I get eye strain from PWM flickering and graphics driver. There may be other causes that I am not aware yet, but as far as I know, these are the causes that I have identified and confirmed.
These are the list of devices that I can use without any eye strain whatsover:
Lenovo Thinkpad T420s
Screen brightness 100% and Intel Graphics Card set to Maximum Performance (to eliminate PWM)
Intel graphics driver dated 2011. If I upgrade to any newer driver (e.g. dated 2013, 2015 etc), I get eye strain. Only the 2011 driver I get no eye strain whatsoever.
Windows 7 Pro.
CPU: Intel Core i5-4460
GPU: PALIT gtx 760 jetstream 2G GDDR5
BenQ flicker free monitor (using VGA connector)
HTC One - SuperLCD3 display panel
HTC One Max - SuperLCD3 display panel
HTC M9+ Supreme Camera Edition - Super LCD3, Android 5.0
Sony KDL-50W704A 50 inch LED Smart TV
Samsung PS51F5500 51 inch Plasma Smart TV
Here are some devices that I have tested and found to cause me eye strain:
Smartphones - Note 5, Note 4, S3, S7 Edge, HTC U Ultra, LG V10, Huawei Mate 7, Lenovo phones etc
Laptops - Lenovo T430, T440, T450, X1 Yoga
TV - many Samsung and LG LED TVs (from looking at them in the store)