safety tests

Learn more about the different lasers used in Laser Eye Surgery in this video.

But what do these really mean? Let’s find out.

What is ‘spot size’?

The beams of different lasers come in different shapes and sizes. The point where the laser touches the eye is known as the “spot”. The smaller the spot, the more focused the laser – meaning that the beam has a higher intensity that moves around the eye at a faster rate. A smaller ‘spot’ helps to ensure that only the required tissue is removed, making for more precise treatment.

The Carl Zeiss Meditec VisuMax laser is more precise and energy-efficient than any other system. Its incredible precision means that it is the only laser suitable for keyhole Laser Eye Surgery: ReLEx SMILE.

At 0.7mm, the MEL 90 has the smallest beam available. This creates a high-intensity beam that moves at a rapid rate, making for the most precise results.

Click here to watch a video relating to this FAQ.

What is ‘eye tracking’?

There is nothing that can help it – it’s a given: your eye is going to move during surgery. Luckily, eye-tracking technology ensures that this movement doesn’t interrupt your treatment.

Perhaps the most important consideration when performing Laser Eye Surgery is that the laser delivers its beam in exactly the right place. We achieve this with the help of various methods, including video infra-red, 3D, and LADAR technology – all of which detect the position of your eye.

Most eye trackers can operate with a minor delay – less than ten milliseconds (that’s one-hundredth of a second!).

In this short video, Prof Reinstein explains eye tracking in more detail.

What is the importance of treatment time?

As we mentioned before, Laser Eye Surgery treatment itself is usually a painless procedure. While inflammation and other processes that occur during your treatment may cause discomfort, in general, the faster the laser treats your eye, the more comfortable you will be.

Furthermore, there is growing evidence that suggests faster treatment also means a swifter and smoother recovery.

Mr Glenn Carp explains more in this short video on the importance of treatment time.

What is the importance of safety testing?

Our vision is one of the single most important assets we have – and we treat it as such. Before every surgery, we carry out a thorough safety check, including two separate checks of laser equipment and instruments by the nursing staff and the surgeon.

A final check tests the laser on a calibration foil before the procedure is begun. These extensive safety checks allow our surgeons to ‘test drive’ the laser. This not only ensures that the laser is working correctly but also informs the surgeon of how the laser will act upon contact with the eye.

Watch this brief video to find out more about the importance of safety tests.

What is the difference between LASIK, LASEK, and PRK?

When it comes to Laser Eye Surgery, there isn’t a ‘one-size-fits-all’ approach. There are several procedures that may be more suitable for each patient, depending on factors including prescription and eye health.

The three main Laser Eye Surgery treatments are LASIK, PRK/LASEK, and ReLEx SMILE. While all of these treatments reshape the ‘stromal’ tissue of the cornea with a laser, they all do so in slightly different ways.

LASIK Surgery

In LASIK (Laser in situ Keratomileusis) surgery, surgeons use a specialised instrument – called a microkeratome – to create a small flap in the epithelium of the cornea. They then employ a state-of-the-art Excimer laser to remove a pre-determined section of the corneal tissue from the exposed bed.

The amount of corneal tissue removed is calculated based on your prescription to improve the power of your eye. Once this is done, the epithelium is replaced and, within minutes, your cornea will hold itself in place and, within a few hours, the healing process will have already begun. LASIK can be used to correct short-sightedness (myopia), long-sightedness (hyperopia), and astigmatism.

PRK/LASEK surgery

PRK/LASEK (Photo-Refractive Keratectomy) is the original method of Laser Eye Surgery. It has been successful in treating hundreds of thousands of people over four decades. It involves creating a small flap in the cornea (in PRK, the epithelium is completely removed while, in LASEK, it is smoothed back into place). This exposes the stromal tissue so that it can be easily removed to reshape the corneal bed.

The reshaping of the stromal tissue allows light to reflect into the eye more effectively, thus addressing the refractive error. Generally, at London Vision Clinic, PRK/LASEK is only used when LASIK or ReLEx SMILE is not suitable. Nonetheless, all three treatments are able to treat a wide range of prescriptions.


The latest development in Laser Eye Surgery treatment is ReLEx SMILE – a minimally-invasive procedure that removes the need to displace the corneal epithelium. The Carl Zeiss VisuMax laser instead creates a tiny keyhole in the cornea, through which it sends a series of pulses to create a channel to the corneal bed. Through this channel, the surgeon can draw out tissue, reshaping the cornea.

Due to the non-invasive nature of the SMILE technique, patients usually feel nothing during the procedure. What’s more, SMILE is often an option for patients who are told they are unsuitable for other types of Laser Eye Surgery, including those with extremely high prescriptions, drier eyes, and thinner corneas.

To learn more about the differences between PRK/LASEK, LASIK, and ReLEx SMILE, watch our short video.

How exactly does Laser Vision Correction work?

When trying to understand how Laser Eye Surgery works, it is important to first understand how the eye itself works. We can think of the eye as a kind of biological camera (it was the inspiration for the technology, after all!). Our cornea is the equivalent to the camera lens, while the retina (positioned at the very back of the eye) is the film.

Just like the lens of a camera, the cornea provides most of the eye’s focusing power. In a perfect situation, the cornea focuses light directly onto the retina. However, in imperfect situations, the light is reflected either too short of the retina or too far. This is usually caused by a problem with the length or shape of the eye. As a result, refractive errors such as short-sightedness, long-sightedness, and astigmatism occur.

All forms of refractive surgery – including Laser Eye Surgery – is based upon the same principle: reshaping the corneal bed adjusts how light enters the eye.

As such, all Laser Eye Surgery treatments are designed to reshape the cornea to allow light to reflect more effectively onto the retina. This is done with the use of ultra-precise lasers that remove a pre-determined amount of tissue from the corneal bed.

Watch this short video to learn more about how Laser Vision Correction works.

Do you treat both eyes at the same time?

If both of your eyes require correction, this is usually done during the same procedure. That isn’t to say we treat each eye at exactly the same time.

Our expert surgeons perform treatment on one eye at a time. We usually treat both eyes during the same procedure as spreading treatment across two occasions extends the healing time and takes up more of your day!

In this short video, Professor Dan Reinstein answers this FAQ in more detail.

What will I feel during the Laser Eye Surgery procedure?

The vast majority of our patients report that their surgery was virtually pain-free. That’s because, with the help of less invasive techniques, and the use of a topical anaesthetic, there is usually very little to feel.

During LASIK treatment, it is normal to feel some pressure as the corneal flap is created. This can give way to mild discomfort and/or irritation following the procedure, due to the natural inflammatory reaction of the eye. Discomfort and irritation following PRK/LASEK typically last a little longer (up to one week or more after surgery). However, your surgeon will provide you with pain-relieving eye drops to minimise your discomfort.

Check out our short video explaining what you’ll feel during the procedure.

What happens if I look away, blink, cough or sneeze during the procedure?

Again, it is completely normal to sweat the small stuff when it comes to your vision. But, to put it simply – don’t! To get straight to the crux of this one: if you look away, blink, cough, or sneeze – don’t worry, nothing will happen.

Thanks to the use of eye-tracking technology, your treatment won’t be interrupted if you move or close your eye. These state-of-the-art instruments (including video infra-red, 3D, and LADAR) continuously detect the position of your eye, ensuring that the laser is only delivered exactly where it is needed.

Click here to hear Professor Dan Reinstein answer this question in more detail.

What is the risk of a complication during Laser Eye Surgery?

Since its introduction around 40 years ago, Laser Eye Surgery has become the most popular elective surgery in the world. With over 50 million procedures performed to date and a decades-long record of innovations and advancements, Laser Eye Surgery is considered one of the safest options for vision correction.

That being said, just as contact lenses are not risk-free, neither is Laser Eye Surgery. That being said, we are happy to report that, when carried out by expert surgeons, the risk associated with Laser Eye Surgery treatment is similar to that presented by daily contact lens wear – and even safer than extended contact lens use.

At London Vision Clinic we take safety and patient care extremely seriously. That’s why, for us, minimising risk begins before you even get into the surgical theatre. We offer one of the longest and most comprehensive consultations and screening processes to fully assess your suitability for treatment. Typically, our patients spend around two hours – often longer – with our surgeons and optometrists, during which time you will undergo a thorough assessment and discuss the treatment and associated risks.

So, what do we mean by ‘complication’ during Laser Eye Surgery?

Loss of Vision

Perhaps the biggest fear among those considering Laser Eye Surgery is loss of vision should something go wrong. By damage to vision, we usually mean some blurring, doubling, distortion, or something that affects the vision to an extent that it can no longer be corrected with spectacles to the level before surgery.

We define a ‘small amount of damage’ to mean that the eye has lost two lines on the vision chart, even with spectacles, compared to the vision before surgery. For an eye that could see 20/20 with glasses before surgery, the vision with glasses after surgery would be 20/30, which is still within the legal driving standard. In the hands of expert surgeons, like those here at London Vision Clinic, the risk of a small amount of damage to the vision is estimated to be approximately 1 in 1,000 for most cases.

Furthermore, it is extremely unlikely that an expert Laser Eye surgeon would face a complication following surgery that they would not be able to fully, or almost fully, correct. At London Vision Clinic, not only do we have every single diagnostic and therapeutic option available to us in the unlikely event that we would need it, Professor Reinstein and his team have been responsible for developing many of these tools for the benefit of experts around the world.

Our Statistics

We understand how important it is for our patients to be as informed as possible about the potential risks of Laser Eye Surgery. That’s why we keep meticulous records of all our statistics – including follow-up rates that are second to none. In recent years, London Vision Clinic has published more scientific papers in the field of refractive surgery than any other provider. More than that, we are proud to be a leading developer of complication repair techniques and technology.

We manage to see 90% of all patients we treat at 1 year and many continuously thereafter for routine follow-ups. In comparison, many providers discharge their patients once they are satisfied with their vision at 1-month or 3-months following treatment. They are, therefore, unable to provide statistics for 1-year outcomes.

Our data shows that there is a 0.02% chance (that’s 5 eyes out of 25,500) that our patients experience complications that cannot be corrected to within two lines of their original best spectacle-corrected vision where we treated short-sightedness (myopia) up to ‑14.00 D, long-sightedness (hyperopia) up to +7.00 D, and astigmatism up to 6.00 D, as well as eyes with the more unusual form of mixed astigmatism.

If you would like more information about the risks of Laser Eye Surgery, don’t hesitate to contact us. We strive to properly inform each and every one of our patients openly and transparently.

In this short video, Professor Reinstein explains how the chance of complications largely depends on the surgeon.

Will I need a general or topical anaesthetic during the treatment?

While in most cases, patients feel very little during surgery – and virtually no pain – all clinics should routinely provide you with a topical anaesthetic to make sure of this.

“The saying is ‘No pain, no gain’ but I can honestly say there was no pain involved with the procedure and the gain was instant- I was reading the small print on the back of a medicine packet within seconds.” —Pamela A., WP Consultant, from Sutton, Surrey

Click here for a short article and video explaining this FAQ.

Can I take a tranquiliser or sedative (i.e. Valium) before the procedure?

We typically advise that you do not take a tranquiliser or sedative before your treatment.

Before you are approved for your procedure, you will once again be examined by your surgeon and give your informed consent – so, you will need to be fully alert. Don’t worry, though; it is extremely rare for a patient to be so nervous that they feel they require a tranquiliser or sedative for the procedure. Nonetheless, you can discuss this further with your surgeon, who will advise you further before your treatment.

Watch Mr Glenn Carp talk about the lack of need for sedatives.

What is Wavefront? Is it better than conventional Laser Eye Surgery?

Wavefront is a type of measurement that maps the unique imperfections of the surface of your eye, called “higher-order aberrations”. These irregularities in your cornea and other parts of your optical system significantly affect the quality of your vision, even beyond common refractive errors such as short-sightedness, long-sightedness, and astigmatism.

To detect these aberrations, a wavefront aberrometer records data from several spots on the surface of your cornea. This produces a map and visual system analysis that can be fed into the laser ready for treatment.

Different analysers measure using a different number of spots, ranging from as low as 60 to as high as 900. At London Vision Clinic we use the Zeiss WASCA, which is at the higher end with a resolution of 650 spots. This technology allows us to create a highly detailed picture of the location of imperfections – much like a high-resolution photograph. In comparison, a low-resolution analyser provides more of a watercolour impression – a general idea of the landscape.

Some clinics promote Wavefront-guided LASIK, or iLASIK, to suggest it is superior to other forms of LASIK. In reality, though, Wavefront-guided LASIK is simply a marketing term for what is generally accepted as the equivalent of Gold Standard Wavefront-optimised surgery.

There are very few cases in which actual Wavefront-guided surgery makes a measurable difference to the outcome. While Wavefront measurements allow surgeons to produce a marginally more accurate treatment plan, for 99% of patients, it is simply considered a useful diagnostic tool, not a device to apply treatments with. Of course, where the eye’s wavefront could be helpful to treatment, we would employ this.

Click here to watch Prof Reinstein explain the difference between Wavefront and glasses prescriptions.

How does treatment for reading vision differ from conventional Laser Eye Surgery?

As we get older, the quality of our vision naturally begins to deteriorate. This phenomenon is known as Presbyopia. The procedure used to correct this deterioration (PRESBYOND® Laser Blended Vision) does not differ mechanically from other Laser Eye Surgery treatments in any way—we can achieve the PRESBYOND® Laser Blended Vision technique with LASIK, PRK/LASEK, or ReLEx SMILE surgery.

The difference is in the way we correct each eye in relation to the other.

Watch Dr Glenn Carp explain the treatment in more detail.

What is IntraLase™, and is it better than conventional Laser Eye Surgery?

Again, IntraLase™ is essentially basic LASIK; however, instead of using the traditional microkeratome instrument to cut the corneal flap, surgeons use a different ‘femtosecond’ microkeratome laser.

“Intralase” is simply the product name used by Advanced Medical Optics (AMO) for their femtosecond microkeratome laser. AMO Intralase, Carl Zeiss VisuMax, and Ziemer FEMTO LDV are the leading manufacturers of this technology and they claim that the adoption of this type of laser reduces complications and can even increase the accuracy of results.

Femtosecond treatment, or IntraLase™, are the standard at the London Vision Clinic.

Find out more about femtosecond lasers and why they are standard practice at London Vision Clinic.

Can I bring someone with me when I have the procedure?

Many of our patients prefer to bring a chaperone with them on the day of their procedure – and we encourage this. Feel free to bring one or two friends or relatives with you for support, but please be aware that only clinical personnel are allowed in the theatre during the procedure.

What will my vision be like immediately after the procedure?

In most cases – following LASIK and ReLEx SMILE surgerythe improvement of your vision is virtually simultaneous (we call this the”wow” effect). Having said that, it is normal to experience some blurriness and glare as your eyes heal fully – these typically reduce within a few weeks.

With PRK/LASEK, the visual improvements are more gradual, with vision sometimes taking up to a week to stabilise and settle to optimum levels.

How should I be getting home?

We strongly advise that all patients make suitable arrangements to get home after surgery – ideally, this will be having someone drive you (another good reason to bring a friend or relative with you on surgery day!) or a taxi.

While our clinic on Harley Street has excellent Underground links, we advise against this form of transportation in the first 2 days following surgery. Your surgeon will discuss this with you in more detail at your one-day follow-up consultation.

Click here for more information relating to this question.

Should I book a hotel near the clinic?

If you’re travelling from outside of the UK or if you live outside of London, you may find it more convenient to stay overnight in a hotel. This will make it much easier for you to attend both your surgical appointment and day 1 consultation.

Below is a list of hotels close by to our clinic (ranging from £80 to £180 per night for a double room – please contact the individual hotel for the most up-to-date information):

In this short video, Katie, one of our patient care coordinators, answers this FAQ in more detail.

What should I do when preparing for Laser Eye Surgery?

Feeling nervous, anxious, or even uncontrollably excited (seriously!) before your surgery is a completely normal and expected reaction. Something you can do to try and curb these feelings is to help yourself feel more prepared. There are some things you can do to achieve this.

Take a look at our checklist below, but remember: if you have any specific questions about how best to prepare, one of our friendly clinic coordinators is only a phone call away!

  • Depending on your occupation, you may need to arrange to be away from work for up to four days following LASIK and up to fourteen days following PRK. Please speak to an optometrist regarding your case.
  • Arrange transport, you won’t be able to drive yourself home and most public transport options are not recommended.
  • Arrange care for children or infants as they are not able to come with you to the surgery.
  • If you are travelling far, you may find it more convenient to arrange local accommodation. Our clinic coordinators are happy to help you with this.
  • Avoid consuming alcohol 24 hours before and 48 hours after your surgery, as this tends to dehydrate your eyes.
  • Remove all eye makeup a minimum of 24 hours before surgery. And ensure your face and eyes are completely free from all makeup on the day of surgery.
  • Don’t wear perfume or cologne; they often contain alcohol, as can hair products such as hair spray and mousse.
  • Wear comfortable clothing and avoid anything that may generate lint such as wool.
  • Just before your procedure, we’ll ask you to sign your informed consent form and pay the balance of your treatment fee.

Click here for more tips on preparing for Laser Eye Surgery in a video explanation by Professor Dan Reinstein.

Ready to take the next step toward clearer vision? Start your journey today by getting in touch with one of our Patient Care Coordinators. Alternatively, Book a Consultation today.

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