The higher the vertical refresh rate is, the less flicker you will notice, therefore less eye strain. The horizontal and vertical scan rates combine to provide the ability to produce high resolution, flicker-free images. Flicker is caused by untimely fading of phosphor due to a slow vertical refresh. And, even if your eyes don't pick up the flashing, your brain may, causing headaches, eye strain and fatigue. The standard refresh rate for a flicker-free display is a vertical scan rate of 75Hz or higher.
Dot pitch relates directly to the image quality of a monitor.
It's the measurement of the diagonal distance between two phosphors of the same color. For example, the diagonal distance from a red phosphor dot to the next red phosphor dot. Aperture grille tubes use stripe pitch or aperture grille pitch to measure the horizontal distance between its phosphor stripes. A general rule is the smaller the dot or stripe pitch, the better the display. Images look finer and crisper when the dot pitch is smaller.