I have read any number of posts regarding the safety of glasses but none that address the question of the two and three portion lenses and how one sees through them. I have trifocals and I know that walking over uneven surfaces or down steps can be a problem. The magnification is changing as you switch from one portion of the lens to another. And I know that in the shop these three different viewing areas cause me to be concerned.
A number of weeks ago after I had turned off my table saw I reached over the blade in what I thought was a safe distance only to find that the tip of my middle finger touching the blade. I was sure that I had plenty of separation between hand and blade but that was not the case. A small Band-Aid was all that was needed in this case.
Then I ran into someone who works at the local hospital in the emergency room. I asked him about emergency room visits after table saw accidents and he says he has seen a few. I mentioned my near catastrophe and he said that he has heard this from other woodworkers and, in fact, he said the last visitor with such an accident mentioned the cause as being the bifocals that he was wearing.
Can bifocals and trifocals be a problem in the shop? Has anyone else encountered this problem? If so, how have you addressed the problem?
Tim
Replies
it is not
the glasses that cause the problem, but the indidual. just common sense
ron
but don't ignore the different magnification shifts
The individual does not control the three separate magnification settings of these trifocals. Well, ultimately yes, but if one looks through these glasses at an angle and does not move their head to correct for which portion of the lens that is being used sometimes things are closer or further away then is reality. This is the point I am trying to make. Have others experienced the same thing in the shop?
f------ spam filter
sent you a PM
ron
eyeglasses and safety
I'm new to tri-focals, and find them a pain. I can see where magnifications differences might create a safety issue, but I preach waiting until the saw blade has come to a stop.
For shop use, a separate pair of bi-focal glasses might be better - one in which the main area is ground for "intermediate" distance, with a bi-focal spot for close-up reading, measuring, etc.
How long have you worn them
Glasses are like any tool. It takes a while for your brain to understand how to use them. It is clear you weren't seeing well when you almost had an accident. I wonder if blaming the glasses is the thing to focus on. I found moving from regular glasses to multi focus eye lens took a period of adjustment. It made me angry to have half the world blurry. I use "Verilux" lens so things are either in focus or not. I don't notice they cause what I'm looking at to move in or out.
I have a set of tri-focals, but I don't remember them causing the effect you are saying. I bought them for driving as vision to the side seemed better. I remember that things were either in focus or not. I'll have to find them, put them on and see if they make things jump for me... but it won't be a fair test as my correction is probably not the same as yours.
Peter
A while ago, I got a pair of progressive lens glasses. I'll admit I didn't give them much of a chance, but I couldn't get used to them. Once while jumping off a boat, I mis-judged the distance and almost ended up in the drink, as if the glasses caused a depth perception issue. After that, I traded them for line bi-focals.
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