I have one of the little Fowler 20X pocket microscopes. They also make a 40X version. It's great for inspecting cutting tool edges, particularly when the tool is mounted in a turret and can not be removed for inspection with out recalibrating the tool position. Also good for checking the tip radius and things like that with the built in reticle scale. Being near sighted, I can not read the scale with my glasses off as the eyepiece is set for standard distance vision for focus on the reticle. The graduated scale looks like a fuzzy millipede. Focus on the part is no problem as that is set by positioning the microscope. With my glasses on it is not a problem, but the eyepiece is spaced too far away from to have a full field of view. If your glasses have a correction of -2.5 diopter or more you may have the same problem. Now if you a cheap old coot like me, you probably have a few pair of older glasses around that you have replaced, but are holding onto just in case. I keep my most recent pair in the car in case something happens while I am out, and the next most recent pair in the house in a convenient location so I can use them to find my regular pair when I lay them down somewhere. Now days most of the lens are currently made of polycarbonate or some other plastic. This means that it is machinable. I took the right lens from an old pair (I use my right eye for a microscope), and after making a simple cutter, cut a disk out of the distance vision section. The lens was gripped in 4 jaw chuck and the lathe run about 700 rpm. This disk was glued into an machined adapter that is a slip friction fit on the eyepiece of the microscope. The adapter has a small lip for the disk to rest on, and the edges are rounded for comfort. The cutter is just a short length of 12L14 steel that is bored out to the diameter of the disk. The outside is turned down so there is about 0.025 wall and teeth filed in with a small triangle shaped file. No precision required. 10 minutes work max. The adapter is made of aluminum and has a wall thickness of 0.015 and a small slit was put in one side so it could be deformed a little bit to make it grip the eyepiece with a light friction fit. The adapter has taken up permanent residence on my microscope, but can be slipped off if someone with normal vision is visiting the shop and needs to use it. I am planning to do the same thing to the tool makers microscope that I am rebuilding so the cross hairs will be clearer. Full field of view and no more fuzzy millipedes. I can easily make a measurement with it now.