Eyeglass Lens Fabrication

Comment #20 at http://bbs.homeshopmachinist.net/archive/index.php/t-53701.html is from someone who has a coating "infused" into the lens to make it more durable.

Worn glasses since 5th grade. One thing I learned is that scratch resistance is the plastic. It's not a coating. And the UV coating is not scratch resistant. I find it scratches relatively easy. Over time it seems like most of the scratches were in the coating not the plastic.

The damage you show is from perspiration. Which degrades the coating. Most UV coatings are dies made from a blend metals. Metals that can react with perspiration or other chemicals that come in contact with them.

So many years ago I tried the photochromic lens. These are naturally UV protective. So no coating to scratch or to degrade.

I wasn't sure if photochromic lenses were the same as what I know as photogray. I got my head spinning a little when I tried to read the chemistry at http://en.wikipedia.org/wiki/Photochromic. I was happy they included "Trivially, this can be described as a reversible change of colour upon exposure to light."

I didn't know that photochromic lenses were UV protective. I want to keep some sort of UV protection. My doctor has been counting dead retina cells for years. I think I am up to 9 or 10 now. As near as I can tell at my present rate I will be blind at about age 23,418 years. I'm not very worried since I am only hoping to make it to about 90. Still, I do want to take all reasonable precautions.

Many years ago I had photograys that were very slow. I would come inside and be blind for about 10 minutes until they lightened up. I'll ask my doctor but I think they are faster now.

Perspiration can be a bit of a problem in Florida. Our summer is 10 months long with 1 month of spring and 1 month of fall. Normally winter is about 3 days long but I haven't turned on my furnace in about 3 years. I'm not sure how I can keep perspiration off my glasses.

Thank you for your reply,
Bruce

I think the coatings are mostly a high profit add-on for the optometrists. After having the previous 2 coated pairs replaced under the one-year warranty for scratching and peeling off, I ordered the pair I have now with no coatings. After a year, I can't tell they have scratched any worse than the scratch-resistant coated ones. And they surely don't have any worse reflections than coated ones when the coating starts to fail. I'm sure the best way to clean any glasses is with soap and water and dry with a cotton cloth/towel, and I try to do it when I can. But at times I use a dry cloth, and have the scratches to show for it.

I guess my glasses have an alcohol problem.

Thank you,
Bruce

Switch from alcohol to these.

These work better than your alcohol (read the reviews)

I have been using them for a few years when a friend told me about them. You do not need liquid, just the wipe. They take off all oils, smudges, etc.

I use micro-fiber too, but a whole lot cheaper than that. I bought a package of half-a-dozen full duster sized for not too much more than those people want for two. I bought them for cleaning windows and such.

Thanks for the suggestion.

I assume that they work on plastic without scratches as well as glass.

Yes, I only have plastic (non-prescription plastic sunglasses).

Your problem seems to be similar to mine. My glasses were from a national chain. The coating was "anti glare, anti fog".I used only their cleaner with clean t shirt material to wipe. The coating was going in less than 60 days. They told me it was from using alcohol cleaner and thus voided the warranty. Never again. The coating is applied to the surface of the lens and is impossible to remove completely.I get safety glasses and am married to plastic lenses, I'd get glass lenses in a minute if I could.

The last set of glass lenses I found was 12 years ago, and $300 for the lenses, single vision. Nowadays, I order from eyebuydirect.com. Replace them when they get scratched.

Try Zenni Optical.

Cheapest place on the planet.

For many years I have insisted on glass lenses for my progressive glasses, thinking that they would scratch less than plastic. A year or so ago I got to the point where standard reading glasses didn't have enough magnification (and don't correct for my astigmatism), and ordered a prescription set of computer glasses, which I reluctantly accepted to be done in plastic. My glass progressives and my plastic computer glasses were both delivered to me on the same day. Now, a year or so later, my glass lenses need replacing due to scratches, while the computer glasses are still fine! Both pairs are uncoated, so I have no experience with coatings.

A great deal of my work is done at the computer, and also at mills, lathes, etc., where I use the computer glasses, so I wear them nearly as much as my progressives. I use a single case to keep whichever ones I'm not currently wearing, so that can't have anything to do with it. I'm a very oily-skinned person, so I do have to clean my glasses frequently, usually with a corner of my handkerchief. The visible scratches are all on the outer surface of the glass lenses, while the oil is usually on the inner surface, so I don't believe the scratches have anything to do with cleaning.

I rarely am aware of the circumstances that cause the scratches, although I have dropped them (or had them knocked off) more than once. I presume that at least a few were caused by flying metal chips (aluminum oxide is harder than glass), but I believe all were caused by something other than cleaning.

My next progressives will definitely be plastic...

I have not been able to train myself to accept progressive lenses. As far as I know, the coatings are either metallic, oxides or fluorides. Most are not particularly hard. And the metallic ones are particularly sensitive to the acids in the sweat.

On the other hand, oils are no problem (after cleaning), nor cutting oils. Neither intentionally contains etching acids.

Gross scratches are no problem for me. A drop of cleaner blurs the edges. The rest is still works right.

As far as the astigmatism concerns, I had it for my adult life. A pain in the royal behind. Finally I figured out, that when I controlled blood pressure and sugar, mainly by eating sensibly and frequently, most went away. Now I do not need any correction for that.

I had glasses in late high school or early college, but did not wear them regularly. At somewhere around age 40, I had to get glasses, and I immediately went to progressive lenses. At first, rectangular objects appeared curved, but I soon got over that. I've been using them for well over thirty years now, and never had any coatings that I'm aware of...

I had not heard of a connection between BPr, BSu, and astigmatism. That is really interesting, and I will definitely investigate further! Thanks for the info!

Just in case anyone wants to read it, I had started a thread some time ago "Plastic or glass?", wanting to hear what other's had to say about the subject. I still insist on glass for my single-vision lenses, despite the increasing difficulty in doing so. My present pair of glasses are around 5-6 years old, with out a scratch. I clean them with whatever is handy at the moment. Not sure how much longer I'll be able to get them in glass, but I'll keep trying until it seems to be an impossibility. I also always get "Photo Grey" lens treatment, which is about 1/5th the cost of "Transistions" treatment.

Oh, guess I should like the other thread

LINK

Tom D.

Thanks Tom. I missed that earlier thread.

I too clean my glasses with whatever's handy, although I do limit that to the cleanest cloth around at the moment. I don't use paper anything.

You're either a lot more careful or a lot less active than I! I have several pairs of previous glasses, one of which I keep in my computer bag, and occasionally use when I forget and leave my regular ones somewhere. All of these were glass and were replaced because they got too scratched up. The only times I've ever been aware of when a scratch occurred was when they got knocked off, usually while gardening.

Th corrective lens was discussed fine here. What was still missing are the two orbs in your face: your eyes. Their decline IS NOT inevitable, you can do things to maintain them. like you maintain your beloved machines.

The knowledge comes from biochemistry. Your participation in it is simple, if not part of SAD (standard American diet). Green leafy vegetables and colorful berries mostly daily supplies, what the eyes need to stay healthy.

I have an inherited problem, where I was forced to take this seriously. With this help, so far so good, and I am your age DK.

I went in to get new glasses this week and I asked about cleaning the new glasses with a product I make. 1/4 alcohol and 3/4 distilled water with a little hand soap. Then I use Viva towels. She said not to use them that the towels would scratch the lens. I asked if there was some study that proves them to be bad. She said no it is just what I tell everyone. I told her to look at my old glasses and show me all the scratches. She couldn't find any and this is regular plastic from 2008. I'm getting Trivex in the new glasses which is much harder and until someone can show proof that Viva ruins lenses I will keep using them.

Thanks for the input. I believe it is common knowledge that clay is used as a filler to give many kinds of paper a smoother surface, so probably many people assume it is used in all papers. Clay will almost undoubtedly scratch glass.

Since the primary purpose of paper towels is to absorb liquids and be cheap enough to throw away after one use, they may well not have anything beyond wood pulp. (I'm guessing - I have no specific knowledge, and have done no research...)

I do know Viva is a quality brand; do you believe it is superior to other brands, when it comes to cleaning glasses?

I can't say. I haven't used any other brand because the felt so scratchy to the touch. I called Viva and they said they could not recommend them because they haven't been specifically tested on eyeglasses but hundreds of people call to say they have used them. I called WD40 up and asked them if I could use their product on my intake when I replace the plugs and you get the same story. Talk to the manufacture of your car. They just don't want to be sued for giving truthful advice. I used it and it worked perfect for centering the gasket allowing it to slide. Everyone is afraid to give advice that is why these forums are so nice.

You don't have to buy glasses at the same place you get you eye exam performed. Ask for a copy of your prescription and get your glasses made anywhere you want including other states via the internet. You can also ask for glass lenses which are more scratch-resistant than polycarbonate or acrylic (plastic) lenses, but glass weighs more, costs more, and are less shatter-resistant. Most glass provides UV protection and is not affected by alcohol.

Some 20 years ago I needed anti-fog lens cleaner for my (then) glass lenses. Ever since I found no reason to use other. A drop on each lens, gently rubbed with the fingertip (yes, the finger). Then wiped off, gently again with a tissue. Breath on the lens clears it up optically. I have never had problems with the coating. It may help, that I respect the acidity of the sweat of an unclean hand, and do not touch the glass, except the frame in normal use.

"Should have gone to Specsavers"

I stripped the anti-reflective coating off of mine with glass etchant (ABF). No problems.