Why Do We Blink?

Blinking takes place approximately ever few seconds and the reason why we have to blink is because we need to keep our eyes clean and moist. Every time we blink, we wash our eyes. Above each eye is a small tear-glad. This tear-gland slowly produces tears all the time that we are awake. When we cry, we make more tears than the eye need for keeping them clean, so most of them spill over the edges of the lower eyelids and run down our cheeks. This is a natural reaction to the emotion known as feeling sad, although we can also cry when we are feeling overwhelmed with happiness and this promotes the same reaction.
If you've ever had a no-blinking contest you will soon realise that blinking is a natural reaction and you are unable to prevent yourself from blinking for very long. This is because it is built within us the necessity of keeping our eyes clean and therefore no matter how hard we try, we just have to blink.

To keep the surface of the eye moist