Free Form Front and Back Grinding ?'s

[skirk1975]

Some free form lenses are ground on the front and the back while others are just on the back. Is there any advantage of one being better than the other ???

[OPTIDONN]

I just spoke with a SOLA tech. rep (who is just awsome!) about the same thing. She said that there is a theory about backside curves. It gives you a wider field of view. Like a key hole effect. The closer you are to the key hole the more you can see. The closer you are to the curves the better. A wider field of view.

[Jacqui]

I've had both, couldn't tell much difference except appearing wider with the Autograph.

[AWTECH]

As one of the few who actually have non-spherical lens surfacing capabilities, which you refer to as Free form, the first problem is existing patents. Without considering these, I believe the back surface should have the non-spherical and the front should be spherical. This gives a product where the determined Rx is closest to the patients eye and it just looks best. When you edge the lens all of the irregularities are away fron the front of the eyerim which looks best.

We use our process to produce very exact ICE-TECH Advanced Polarized Lenses. This keeps the polarized film very close to the front of the lens allowing us to produce an extremely thin lens. If we ad a bifocal segment to the back surface of this polarized lens it can not be seen when worn. This technology is so successful even in clear lenses with our AR you can not see the bifocal zone.

Marketing sometimes just means making it different so I think as this type of technology expands you will see many combinations proclaimed as the best.