I noticed that visual confusion tends to give me headaches (I often get them in stores, for example), and that blocking off my peripheral vision by wearing a hood helps. So I bought glasses with thick stems, to make my field of vision smaller all the time.

I'm nearsighted enough that all I use my peripheral vision for is seeing whether there is movement behind me (which I can still do - the glasses only cover the middle part), so the only cost was restricting my choice of frames to styles with thick stems. Anything that prevents headaches is a productivity boost for me, because I tend to procrastinate and loose focus a lot more when uncomfortable.

I'm not sure whether it actually worked - stress and changes in the weather cause so much noise that it would be hard to measure. If my stress level ever gets more consistent, I might try making something even wider that fits over the stems and experimenting with that.