f-lux is available for your computer. Screen time does not damage the brain. It just is processing intense. It can fatigue it. Flat screens are much easier on the brain than the old tube type screens due to flicker/refresh rates. Somebody did some research and found that BenQ makes a display with lots of adjustable parameters that may be helpful.

I can spend hours with a computer display as long as there is not a lot of movement/animation to challenge my brain. Early in my recovery, I would need to step away from my tube based display every 20 to 30 minutes or so. When I replaced it with an LED display, my tolerance went way up.

A challenge I have when doing computer work is the layering of various windows. If I need to transfer info from one window to another, I tend to get fatigued. I solved this problem by getting a second screen. Most computers will work with two screens without any extra equipment/adapters other than a video cable adapter.

PM me if you need help with your specific system.