The advanced optics of Frequency 55 Aspheric let you enjoy an unsurpassed level of visual quality. By focusing light to a common focal point on the back of your eye, instead of a general area, the aspheric design gives you more precise, crisper vision. Beyond outstanding vision, the patented UltraSync manufacturing means Frequency 55 Aspheric also offers exceptional comfort, handling and performance. This lens may correct up to .75 D of astigmatism.