Refractive
  What?
  For who and when ?
  Preperation
  What to expect?
  Treatment
     Non-surgical
     Excimer Laser
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     keratoplasty
     Radial keratotomy
     Tosca-Wasca
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Cataract

Corneagreffe

 

   
  Technical principles of the Excimer Laser

The Excimer Laser is a pulsed gas-laser, with a mixture of rare gases (10% of Argon, 0,2% Fluorine, 40% Helium, 49,8% Neon) which, when excited by electrical energy, emits an UV-radiation of 193 nanometers. This radiation is able to cause a photo-ablation, i.e. pulverisation of tissue by breaking the bonds of the molecules.

By using the photo-chemical effect of the Excimer Laser the ophthalmologist can re-shape the cornea and thus correct myopia, astigmatism and presbyopia.

The application of the Excimer is to be found in Lasik photo-refractive keratotomy (PRK) and photo-therapeutic keratotomy (PTK).

Our latest and third generation Excimer laser Mel 70 Asclepion Meditec has the most sophisticated up to date technique with incorporated flying spot technology and Gaussian distribution and active eye tracker.

This way of treatment produces a very regular and silky surface. Besides, this laser has topolink assisted possibilities (Customised ablation based on topography - Tosca and Wavefront measurement - Wasca). This means, that the laser computer uses processed information obtained by videokeratographic measurement, in order to treat only well selected areas of the cornea.


After the removal of the corneal epithelium, the laser treatment is applied
to the eye surface. The laserlight pulverizes a minute layer of the cornea.
  
     
 
How is Excimer surgery executed?

As a thin layer of tissue is removed from the cornea, an important change in the refractive state of the eye occurs. Computer calculations have shown that the removal of about 10 micron (10/1.000e mm) of the cornea corrects 1 dioptre of myopia. The computer calculates to which depth the Excimer Laser has to work in order to correct certain degrees of myopia, hypermetropia and astigmatism.

With the Zeiss Meditec Mel 80 Excimer Laser myopia can be treated up to -20 diopters. The accuracy of the correction depends on the degree of myopia that has to be treated.

More than 99% of the treated patients obtain a result between 0 and + or -1 dioptre.

With the Zeiss Meditec Mel 80 Laser also hypermetropia can be treated until 4 dioptre.

Astigmatism can also be treated with the Excimer Laser. With the modern computer technology and new modules, it will be possible to treat irregular astigmatism.

It is also possible to treat superficial opacities of the cornea (for which a corneal transplantation was necessary before) and recurrent corneal injuries or erosions with photo-therapeutic keratectomy (PTK) with the Excimer Laser.
 
     
 

Left topography demonstrating that a –7.75 D has been completely corrected
to the –0.75 D target with Lasik
technique. Right down before - right up after treatment: left difference map.
Extreme precision of Lasik with the Mel 70 Asclepion Meditec Laser in a case of important astigmatism (5D). Right low before, up after, left difference map demonstrating that the astigmatism has been completely eliminated (blue-green colour = perfect treatment).
 
     
 


Is this new method safe and medically justified?

The first investigations with the Excimer Laser were done in Berlin by Professor Seiler and published from 1988 on. In 2002 in the U.S., more than 2.000.000 eyes were treated with the Excimer Laser.

1. The Excimer Laser surgery can be dosed to 1m (1000m = 1 mm).

2. With its wave-length of 193m the Excimer Laser does not cause cancer.

3. In many Private and University Centres in Europe, in the U.S. and in the rest of the world the treatment is applied. The Lasik method was introduced by Professor Pallikaris in Greece and is considered as the most advanced method for treatment of low, moderate and high myopia.		  
Dr. F. Goes with Professor Theo Seiler
in Dresden, the inventor of Excimer
laser corneal surgery (1994).
 
     
 
Extreme precision of Lasik with the Mel 70 Asclepion Meditec Laser in a case of important astigmatism (5D). Right low before, up after, left difference map demonstrating that the astigmatism has been completely eliminated (blue-green colour = perfect treatment).
  
     
 


What are the advantages of the Laser compared with the radial keratotomy for myopia?

Till now, in case of myopia surgery, the Radial Keratotomy was used but:

1. One can work more accurately with the Excimer Laser (up to 1m) than with the Radial Keratotomy (accurate up to 10-20m).

2. The cornea is less injured with laser treatment. After laser-surgery the scar is barely visible under the microscope and disappears completely after a few months. The scar remains visible after radial keratotomy.

3. Once healed, the eye that has been operated on with laser, has less sight-fluctuations.

4. After the wound has healed the cornea is not weakened after Laser treatment. After Radial Keratotomy the cornea remains weaker for the whole life.

5. There is less risk of infection.