LASIK ('laser-assisted in-situ keratomileusis') is the most widely performed laser eye surgery to correct short-sight, long-sight, astigmatism and presbyopia (the need for reading glasses). Learn about the A-LASIK procedure developed at Focus Clinic

Original Image Example before LASIK
Modified Image Example after LASIK
Example after LASIK Example before LASIK

LASIK Surgery

LASIK (‘laser-assisted in situ keratomileusis’) is the most frequently performed laser eye surgery to correct myopia (short-sight), hyperopia (long-sight) and astigmatism.

LASIK may also be combined with Blended Vision to treat the need for reading glasses.

Focus has a 100% 20/20 vision success rate for all common short-sighted prescriptions using it’s A-LASIK technique

In common with all forms of laser refractive surgery, LASIK changes the curvature of the cornea so that light entering the eye will be correctly focused on the retina at the back of the eye, resulting in a clear image.


A-LASIK laser eye surgery at Focus Clinic

  • is considered pain-free by most patients
  • is performed as a day-case with the whole visit lasting 2 hours
  • treatment completed within 10 minutes for both eyes
  • gives excellent vision in 4 hours for most patients

The most important step is to find the right surgeon, as it is the single biggest factor affecting the quality of your vision after treatment. At Focus, you will have a world-class clinician perform your LASIK. After consultation, if we find that you are not suitable for LASIK, a number of other vision correction options could be available. Alternative procedures include: PRK (also referred to as LASEK) and phakic IOL surgery (ICL), where an additional lens is placed inside your eye. We will determine if one of these procedures is suitable for your eyes and, if so, which technique will be best.


The LASIK procedure

How does Focus’ A-LASIK correct vision?

At Focus, your surgeon will perform more than 150 steps on each eye with our advanced A-LASIK procedure, developed by chief surgeon David Allamby. A-LASIK has resulted in a 100% success rate for all common myopia prescriptions and a boosted safety profile. For LASIK in general, ninety percent of the treatment is done manually by the surgeon, with the lasers active for only 10% of the duration. Hence, getting an expert surgeon is very important.

Your surgeon first uses a femtosecond laser to create a thin, circular “flap” in the uppermost layer of the cornea. (N.B. some clinics still use a mechanical blade tool called a microkeratome for this step, but which is outdated and should be avoided)

the laser will remove a very small thickness of corneal tissue – typically 1/10th to 1/20th of a millimetre – to fully correct your vision

The curvature of the cornea is changed by this cool ultraviolet laser (without heat) by evaporating microscopic amounts of tissue. The new shape creates clear vision by correctly focusing light onto the retina inside the eye. For short-sight, the cornea is made flatter, whereas for long-sight it is made steeper.

LASIK, like PRK, can also can correct astigmatism by smoothing a rugby ball-shaped cornea into a rounder, more normal shape. It is a common myth that LASIK cannot treat astigmatism.

After the laser reshapes the cornea, the flap is then folder back into position, covering the area where the corneal tissue was removed. Then the cornea is allowed to heal naturally.

the surface skin cells will have sealed the edge of the flap in just 4 hours.

LASIK eye surgery requires only topical anaesthetic drops, and no bandages or stitches are needed.

Who can have LASIK?

  • short-sight – most myopia prescriptions can be corrected with the laser combination used at Focus Clinic
  • long-sight – mild to moderate (high degrees of long-sight may not be treatable)
  • astigmatism – most prescriptions can be treated
  • reading glasses – most patients age 45+ can have clear close vision with LASIK Blended Vision

We can give you a good idea of your suitability initially over the telephone and confirm this after seeing you for a consultation.

Before, during and after your LASIK treatment

Before your LASIK surgery

We will perform a complete eye health examination to ensure your eyes are suitable for the procedure. We will assess and measure:

  • how well you can see with and without glasses (visual acuity)
  • the thickness of your cornea
  • the shape of your cornea
  • pupil size
  • presence and degree of any dry eye
  • your prescription, also known as your ‘refractive error’
    • short-sight (myopia)
    • long-sight (hyperopia)
    • astigmatism
    • presbyopia (loss of reading vision)
  • any other eye problems

It is important to assess the level of tear lubrication of your eyes (dry eyes). LASIK and other forms of laser eye surgery are known to make the eyes temporarily drier for 3-6 months and so you need to have adequate tears prior to any treatment. Additional drops, supplements or other measures may be recommended to improve your tears prior to the procedure.

A map of the shape of your corneas will be created using a tomography scanner (also sometimes referred to as topography), which helps determine the strength of the clear window at the front of your eye.

The optical quality of your eyes will be measured with a so-called wavefront scanner. This measures any imperfections, or ‘aberrations’, in the optical quality of your eyes as a camera. Some eyes have better optics than others – some are more ‘Canon’ and others ‘Kodak’.

We will ask about your general health and history of any medical problems, as well as any medications you are taking, to see if you are eligible for surgery.

You can see more information further down this page on factors that could mean you are not suitable for laser vision correction.

You should leave out any contact lenses just prior to your consultation. We can determine most patients suitability at the first visit, although you may be asked to leave your contact lenses out for a longer period and be reassessed.

However, prior to surgery, you should stop wearing lenses for one week (for soft lenses, and longer for other types – we will advise you), as contacts can alter the natural shape of your cornea and alter your prescription. We will remeasure your true prescription, as well as performing all the scans, once again on your treatment day.

During the LASIK procedure

Anaesthetic eye drops are applied to fully numb the surface of your eye to ensure there is no pain during the procedure. If you are very nervous, we can provide a tablet to help you relax, though most patients manage perfectly well without the need for a sedative.

Your skin on the face and around the eyes is cleaned and you will have a paper hat to keep your hair away. You will lie down on the laser bed and positioned so that you can see a small blinking green light.

A small speculum will be used to keep your eye open. While it is in place, you cannot feel it and you can blink as normal. It will feel exactly as if you are blinking, even though the eye does not close. There is no need to try to keep your eyes open.

Your surgeon uses the first Ziemer LDV femtosecond laser to create a corneal flap. You will feel a sense of pressure for about 25 seconds. This is an extremely precise laser that uses a finer pulse for better healing.

Your prescription will already have been programmed into the second WaveLight ‘excimer’ laser. After the flap has been gently folded to the side, the excimer laser will correct your vision usually in just 5-10 seconds. You simply need to look at the green light.

The laser has an auto-tracker to keep the treatment in exactly the right place, so even if you move your eye it will not affect the result.

the laser treatment itself takes 5-10 second and is painless

LASIK is performed on each eye separately, usually on the right eye first followed by the left eye. Each eye is completed in 4-5 minutes.

Just after your LASIK surgery

The A-LASIK technique used at Focus Clinic can often give dramatically better vision immediately after treatment. Watch the video below to see some patients’ reactions to how well they can see as they sit up after surgery.

Happycam video here

You will rest in our chill-out room for 20 minutes and have a drink and biscuits as you prefer. After this you will be ready to go, and the person who came with you can escort you home. You will not be able to drive yourself until we have confirmed your vision meets the legal requirement at your next day checkup.

Your eyes will feel watery, gritty and/or heavy for around 3-4 hours after your procedure. Anaesthetic drops are supplied in your take-home pack, which you may want to use once or twice.

Vision is initially slightly misty. By around fours hours later, you can expect your eyes to settle and for the eyes to feel fairly normal. By then, vision is typically excellent.

Many patients may be able to go back to work the next day, after you have had your first follow-up eye examination. At this appointment, we will measure your vision and confirm healing is progressing as planned. Most patients have better than 20/20 vision by this time.

We will supply an instruction sheet for various do’s and don’ts. We recommend that you refrain from exercise for one week, to avoid any risk of injury to your eyes.

After your first day check, we will see you at one week and one month after treatment. Additional checks are usually then at 6 months and 1 year after correction.

The speed of recovery depends on your initial prescription. For most people, vision improves greatly in the first few hours. Short-sighted treatments settle very quickly and remain good, as do those with astigmatism.

Long-sighted treatments, especially those of higher amounts, may take several weeks or months to fully stabilize. Reading vision is usually very good but distance vision can be slightly blurry at first. This settles as the cornea stabilises into its correct shape.

For most patients, we assess at the six-month time point to confirm the outcome of the procedure. In a small percentage of cases, re-treatment may be needed (less than 1% for most short-sighted prescriptions).

As with any other type of surgery, always follow our instructions and take any medication or drops as prescribed. it is important to avoid rubbing your eyes putting undue pressure on the flap before it has properly healed.

Who is not suitable for laser eye treatment?

Most people who have healthy eyes and have short-sight with or without astigmatism are good candidates for LASIK eye surgery, except for extreme prescriptions. Mild to moderate degrees of long-sightedness can also usually be treated. We can also treat many patients who need glasses for reading with our LASIK Blended Vision procedure.

Most LASIK patients are between the ages of 21 and 65. The minimum age is 18 years old, but often short-sighted prescriptions have not stabilised until the 20s.

There is no upper age limit for laser correction as long as the eyes are healthy, though patients who are 60+ may be better served with a refractive lens exchange procedure depending on the prescription and eye anatomy, and our clinicians can advise you on this choice.

There are several possible conditions where LASIK surgery might not be advisable:

Severe refractive errors

If your prescription is very high or extreme, LASIK may not be a viable option. The treatment can greatly reduce the severity but you might still require glasses afterwards.

We can, however, treat around 98% of all short-sighted prescriptions, including those with astigmatism, if all other suitability criteria are met.

Dry eyes

This is the most common complication from laser eye surgery world-wide, but which is mainly avoidable with proper patient selection and pre-treatment to improve eye lubrication.

At Focus, by 12 months after surgery, we see less than 0.5% of patients for ocular dryness and 0% by 2 years. We have a rigorous selection process and may spend several months getting your eyes ready for LASIK surgery. It is time very well spent.

Both the quality and the amount of tears you make are involved in the development of dry eyes, but quality is the biggest factor. Most dry eye arises from excess evaporation and pre-operative therapies are directed at decreasing this back to normal levels.

Unstable prescription

Your prescription should be stable for 12 to 24 months before undergoing laser eye correction, either LASIK or PRK / LASEK. Some patients may be stable by 18 if they become myopic when very young, but more typically they will be age 21 or older.


If you have keratoconus or another corneal thinning problem, such as pellucid marginal degeneration, you will very likely be unable to have laser eye treatment.

Recent advances in stabilising and strengthening the cornea using collagen cross linking have allowed some patients to have surgery as part of the treatment of their keratoconus.

Some surgeons have advocated cross-linking for all LASIK treatments, known as LASIK Extra. This is not necessary or recommended and not practiced at Focus Clinic.

Large pupils

This was once considered to be more important than it is today. It links to the risk of experiencing problematic night vision issue after LASIK, including glare, halos and star-bursting of light. However, this risk is mainly associated with having large pupils PLUS the magnitude of the prescription, so that highly short-sighted patients are more at risk than mild to moderate myopia. Patients most at risk are those with very high prescriptions (e.g. -7.00 to -8.00 dioptres or higher) and large pupils (e.g. 8mm or bigger), and such patients need to be counseled appropriately.

Other eye problems

These include cataracts, glaucoma, previous ocular herpes infections, diabetic eye problems, prior eye surgery or other health conditions.

Immune disorders

These problems of the immune system include rheumatoid arthritis, systemic lupus and other collagen vascular diseases. HIV is not an impediment to treatment if white blood cell counts and viral load are well controlled. Use of medications such as steroids and immuno-suppressants, e.g. methotrexate, 5-MP and azathioprine, can delay or affect proper healing of the eye after LASIK.

If we find any reason why LASIK or other refractive surgery procedure is not appropriate for you, we will advise you accordingly.



LASIK results

Focus has achieved excellent results from its advanced A-LASIK procedure, with 100% of patients with all common short-sighted prescriptions achieving 20/20 or better vision

we know of no other clinic that has matched the results achieved at Focus Clinic using A-LASIK

Unlike most clinics, we publish a full breakdown of the results we have attained, based on the strength of the prescription. This is so you can see how we have performed for prescriptions like yours, without having to come in for a consultation. Most clinics will want you to book and attend their clinic before giving you these details.

You can click here to learn more about our renowned results after LASIK.

You can also learn about A-LASIK’s excellent safety profile. Again, unlike other clinics, we publish our key safety statistics so that you can see the incidence of issues that can occur after LASIK. Like any surgery, complications can occur after LASIK surgery, such as infection or night glare (starbursts or halos that are most obvious when looking at lights at night).

You can click here to learn about our safety statistics and how they compare to standard published rates from medical literature.

Whenever we are dealing with surgery, healing and other factors can affect the final outcome. Most treatments will achieve the full correction plus or minus 5-10%. This variability, or ‘tolerance’ in engineering terms, is always found in any physical adjustment, especially biological treatments. The aim of good practice is to keep this tolerance to a minimum through careful measurement and excellent surgical technique.

A small number of people will need a LASIK enhancement, or re-treatment procedure, a few months after the primary LASIK surgery to achieve the best result. We normally wait 6 months until the final result of the first surgery is achieved.

The accuracy of initial primary treatments at Focus is unusually high, with a very low-re-treatments rate compared to published studies.

The re-treatment rate for typical short-sighted patients at Focus was only 0.59% (from patients treated in 2014), compared to standard international published rates from other clinics of 3-5%. This means 5-8 times fewer second procedures compared to typical results within the sector.

patients at Focus needed 5-8 times fewer re-treatments

While LASIK surgery has a very high success rate, it is important that you discuss all aspects of the procedure before going ahead with surgery. Each person is unique and you will discuss your individual expectations and risks with one of our surgeons beforehand.

Correcting e.g. short-sight and astigmatism is designed to give you clear distance vision without glasses or contact lenses. It is normal to still need reading glasses once you reach your 40s, due to the age-related loss of near vision known as presbyopia.

It is possible to help both far and near sight with laser eye surgery with LASIK Blended Vision. Please contact us for more information if you need glasses for reading.

Choosing a LASIK surgeon

During the LASIK procedure, the lasers are only active for 10% of the time. The surgeon is manually performing the remaining 90% of the operation, so you want to ensure you have the most skilled and experienced surgeon you can find. At Focus, you are reassured that you will have a world-class surgeon for your treatment.

Your surgeon is the single most important factor in the quality of vision you will achieve. Like winning in Formula One, having a technologically advanced car is essential, but it is the driver who wins the race. We provide outstanding technology with the Ziemer and WaveLight platform combination, but even better surgical skill.

As you compare laser surgeons and clinics (which we recommend that you do), here are important points and questions you will want to ask:

  • How good are the reviews on consumer feedback sites, such as Trustpilot and Google+?
  • How many LASIK procedures has the surgeon performed?
  • Does the surgeon operate at their own clinic, or are they a hired ‘gun’ at a commercial centre?
  • On the website, can you easily find published vision success rates for prescriptions similar to yours? (% achieving 20/20 vision; % achieving better than 20/20 vision. If a clinic is boasting a ‘100% 20/40’ success rate, considering another centre as 20/40 is much worse than 20/20; every centre should be 100% 20/40)
  • Does the surgeon publish their complication rates?
  • Is the outcome guaranteed for life?
  • Will you see your surgeon before the treatment day?

We always recommend visiting more than one surgeon or clinic for a pre-operative assessment. It’s always good to be able to compare and have choices.

Remember, if at any time you feel pressured to proceed or that you are being ‘sold’ to, take that as a red flag that you should go somewhere else. There should never, ever be pressure to proceed with elective surgery.

LASIK myths – what should you believe?

The Internet is a tremendously rich source of medical information, much of which factually correct. There is also a considerable volume of incorrect information and misleading or confusing claims. How best to sort through what you find after an Internet search?

There are several common myths and misunderstandings about LASIK and laser eye surgery in general. Here are the most common ones:

LASIK myth #1: Laser eye surgery wears off

Not true, depending on what type of glasses you wear. A confusing aspect is that there are, in fact, 4 reasons to wear glasses and the long-term effect depends on which type of refractive error you have:

  1. Short-sight
  2. Astigmatism
  3. Long-sight
  4. Presbyopia

Correcting the first two conditions, short-sight and astigmatism, is very stable and we expect a lifetime of benefit, as long as the prescription was stable before LASIK surgery.

the key factor is that short-sight or astigmatism is no longer progressing before treatment

The long-term re-treatment rate for patients at Focus with short-sight and astigmatism is just 1 in 800; correction provides a very stable outcome.

At Focus Clinic, we provide a lifetime care guarantee for distance vision corrections for short-sighted treatments and will retreat without charge if ever needed.

The last two conditions, long-sight and presbyopia, are age-related and naturally worsen over time. LASIK can correct these problems though the effect can decrease as the conditions progress. We can advise you on your prescription and the likely length of benefit you can expect.

LASIK myth #2: LASIK is painful

Anaesthetic eye drops will keep your eyes comfortable during the 10-minute procedure. They will keep your eyes numb throughout the treatment. While the Ziemer femtosecond laser creates the corneal flap, you will experience a sensation of pressure for 20-25 seconds. The vision correction excimer laser is fully painless and takes 5-10 seconds for most prescriptions. If you are anxious, a sedative can be given to help you relax.

LASIK myth #3: LASIK is quite new, so long-term side effects are unknown

Laser eye surgery has been available for nearly 30 years, with the first procedures done in the late 80s. No long-term side-effects have occurred over more than 2 decades. Complications are rare with an expert surgeon on well-selected candidates, and if present typically arise soon after treatment and will be treated at that time.

LASIK myth #4: LASIK cannot correct astigmatism

Not true. LASIK can treat astigmatism very effectively. The myth arose because early lasers in the 1990s could not correct astigmatism.

Types of LASIK

We perform LASIK for 97% of all laser eye treatments at Focus, with the remaining 3% being PRK (also sometimes referred to as LASEK). LASIK provides minimal discomfort and an extremely rapid vision recovery over a few hours. PRK, in comparison, takes several days to heal even though the final results are the same.

There are several types of technology that can be used in LASIK surgery, some being more modern and sophisticated than others. At our clinic, we only offer the most advanced procedure.

You may see low headline price offers from various clinics, which are for older and out-of-date  technology, which you should avoid. For example, flap creation in LASIK used to be done with a blade device (and some clinics still offer this) but no leading surgeon we are aware of world-wide using this approach any longer.

Modern flap creation is done with a very precise femtosecond laser; at Focus we prefer the very precise energy focus of the Swiss-made Ziemer LDV system. The second stage of actual vision correction is done by another laser (an excimer laser), so this two-laser technique is sometimes called All Laser LASIK, Dual Laser LASIK or more commonly Femto-LASIK.

There are 3 main types of LASIK technology available when it comes to the excimer laser reshaping of your cornea; the first is the main treatment for most patients and the second and third are for more specialized cases:

  • Wavefront Optimised LASIK — the biggest jump in better laser vision results was from the development of treatments that preserve the natural ‘aspheric’ shape of the cornea, the clear front window of the eye (high end camera lenses also use aspheric optics to produce crisp, high-definition images). Wavefront optimised laser eye surgery uses the precise curvature data information from scans of your cornea, reducing so-called spherical aberrations that can occur with non-aspheric laser refractive surgery.
  • Wavefront Guided LASIK — is only needed for a small number of patients who eyes have high levels of optical aberrations. Wavefront optimised treatments (above) deliver the same results for most patients, whilst also removing less tissue (leaving the cornea stronger and with less chance of dry eyes). Wavefront-guided treatments use measurements of how light waves travel through your eye (using an aberrometer) to target significant imperfections of optical quality, for specific patients who have marked aberrations. Such treatments are know as ‘custom LASIK’, and include topography-guided LASIK (see below). Whilst some clinics market laser eye surgery on the benefits of custom wavefront LASIK for everyone, the science does not support the claims; wavefront-optimised correction is the right choice for most patients.
  • Topography Guided LASIK — Uses precision maps of the corneal surface to create a custom LASIK procedure. Topography-guided laser treatment aims to regularise the corneal shape to improve optical quality, and can address visual aberrations, as well as physical abnormalities such as corneal scars.

When you attend Focus for your consultation, one of our clinicians will determine which type of LASIK is most appropriate to your ocular anatomy and optics. Most patients are best helped using wavefront-optimised LASIK.

wavefront-optimised LASIK has achieved a 100% 20/20 success rate at Focus for all common short-sighted prescriptions

Contact us on 0207 307 8250 to learn more about the various treatment options available at Focus.

Common Questions

There are a number of frequently asked questions on LASIK eye surgery, such as

  1. Who is eligible for treatment?
  2. Does it hurt?
  3. Does LASIK wear off?

Please visit our common questions on laser eye surgery page for more information.

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4th Aug


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 David Allamby