The solution for me to eliminate headaches when working at computer screens was getting an extra set of intermediate distance glasses specifically for computer work. The "computer screen distance" of 3 ft is in between book-reading distance of 1 feet and driving distance 20'+ feet. I also avoid progressive lenses or high-index lenses for computer work. I commented about how arrived at this solution previously: https:…
> I also avoid […] high-index lenses for computer work. Yes! You're the first to mention this. It's not refractive index itself that's the problem, it's dispersion (roughly, the degree to which refractive index varies across the visual spectrum, described by ‘Abbe number’). We've all seen pictures of a prism splitting a beam of white light into a rainbow — for visual purposes, the less split the better. Higher-index…
That’s why our cone response to the spectrum looks like https://en.m.wikipedia.org/wiki/Cone_cell#/media/File%3ACone... instead of having cleanly segregated red vs. green responses. If it was segregated, we could only focus on red or green but not both. By having a heavy overlap, we can get a sharp focus on yellow. And, the visual system makes the full spectrum work by deriving the red vs. green concepts from the difference between the two cone responses. Blue focus is accepted as a necessary sacrifice.
