A Question To Professional Eye Care Providers: What does this formula do?

[VGI]

http://www.allentownoptical.com/2009...on-sunglasses/

As some would know, I am just a consumer and can only post limited questions and only in the "Just Conversation" portion of the forum.

But I am interested in what this formula does, particularly where astigmatism and aberrations are concerned. I only know that it DOES NOT Completely Eliminate aberrations/distortions, but it only "compensates for it." And that's the extent of my knowledge about it. Bleh.

In any case, this thread feels like I'm playing around with the forum rules again, so if I am breaking the rules, then feel free to close/delete this thread. Am just shooting at stars here.

[MikeAurelius]

You are correct in your statement, it does compensate. It corrects for the tilt and wrap effect and allows easier accomodation by the wearer.

As far as abberations and/or distortions, those are two completely different issues. Abberations and distortions are errors in the surface quality of the lens that affect the rays of light passing through it, causing focus to be be changed. Most of these errors in surface quality are caught in final inspection, but some do pass through and are usually caught by the dispenser.

Compensation for the frame is a standard manufacturing procedure that is done very frequently when the frame is different from a "standard" spectacle frame, ie: it has more pantographic tilt or has a wrap to the lens. If the lenses are not compensated for the tilt and wrap, the wearer will experience induced astigmatism because of the way the rays of light pass through the lens.

That's about as specific as we can get in a discussion with a consumer. I hope this gives you enough information.

I will remind you that you really need to have these discussions with your dispensing optician, in person, and not over the internet on a forum dedicated for the use of optical professionals.

[Wes]

"As far as abberations and/or distortions, those are two completely different issues. Abberations and distortions are errors in the surface quality of the lens that affect the rays of light passing through it, causing focus to be be changed. Most of these errors in surface quality are caught in final inspection, but some do pass through and are usually caught by the dispenser.".
Huh???

[MikeAurelius]

definition of abberation: "failure of a mirror, refracting surface, or lens to produce exact point-to-point correspondence between an object and its image"

[Wes]

These are the aberrations under discussion: http://scienceworld.wolfram.com/phys...errations.html

[MikeAurelius]

Not to pick nits, but that's practically the same definition with simple expansion, a difference which is no difference.

[Wes]

Consumer: believe what you want.
Opticians: do your research.

[SeaU2020]

Looks like a nice time for a group hug!