Reading glasses, intermittently. They're something like +0.5 or +1.0 diopter (I have perfect vision; adjust accordingly); enough to push my monitor toward (but

Reading glasses, intermittently. They're something like +0.5 or +1.0 diopter (I have perfect vision; adjust accordingly); enough to push my monitor toward (but not at) the edge of my focal range. I code for a few hours with them off, then for a few hours with them on. I usually switch when I feel strain setting in.