Why don't they?

[dsrtao]

Heinlein observed that the answer to any question starting "Why don't they -- " is "Money".

The iPhone and the Droid and many other touchscreen phones have an oleophobic coating that means that skin oils will wipe right off.

Why don't they sell this for eyeglasses?

Given the outrageous cost of non-Internet-ordered glasses, money seems unlikely to be the answer. I can get lenses with custom grinds, custom tints, anti-reflective coatings, anti-UV coatings, anti-scratch coatings... why not anti-fingerprint?

Comments

[dlevey.livejournal.com]

I wonder if the coating has refractive properties which would need to be taken into account when choosing the lenses and grinding...

[the-nita.livejournal.com]

That at least sounds plausible - especially given that "anti scratch" is like "water resistant" - given any reasonable period of time, no, no it isn't.

[seawasp]

At least until they make them with CVD diamond coatings.

[dsrtao]

Diamond has a refractive index of 2.417. The "high index" glass lenses I see go to 1.9. I'm guessing even a very thin layer of diamond would have to be accounted for in the grinding stage, as opposed to a post-production process.

On the other hand, diamond lenses would be very thin indeed, but weigh about as much as glass lenses for the same prescription. Diamond density is 3.5, crown glass 2.5, and polycarbonate 1.2.

[seawasp]

Diamond would have to be a flat coating. It is difficult to use for lenses because of its extreme variation of index of refraction across the spectrum (the same phenomenon that makes it sparkle so beautifully).

[be-well-lowell.livejournal.com]

Why don't they sell this for eyeglasses?

They do. Usually as part of an anti-reflective coating package. I've definitely been offered such a package when buying my glasses from an independent optometrist. I've seen expensive sunglasses in a bicycle store that were not only oleophobic but hydrophobic (yes, that is the right word) as well. The store staff didn't really recommend them, though, saying that it won't stay oil-repellent that long.

[dsrtao]

Ah-hah! Two good answers in one post.

Now I get to worry about how long my phone's coating will hang around.

[cvirtue.livejournal.com]

I wash my glasses (soap and water, cotton cloth to dry) about every other day. I hazard a guess that people don't wash their PDAs/etc. that often.

[cellio]

Thanks for the tip. I've never been offered this, but now I know to ask about it.