Back To Basics: Understanding The Use And Limitations Of A Lens Measure

By Dick Whitney, Carl Zeiss Vision
ANSI Z80.1 Chair, Vision Council Lens Tech Committee Chair,
Executive Director of Optical Heritage Museum

Monday, April 11, 2016 10:10 AM I have been thinking about topics that might be of interest to the readers of the Opticians Handbook and I began thinking about a number of “old devices/inspection techniques” still used today that would be fun to write about and perhaps give the reader some new information of interest and the lens measure (lens watch or lens clock) came to mind.

Diopter (1.53) – A Simple, Yet Sometimes Confusing Ophthalmic Lens Term

By Dick Whitney, Carl Zeiss Vision, ANSI Z80.1 Chair
Vision Council Lens Tech Committee Chair, Executive Director of Optical Heritage Museum

Monday, March 28, 2016 3:15 PM For many of us in the ophthalmic lens business, a term frequently heard is Diopter. While it is commonly used, it has been my experience that many people are unclear about the proper meaning(s).

Improving Free-Form Lenses With Variable Base Curves And Digital Individualization (Part Two)

By Mark Mattison-Shupnick, ABOM
Monday, September 14, 2015 9:05 AM Do you agree with the statement, "Free-form, i.e., digitally-compensated lenses produce more satisfied patients"? I know most do agree, because when I ask that question to those in attendance at my classes, almost all of them selling digital lenses say they agree.

Choosing Base Curves

By Brian Boddy, ABO-AC, Acoma Optical, Mark Mattison-Shupnick, ABOM
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.

Ophthalmic Lens Design

By Staff
Thursday, November 10, 2011 9:43 PM Take the CE course at

Lens Design

By Darryl Meister, ABOM
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.

Base Curves

By Staff
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.

Base Curve Selection

By Darryl Meister, ABOM
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.

Mechanical Factors of Lens Form

By Darryl Meister, ABOM
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.

Optical Factors of Lens Forms

By Darryl Meister, ABOM
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.