Common Questions About Laser Eye Treatment at London Vision Clinic

Lizzie - Laser Eye Surgery team member at London Vision Clinic

Does Laser Eye Surgery hurt?

The procedure itself is pain-free. With LASIK, you may experience a pressure sensation when the surgeon creates the corneal flap, and some discomfort or irritation for up to 24 hours after surgery. With PRK, you may experience irritation for one week or more after surgery. Because discomfort can occur in some patients during the healing phase, we provide pain relief medication in eye drop form to help eliminate this.

Click here to watch Professor Dan Reinstein explain this FAQ.

How long does laser eye treatment take?

The operation takes just minutes, and the laser itself is only active for seconds. Preparation for surgery on the day takes between 30 minutes to one hour.

Click here to watch a video relating to this question.

What is the waiting list to have London Vision Clinic perform my eye laser procedure?

Generally, waiting lists range from 1 to 6 weeks. The exact time varies throughout the year—the best way to find out the current waiting time is by contacting one of our Patient Care Coordinators.

Where do you perform the treatment?

We conduct all Laser Eye Surgery treatments in our clinic on the world renowned Harley street, London in the UK. As well as being known as a leading global Laser Eye Surgery hub, Harley street is within easy reach of the London Underground and many major bus routes.

What kind of laser do you use in the laser eye treatment?

Our laser eye surgeons use the Carl Zeiss MEL 90 laser for two simple reasons. 1: It features the latest advances in laser technology. And 2: brings the clearest advantages and highest benefits for patients.

Discussions about Excimer laser technology can get technical. But in order to make an informed decision about any treatment you are considering, it’s important to cover a few key aspects. One thing to always remember is that a good laser makes a huge difference, but finding a good laser eye surgeon who has the experience and expertise to use that laser is just as critical to successful treatment.

From a patient’s perspective, four areas differentiate the types of lasers used for Laser Eye Surgery. These are:

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

Watch a video about the type of laser used in laser eye treatment at London Vision Clinic.

What is spot size?

The beam of a laser will be a certain size and a certain shape. The point where the laser touches the eye is a “spot”. The smaller the spot, the more focused it is, creating a higher intensity beam that moves around the eye at a faster rate. This also means the laser only removes the material it needs to, providing a more precise treatment.

At 0.7mm, the MEL 90 has the smallest beam available. This creates a high intensity (more focused) beam that moves at a rapid rate, necessitating increased reaction time, which the MEL 90 also certainly has. The result is the most precise laser available.

Click here if you’d like to watch a video about this FAQ.

What is eye tracking?

It’s a given: Your eye will move during surgery. Eye-tracking technology simply ensures your safety when this happens.

Compensating for eye movement is a key factor in ensuring that the laser delivers its beam in exactly the right place. To do so, there are different methods (video infra-red, 3D, LADAR), all of which involve detecting the position of your eye.

There is a minor lag between the laser noticing your eye has moved and compensating for that movement. All trackers, to date, provide approximately the same level of delay time—most operate with a delay of less than ten milliseconds (one hundredth of a second).

Watch a short video of Prof Reinstein explaining eye tracking.

What is the importance of treatment time?

While the actual laser treatment itself isn’t painful, the other processes that happen during treatment may cause some discomfort. The bottom line is, the faster a laser treats your eyes, the more comfortable you will be. There is also growing evidence that faster treatment means a swifter recovery.

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

What is the importance of safety testing?

Every single surgery carried out must first pass a thorough safety check. This includes two separate checks of the laser equipment and instruments by nursing staff and then by the surgeon.

Every time the laser is used, it is first tested on a calibration foil as a final check before starting the procedure. This feature enables the surgeon to test-drive the laser, in order to know how the beam will act when it touches the eye.

Watch a brief video about the importance of safety tests.

What is the difference between LASIK, LASEK And PRK?

Watch a short video on this FAQ and find out exactly what differentiates the treatments.

LASIK, LASEK and PRK are all procedures performed on the ‘stromal’ tissue of the cornea with a laser. Removal of this tissue from the cornea does not usually lead to regeneration of stromal tissue, and therefore produces permanent re-shaping of the cornea, changing its focusing power for good.

LASIK surgery:

LASIK (laser in situ keratomileusis) is a form of corneal surgery in which a surgeon uses a specialised, precise, and computer-controlled corneal flap-making instrument, called a microkeratome, to create a thin corneal flap in the ‘epithelium’ or outer surface of the cornea.

The surgeon raises the flap and lays it back whilst still attached to the cornea. They then use, in the case of London Vision Clinic, a state-of-the-art Excimer laser to remove a pre-determined amount of corneal tissue from the exposed bed of the cornea.

The calculation of the amount of tissue the laser removes is based on the pre-operative determination of the power of your eye; these measurements are usually in agreement with recent prescriptions for your glasses and/or contact lenses. The surgeon finally replaces the corneal flap and within minutes, natural forces hold it down on the cornea.

Usually within just a few hours, the epithelium of the cornea begins to grow over the edges of the corneal flap to seal it into position. This type of treatment commonly known as LASIK is used to correct short-sightedness (myopia), long-sightedness (hyperopia), and astigmatism.

PRK surgery:

PRK (Photo-Refractive Keratectomy) is the original laser vision procedure which surgeons have successfully used it to treat hundreds of thousands of people since the 1980’s. PRK introduced the Excimer laser as an ultra-precise alternative to traditional scalpel-based refractive surgery procedures, such as Radial Keratotomy (RK), which surgeons rarely perform today.

During the procedure, instead of creating a small flap in the epithelium like in LASIK, it is completely removed. The epithelium grows back over the following few days, and thus means a longer period of recovery.

LASEK surgery:

LASEK is a hybrid of PRK and LASIK surgery. The main difference being that it’s goal is the complete preservation of the corneal epithelium. Rather than creating a corneal flap like in LASIK, or scraping and removing the epithelium like in PRK, LASEK treats the epithelium with alcohol to loosen and separate it from the stroma, ready for a surgeon to then roll it back.

The laser removes the underlying stroma and the surgeon rolls the epithelial cells back out, re-positioned and smoothed. The potential advantages of LASEK over traditional PRK are to reduce postoperative haze, speed visual recovery, and decrease postoperative pain.

Generally, at London Vision Clinic we only use PRK or LASEK when we are unable to treat a patient with LASIK. That being said, in the hands of an expert surgeon, all three treatments treat the full range of prescriptions, as well as produce the same visual outcomes.

Watch a video on this FAQ and find out more.

How exactly does laser vision correction work?

The main function of the eye is to focus light. If you think of it as a camera, the cornea is the lens and the retina is the film. The cornea, on the surface of your eye at the front, provides most of the focusing power. In perfect eyesight, it focuses light rays precisely onto the retina at the back.

Your eye’s own internal lens fine tunes light, so you can see clearly enough to read, for instance. In perfect vision, light enters the eye through the cornea and is focused at a single point on the retina. When you have a refractive error, this means that light rays bend and don’t form a sharp focus on the retina. This is normally due to a problem with the length or shape of the eye.

Any operation that corrects the focusing of the eye is called refractive surgery. Laser eye surgery is simply a form of refractive surgery that uses a beam of ultraviolet light to reshape your cornea. Adjusting the curve of your cornea allows light to be focused correctly on the retina.

Refractive surgery is the world’s most common planned surgical procedure. The most popular method of which is LASIK, a procedure carried out on more than 90% of patients. In LASIK, the surgeon first uses a device called a microkeratome to create a very thin corneal flap of tissue in the ‘epithelium’ or skin of the cornea, about a tenth of a millimetre thick.

They then lift this corneal flap back on a hinge, and use the laser to sculpt the bed of the cornea. The laser can be used to flatten the cornea to correct short-sightedness, make it steeper for long-sightedness, and create better symmetry to correct astigmatism. When the surgeon puts the corneal flap back, it quickly adjusts to its new shape.

With LASIK, the healing process is surprisingly short. In the vast majority of patients, the epithelium automatically seals the corneal flap within hours after surgery. Most patients feel little or no discomfort as their eyes heal, rather noticing a significant vision improvement immediately. The rapid visual recovery time means most patients are back at work the next day and have soon returned to their normal routines.

Click here for a video explaining more about how laser vision correction works.

Do you treat both eyes at the same time?

Yes, we do treat both eyes within the same procedure, but no, we don’t treat each eye at exactly the same time.

The treatment is performed on one eye and then the other. Having your eyes treated on different occasions extends the healing and takes up more of your day. Most patients find it more convenient to have both eyes treated within the one procedure.

Click here to watch Prof Reinstein explain more about this FAQ.

What will I feel during the Laser Eye Surgery procedure?

Patients of Laser Eye Surgery are given a topical anaesthetic so the procedure itself is virtually pain-free.

During LASIK you may feel some pressure when the corneal flap is created, and minor discomfort or irritation for up to 24 hours after surgery. With PRK, your eyes might feel irritated for a week or more after surgery. Your surgeon will provide pain-relieving eye drops to minimise any discomfort you have.

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

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

To get straight to the point of this FAQ, the answer is: Nothing will happen.

Although your eye will move during surgery, eye-tracking technology ensures your safety when it happens. Compensating for eye movement is a key factor in ensuring the laser pulses exactly the right place.

There are different methods (video infra-red, 3D, LADAR), all of which involve detecting the position of your eye. There is a minor lag between the laser noticing your eye has moved and compensating for that movement. However, all trackers, to date, provide approximately the same level of delay time—most operate with a delay of less than ten milliseconds.

Click here to watch Dan Reinstein answer this FAQ.

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

With over 50 million procedures performed world-wide to date and a 25 year track record of improvements, Laser Eye Surgery is one of the safest options for vision correction. Just as contact lenses are not risk free, neither is laser eye surgery. However, in expert hands, the safety of laser eye surgery is similar to that of daily contact lens wear, and even safer than extended wear contact lenses.

It is not possible to fully summarise this information here, and all our patients undergo an extremely detailed process to gain informed consent for surgery. Patients at the London Vision Clinic will spend at least two hours, and often longer, for full assessment and discussion about risks with our surgeons and optometrists before proceeding to vision correction surgery. If a patient wants more time, this is easily arranged. This investment of time on our part for each patient, we are confident, is second to none.

The fact is that an expert laser eye surgeon will have the knowledge to manage complications properly and will most probably be able to correct complications that may occur. One may think of this in terms of the difference between a GP or a midwife delivering a baby versus a specialist obstetrician.

When we define what constitutes a complication, one way is to think in terms of damage to the vision. Damage to the vision would mean some blurring, doubling, distortion or something not right with the vision that could no longer be corrected by spectacles to the level before surgery. Overall, 98% of people with a refractive error have blurring, doubling or distortion without glasses, but can see down to the 20/20 line with glasses. Scientifically 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 an expertly trained surgeon, operating with the optimal technology for diagnostics and treatment, the chance of a small amount of damage to the vision is approximately 1 in 1,000 for most cases.

The chances are extremely low that an expert laser eye surgeon would face a complication that he or she would not be able to either fully correct or almost fully correct. This is because an expert surgeon can manage most complications, as long as they have advanced diagnostic equipment such as the Artemis Insight 100 Insight VHF digital ultrasound scanner and high resolution OCT (optical coherence tomography), and the repair tool technology: phototherapeutic keratectomy (PTK) technology and topography-guided laser technology. At the 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.

We keep meticulous records of all our statistics and have follow-up rates that are literally second to none. Over the last 15 years, the London Vision Clinic has published more scientific papers in the field of refractive surgery than any other provider, and we are leading developers 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-up. Most providers discharge patients once they are seeing well after 1 month or 3 months, and are therefore unable to provide final statistics for 1 year outcomes. Our own audited track record for patients in whom we were unable to recover vision to within 2 lines of the original best spectacle corrected vision shows that the chance of this happening is 0.02% (5 eyes out of 25,500 procedures) 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.

For more information on the risks of laser eye surgery and their management, do contact us. We are happy to talk about this openly and transparently.

Watch Dan Reinstein explain how the chances largely depend on the expertise of the surgeon.

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

All clinics should provide you with a topical anaesthetic so the procedure itself is virtually pain-free.

“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?

It is advised not to take a tranquiliser or sedative before having Laser Eye Surgery.

This is as you’ll need to be examined by your laser eye surgeon and be fully alert to go through the informed consent process. It’s extremely rare for a patient to be so nervous they need a tranquiliser or sedative during the procedure, however, if you’d like to discuss this with your laser eye surgeon prior to the actual treatment, you are encouraged to do so at that time.

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

What is wavefront, and 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 of your cornea and optical system affect the finer quality aspects of your vision, beyond the normal refractive errors treated by a glasses prescription such as short-sightedness, long-sightedness, and astigmatism.

To do this, a wavefront aberrometer is used to record data from several spots on the surface of your cornea. This produces a map of the imperfections on the surface of your cornea, as well as a visual system analysis that we feed into the laser.

Different analysers measure using a different numbers 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 provides a highly detailed picture of the number and location of imperfections, much like a high-resolution photograph. In comparison, a low-resolution analyser is more like a watercolour painting: it only provides a general impression of the landscape.

Some clinics promote wavefront-guided LASIK or iLASIK as if it is superior to other forms of LASIK. The truth is that wavefront-guided LASIK is only a marketing term for what is now accepted to be equivalent to the gold-standard of wavefront-optimised surgery. There are very few cases where an actual wavefront-guided surgery will make a difference… the cure to all imperfections. Wavefront measurements do allow a surgeon to produce a marginally more accurate treatment plan, but in reality, for 99% of patients, it’s just a useful diagnostic tool for evaluating the quality of the optics of the eye, not as 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?

The procedure to correct reading vision (PRESBYOND® Laser Blended Vision) does not differ mechanically from conventional Laser Eye Surgery in any way—we can achieve the PRESBYOND® Laser Blended Vision technique with LASIK, PRK or LASEK surgery.

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

Click here for a more detailed explanation of reading vision treatment.

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

This again is 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 lasers can reduce complications and even increase accuracy of results. Femtosecond treatments are the standard at the London Vision Clinic.

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

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

You are certainly welcome, and even encouraged, to bring 1 to 2 relatives or friends along with you to the clinic on the day of the procedure. However, we only allow clinical personnel in the theatre during the procedure.

What will my vision be like immediately after the procedure?

Following LASIK and ReLEx SMILE surgery, vision improvement is virtually instantaneous (the so-called “wow effect”). Many patients say it’s like looking through a clear windscreen. With PRK or LASEK, the visual improvements are more gradual, sometimes taking up to a week to reach their optimum level and stabilise.

How should I be getting home?

From our clinic in the UK based on Harley Street, London, we advise patients to be driven home or to take overground trains.

We advise against taking the London Underground in the first 2 days after surgery. Your Surgeon will suggest when you should next use the underground at your one day post-operative visit.

Click here for the video relating to this question.

Should I book a hotel near the clinic?

If you’re traveling from outside of the UK or if you live outside of London, you may find it more convenient to attend your surgical and day 1 appointment by staying in a nearby hotel. The following is a list of hotels in close proximity 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 a short video Katie, one of our patient care coordinators, answers this FAQ.

What should I do when preparing for Laser Eye Surgery?

First of all, it’s helpful to point out that feeling nervous, anxious, or uncontrollably excited (some patients!) before surgery is a completely natural and expected response.

Normally a lot of the nerves can be curbed by simply getting more prepared for the day of the surgery. Review the checklist below and if you have any specific questions as to how you can best prepare, your Laser Eye Surgery clinic will always be just 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 individual case.
  • Arrange transport, you won’t be able to drive yourself home and you may find public transport to be tiring.
  • 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. The clinic should be happy to help you arrange this.
  • Avoid 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 complimentary free from all makeup on the day of surgery.
  • Don’t wear perfume or cologne; they can 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 to pay the balance of your treatment fee.
  • Bring your diary if you would like to make your aftercare appointments while you’re at the clinic.

Click here for a closer look at preparing for Laser Eye Surgery and a video explanation by Prof Reinstein.

Ready to take the next step toward greater vision? Start your journey by sending a message to one of our Patient Care Coordinators today.

Dr Tim Archer
Dr Tim Archer

Dr Timothy Archer graduated from Oxford and Cambridge Universities with an undergraduate degree in Mathematics and a postgraduate degree in Computer Science. He joined the clinic in 2003, where he established his career specialising in laser refractive surgery research alongside Professor Reinstein. Today, he manages the in-house research team, of which achievements include 124 peer-reviewed papers, 32 book chapters, over 100 scientific articles and a published textbook. He also oversees and edits the content on London Vision Clinic’s website.