A recent visit to the ophthalmologist came with a recommendation that to make using safety glasses in the shop more pleasant, get reading safety glasses with a diopter of 1.0. These magnify about 25% making the small makes on a ruler more visible in the poor shop lighting. The above examples show the small difference, but the magnification stops the small lines from "moving", I have astigmatism which gives the perception of the lines on the ruler bending or jumping as I stare at them. First I tried some regular reading glasses from the local discount store. They helped so I investigated getting safety glasses that had magnification. There are several brands available on Ebay, Amazon, and even safety equipment supplier starting at about $5 with most costing less then $15 each.. I found two styles, full lens magnification and bifocal with only the bottom half of the lens that magnify.
I also investigated what is diopter. it is a measurement of the focal length of the lens. 1.00 diopter focuses at 1 meter (about 39 inches) and magnifies 1.25x and 2.00 diopter focuses at 1/2 meter (about 20 inches) and magnifies about 1.5x. The disadvantage is that past the focal length everything gets fuzzy (that is the advantage of bifocals)
I have shared these safety glasses with several friends and they all have liked the magnification when setting up measurements and when grinding or sanding items to the layout lines.
They grab the safety glasses before they start, because they can see what they are doing better than without the glasses. This also helps with crimping cat 5 cables for network cables (it is easier to see the colors), scroll sawing patterns, even sewing items.
These glasses are available in clear, smoked. amber, yellow, and other colors. I am going to get some smoked glasses to wear when I am welding. (in addition to the helmet, the magnification is nice)
I currently have 5 pair in my shop by the major equipment, so that they are at hand and I take them off when I go to walk away because everything gets fuzzy.
These glasses even work when using other magnifier, so you do not have to remove them when you need more magnification.