The refresh rate on a LCD is different from a CRT. In a CRT even if nothing changes on the screen the monitor always redraws what's on the screen. Therefore you always want to set the refresh rate as high as possible otherwise you might notice the screen blinking.
The pixels on a LCD monitor are always on (* more on this later...). Therefore, the pixels are always on unless something changes. The refresh rate refers to the rate at which the video card sends the video signal to the monitor. So basically 60Hz means the video sends a signal to the monitor 60 times per second (60 frames).
* Monitors using TN or e-IPS panels have pixels that actually flashes between two color all the time to create a 3rd color. These panels are known as 6-bit panels or rarely referred to as 18-bit because each primary color (Red, Green, Blue) only uses 6-bits of data to represent each color; 3 colors x 6-bits = 18-bits. This basically means TN and e-IPS panels can only create 64 shades of each color (2^6 = 64). As a result these panel types can only create 256k colors (64^3 = 256k). However, these panels are advertised as being capable of producing 16.7m colors.
How do these monitors create 16.7m colors out of only 256k? Temporal dithering... also known as A-FRC (Advanced Frame Rate Control). It basically flashes extremely betwen two colors to create a 3rd color. So fast that your brain registers solid colors. For example, say purple is a color that is not part of the real 256k colors a TN / e-IPS panel can produce. Using A-FRC the pixels flashes between Red and Blue to simulate purple.
S-PVA, S-IPS, H-IPS, P-IPS are 8-bit color panels and they can truly create 16.7m colors without have to resort to temporal dithering. 8-bit colors means there are 256 shades (2^8 = 256) of each color. As a result in this increased number of shades 8-bit panels can truly produce 16.7m colors (256^3 = 16.7m).