To inform personnel of possible ways to avoid eye strain. Bright lights from other sources that are reflected off your computer screen can force you to strain your eyes.
Sunlight is a common source of glare.
Keep shades, curtains or blinds closed enough to filter out the sun. Sit at a right angle to the window. Never shine a lamp directly onto the screen. Move bright metal or glass objects away from the screen. Play with the VDT's contrast and brightness controls until your eyes feel comfortable staring at what's on the screen.