Trudi asked

Hello Dave,
I had my eyes lasered in Dec 2009. My prescription was SPH -4.50 & -5.00. My left eye (which had the worst prescription) is perfect! I have had enhancement surgery on my right though as a slight astigmatism remained. I had enhancement surgery (using the LASEK method this time round) 4 wks ago and the vision is not yet as good as it was after the first surgery, before the enhancement. I am beginning to think I should have lived with the result I had after the first surgery and been grateful. Do you think my eye will heal to at least what it was after the first surgery?

Also, I have regular post-op check-ups with various different opticians (dependant on who’s in on the day of my app) and each tells a different story about healing and drops. I have been told that keeping the eyes wet with blink drops is *very important* to aid healing. I have also been told by another optician that I only need to put drops in when my eye feels dry. What is your view?
Thanks.

Trudi, for the lubrication, I would recommend regular instillation rather than just when they feel dry. The nerves are lasered during the treatment and see the eye is somewhat insensitive for a while, so you may not be aware of some dryness and so not lubricate. Aim for 4-6 times a day over the next couple of months. I prefer the preservative free version (you can buy e.g. Blink or Refresh over the counter at Boots) which will be less irritant with regular usage over an extended period. These are the ones in individual droppers. One vial should last you a day, one drop in each eye every 3-4 hours.

For surface laser correction (PRK/LASEK) the full result can take months to fully settle and the vision is often a bit off at 4 weeks post-op. You should find it will settle more over the next 4-8 weeks.

Zoe asked:

I am interested in laser eye surgery, but am very short sighted(-10) would it still be possible?

Zoe, yes it certainly may be possible. It will depend mainly on your corneal thickness and pupil size in the dark. The best way to know is to have a consultation and have the measurements taken. Not all patients are suitable at this level of prescription though. If LASIK is not possible, PRK with mitomycin may still be.
The WaveLight laser that I use takes relatively little tissue per dioptre, so I find we often have a good chance to treat higher myopia. If there is not quite enough tissue in the cornea, and you are 40+, a good option can be to leave you between -1D and -2D, so at least you will be able to read without any glasses.

Steve asked about cTen laser correction:

Hi Dave. Thanks for providing this blog, in anticipation of surgery it’s very much appreciated.
I’ve heard of a superioir procedure called CTen which seems to be a significant advance in corrective eye surgery, but can’t find any providers. Can you shed any light?

The cTen system is from an Italian company called iVis Technologies. It incorporates a 1,000-Hertz excimer laser (iRES) and a software planning system called CIPTA. cTen is an acronym for Customised, TransEpithelial, No-touch surgery.

It is promoted for complex cases where there is irregularity of the cornea, e.g irregular astigmatism. They use the excimer laser to remove the epithelial skin layer and use topography information from a Scheimpflug camera scanner to correct imperfections across the cornea stroma. The makers suggest this is a bette way of performing PRK.

Not really a significant advance as all this technology is currently available. We use the same Scheimpflug approach already with our WaveLight laser in its T-CAT (topography guided) mode, and all lasers can be used to remove the epithelium down to a desired depth the leave a smooth surface.

For virgin unoperated eyes, there is no significant benefit to use the CIPTA platform. The procedure here is just PRK. Also, the no-touch laser removal of epithelium approach adds little, as standard alcohol based removal is quick, effective and predicable, and is used around the world as standard. I do agree with iVis that topography guided correction is most useful for irregular corneas over wavefront guided, and I use T-CAT for these complex cases.

The above helps explain why you can’t find any providers. The gold standard procedure for us is thin flap femtosecond Z-LASIK. If we need to do surface laser, we do PRK.

This is a common question about laser eye surgery safety I get asked by patients:

What happens if my vision isn’t right after treatment?

Most people don’t realise that the effect of laser eye surgery, including LASIK, LASEK and PRK procedures, CAN be fully reversed.

Although this isn’t necessary because if the prescription for glasses hasn’t been fully corrected then a second treatment is easily performed to fix that and stay free from the need for glasses or contact lenses. If the effect of the laser correction is a bit too strong or too weak, we call this an over-correction or an under-correction respectively.

All over- and under-corrections can be treated easily. In fact, as I mentioned, the whole laser eye treatment can be reversed. The move over to the Ziemer blade free system (Z-LASIK) has dramatically reduced the need to re-do LASIK treatments.

Most clinics quote enhancement rates of around 5%.  BUT with Z-LASIK for short-sight I have only had to adjust one case in the last 200, so that’s a 0.5% rate. Without any hype or spin, that’s just very impressive and a great step forward.

To fully reverse the effect of e.g. a short-sighted laser eye treatment, we remove some tissue from the outer part of the cornea to put the corneal curvature back to where it started. So now an equal amount of tissue has been removed across the cornea and so the focus would be back where it started. Of course, the cornea is a little thinner than before, but still strong enough for its role.

It’s the accuracy of the dual laser approach that allows such a very low enhancement rate, which means 99.5% of short-sighted patients are on target and very happy with only one treatment and without the need for a top-up.

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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!

You will have a choice of procedures when you come to have laser eye surgery. But which one will be right for you?

Basically though, there are only two laser eye treatment procedures available, but each one has options within.

Option 1: LASIK (the most common and most popular)

Option 2: Surface Laser (with various forms… PRK, LASEK, epiLASIK)

Let’s begin with option 1, LASIK, which is by far the most common laser eye procedure, accounting for more than 90% of all laser vision corrections. Why is it so popular? Well, it is pretty much painless both during and after surgery and great vision is there by the next day. Patients can also work again the next day so very little downtime. This is the procedure that spreads quickly by word-of-mouth due to it’s powerful ‘wow!’ effect. The flip side here is that some patients are cautious about having a corneal flap created with a mechanical blade device and questions around long-term stability of the cornea.

These issues have driven the rapid move over to blade-free (dual laser) LASIK. Here the blade is eliminated in favour of a laser to create the corneal flap and the flaps made are much thinner and more accurate. More on this very soon in the next article.

Next, option 2, Surface Laser, comes in the guises of PRK, LASEK, epiLASIK, epi-flap, etc. At the risk of upsetting some colleagues and equipment suppliers, these are all basically the same procedure! Whichever variation you get, your final vision result will be the same. Some doctors and clinics use different names but there isn’t really a big difference at all. Vision, recovery time, post-operative pain – all the same across the board.

This is the laser eye surgery procedure that is very well remembered by patients… because it is painful for 2-3 days afterwards! And it takes several days for vision to recover. So there is not much word-of-mouth spread, and no ‘wow’ effect. When friends ring up the next day to see how you are doing, you will tell them you can’t see well yet and it really hurts!

So why do some doctors or clinics advocate PRK as the best choice? There is no flap cut hence eliminating blade-related potential complications and the cornea remains stronger compared to the same prescription after a LASIK eye procedure.

OK, enough for now. More on this topic very soon and on how the introduction of thin-flap blade free LASIK changed the game.

Live video of Paul Ross having his laser eye surgery on the ‘This Morning’ TV show.

Fern Britten and Philip Schofield interview Paul Ross and Dr. Dave Allamby about laser eye surgery.

Following a recent question posted on this blog, I can add the following CAA PDF download which has additional information:

Download CAA Pilots and LASIK or PRK PDF file or visit the CAA website

Following on my reply to Peter’s comment on whether or not LASIK is acceptable for joining the UK police force, I thought I would add this info to clarify. You can see an excerpt form the official police eyesight form below.

YES, LASIK is fully acceptable for the police force, as is LASEK, PRK and ICRS (Intra-Corneal Ring Segments). The main criteria is whether or not the cornea is weakened following surgery and LASIK, PRK etc. are NOT considered to affect the strength of the cornea versus possible trauma from working as a police officer.

However, radial keratotomy (RK, ‘microsurgery’), arcuate keratotomy (AK) and corneal grafts are all procedures that do weaken the cornea and applicants who have had these treatments WILL be rejected by the police.

Get more information on eyesight requirements, LASIK and the police at the official police website here or download the eyesight police criteria PDF form here.

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.

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!

Here is Part 2 of the Essential UK Guide to Laser Eye Surgery slideshows. It covers how to read your prescription and know what all the numbers mean.

This is really useful to know for when you call up a clinic to find out if you are suitable for LASIK or PRK laser eye surgery, they will ask you for your prescription. They can also tell you what the maximum prescription treatable limit is, so you will know if you are within the range or not.

You can see it here:

Essential UK Guide to Laser Eye Surgery Part 2 – Reading Your Prescription

[tags]clinic, guide, laser eye surgery, LASIK, London, PRK, UK [/tags]

What is the difference in the two laser eye surgery procedures?
There are basically two laser refractive procedures to correct myopia (short sight), hyperopia (long sight) and astigmatism: 1) LASIK and 2) LASEK. [You can consider LASEK and PRK as basically the same procedure for most discussions - they are both forms of 'surface' laser eye surgery with pretty much identical results].

Both LASIK and LASEK procedures are very safe and will give you the same final results. It can be quite confusing if you are thinking about laser vision correction and want to know which procedure would be best for you. While both LASIK and LASEK can give you excellent vision in a safe and reliable way, some surgeons prefer one or the other, or may indeed only offer one type anyway!

How is the prospective patient supposed to decide?!
What happens in practice is that patients are greatly influenced by what their particular clinician says, and understandably so. It is always worth seeking a second opinion and comparing the findings and comments of each centre. This shouldn’t threaten any clinic worth its salt. Some patients feel more confident with one person or another, based on perhaps only “chemistry”, but it is very important to know the difference in the techniques.
LASIK and LASEK are both very effective procedures and can be used to treat myopia (short sight), myopia myopia(long sight), astigmatism (irregular corneal shape) and reading vision problems.
Please note that most clinics do not have the correct technology required to correct reading vision problems and higher levels of long sight.

[tags]astigmatism, FOCUS Laser Vision, LASEK, laser eye surgery, LASIK, long sight, short sight, surgeon, Technology[/tags]

Video showing a very brief overview of the PRK surface laser procedure, as well as covering short sight, long sight and astigmatism. LASIK remains the most popular laser eye surgery procedure worldwide. In Italy, though, surface laser (PRK, LASEK) is very popular.