The topic is a bit old now, but I feel like I have the same problem.
I was on build 1803 on my office laptop (dell latitude 5580), I never had a problem with it. I decided to try build 1809 as my IT company feels the need to make us apply the latest updates (for obvious reasons) from time to time and I knew I could come back to 1803 within 10 days anyways.
I installed 1809 and it instantly got strainy for me. I reversed it with the W10 recovery tool and since I got back to 1803, I still feel the strain everyday, even after a 2 days break.
I feel like something changed in the display, the brightness, the colours, I don't know what exactly. I keep on having mild eye strain and a light headache, which never happened before with this device.
No changes in drivers apparently.
Do anyone has an idea ?
I'm really confused, it could be either purely psychological or some kind of "invisible" updates that don't get removed with the recovery tool ?