lol I'm getting a periscope!
Health and safety say
the monitor should
eye level should be 1/3 from top of screen
screen should be at 90 deg to windows
screen should ideally be tilted slightly down and slightly to left or right (only a couple of deg)
artificial lighting should always be used - lighting should not fall directly onto the screen .... or "halo" your silhouette
contrast should be high ... brightness as low as possible
refresh rate as high as practical (not much option if LCD).