Wellington Eye Clinic in General Media

Laser refractive surgery has come a long way. In 1991 the first LASIK procedure was performed on a seeing eye. This was 18 years ago. Prior to this, PRK was performed and this procedure, too, has stood the test of time as it is still done today when LASIK is not possible.

The safety and efficacy of these procedures has improved beyond recognition since then.

More than 20 million laser refractive procedures have been performed world-wide since those early days. Recent publications looking at patient satisfaction surveys show a 95 per cent plus satisfaction rate. That is very satisfactory but there is obviously still room for improvement.

Today it is widely accepted that LASIK is safer than contact lens wear in terms of sight-threatening complications. LASIK infection occurs in one in 10 000 procedures on average and these cases normally do quite well anyway, as the flap can be lifted and the infection physically washed out and cultured for M, C & S.

Another concern over the years has been that of post-LASIK ectasia, but this too has proven to be very rare. When pre-operative evaluations are very thorough and include modern techniques of imaging of the cornea (like the pentacam), these potential problem cases can be identified and excluded as refractive candidates.
The field has continued to improve in terms of technology and some of the advances are discussed below.

In the past, the results achieved with LASIK were widely regarded as being very good in daylight but less good in poor light conditions as seen at dawn and dusk or at night. This was as a result of induced spherical aberration that was induced by the laser’s ablation profile. In 1999, Wavelight introduced an ablation profile called “Wavefront optimized” that corrected for this and at once, the quality of night vision increased dramatically and complaints of night vision following LASIK greatly reduced.
There were patients, however, who complained of visual quality problems despite having full correction with spectacles or contact lenses. These patients were suffering from what today is termed “higher order aberrations”. These higher order aberrations (most commonly coma and spherical aberration) can only be corrected by customized laser ablations and cannot be corrected by glasses and contact lenses. Wavefront-guided procedures then ensued with the third center worldwide to do such treatments being in Dublin. This was done in September 2001. The results were excellent, but further analysis of the data found that Wavefront-guided procedures were only beneficial when there were pre-existing higher order aberrations. In the absence of higher order aberrations, there is no advantage in doing Wavefront-guided procedures over Wavefront-optimised procedures. In a certain percentage of patients where there were pre-existing higher order aberrations, it sometimes happens that Wavefront maps of adequate quality and repeatability could not be obtained. This disqualifies the patient from Wavefront-guided procedure and other forms of customization were required. These followed in 2004 (topography-guided) and in 2005 (pentacam-guided), where data from the corneal surface is used to further customize the ablation profile and improve the visual quality of the results. A fourth modality was added, called "Custom Q" where it became possible to not only dial in to the laser the exact refraction required, but also the final asphericity of the corneal shape. This again increased the yield of patients with excellent visual quality outcomes. Incredibly, the bar is being raised even further. Wavelight are about to embark on a three center clinical trial (in Dublin, Zurich and Cologne) looking at using the ultimate Holy Grail in optics, namely “ray tracing”, to drive customized treatments. This technology is going to leave absolutely nothing to chance with each and every light ray entering the eye being accounted for in terms of where it enters the cornea, where it exits the cornea, where in enters and exits the lens and where it strikes the retina. This loop is then reiterated by software using computer modeling to design a treatment ablation profile that takes each ocular surface and interface into account. To date, every ablation profile being used in all excimer lasers uses a generic eye model from the early to mid 1900’s (Gullstrand eye model) to help calculate the ablation profile. With ray tracing, the exact measurements from the patient’s own eye are used to refine the ablation profile. Ray tracing holds the promise to deliver the best possible vision and quality of vision post-operatively. It is very exciting that this groundbreaking technology is being trialled in Ireland.

Further developments that are improving outcomes include the use of thinner corneal flaps for LASIK. This saves tissue and preserves greater corneal strength post-op. the recovery is also faster with thinner flaps. These thin flap LASIK procedures have been termed SBKM (Sub-Bowman’s Kerato-Mileusis). It allows for bigger refractions to be treated that previously may not have been qualified for LASIK. These flaps can med made with both femtosecond lasers as well as modern microkeratomes. The jury is still out on which technology creates the better flap, and it may be many years yet before one technology is proven to be definitely better than the other. Both femtosecond lasers and microkeratomes have their specific advantages and disadvantages. In experienced hands, the microkeratome takes an awful lot of beating, in the author’s opinion.

In certain cases the use of a flap is contra-indicated. Examples include very thin corneas, patients with dry eyes and certain sports and occupational hazards (e.g. karate, kick-boxing, police work etc). In these situations, the possibility exists for the LASIK flap to move if the correct amount of energy was applied to it in exactly the correct spot (e.g. a punch to the eye). In these cases, to avoid the possibility of the flap moving, the surgery is performed without the use of flap, directly on the surface. This is called PRK or LASEK. Nowadays, thanks to the use of Mitomycin-C (applied to the surface for 30 seconds post-op) the incidence of corneal haze has been greatly reduced and it has become clinically insignificant in almost all cases of surface ablation. Thanks to advancements in the bandage contact lenses that are used for five days post-operatively following PRK or LASEK the visual recovery has improved in terms of speed, discomfort and quality of vision.

There are situations where laser refractive surgery is not the procedure of choice and where other procedures may be more suitable. This includes indications like very high myopia, very high hyperopia and extreme astigmatism. Certain corneal diseases are also a contra-indication to routine laser refractive surgery. In the same way that laser surgery has evolved, however, so has intraocular surgery, and there would be very few situations now where we would not be able to offer the patient a procedure to improve the quality of vision and therefore the quality of life. Even conditions like keratoconus can now be treated and stabilized by corneal cross-linking making the use of corneal transplants less likely.

It is incredible to think that what we until very recently only dreamt of in terms of what we could do for our patients is now commonplace. It is indeed a very exciting time to be in ophthalmology.

Mr Arthur Cummings, Consultant Ophthalmic Surgeon

Dr Charl Weitz (Fellow)
Wellington Eye Clinic, Dublin

TV3 Ireland AM

Louise's Diary - 40s

Hello everyone, Louise here for the 40's,

Hope you all are enjoying the fantastic weather, there is nothing like a bit of sunshine to brighten us all up.

I dreamed and I wished and it all came true, thanks to Laura, Marie, Glow magazine and Ireland AM.

We all met as strangers and ended up as friends. It was great to meet the other ladies for the Life Makeover and I could relate to all of them.

I know that I am seeing life through new eyes, and I don't only mean since I had laser eye surgery at the Wellington Eye Clinic! I have never felt so free in my life, everything is so much more clearer to me, I have learned that life is for living and that we can do anything that we put our minds to!

Getting shot of my glasses was freedom, I'm in my new life now.

Take care,

Louise xx

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Clinical Review Monday, June 8th 2009

Laser refractive surgery: where are we now? And explain how far laser eye surgery has come since 1991

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Louise's Diary - 40s

Clinical Review
Monday, June 8th 2009