[Excimer laser: history, development and comparison of equipment]

We first present the history of the Excimer Laser technological development which began in 1975 with Velazco and Sester's research. We report various studies about lasers conceiving, treatment parameters, laser-tissues interactions, and treatments evolution. In the second part, we compare different Excimer laser systems and their capacities. Three current technologies are used for clinical application: the broad beam lasers, which use a diaphragm or a disc with multiple apertures, the scanning slits and the flying spots. Advantages and disadvantages of the various delivery systems are discussed.