The Latest in LASIK: iLASIK
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VISX Inc.’s CustomVue™ Star S4™ Laser system with WaveScan™ has been a great success with ophthalmologists. It is a complete system for delivering refractive eye surgery and includes these components:
Comfortable patient bed
A wavefront diagnostic system
Excimer laser for treatment
Iris Registration for tracking the eye’s involuntary movements during treatment
A microscope for your eye surgeon to see your eyes clearly
What is WaveScan™ technology?
In order to give you an accurate and effective vision improvement, your eye surgeon must first diagnose your eyes’ refractive errors. In other words, he or she has to measure and record exactly how each of your eyes bends (refracts) light. Wavefront-guided LASIK treatment such as the CustomVue system delivers is based on Wavefront information about your eyes. WaveScan™ is the VISX/AMO trade name for Wavefront.
How it works
When you are comfortably seated at the CustomVue system, a light is shone into each eye in turn, and received back as your eye reflects it back. When first shone to your eye it travels in a straight line. When it returns, the straight line is changed according to the microscopic contours of your eye.
If you imagine …
… the light as a clump of parallel lines traveling with their front ends all lined up evenly, and then imagine the clump returning with the front ends all at sixes and sevens, some jutting forward and some lagging behind, that is more or less the idea of wavefront diagnosis.
When the light has returned from your eye and registered in the CustomVue computerized system, it is now digital information and is expressed on the computer monitor as a colored three-dimensional map. Your eye surgeon will analyze the two maps, one for each of your eyes, and use the CustomVue software to plan your treatment.
Those two maps give the unique contours of each eye, and nobody else has those exact contours. Your two eyes will receive unique treatments to match, modifying
these contours so that your corneas will bend light in a way to give you clearer vision. You can read about this in much greater detail in the VISX patient manuals.
Eye Aberrations
Our eyes have two sets of aberrations, meaning variations from a theoretically perfect eye:
Lower order aberrations – of which there are three: myopia, hyperopia, and astigmatism; and
Higher order aberrations – of which there are an unknown number, at about 60 discovered so far.
Those terms lower order and higher order refer to the complexity of the shapes as the light returns from your eyes to the Wavefront diagnostic system.
When we go for a vision check to get new glasses or contact lenses, the eye doctor measures only the lower order aberrations. We look through the phoropter, that instrument with many lenses attached, while the surgeon or his assistant asks, “Which is clearer – this … or this?” He is switching lenses to measure our lower order aberrations. The glasses or contacts prescription is based on that information, not on any higher order aberrations our eyes might have. Millions of other people will have the same prescription as you.
WaveScan™ technology measurers the far more subtle higher order aberrations and includes it in the two maps. Nobody has the same maps as you.
Some examples of higher order aberrations would be:
Halos around lights at night
Double vision or “ghosts”
Glare
Starburst effects at night
Many have no names other than mathematical expressions.
Combining IntraLase and CustomVue
The procedure called iLASIK diagnoses your eyes’ refractive errors with CustomVue’s WaveScan system and creates the corneal flap with the IntraLase laser. Then it proceeds with treatment using the same excimer laser used in all refractive surgery.
That combination makes iLASIK an excellent option for a great many people. It has a wide candidate pool. You would very likely benefit hugely from having it done if you suffer from nearsightedness, farsightedness, or astigmatism.
If you would like to know more about how best to have laser vision correction, the first thing to do would be set up a consultation with an experienced and qualified LASIK surgeon. You can ask all your questions and receive clear answers, and get good advice on which procedure would be most effective for you.
