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TECHNOLOGY The Lasik Surgery Clinic
VISX® Technology

VISX® STAR S4 IR Excimer Laser System
Every year, more doctors use VISX® lasers to perform laser vision correction surgery than any other system. The VISX® STAR S4 IR excimer laser system is a unique laser platform developed in conjunction with the original dependability and performance of VISX® technology.
Your individual eye information is first programmed into a computer that controls the laser. The laser then produces a series of rapid pulses that remove specific amounts of corneal tissue. This laser emits a beam of cool ultraviolet light that does not penetrate into the eye hence inner parts like the iris, lens and retina are unaffected by therapy.
This system is able to offer you precise, custom corrections through several distinct features:
- Iris registration technology
- Active eye-tracking
- Automatic centering to the pupil
- Variable laser beam size
- Variable repetition rate of treatment
The iris registration technology used here is the first FDA-registered, fully automated, non-contact means of aligning the cornea to the laser treatment. Iris registration improves the outcome of treatment by taking into account that each person’s iris is as unique as a fingerprint. This technology is able to match the laser treatment with the appropriate corneal site through the identification of multiple reference points on your iris. The human eyeball rotates ever so slightly when changing from an upright position to lying down and vice versa. This rotation is recognized with VISX® technology and re-registration can be carried out automatically to align the treatment in spite of this rotation.
The human eye is capable of numerous involuntary movements and these will occur during the LASIK procedure. The STAR S4 uses infrared cameras incorporated into an eye-tracking system developed by ActiveTrak®. The cameras capture information from all three dimensions of eye movement that may occur throughout the procedure. This is analyzed so that the precision of the laser correction for your treatment is enhanced.
The ActiveTrak® system also automatically locates, and adjusts for, changes in the pupil center regardless of pupil size so that treatment is centered without the need to expand the pupil.
The ability of the laser beam to change in size through a range of 0.65mm to 6.5mm over the treatment area allows for faster correction along with less unnecessary tissue removal. This is capable of allowing more precise therapy and faster healing.
The dynamic beam size is complemented by a variable repetition rate of treatment so that your time in treatment is optimized.
| The VISX® STAR S4 IR Excimer Laser System is approved by the U.S. FDA for: |
| LASIK |
Myopia |
Up to -14.0 DS with or without astigmatism -0.5 to -5.0 DC |
| Hyperopia |
+0.5 to +5.0 DS with or without astigmatism up to +3 DC |
| Mixed Astigmatism |
Up to 6.0 DC, cylinder > sphere and of opposite sign |
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WaveScan® technology

WaveScan® technology was born of astrophysics from the desire of astronomers to reduce distortions when viewing distant objects in space through high-powered telescopes. The technology has since been adapted to accommodate the aspirations of LASIK surgery. As a result, we now have a means to measure imperfections in your eye up to 25 times more precisely than the standard methods that were previously available.
In the past, eye surgeons used trial lenses and a device known as a phoropter to measure imperfections. Prescriptions were hence limited to a fixed level of laser vision correction regardless of unique imperfections of vision.
Several features make the WaveScan® Wavefront system highly effective in laser vision correction. The use of WaveScan® technology allows the creation of various optical maps. A WavePrint® map allows for the charting of optical irregularities. This map is unique to your eye and contains a detailed analysis of your vision from which your LASIK surgeon can design the optimal vision correction treatment. Difference maps allow your LASIK surgeon to track changes in the eye from pre-operative and post-operative comparisons.
WaveScan® technology is capable of providing a point spread function that demonstrates to your LASIK surgeon how you would see a point source of light.
All of the data from any pupil shape can be contributed to the system for accurate reconstruction in therapy. Furthermore, the system is capable of capturing and treating irregularities of large pupils up to 7mm in diameter.
Combining the VISX® Star S4 IR Excimer Laser system with WaveScan® Wavefront technology results in a unique form of LASIK therapy known as CustomVue® Wavefront-Guided LASIK. It is called CustomVue because not only can it correct myopia, hyperopia, and astigmatism as accepted with previously available technology, it can also now correct other unique imperfections of your eye. Noting results from FDA clinical studies, CustomVue® treatment can improve vision beyond that possible with the use of contact lenses or spectacles.
| Treatment |
Refractive Error |
Approved Range |
| The VISX® STAR S4 IR Excimer Laser System and the WaveScan® WaveFront System are approved by the U.S. FDA for: |
| CustomVue® Wavefront-Guided LASIK |
Low to Moderate Myopia |
Up to -6.0 D MRSE with or without astigmatism up to –3.0 DC |
| High Myopia |
From -6.0 D to -11.0 D MRSE , with or without astigmatism up to -3.0 DC |
| Hyperopia |
Up to +3.0 D MRSE with or without astigmatism up to +2.0 DC |
| Mixed Astigmatism |
From 1.0 D to 5.0 DC, cylinder > sphere and of opposite sign |
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