Tuesday, March 12, 2013 5:53 PM
Base curves, we've learned are an effective way to provide adequate vision, over the entire lens, for a range of sphere and cylinder prescriptions.
Thursday, November 10, 2011 9:03 PM
The ability of a lens to refract and focus light—by either converging or diverging it—is referred to as its focal power
or refractive power
Wednesday, November 9, 2011 11:55 PM
The "best form" or "corrected curve" shape of a lens is one that provides as close to the the same vision at center and in the periphery as possible, as the eye moves normally behind the lens.
Tuesday, November 8, 2011 9:25 PM
The form of a given lens is determined by "base curve selection." The base curve
of a lens is the surface curve that serves as the basis or starting point from which the remaining curves will be calculated.
Tuesday, November 8, 2011 7:33 PM
The maximum thickness of a lens, for a given prescription, varies with the form of a lens. Flatter lens forms are slightly thinner than steeper lens forms, and vice versa.
Monday, November 7, 2011 5:33 AM
The principal impetus behind lens form selection is optical performance
. Base curves are typically chosen to provide a wide field of clear vision.