I also had trouble finding that sweet spot for small flies when I wore progressive lenses and had a major astigmatism. The visors/optivision might be too close to your eyes. If a table top magnifier gets in the way, try a smaller magnifier that fits on your vise. Although the latter type of magnifier can still get in the way, it is easier to work around and I got used to it. I found that being able to adjust the distance between the magnifier and the fly helped quite a bit. (The only reason I dont' have the progressive lenses or astigmatism anymore is b/c of lasik surgery, not b/c I found some other option with glasses.)