Diffractive Optics?

[AdmiralKnight]

Had an interesting seminar at the office yesterday. Our Eschenbach low vision rep came around and did an hour long talk about the various low vision aids they offered... one of them really caught my eye. They were high-plus readers (anywhere from +8 to +24)... but they were THIN. The +24 looked like it was the thickness of a standard +2.50. The rep didn't have any real technical information about them, but knew they used Diffractive optics. The lenses themselves looked like a fresnel lens laminated between two lenses... does any one have any info on this technology, or how the lenses themselves worked? They were quite interesting.

[Barry Santini]

Refractive vs. diffractive = both bend light in preditable ways. Diffractive cuts thickness and cost, but comes with a phase degradation issue, which results in loss of contrast.

This trade off, for high-plus LVA, is appropriate, IMHO.

Barry

[Ory]

The Noves lenses are simply a fresnel lens. As Barry pointed out, you get some degradation so I've found you need a bit stronger magnification than you might predict.

Your rep is Ryan? He's a good guy, up to date on their gear. I really like Eschenbach for low vision stuff.

[renee1111]

Your rep is Ryan? He's a good guy, up to date on their gear. I really like Eschenbach for low vision stuff.

Your right, Ryan is great rep! And Eschenbach's Microlux Telescope is one of my favorites.

[AdmiralKnight]

Yup it was Ryan. His presentation was great, I was just looking for some more info than he had heh