I'm putting together a CE entitled Progressive Lens Characteristics, and part of the course will attempt to define the various terms used by manufacturers to describe their designs. I know some of the terms I'm listing here are archaic, but I was hoping to enlist y'all in helping me put together a complete lexicon of PAL terms.
- Hard Design- a design where the edges of the channel and reading area are marked by a rapid increase in unwanted astigmatism
- Soft Design- a design where the edges of the channel and reading area may be smaller, but are bordered by a less dramatic increase in unwanted astigmatism
- Symmetric- a PAL with one, symmetric design for both lenses. Lenses are tilted to create a right or left lens
- Asymmetric- a PAL design in which lenses for right and left have different characteristics between the temporal and nasal areas
- Mono-design- a PAL that carries the same design throughout all add powers
- Multi-design- a PAL that changes in design as the addition power increases
I realize that there are many other terms used to describe PALs. If any of you could
list a few more (or refine the definitions for the terms I have) I would be most appreciative. This will only be a one hour course (and I'm not presenting this one until October), so we won't be spending a huge amount of time on terms- but I'd like to be able to supply a handout. In particular, some help with the terms relating to new designs that attempt to provide an accurate Rx at the retina would be greatly welcomed.
Also, for you manufacturer types. Other than a power grid and a graphic showing the speed and location of the power progression, what other graphics do you feel would be helpful in determining the characteristics of a progressive addition lens.
Just splashing my feet in the Oasis that is this forum,
Pete
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