Fresnel material? Could it be improved?

[Uilleann]

I know the Abbe hounds and all the Trivex fanboys(& girls) will salivate over this one.

The CA in even moderate power Fresnel press on prisms is ridiculous as we know. So the question is:

What are they [Fresnel Prism & Lens Co.] currently using for their material, and could it in any way be improved? Better Abbe? Better overall clarity? Slightly larger or smaller prisms on the lens surface based on lens power perhaps? More or less flexibility of the plastic? Better adhesion characteristics? What would you like to see?

[Jacqui]

I don't know, I only use them as trial lenses for hemianopsia and macular degeneration.

[jefe]

I know the Abbe hounds and all the Trivex fanboys(& girls) will salivate over this one.

The CA in even moderate power Fresnel press on prisms is ridiculous as we know. So the question is:

What are they [Fresnel Prism & Lens Co.] currently using for their material, and could it in any way be improved? Better Abbe? Better overall clarity? Slightly larger or smaller prisms on the lens surface based on lens power perhaps? More or less flexibility of the plastic? Better adhesion characteristics? What would you like to see?

It appears to be vinyl. I wonder if it were possible to make it in something like Trivex and apply it by using a Chemistrie-type mounting system as opposed to using an adhesive. At least there would be no bubbles, and the lenses would be edged to shape rather than being cut with an exacto knife.

[AdmiralKnight]

I doubt anyone would want to pay for a better fresnel. They're designed to be disposable diagnostic tools, not something to be worn for any extended period of time. For the cost of a better fresnel, it'd probably be pretty close to the cost of just making a new set of lenses with the prism ground into it.

[jefe]

I doubt anyone would want to pay for a better fresnel. They're designed to be disposable diagnostic tools, not something to be worn for any extended period of time. For the cost of a better fresnel, it'd probably be pretty close to the cost of just making a new set of lenses with the prism ground into it.

There are times when the magnitude of the prism ordered creates issues with great thickness. The fresnel's thickness of only 1 mm. sometimes makes it the best option.

[uncut]

Adhesion may need to be improved, or method of application, due to the newer slick, anti-fog/anti-stat AR coatings? Appearance could be improved if they had an AR coating.

[rbaker]

As long as the flexable membrane is injection molded from an optically clear material it should do the trick. The existing product on the market has worked just fine for over fourty years.

If it aint broke, dont fix it.

[Chris Ryser]

If it aint broke, dont fix it.

rbaker.....................is right.

Press on prisms are a temporary crutch and you want it to become an equivalent match to an AR coated lens with all the goodies. That is like having champaign taste with beer money.