OT: Kudos Zenni Optical

[randyjaco]

I just got my new glasses back from Zenni Optical. The lens are perfect and they fit beautifully. Why is it that my American made glasses that I pay 3-4X more for require 15-30 minutes for some air-head to get to fit right; and some guy in China can get it right the first time, thousands of miles away. Once again, it is no wonder why manufacturing goes overseas. America just doesn't try hard enough. So sad. It is hard to buy American, if you have to settle for second rate.

Randy

[Evan]

Where do you think the "American" frames and lenses come from? Nobody customs grinds lenses any more. They come in pre ground prescription strengths and the most they do is to trim the edge to fit the frame. Even that is automatic. They use a CNC lens trimmer that is programmed by entering the frame number and the lens number. A well trained monkey can do it. Even eye testing is fully automated now.

[hardtail]

When my local optometrist quoted me $400 just for lenses to fit my experienced frames I said enough..........and actually used Zenni, got the full deal for around $80 shipped to my home.........I don't mind supporting local business IF they are somewhat reasonable and liberal vaseline is provided........

[aostling]

I just got my new glasses back from Zenni Optical. The lens are perfect and they fit beautifully.

I've bookmarked the website: http://www.zennioptical.com/home.php.

I know my PD, but I see no information on how to determine the correct frame width and temple length, presumably from measuring a pair of glasses which fits. Is there some fitting information which I am missing here?

[Evan]

They have a FAQ that spells out how to measure the frame size you need. You also need to know your interpupillary distance. I am certain you can figure out a way to measure that.

My wife has purchased several pairs of glasses with complex astigmatism and bifocal blended lenses and is very happy with all but one pair. The frame on those doesn't fit quite right but they are still very usable. She has three pairs of glasses for less than the cost of one pair bought locally. I am going in for an eye exam next week maybe and will be ordering a couple of pairs myself.

Eyeglasses is one of those things like hearing aids where the markups are obscene. I don't mind paying somebody well for valuable services rendered but I don't think I should be single handedly putting their children through college.

[Evan]

When my local optometrist quoted me $400 just for lenses to fit my experienced frames I said enough......

A friend of mind is the optician at a local eyeglasses store that shall remain unnamed. I buy prescription lenses from him for various projects. The good ones with antireflection coating he sells me for $30. The cheap ones for plain reading glasses he gives me for free.

[metalmagpie]

Nothing against ZI, but there are options. I looked into it extensively a few years back and decided to go with optical4less.com (Hong Kong). Their glasses are excellent quality, and, like others that posted here, fit perfectly out of the box. (You give them measurements from glasses that fit, and they make them to your measurements.) They might cost a tad more than ZI but I like them just fine. I typically buy two pairs at a time to get free shipping. They show up in 2 weeks, about $50. I have had luck so far using their confirmation email as the "receipt" to give to my health insurance.

At my eye exam, I ask the doc to write me a prescription for lenses with the correct strength reading glass magnification, but with a focal length of 18". These work out perfect for shop glasses. I buy my glasses with the same lenses they use in safety glasses, use them for grinding, power wire brushing, welding, layout, machining, sawing, you name it.

As a side note, a few years ago at a garage sale a guy had a whole pile of reading glasses, 25 cents per. One of them was quite dark tinted. I bought them, not knowing what I'd ever use them for. I use those every single time I make a torch cut now, either oxyfuel or plasma! Best burning goggles I ever got!

metalmagpie

[RTPBurnsville]

Great information...... I was just about to go shopping for new glasses this weekend and this will save me a bundle. The information on that site alone was priceless. After asking for years for an explanation I finally get it. Thank You!

Robert

[rockrat]

They come in pre ground prescription strengths and the most they do is to trim the edge to fit the frame.

I'm no optician and I would probably make a spectacle of myself trying to act as one on tv but...... I have an astigmatism that is sorta specific and there is some fiddling that has to be done to my lenses when I first pick up my glasses from the store. Is that correction already ground into the lenses in China and shipped to the US to sit on a shelf until I need them? It would seem that other than a general overall change to ones vision, each lens would have to be specifically ground, especially with an astigmatism.

rock~

[whitis]

I'm no optician and I would probably make a spectacle of myself trying to act as one on tv but...... I have an astigmatism that is sorta specific and there is some fiddling that has to be done to my lenses when I first pick up my glasses from the store. Is that correction already ground into the lenses in China and shipped to the US to sit on a shelf until I need them? It would seem that other than a general overall change to ones vision, each lens would have to be specifically ground, especially with an astigmatism.

rock~

They can't really fiddle with the lenses because they have already been ground, edged, etc. Pretty much cast in stone at that point. They fiddle with ear pieces, nose pads, etc.


Tradionally, one hour lens places stocked many combinatations of strengths of lens and magnitudes of astigmatism. They get your prescription and they pick out a lens which matches those two parameters. Assuming a mechanical (rather than CNC) machine they rotate that piece of glass to match your astigmatism angle or dial in a setting that accomplishes the same result. They dial in an offset to match your interpupilary distance and insert a cam that matches your frames. The machine edges your glasses by following the cam to make copy (the lens) that matches the original (the cam). Instead of having to stock lenses matching all combinations of four numerical parameters, it has been reduced to two (plus plastic/glass, AR/no AR). Bifocals or progressive lenses are more complicated.

A 1971 patent on a cam follower machine:
http://www.freepatentsonline.com/3738064.pdf

Cams limit you to fitting frames which you have the cams in stock which is likely to be just the frames you sell, not customer frames purchased someplace else. CNC edging is more flexible. Also, you can handle more bizzare frame designs.

CNC version:
http://www.youtube.com/watch?v=TmYaF4oJEfs

A simpler machine:
http://www.youtube.com/watch?v=Kw25zxfOmR0

Another which also drills for rimless glasses:
http://www.youtube.com/watch?v=u94fTrgR2sY

Some extra steps, including tracing a customer's existing frame:
http://www.youtube.com/watch?v=kfk0njhC8Yg

For mass production, there are robots to load lenses into the edger:
http://www.youtube.com/watch?v=LLj-AV5s1-A

Even with the inventory method, somebody still has to grind lenses in proportion to incoming reorders. With machines that can set up automatically for each lens, you could just in time manufacture the lenses.

These days they can CNC "grind" a complex lens pretty quickly:
http://www.youtube.com/watch?v=Wyjrx9Qdswk