I’m getting ready to buy my next pair of eyeglasses and retire the reading glasses I now use. Presently, I have glass lenses and am happy with them but I did not buy them to use in the shop. I’d like to know what works best in the shop and any tips for keeping them clean during the day and over the long road.
Thanks,
Richard
Replies
I have plastic lenses in my everyday glasses, but glass lenses in the safety glasses I use in the shop. Plastic lenses attract sawdust more than glass, and they hold on to it when I try to wipe it off. Also, the surface of plastic lenses gets scratched more easily than glass.
I'll second that about the plasic attracting more dust then the glass. Just in case your looking for some stylish frames too, I saw an article in a old, 1983'ish, FWW about making wood frames! LOL
Steve
Here's some general remarks about eyeglasses.
The optical power of spectacle lenses is measured in units called Diopters.
Glass is heavier than plastic. This becomes significant for people who are far-sighted (hyperopes; hyperopia). As we grow older the subcutaneous adipose tissue beneath the skin of the bridge and sides of the upper 2/3 of the length of the nose may atrophy. So the cushioning support for the nasal parts of one's spectacle frame may be very thin to absent. This may result in deep pressure marks by nasal pads of a frame or from the bridge of the frame int he nasal region. So even if you think you'd prefer glass lenses, in such special cases I'd advise plastic lenses.
It's true that plastic isn't as resistant to damage from flying fragments of wood or metal. There are coatings available which reduce the damage from that quarter of our exposure in the shop. Modern plastics are available which are pretty tough, too.
Don't rush to your Optician and buy a new set of spectacle lenses just because your lenses have suffered a few hits from tiny flying objects. As long as the "dings" aren't in your visual axes, don't worry about them. If you have to take your glasses off and hold them up toward a light to look through them to see the impact spots, save your money. If the impact spots are frequently seen with the glass on your face while you work, buy new lenses.
Because it is currently thought that life-time exposure to UV rays may be a contributing factor to the development of cataract, it's a good idea to choose lenses, be they glass or plastic, which offer UV protection. You'll likely wear your shop glasses outdoors too, at least occasionally.
The format of your glasses is important to your comfort and efficiency. That is, do you need single vision glasses, bifocal glasses or trifocal glasses? If you are one whose basic refractive error is small, you may be able to get by with single vision lenses only. And those single vision spectacles would be used for near work only. "Half glasses" are nice for desk tasks like reading or drawing but let you down when you move to your tools and want protection from flying fragments coming off the cutters of your machines and hand tools. So you might elect to wear bifocals in the shop even tho' your distance vision is perfectly adequate without any optical correction when looking in the distance.
One's age is effectively important in 98% of cases. As we hit the 42-46 year age mark, our need for help with our weakening accomodation (near focusing power) gradually becomes obvious to us. If you find, as you get into that age bracket that you are gradually holding reading matter further away from you to read it clearly, you are said to be becoming "presbyopic." The need to start wearing reading glasses or bifocals occurs, generally, a bit earlier in far-sighted folks and a bit later in near-sighted folks.
Somewhere along about age 50-57, when the power of the bifocal addition to one's spectacles has slowly been increasing, you may want to consider switching to trifocal lenses. This is because when the power of one's reading glasses or one's bifocal segment (lowest segment) in one's glasses gets up around 2.0 to 2.50 Diopters, the depth of field/depth of focus through the reading glasses or bifocal segment becomes narrowed. Such a person who chooses to stick to bifocals will find that there's a special region---just beyong the near/reading range, where objects of regard become a bit blurred---the subject finds that he has to lean closer, or move the object closer to himself, in order to get it into clear enough focus. Another example might be when working at the tablesaw; the subject finds that he can't see the blade entering the work clearly enough through the top part of his bifocals, or with his naked eye, if he isn't wearing any optical correction. If he wears only reading glasses, he might find he has to move his head an inch or three closer to the cutting area. A segment incorporated into his spectacle lenses is focused for just such a distance. In other words, trifocals may be the best choice at this time in life. They provide clear vision in the "intermediate range."
Near sighted folks (Myopes) have a different natural optical system. Mother nature has equipped them to see clearly at near but blurrily at distance. As with all optical errors, the degree of myopia human beings exhibit varies greatly. The Myopic individual may be able to read clearly without glasses until quite late in life. But even if the degree of one's myopia makes seeing clearly at the reading and tablesaw ranges, NOT wearing spectacles offers no protection from flying fragments. I would advise ALL woodworkers to wear spectacles (or other types of protective devices such as goggles or face masks) when performing woodworking cutting operations. Spectacles with safety glass lenses or hard plastic lenses are readily available with no optical power in them.
How to clean spectacle lenses: Most Opticians and Optical Shops sell commercial products for the purpose. They're fine to use. I use ordinary bars of hand soap with a little tap water and a Kleenex to clean my own lense. Fairly inexpensive and usually convenient. Doesn't hurt either kind of lenses as long as one avoids scrubbing over the lens surfaces with some sort of abrasive he didn't realize was present.
With regard to other types of spectacle lenses: There are special formats for special occupation tasks. Painters may choose to wear a special type of trifocal lens in which the intermediate segment is placed up in the top of the lens, just beneath the uppermost part of the spectacle frame. So when the painter is having to paint trim up above his head, he finds the trim is sometimes too far away to see clearly with his bifocal segments and besides, to use the bifocal segment he would have to tilt his chin up at quite an uncomfortable angle. The intermediate power segment placed above the distance part of his lenses enables him to see such jobs clearly and comfortably.
This is all written off the cuff so I may have forgotten to address some item of interest.
William
William as you seem to know a lot about eye glasses. Do you know of any coating etc that can be added to the lens to reduce the static build up ?.I find that my glasses coat with sawdust in a few minutes with most of the build up in the centre of the lens.While working it is very difficult to keep rinsing the glasses so I find that I go through a lot of pairs.Any help in this direction would be greatly appreciated
Static build up: I'm not knowledgeable about this. So take my remarks with a grain of salt.
Ground yourself from time to time. Buy a commercial lens cleaning preparation from your Optician which purports to reduce static build up. Keep the lenses clean but don't do much rubbing of them when cleaning them. Soapn' water good as anything for cleaning.
How many woodworkers have trouble with "static" electric charge building up on their spectacles attracting and holding fine debris? I'd like to hear comments from many re this. It doesn't happen to me (noticeably, anyway)
"Lineless" bifocals are perfectly acceptable lenses. but expensive. The grinding of such lenses produces a modest amount of distortion when one's visual axis moves out of the zone in which the gradient has been produced. Some folks have a hard time adjusting to them. The manufacturers have similar but still differing products. Most Opticians will sell you a pair and guarantee to replace them with standard lenses at no additional charge should you find them unacceptable. I personally chose to avoid them as mostly a cosmetic "frill" for which I am unwilling to pay the extra money. Ladies buy more of them than men. It's not that they're effeminate, it's just that hiding one's age with lineless bifocals appeals more to the gentler sex.
Sarge: Well, I did eye surgery for 31 years. But changes may have transpired in the Lens field with which I'm unfamiliar.
Did I forget a question?
William
I make something, sometimes twice, each year.
William --
On sawdust and static.... I do think that plastic lenses attract fine dust more than glass, but I don't have a really clear experiment to suggest to you. However, I am quite sure that wiping sawdust off plastic lenses does not work as well as off glass lenses. This effect is truly a "static electricity" effect. Wiping the plastic puts a charge on it which attracts the dust. You can do a simple side-by-side experiment to confirm this one.
William,
You asked about woodworkers having sawdust build up on plastic lenses due to static electricity. I have that problem very frequently. I live in an arid climate but when the humidity rises, the problem tends to be less. You have aswered several questions that were also on my mind, thanks.
Steve
Edited 3/1/2003 6:37:44 PM ET by Steve
William
If you're not an optometrist, you grossly missed a golden opportunity. ha..ha..
Have a great day...
sarge..jt
What is your opinion of the continuous gradient type of lenses which are sometimes prescribed as a form of bifocals? Is there a downside?
To William and all others,
Thanks to you all for the input. Although I am 57 this will be my first replacement for my full size glasses. I do need them for my woodworking, reading etc., but I haven't had any distant correction so far. The doctor said I should consider it but as of yet haven't seen the need.
I think I'll stick with glass lenses for the static build up many of us are having. I may also try the static reduction solution but I guess I have it pretty good so far. So much to be thankful for!
Again, thanks to everyone.
Richard
If your glasses aren't "safety" glasses you should wear them over your regular glasses. Regular glasses, even shatterproof aren't enough. Lee valley carries them I believe.
I have gradient glasses. Basicly you have to point your nose at what you want to look at. Not always possible. bobl Volo Non Voleo Joe's BT Forum cheat sheet
What are your views on progressive lenses? I am far sighted and have been wearing them for years without complaints. I also chose plastice lenses for their light touch on my nose.
Thanks for the informative writeup.
Dick
Re-read Reply # 8 re "lineless" bifocal/trifocal lenses.
"Progressive" is a more sophisticated term, originated by manufacturers, and possibly effective as a marketing tool.
Nothing wrong with wearing them if you're able to adapt to them without much trouble. Note again that Opticians usually replace them with conventional lenses should the buyer not be satsified with them.
WilliamI make something, sometimes twice, each year.
senior,
I usually wear contact lenses and eye protection over them. When doing fine work, I have to use my reading glasses as I'm unable to focus very well up close (under about 18 inches). This is the long arm syndrome.
I discovered this weekend that wearing my gradient bifocals was wonderful for the shop. I was able to see without constantly removing or replacing glasses and then wondering where I'd put them down. This is the short attention span syndrome.
The only drawback to the bifocals that I've found is that there is a lot of distortion to straight lines. I held up the clock I was making and it appeared to be pear shaped. I was startled until I noticed that moving my head caused the shape to change. That's when I realized how much distortion there was. Hope I get used to it eventually.
Good luck,
Kell
My emplyment required safety glasses and I have worn them for the past 40 years. I found that the advantages of bifocals, and then trifocals out weighed any precieved inconvenience. ANSI standard safety glasses can be had in both glass and polycaronate lenses.
ANSI spec frames are constructed so that a sharp blow to the eye will not pop the lense out of the frame into the eye. There are a number of frame styles that meet ANSI. I wear my safety glasses all the time and as a Safety Specialist I encouraged employees to do the same because the employer looses his employees services whether he is injured on the job or at home. Safety glasses saved my eye from a flying cold chisel on a home project.
The last time I got a new prescription (retired and on my own nickel) I wanted phototropic and I found that was not available in ANSI polycarbonate. The plastic lenses I bought no longer meet the ANSI spec but my frames do. I feel confident that I have the protection that I need in my shop.
I choose trifocal lenses because they do not have the distortion the is built into the gradient focal lense. I think that the distortion would have been intolerable on some of the jobs I have had.
BJ
Gardening, cooking and woodworking in Southern Maryland
Edited 3/3/2003 11:36:18 PM ET by Bee Jay
I've tried static reducing eyeglass cleaners. They don't work. I have polycarbonate lenses, which seem to like dust alot. Instead of washing or wiping them clean, I blow them off with an air chuck attached to my compressor. It's important to use the clean air line and not the one attached to the in-line-lubricator,( helpful shop tip # 243). If you don't have a compressor, get one. I understand they're good for other things as well.
Glendo.
tell your optomertrist (did I spell it right?) that you will be wearing them to work in the shop. It may be appropriate to adjust the focal length to compensate for the distance you are from your work, if this is not similar to the distance you may be from a book when reading.
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