Julie asked:

Dear Dave, I am about to get an enhancement surgery since my eye changed to -1.0 after just 10 months. I got the flap cut with the laser. I see that this type of cut heels quickly and I know doctor will not be using the cutting laser again, so how is he going to lift the flap? I’m terrified and thinking that I will be better off wearing glasses again. What do you think?  Thank you

Hi Julie
We lift flaps manually, using a special instrument designed for lifting, which is usually a fairly simple process. It should be possible to lift a femtosecond flap at 10 months, but you wont know until it is tried. I had one patient that proved impossible to lift after 6 months, but that was unusual. You could opt for PRK enhancement with mitomycin, but I would opt normally to lift the flap first. You can discuss this with your surgeon before going ahead.
We are now hitting 100% for patients seeing 20/20 or better at my clinic, Focus, so enhancements are getting increasingly rare. If they do happen, it is usually for patients with very high myopia.
Best regards, Dave

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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.

Anne asked:

Hi Dave,
I’ve come across a lot of comments from lasik patients re: dry eyes. Many of these did not suffer with dry eyes prior to surgery. Can this become a long-term issue as many people say they are still experiencing dry eyes 6 months down the line? Also, is it something that can be avoided through the laser used and surgeon’s experience/ability? I know that you say patients do not experience TLS with the Ziemer laser, so can the same be said of dry eyes?
You mentioned in one of your previous replies that there was someone in the Cheshire area I could go to for a consultation (with a view to having surgery with Focus), please could I have their contact details?
Many thanks, Anne

Hi Anne,
A temporary reduction in tears following LASIK happens in all cases, although many are unaware of it. It happens because the superficial corneal nerves are cut during flap creation. The cornea becomes number and the nerves have to re-grow to supply the surface with normal sensation. This takes 3-6 months with a thin femtosecond flap, longer with a thicker blade flap.

The thinner the flap, the less distance to re-grow and so the sooner the cornea returns to normal. So having patients report still having dryness at 6 months is not unusual, especially if they had a thicker flap.

In some cases of ongoing dry eye, there can have been some pre-existing deficit in the tear film or tear quality that gets exacerbated by the temporary numbness in the cornea and other factors (e.g. loss of goblet cells).

I find ongoing dryness is rare in my clinic, and I think that is because we are rigorous in diagnosing, and treating where needed, prior to surgery. Technology cannot avoid the creation of some dryness (whether symptomatic or not). However creating a thin flap with a femtosecond laser makes for less dryness of shorter duration.

But it is the skill of the surgeon and clinical team that heads of problems before they are created, by not operating on patients who may lead to later trouble. Patients with marked dry eye should not have LASIK. Some dryness though can be managed and treated pre-op and so allow those patients to still be eligible for LASIK and without long-term problems.

Anne, call one of my team on 0845 5000 500 and we can connect you with our optometrist in Cheshire for an assessment.

Amar asked:

You mentioned using mytomycin C for LASEK procedures. Is this generally a safe drug to use on ones corneas? In your opinion, what does a femtosecond laser offer over a microkeratome procedure. Can it be said if one is better than the other? Also, in higher prescriptions, given all other parameters are met including corneal thickness, which flap creation technique would be more advisable. Can both options create buttonholes?
Thank you so much for your help, Amar

Thanks Amar. MMC (mitomycin) appears to be safe. In 2000, Majdamur and colleagues were the first to describe MMC effects on post-PRK and postradial keratotomy subepithelial fibrosis (haze formation). We have not seen significant complications with its use over the past decade and I do use it on eyes where there is greater risk of haze.
I have written plenty on femtosecond lasers and blade keratomes, and you can see those posts under the lasik and safety categories. Both can create buttonholes, but the great advantage of the femotsecond laser is that you can identify the hole without lifting the flap and so get a complication-free healing, which isn’t always the same with a blade cut. In that case, the flap is already lifted by the keratome and there are risks of scarring at the edge of the hole and possible epithelial ingrowth.
Go for the femtosecond flap if you have the option.

I was recently asked by Kaz to explain the Z-LASIK procedure in more detail. Watch this video and in a second post I will run through why I consider Z-LASIK combined with the WaveLight excimer laser to be the ultimate in LASIK laser eye surgery.

The choices can seem bewildering! You want to have laser eye treatment e.g LASIK and now you need to choose the clinic for your surgery.

But which one?

There are over 100 clinics in the UK, although 75% of those are made up of only three large business laser chains: Optical Express, Optimax and Ultralase. The other 25% are mainly owned by doctors and optometrists, who practice from their centres.

80% of UK centres have adopted the advanced blade-free femtosecond lasers, and so now offer blade-free LASIK (a.k.a all-laser LASIK, Intralase, Z-LASIK). These include:  FOCUS Laser Vision , Optimax, Optical Express, Ultralase, Moorfields Eye Hospital and Centre for Sight.

20% of UK centres have not yet invested in this technology, and only offer bladed LASIK, where a device containing a short blade is used to cut the LASIK flap. These centres include Advance VisionCare and Accuvision in London

Having your laser eye treatment with a blade free femtosecond method has rapidly become the standard of care for UK LASIK laser eye surgery.

For LASIK laser eye surgery safety, there are 3 things you must look for when you plan to go ahead. This LASIK safety trio means a more accurate result and the safest procedure we know of today:

1. Choose a blade-free all laser LASIK technique – using the latest femtosecond lasers means no blade is used in the surgery. Check with any clinic you talk to that they can offer blade-free LASIK – if they can’t then they are out of date and should be avoided.
2. Wavefront-based LASIK is a must today, so make sure you go for that option. For example, at FOCUS Laser Vision we only do wavefront treatments so that is taken care of. At other centres such as Optical Express, do not choose their non-wavefront option.
3. Get the safety and reassurance of NHS consultant corneal specialist surgeons to do your treatment – the three laser eye chains do not offer this for the great majority of their treatments. Premier centres like Moorfields Eye Hospital, Centre for Sight and FOCUS Laser Vision do.

WHENEVER a patient undergoes any type of surgical treatment there is a possibility for a complication. The main questions are: are these complications serious and could affect the final outcome – or minor and short lived and which do not affect the ultimate vision? Also, what are the chances of a complication occurring that would require adjustment or follow-up correction?

LASIK surgery is no different from any other operation, despite how it may be pitched by some clinics, in that it IS a surgical correction and should be approached as such. However, and fortunately, most complications are in fact minor and easily resolved.

Technology

LASIK risk continues to drop as doctors and engineers perfect the equipment used in the treatment. Advances in technology have made a big part of the difference here so make sure you are getting that latest equipment and not an older fashioned approach.

The risks drop as doctors continue to screen for the right candidates to have the procedure, and screen out those with any chance to have a problem. Research also shows that with the right pre-testing and surgical handling, the risk of complications in LASIK surgery is less than 1% and most of these are minor problems which will be fully corrected afterwards without undue ongoing problems.

The most common risk with LASIK surgery is a complication with the flap, created by the surgeon in the first part of the procedure.

In the original LASIK procedure, the flap is cut by a surgical blade device known as a microkeratome. The blade cut is, however, less precise than those from newer femtosecond lasers.

Blade Free LASIK

LASIK risk is reduced by the newer “bladeless” dual laser technique.

In bladeless (blade free) LASIK surgery, the risk of complications is lower because the blade or microkeratome is no longer used. It is replaced by special type of infra-red laser that greatly reduces human or machine error.

The original laser to make a LASIK flap came from the USA, manufactured by Intralase. You may see this surgery called IntraLASIK or iLASIK.

The newer machine is from Switzerland and produced by the Ziemer Group of companies. There appear to be some advantages of the tighter focus of the Swiss laser. This procedure may be called Z-LASIK.

Summary

When assessing these LASIK risks it is recommended that when you are considering surgery that you ask your doctor what technology the clinic has and whether or not a blade free dual laser approach will be used.

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

Let’s look at the second of Carlo’s questions on laser eye surgery:

My name is Carlo and I have recently discovered this great blog. I would like to ask a couple of questions regarding eye surgery:
Question: Is it true that the LASIK procedure has not been approved for air-force pilots and astronauts in the US but PRK and LASEK has?

No, this is not true.

LASIK was approved for use on consumers a decade ago and reportedly more than 11 million LASIK procedures have been performed in the US. This means LASIK laser eye surgery is the most-common American elective surgical procedure.

NASA has approved LASIK for use on pilots, mission and payload specialists who face extreme and often physically demanding conditions in space. The all-laser LASIK technologies, using a blade free femtosecond laser approach, have also been cleared for U.S. military personnel, including most recently Air Force pilots.

“NASA’s approval is further evidence that today’s LASIK exceeds all established standards of safety and effectiveness,” said Steven Schallhorn, M.D., retired captain of the U.S. Navy.

Though LASIK has been around for a long time, concerns about the harsh environment in aviation prevented its use. To date, aero-medical professionals have been cautious of employing the procedure on military pilots who often encounter environmental extremes such as high altitude, dry air, wind exposure and “G” forces. In space, other conditions further add even higher levels of concern due to the very high level of precision needed during flight and space walks.

Defense Department’s research into laser vision correction included the following results:

# In a study of different methods to create the LASIK flap, 370 naval personnel underwent bilateral (both eyes) wavefront-guided LASIK with either the femtosecond laser (blade free) or microkeratome blade. 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

# In an evaluation of 785 pilots, 89% of Navy aviators evaluated their ability to land on an aircraft carrier as moderately to significantly better after laser eye surgery. None said it was worse after treatment

# A separate study determined that over 90 percent of marksmen had improvement in marksmanship skills after laser eye surgery; an impressive finding given the visual precision of marksmen

LASIK, particularly blade free femtosecond LASIK, appears to have established itself as a very effective and reliable procedure. The move from blade to laser blade free has allowed another significant improvement in results (now targeting better than 20/20 as a standard of care) according to the above research findings.

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

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.

Ultralase laser eye surgery chain has increased prices again. They recently moved to only offering blade free LASIK using the American Intralase femtosecond laser, removing the cheaper option of keratome LASIK.

Ultralase laser eye clinics price for Intralase LASIK including the upgrade for wavefront based correction is now £1,945 per eye.

Click here to the US govnerment clinical laser eye surgery trial results for the Bausch and Lomb laser used by Ultralase and how it compares to the VISX laser used at major competitor Optical Express and the WaveLight laser used at FOCUS Laser Vision.

Private equity company 3i recently paid a whopping £174 million to purchase Ultralase (read the blog post here) so perhaps they would like to start getting some money back…? Just a thought.

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.

Moria will unveil their new One Use-Plus SBK microkeratome at the upcoming 2008 meeting of the American Society of Cataract and Refractive Surgery in Chicago. Moria will present the clinical outcomes of their clinical trials. In eyes receiving this Moria SBK (ultra thin-flap LASIK), the flap thickness accuracy, speed of sight improvement, higher order aberrations and smoothness of corneal bed underneath the flap all compared favorably or equally to femtosecond (dual laser) SBK flap technology, according to Moria.

With many surgeons wary of creating ectatic (excessively weakened) corneas with their LASIK procedures, the interest in using thinner flaps has risen. Some surgeons routinely use flaps in the 130-µm range or thinner, using either mechanical microkeratomes or femtosecond lasers. I myself routinely create flaps that are 110 microns using the Ziemer femtosecond laser, without problems.

However, there can be additional risks when working with ultra-thin flap (less than 100 microns), such as microstriae (micro wrinkles) appearing in the flap afterwards.

I will be visiting their stand at the ASCRS meeting to check these results for myself and will report back to you!