Refresh Rate
The rate at which a computer monitor or television screen is redrawn per second.
Refresh rate is measured in hertz (Hz). Typical refresh rates for monitors are 60, 75, and 85 Hz. The higher the refresh rate, the less image flicker you will notice on the screen.
Refresh rates below 60 Hz will produce noticeable flicker, which is eye straining. To avoid flicker, you should set your monitor to use the maximum refresh rate for a given monitor.