The May 2005 acquisition of VISX saw AMO inherit a large installed base of refractive surgery technologies, which not only complemented its refractive IOL portfolio, but also transformed AMO into the world's leading refractive surgical company.
VISX brought with it a catalogue of technology platforms, including the STAR S4 laser system, the WaveScan wavefront system and CustomVue custom ablation technology.
By September 2005, the first milestone, as a result of the acquisition, was achieved when AMO received FDA approval of STAR S4 IR excimer laser system with the CustomVue procedure for the reduction or elimination of myopia and myopic astigmatism from -6 to -11 D with up to -3 D of cylinder. The scope of treatment was then expanded with a further approval of the technology for use in wavefront-guided excimer laser procedures for correction of hyperopia from +3 D of sphere and +2 D of cylinder, and mixed astigmatism from 1 D to 5 D of cylinder.
In clinical studies submitted to the FDA, 98.3% of those receiving the CustomVue high myopia treatment were corrected at six months to 20/40 or better and 84.3% were corrected to 20/20 or better without spectacles or contact lenses.
The STAR S4 IR system has several design features, which allow the surgeon to offer tailor-made refractive solutions to each individual patient. The system integrates data collected by the WaveScan wavefront system and uses several features to deliver precise custom ablations:
Why do we need to be so precise?
"Companies competing in the refractive surgery market are not trying to improve the way that myopia and hyperopia are treated, because we are already very good at that. They are trying to introduce system modifications so that we can improve patient outcomes by addressing the issue of aberrations," says Paolo Fazio, MD, Director of the Refractive Surgery service of the Centro Catanese di Medicina e Chirurgia in Catania, Italy.
Since the laser beam is more efficacious when hitting the central part of the cornea, because of less reflection and less distortion of the area of projection of the beam, an oblate cornea (flatter in the centre) often results following conventional myopic laser treatment. A more oblate cornea of the virgin one induces an increase in positive spherical aberration with a detrimental effect on the quality of vision.
"Basically two different strategies can be applied to overcome this problem: