Actually current HSE guidelines state that the angle of the back of your chair is more important than the height of the screen. A paper published in 2009 suggested that a 135 degree seating angle provides the best comfort while putting less strain on your back however this is not feasible for many people as they find themselves slipping off their chair so 120 degrees to 100 degrees is considered optimal.
I cannot remember the name of the paper but could dig it out if you are interested Tiswas.
Actually current HSE guidelines state that the angle of the back of your chair is more important than the height of the screen. A paper published in 2009 suggested that a 135 degree seating angle provides the best comfort while putting less strain on your back however this is not feasible for many people as they find themselves slipping off their chair so 120 degrees to 100 degrees is considered optimal.
I cannot remember the name of the paper but could dig it out if you are interested Tiswas.