OT: Lose the eyeglass fog

Couple days ago, I finally got fed up with the scratches on *both sides* of my eyeglasses. Objects appeared to be in a light 'haze' all the time. It turns out the the scratches weren't in the glass at all, but were abrasions in the very soft AR (Anti Reflective) coating on the inner and outer surfaces.

I put on my backup pair of glasses and followed advice gleaned from the net. Popped the lenses out of the frame and ground the AR coating off all surfaces using Brasso on a felt polishing wheel mounted on my Moto Tool. I remounted the lenses and cleaned them up.

The haze is completely gone and my vision is very sharp and clear, now. Just like when the glasses were new.

Minus the coating, the reflections in the lens make me look somewhat geekier. That appears to be the only downside, however.

Note that doing this with *plastic* lenses would be riskier. One would want to grind more slowly and keep the lens cool to the touch.

--Winston

Reply to
Winston
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For those of us with high-diopter lenses: Since the AR coating has a different index of refraction than the lens material, the lens is ground to account for an AR coating. Remove it and the prescription is wrong, although it will be clear!

Your friendly neighborhood glasses maker can send the lenses off to be stripped and recoated; takes about a week. The new AR coatings are much more scratch resistant than the older versions.

Yoyu just need to stumble around half-blind for a week, wearing even older glasses, while your kids mock you for horrible taste, etc. if your older pair is as out-of date as mine.

Fred

Reply to
Fred R

That could very well be. Imagine my suprise when I discovered the tolerences for lens compliance to prescription. I had a new lens replaced because my right eye ached. Turns out it was within tolerence... barely. But there was a 25% variance "allowance". I can only report what happened to me YMMV.

Reply to
John Hofstad-Parkhill

Ah, that explains it. I had a pair made a while ago that were unusable. The only area in focus appeared at 2 o'clock about 10 degrees off center. Doc was a little upset when I told him that.

Same prescription, different lab produced glasses that worked perfectly.

Apparently, there is no way to measure an existing pair of glasses for magnification, pupil position and barrel (astig) correction. Otherwise he would have done that during his investigation, right?

--Winston

Reply to
Winston

Of course there's a way to measure those things. Every optician has a machine which does just that. That's how they verify they've ground and mounted the correct perscription in the first place. Go into any Lenscrafters and you'll see the machine sitting just outside the door to the lab. It looks a bit like a stereo microscope.

Gary

Reply to
Gary Coffman

That's much more reasonable. I expect that Doc's 'investigation' was somewhat ah, limited.

Thanks, Gary.

--Winston

Reply to
Winston

The basic dioptermeter is nothing more than a dial gage with two reference points to measure surface curvature. The one I have downstairs came in a box of lenses etc. from a yard sale. The more sophisticated ones AFAIK use a light (laser ?) beam to map the properties of the lens. Gerry :-)} London, Canada

Reply to
Gerald Miller

On Tue, 14 Sep 2004 03:48:41 GMT, Gerald Miller calmly ranted:

The machine he referred to was likely -more- than a dioptermeter. The microscope style machine in my local Costco checks the full prescription: magnification, astigmatism angle, and bifocal position. It verified that the prescription on my first lens set was, indeed, incorrectly filled. Correction for astigmatism in the left lens was

15 degrees off spec. Whew, no more headaches!

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Your Wild & Woody Website Wonk

Reply to
Larry Jaques

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