Dear Sir,
Thank you for your interest in TRSC International LASIK Center. Here at TRSC, we use the Carl Zeiss MEL80 excimer laser, which is a wavefront system. The VISX STAR S4 is also a wavefront system, however it is a bit older than the MEL80. The VISX STAR S4 was approved by the FDA in 2003, while the MEL80 was approved in 2006 and I believe it is still the most recently-approved excimer laser. TRSC’s team of surgeons prefer our Zeiss MEL 80 over the VISX because the MEL 80 uses a flying small spot scanning system in which the beam size is as small as 0.70mm throughout allowing for the quickest laser speed compared to other excimer lasers (at 250 Hz).  The MEL 80 also has a 3D eye tracker, and has a speed matching the laser speed (also at 250Hz) and has the quickest latency period of 2 milliseconds.  This is unmatched by any other eye tracker or active tracker of VISX.  The MEL 80 also has wavefront platform using WASCA (Aberration analyzer) that is able to spot check the cornea up to 1,452 points which is more than the Customvue wavefront system of VISX.   The wavefront technology that we use, the WASCA aberrometer, is the most advanced in the world.  Zeiss Meditec (from Germany) in conjunction with Wavefront Sciences (a research company based in California, USA) have developed a measuring tool which no other company can even compare to at this point in time.  
 
At TRSC, we have three levels of advanced treatment:  
1. Premium LASIK (non-wavefront) – Bausch and Lomb Technolas 217z
2. Optimum LASIK (using optimization) – Carl Zeiss MEL 80
3. Ultimate LASIK (using wavefront + optimization) – Carl Zeiss MEL 80 and 250 Wavefront system  
TRSC's Ultimate LASIK is currently the most advanced LASIK treatment available.  As each person is unique, there are many factors that must be considered and in some cases Premium or Optimum LASIK can provide the same or even better results.  Each person must be considered on an individual basis after all possible measurements have been taken.  The LASIK surgery specialist will therefore be the best source to recommend what level of LASIK care is preferred for you, which can be determined after the complete preoperative eye exam.
Thank you again for contacting us. Please let me know if you would like more information about our clinic, price list, or procedures, and I will be happy to send it to you.

Warm regards,
TRSC International LASIK Center