Eye strain from linux graphics
The issue is a bit complicated and requires some context, so:
I've been using Ubuntu 14.04.0 (with updates) for many years and can't switch to any newer Linux distribution. Actually on attempt to upgrade to anything newer I got problems with eyes and head (actually problem feelings are started in muscle at my right head side and then in eyes - irritation, burn, discomfort and so on, then I got a weakness in my full body).
My hardware configuration is same during attempt of upgrade (Dell U2711 (CCFL) display + AMD HD5450 + DVI-I connection) and I have similar filing regardless of used driver (opensource or proprietary). Problem feelings doesn't depends on used graphic card at least I've tried AMD/ATI HD5450 and HD6670, Nvidia Quadro P400 and integrated Intel graphics and monitor (Dell U2711 and Dell U2007 CCFL) and connection type (DVI, DP, HDMI). The hardness of feelings just depends on distribution: the hardest ones on Ubuntu 19.04 and less ones on Mint 19.1
I think that some relevant changes was added to graphic stack around 2014 year or maybe even before 2014 and default behaviour was switched to them around 2014. There are several report of same problem with intel graphic made in 2014:
Actually I can't use any display with LED backlight and still using one with CCFL. Maybe this changes are related to LED display support.
My attempt to play with different configuration options doesn't give me any result (including dithering disabling in graphic card driver mentioned at https://ledstrain.org/d/413-disable-color-dither-method-collection).
Actually this problems affects a lot of people (most of them are united in ledstain.org). Please also join to discussion on https://ledstrain.org/d/683-linux-graphics-stack