Sandor asked this question on Lasik flap healing:

Dear Dave,
Is it true that corneal flaps never heal completely after Intralasik? What is the chance of dislocation during the rest of the patients life?
Thank you in advance, Sandor

Sandor, it’s an important question. It is true that thicker (e.g. blade, keratome) flaps never fully heal. They can be surgically lifted many years after. However, thin flaps such as are created with femtosecond lasers (around 100-110 microns) appear to heal significantly more strongly.

The healing in the uppermost layers of the cornea is different from deeper down. Collagen fibres are more wavy and heal much better when cut with a thin flap. I have found a couple of patients where I have tried to lift femtosecond flaps, and they were fully bonded down and impossible to lift after a year post-op. This has never been the case with keratome blade cut flaps which I have always been able to lift, even many years later.

IntraLasik is just the brand name for flaps made with the Intralase American made femtosecond laser. Using the Swiss Ziemer laser it is called Z-LASIK.

The key question first is the depth at which a flap was cut. One of the major reasons why many clinics have invested in femtosecond lasers over the much cheaper keratomes (10x more expensive for a femtosecond) is being able to cut predictable accurate thin flaps, with their better healing.

If it was a thin flap, e.g from a femtosecond laser (Ziemer, Intralase, Visumax, Femtec), I expect the lifetime chance of dislocation will be zero.

IMPORTANT NEWS for those people considering having LASIK laser eye surgery.

There appears to be a fundamental difference between LASIK flaps cut either with a blade or created with a laser. Laser created flaps mean a safer surgery as the results are more accurate, so fewer enhancements needed, and the eye is left stronger.

Making a replaceable flap is the first part of the LASIK procedure, just prior to reshaping the cornea to correct vision. Until recently (and still in many clinics) the flap was made by a physical cut with a very sharp razor blade contained within a precision device. However several clinics and the major three chain operators have invested in femtosecond lasers to create the corneal flap without the need for a blade.

This is known as blade-free LASIK, dual laser LASIK, Z-LASIK or IntraLASIK depending on which clinic you are talking to.

We know that thicker flaps cut with a blade do not fully heal and can be lifted up surgically even many years later. Traditional blade flaps are thicker and cut deeper into the cornea. However laser flaps are thinner and leave the eye stronger afterwards.

However a key difference highlighted by Professor John Marshall in London is that because these very thin laser flaps pass through near the surface of the cornea where the collagen is different from deeper down, they actually heal down and are not able to be lifted later on. This means the eye regains strength again with a laser flap, but not with a blade flap.

Newer blade machines have been introduced in 2008 and 2009 that cut thinner flaps to compete with the thin femtosecond laser flaps which should benefit from the better healing seen in sub-120 micron flaps

My recommendation to you when choosing a clinic is to be able to select to have a femtosecond laser procedure at a clinic that has that technology. They are more expensive than blade procedures (expect to pay around £300 more per eye) but well worth the likelihood of a long-term increase in safety.

Continuing from yesterday:
Some surgeons recommend PRK or LASEK (both forms of surface laser eye treatment and basically the same) over LASIK. The article referred to by Kay in her original post and advocating LASEK was written by ophthalmic surgeon Sunil Shah, who was one of the creators of that particular approach (and so has some personal interest in writing about it one presumes).

One of the very vocal and respected advocates of surface laser (PRK) over keratome LASIK was Professor John Marshall in London, UK, a founding father of laser eye surgery back in the 80s. Prof Marshall argued convincingly that the cornea was considerable stronger after PRK compared to mechanical (thicker flap) keratome LASIK.

However, the game has changed with the introduction of femtosecond lasers with much thinner flaps. Even Professor Marshall now supports the move to thin-flap LASIK using a dual laser, blade-free approach.

So if a clinic cannot offer dual laser LASIK (and many still can’t) they may offer PRK/LASEK instead. There are some clinical reasons to perform PRK instead of LASIK but the percentage of these cases has shrunk from 10-15% down to around 5% today, with dual laser technology. Patients much prefer femto-laser LASIK over PRK, as the latter is fairly unpleasant for a few days post-op.

In summary, there are definite clinical reasons why we as treating clinics have moved over to wavefront LASIK and using a blade-free dual laser approach. More accurate treatments so better vision, removal of an older mechanical device technology and improved long-term safety.

We discussed in the last post about the two options you have: LASIK or PRK (surface laser), and how 90%+ of treatments are done via LASIK.

LASIK comes in two flavours now: blade or blade-free. The older traditional LASIK technique uses a mechanical device containing a blade (called a keratome or microkeratome) to cut a flap during the first part of the procedure. The newer, more advanced method is to use a special laser (known as a femtosecond laser) to create a flap without a blade.

These femtosecond lasers are hugely expensive (about a quarter of a millions pounds each!) so expect to pay more for this technology. Some clinics have not yet invested in femto lasers due to the high cost involved and continue to use a blade.

The benefits of a laser flap over a blade flap are becoming clear: more accurate treatment, better healing of the flap, greater strength in the cornea post-op due to significantly thinner laser flaps and greater residual thickness. Blade flaps have been used for many years and have been proven safe to date, but thinner laser flaps have added better accuracy and strength. You will see a gradual phasing out of blade flaps over laser flaps over the coming few years.

More tomorrow!

If you read yesterdays post you are up to speed on wavefront technology. OK, so far so good. It seems wavefront correction improves quality of vision after laser eye surgery. And indeed clinical trials confirm that vision results are much better after laser makers added the ‘wavefront‘ upgrades to their machines.

For example, the American made VISX lasers, used at all Optical Express laser clinics, have much better results when using their wavefront upgrade from 2002. I would not recommend having laser eye treatment today in 2008 without choosing the wavefront package on that system.

Wavefront laser eye surgery - is it the whole truth?

So now you want ‘wavefront‘ in your laser eye treatment! Of course, as the results are better. But when laser manufacturers introduced ‘wavefront’ they actually bundled in other improvements which may account for much of the jump in results! They just didn’t tell you. Why? Because it is complicated to describe all these improvements to someone who isn’t familiar with the technology – such as you, the patient!!

And honestly, I bet the sales people at most clinics talking on the phones who want to sell you a consultation don’t really understand it either! However, they have been trained to explain the wavefront part only, as something like this… “we take a scan, a unique fingerprint, of your vision and the use that fingerprint to perfectly correct your vision“. Go on, call them and check it out!

But for you, as a patient or customer, don’t really care about which part of that technology is helping you the most, you just want great vision, right?

So don’t let clinics blind you with science about wavefront scanners, wavefront maps, measuring hundreds of points of light or how much better their scanner is than other clinics scanners. It is usually marketing spin! Take it all with a pinch of salt.

However, you should choose the ‘wavefront option’ because within that package are the big improvements in laser eye treatment over the past several years. The success of surgery may actually be less to do with the true wavefront technology that has helped astronomy, but rather other improvements that may be confusing to patients but get wrapped up in the marketing of wavefront LASIK.

We come back to ethics again here. Is it ethical for some clinics to still sell ‘non-wavefront’ laser eye surgery technology that was replaced back in 2002?

For my own clinic, we do not offer non-wavefront treatments at all. None at all. I want every one of my patients to have the benefit of the newer laser eye surgery results. So we made it very affordable. In fact, we charge less for wavefront LASIK than other clinics do for their ‘entry level’ lower price non-wavefront LASIK. Really.

That’s my plug for FOCUS done! So, do choose wavefront but don’t pay more than you have to!

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To recap from earlier this week, there are two ways you can upgrade your laser eye treatment: (1) upgrading on the quality of the final vision (you will see better afterwards) and (2) improving the safety and accuracy of the laser eye surgery. These are upgrades on what used to be the best treatment only a few years ago, which is known as non-wavefront LASIK and using a blade device to cut a thin flap in the surface of the cornea (the clear window at the front of the eye).

Upgrading on (1) involves paying for what is called ‘wavefront‘ laser eye surgery over ‘non-wavefront’.

Upgrading on (2) means getting rid of a metal razor-type blade in favour of a laser for the first part of the LASIK treatment (lots of names here… blade-free, dual laser, femtosecond, Intralase, Ziemer, Z-LASIK).

Kay’s questions have been about: is it really worth it to pay more? The short answer is that, yes, you should always look for ‘wavefront’ laser eye treatment. But why?

Well, the reason for this is not as obvious as laser eye clinics may tell you!

Wavefront refers to a technology adapted from astronomy which allows better resolution and clarity when looking at images of space. The principle is to remove tiny imperfections of focus, rays of light that are not getting focused properly and which cause blurriness, glare or hide details. Let’s look at an example from astronomy. In this image you can see how a blurry image of a star was improved though wavefront technology to reveal in fact two stars, known as a ‘binary star’.

'Wavefront' laser eye surgery can improve quality of vision

These imperfections of focus (known usually as aberrations) are not corrected by glasses. They are still there even after putting on your glasses or contact lenses. So after correcting your prescription fully and getting clear vision, you can still have imperfections in your vision which are usually more obvious at night.

Check back tomorrow for the next installment and the full answer on whether it is worth it to pay more  in order to get the best vision results (at most clinics – not mine, I add, FOCUS Laser Vision! – we don’t charge extra for you to get wavefront correction! In fact we charge less for wavefront surgery than other clinics do for their non-wavefront treatments).

See you tomorrow!

Following on from yesterdays post on some key LASIK and laser eye surgery questions, lets look at these:

• Do clinics try to sell you on the most expensive treatments?
• Are these expensive treatments no better than the cheaper ones?
• Is there really any difference between blade LASIK and the newer (more expensive) blade free dual laser option?

The main point here is about more expensive laser eye treatments over cheaper ones. What is the difference?

When you buy anything you normally have a choice of quality and price, for example an HD television or more basic one. Or a Mercedes over a Fiat Punto. We all understand that more money usually gets a higher value brand and clinics typically price the surgery this way too.

There are two ways you can upgrade your treatment: (1) upgrading on the quality of the final vision (you will see better afterwards) and (2) improving the safety and accuracy of the eye surgery. These are upgrades on what used to be the best treatment only a few years ago, which is known as non-wavefront LASIK and using a blade device to cut a thin flap in the surface of the cornea (the clear window at the front of the eye).

Let’s look first at spending more to get better quality of vision than the older ‘standard’ treatments (which are STILL available at most clinics, not at my centre – FOCUS, by the way, although there is a good case to abandon this older technology). The high street chains (Ultralase, Optimax and Optical Express) all offer two levels of surgery for quality of vision.

The basic cheaper treatment is called by various names but all are what are termed ‘Non-Wavefront’ surgeries. For example Ultralase call it just ‘laser eye surgery’, Optimax and Optical Express refer just to ‘LASIK’.

The higher quality, better vision treatments all come under what is called ‘Wavefront’ laser eye surgery.

‘Wavefront’ simply refers to a technology that is claimed to offer higher-definition vision, especially at night time, which was introduced several years ago.

Just to confuse you there are different names, again depending on which clinic you visit! For example, Ultralase call this ‘ULTRALASIKplus‘, Optimax opt for the simpler ‘Wavefront LASIK‘, while Optical Express go for the mouthful of ‘Advanced CustomVue Wavefront LASIK‘. Other independent clinics use various names.

At my own clinic FOCUS Laser Vision, we only offer the higher quality vision ‘wavefront’ laser eye treatments. You cannot get non-wavefront eye surgery with us.

Please note that paying more at one clinic doesn’t mean you get better surgery than at another clinic. You need to look at what you are paying for. For example FOCUS Laser Vision charge less for advanced wavefront correction than most other clinics do for older technology non-wavefront treatments. Blowing my own trumpet here, I know! But paying more does not always equal getting more. More on this later.

Kay also asked in her mail about the ethics of treatment offerings and we will cover that topic in the next blog postings. Basically, is it ethical to offer lower quality treatments when newer higher quality ones are available? No-one cares about this for other products and services (is it ethical to sell Fiat Puntos when Mercedes are available?) but it can be a hot topic in healthcare. I will write on this subject during the coming week. And I will welcome your comments!

OK, but are these ‘wavefront’ treatments really better than ‘non-wavefront’? Come back tomorrow to get the truth!

The new femtosecond lasers have eliminated the need for a blade in LASIK laser eye surgery. All leading laser eye treatment clinics now offer blade free LASIK as a safer and more accurate procedure for patients.

Traditional LASIK has used a microkeratome to cut a flap. The microkeratome is a hand-held device, which contains a steel blade that moves back and forth to create a cut as it travels across the cornea. A microkeratome is only capable of making a single, one-dimensional cut across the cornea. As it cuts, the blade oscillates back and forth, which can leave an irregular surface after the flap is lifted. This can affect the quality of your postoperative vision.

One week after surgery more than 76 percent of femtosecond laser patients achieved an uncorrected visual acuity of at least 20/16 (better than 20/20) compared to only 58 percent of microkeratome patients

Because of the unique way in which the All Laser Method (femtosecond laser) creates a precisely positioned layer of micro-bubbles just beneath the surface of your eye, it creates a smooth even surface after your flap is lifted. With this method, a blade never touches your eye.

[youtube]http://uk.youtube.com/watch?v=spJHR3FJvTg&locale=en_GB&persist_locale=1[/youtube]

Tags: LASIK

TECHNOLOGY that has become available over past two years means that reading vision problems can now be very effectively addressed through laser eye treatment. Although at present only a few clinics specialise in this area, it is the fasting growing section of the laser vision arena.

FOCUS Laser Vision specialises in the correction of loss of reading vision, either through advanced LASIK laser eye surgery or through the use of lenses inside the eye (IOLs)

Several approaches to LASIK are showing promise in the treatment of reading vision problems (presbyopia) for patients with otherwise normal distance vision, or long or short sight, according to studies presented at the 12th Winter Refractive Meeting of the ESCRS.

In research presented by Kenneth A Greenberg MD, all patients achieved good distance vision of 20/25 or better and were able to read telephone directory sized print, 12 months after undergoing customised LASIK treatments. The multicentre study involved 28 presbyopic long-sighted patients with an average age of 56 years.

There are three main treatment choices for anyone thinking of having laser eye surgery. But which one will be right for you?

The final choice will be determined between you and your laser eye surgeon. BUT, of course, you have the eyes and your surgeon has the expertise so you will be heavily influenced by what the doctor or another clinic staff member says. It will be better to be prepared. With just a little knowledge you can be actively involved in making the right choice.

I will outline the 3 main options to help you have an informed discussion when the time comes to select which approach is best for your individual eyes. After all, you only have one pair so you want to get it right.

You will be overwhelmed at first by all the terminology, treatments and brand names. Don’t worry. There is no need to be blinded by science or some of the frankly misleading marketing information that is out there.

Firstly, whichever of the 3 treatment types (more on these coming in a couple of days in part 2) you go for, you must go for the wavefront option. The wavefront (or custom) technology has made a huge improvement in vision success rates with many more people getting 20/20 sight or even better.

Different clinics use different names for this technology: custom, wavefront, wavefront guided, wavefront optimised, CustomVue.

Many clinics will charge you more for wavefront based treatments over older non-wavefront options. Is it worth it? Definitely.

Back in 2000 when we were doing LASIK without wavefront, the benchmarks for success were getting 65% of patients to 20/20. In 2008 we expect more than 95% of patients to see 20/20 or better. This improvement has come from better technology, in large part from custom or wavefront based corrections.

Also wavefront laser eye treatment will give better vision at night or in low light situations. Patients will notice less halos and glare from light sources such as car headlights. It is like buying a more expensive camera with a much, much better lens.

This is the year 2008, so get the best current technology for your sight correction – you only will have this done once and you will live with the results for the rest of your life. Think about the computer you had back in 2000 and what is now available in 2008 – that is the level of difference in laser technology too. No brainer, really.

If you can’t afford the price, either don’t have it done yet and save up until you can afford it, or think about financing.

So if you go to Optical Express, go for the more expensive CustomVue wavefront version. Without it, the results really are not at a level that is satisfactory in 2008. If you go to Optimax or Ultralase, pay and get their wavefront guided option.

If you go to FOCUS Laser Vision, wavefront is already included in the quoted price. They don’t do any non-wavefront treatments.

Come back in a couple of days to read part 2 where we will finish this post by looking at safety and healing in laser eye surgery.

The excimer laser produces a high-energy, cool ultraviolet light beam in pulses and delivers the pulses to a surface of the eye’s cornea. These pulses break the bond between molecules and tissue cells so that a controlled amount of tissue can literally be vaporized away to reshape the cornea — one microscopic layer at a time.

With some lasers, e.g. the WaveLight system from Germany, it only takes 5-10 seconds to complete the entire laser process to correct most levels of glasses or contact lens prescription.

You can see above and below to the right just how precise and gentle the excimer laser can be. Above a human hair has been etched into precise grooves. Below even words have been carved into the hair!

The excimer laser is computer controlled and programmed to custom treat each individual eye with a high degree of precision. For most cases, the thickness of the layer removed by the laser is less than the thickness of a human hair. The laser only needs to remove 13 thousandths of a millimeter to correct one unit of glasses strength (dioptre)!

Advanced Medical Optics Inc. in Santa Ana, announced on Wednesday that the Food and Drug Administration (FDA) has approved a new laser for use in laser eye correction. The iFS femtosecond laser is set to be at the centre of AMO’s iLasik products for laser vision surgery. The laser has an increased speed of 150kHz, up from the existing 60kHz.

However, competitor Ziemer from Switzerland recently launched its own femtosecond laser offering more than 1000kHz speed, integral to its Z-LASIK offering. Click here for a discussion blog post comparing iLASIK and Z-LASIK.

AMO has pushed into laser vision correction, including its $800 million buy of Irvine, California-based IntraLase Corporation last year. The iFS laser uses technology from IntraLase. The femtosecond laser is used to create a corneal flap which is the first step in laser vision surgery. Advanced Medical’s lasers have been gaining market share over traditional metal blades. The laser is due to be shipped to U.S. laser eye surgeons in the third quarter, according to Advanced Medical Optics.

Tags: Z-LASIK, iLASIK, AMO, FDA, femtosecond, eye, laser, surgery

The most common reason I hear from people who have not yet decided to go for laser eye correction is that they are cautious and worried that something might go wrong. This is very understandable.

LASIK eye surgery is not for everyone. Some people are very happy with glasses. Some like to have a designer accessory prominent in their appearance. Many people would definitely choose to have laser sight correction if someone could ‘guarantee’ that nothing would go wrong.

LASIK eye treatment has, in fact, become a very safe procedure BUT (there’s always a but!) you need to have certain boxes ticked before you go ahead.

The results you will get, and live with, will depend on four factors:

1. The laser technology used – your surgeon cannot get better results than the laser can deliver
   QUESTION FOR YOU: Which laser is the best? 

    

2. Your surgeon – the laser will only perform as well as the surgeon ‘driving’ it! And even then, never better than the manufacturer made it capable of – see point 1
   QUESTION FOR YOU: How can I know who the best surgeon is? 

    

3. The clinic – will they take good care of you before, during and especially after your treatment?
   QUESTION FOR YOU: How can I select the best clinic? 

    

4. The price you will pay - you don’t always get what you think you are paying for
   QUESTION FOR YOU: How much should I pay for LASIK laser eye surgery – if I pay more, will it be better or safer?

Tune in again next week to see the answers to these questions! The truth is out there! (old X-Files fan – sorry!)

OK. lots of new laser eye surgery names appearing, so let’s confirm what they mean!

Z-LASIK: means blade free LASIK using the new Swiss Ziemer laser to make a corneal flap, rather than a traditional blade.

iLASIK: means blade free LASIK but using the American Intralase laser to make a corneal flap.

So, simple so far. Z for Ziemer’s laser and i for Intralase’s laser. Both of these devices allow elimination of a blade to make a physical cut in the cornea. Instead they use millions of precise laser pulses to create a very accurate flap, removing the potential risks associated with a metal-blade mechanical system.

Click here to watch an FDA animation of mechanical blade LASIK (N.B. Caution: watching this will put you off ever having bladed LASIK in the future! You will definitely want to opt for all laser LASIK after this!)

So what’s the difference between Ziemer and Intralase lasers?

The Ziemer laser is a new system, with potential advances upon the older American Intralase laser flap maker. Ziemer’s lasers, called the LDV, appears to eliminate occasional complications found with iLASIK. Some iLASIK patients (around 7%) get a marked discomfort and aversion to light for several days after laser vision correction, know as “transient light sensitivity”.

This side effect is not seen with Z-LASIK, possibly because of a much more tightly focused laser energy pulse and greatly reduced energy per pulse, compared to Intralase’s looser focus and wider dispersion of energy through the cornea.

Studies are ongoing to compare the two systems in greater detail.

Background on the LASIK procedure:

Creating the corneal flap is the first stage in a LASIK procedure. Treatment to correct your eyesight is actually done on the corneal tissue that’s below the surface and access to it is done by making a surface flap and folding it back (quite painlessly!).

This flap creation is critical for a successful result of your LASIK surgery – it needs to be of exactly the right thickness and in exactly the right place. When the surgery is completed, it’s easily folded back into position and acts as a delicate bandage over the treated eye. It heals up by itself.

The microkeratome devices used in traditional LASIK surgery are hand-held tools with a steel blade that oscillates, moving back and forth at very high speeds. When used expertly it makes a good flap but the thickness can vary more than laser flaps and they can be more irregular, tending to be thinner in the centre.

LASIK complications are quite rare. Fact. But when they do happen, they often arise from a poorly created corneal flap. Use of new femtosecond lasers (Ziemer or Intralase) greatly reduces the likelihood of any such complications.

Since we introduced the Z-LASIK blade free LASIK laser eye surgery procedure into the UK in January 2008, more than 90% of our patients have opted to go dual laser (no blade) for their vision correction.

The LASIK procedure has two parts – the first is the preparation of a thin flap followed by the second stage of vision correction itself. Traditionally, a bladed device has been used to cut this flap and gave some people pause about going ahead with the surgery.

Laser blade free flap makers were introduced in 2002 by the Intralase Corporation in the US. A next generation system was released in 2007 by Swiss ZIemer Group.

The added level of safety offered by eliminating the need for a physical blade cut has proved to be very popular for patients at FOCUS Laser Vision, with 9 out of every 10 people choosing to have Z-LASIK (blade free Ziemer technology). The additional cost of Z-LASIK leaves 1 in 10 people going with the traditional blade version, M-LASIK.

The high cost of femtosecond lasers means somewhat higher LASIK prices, usually around £300 per eye higher than bladed LASIK. The reason is that the blade systems cost around £30,000 per machine compared to £200-250,000 for a femtosecond laser.