VISX has created its 4th generation of excimer lasers, the VISX S4 IR. This laser has a variable spot size. The laser beam spot size automatically adjusts from 0.65 to 6.5 mm for speedy and efficient treatments. Additionally, the laser has 3-D Tracking. If your eye moves in any direction during the treatment, the laser moves with you guaranteeing the accuracy of your treatment. If your eye moves side-to-side, up-and-down, or closer-and-farther from the laser, you have nothing to worry about. Iris Registration and CustomVue are also technologies of the VISX STAR S4 IR. Click on their links in the sidebar to learn more.