Front Surface Lens Warpage

[Dwayne]

Question for you opti-types...

When you have a lens edged in a frame, I've been told that you should clock the front surface with the pins oriented vertically and then horizontally to determine warpage at the front surface. Is this the best way to do this? Obviously, I'm talking about single vision lenses here and not PALs. If so, what's the tolerance for warpage? 0.5D? 1D?

Any advice you can offer would be appreciated.

Dwayne

[HenryB]

To quote Z80.1-1995 ANSI recommendations......"The curves of the two principal meridians should be measured with a sagitta gauge such as a lens clock"

Tolerance is in fact 1 diopter when measuring with this method. This need not apply within 6mm of the mounting eyewire however.

Hope that helps.........