1. You probably blink around 15 times a minute.
2. But the number of blinks varies hugely between people.
3. One blink lasts between 0.1 and 0.4 seconds.
4. Blinking can be voluntary, spontaneous or a reflex.
5. Your cornea is one of the only body tissues without blood vessels.
Your cornea is the clear dome-shaped thing that covers the front of your eye, so blood vessels would get in the way of you seeing properly.
(Cartilage also keeps itself blood vessel free.)