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Overview of commercially available femtosecond lasers in refractive surgery.

PURPOSE
To report on four different commercially available femtosecond laser systems used in refractive surgery.


METHODS
Four systems were analyzed: Ziemer DaVinci system, Zeiss VisuMax, IntraLase FS laser, and 20/10 Perfect Vision FEMTEC.


RESULTS
The DaVinci system attracts attention with its concept of low laser pulse energy and flexible mirror arm as a beam delivery. The low pulse energy makes it compact and robust, because only an oscillator as a laser source is required. Another important feature of the low energy pulses is the reduced bubble formation during the cutting process. The smaller the bubbles, the more precise the cut can be positioned. However, the compact setup limits the system in its flexibility in cutting geometry. The VisuMax also uses the new generation of femtosecond technology, which should make it more immune to environmental and temperature changes. However, it is a bulky system, and the patient has to be moved to the excimer laser system after the flap is created. The IntraLase is the laser with the most clinical experience by far, which should be an important issue in terms of safety and technical support. On the other hand, it uses older femtosecond laser technology. This technology is sensitive to changes in temperature or humidity, which can be an important factor if the surgical environment is not air conditioned. The 20/10 Perfect Vision FEMTEC system is comparable with the IntraLase with respect to its technical parameters. However, no data are available about the amount of clinical experience.


CONCLUSIONS
Although the systems are based on the same principle of photodisruption in corneal tissue, differences exist regarding the concept of these devices.