1. Blinking, the first habit of normal sight an involuntary action. The blink is the quick, light, easy closingand opening of the eye, and it is done intermittently by every normal eye. The rate of blinking varieswith people and also varies with the use an eye is put to. You blink more, for instance, when you lookat something brilliant than you do when you look at something soft in tone.a. Frequently the dividing point between a normal and abnormal pair of eyes is its impulse to blinkunder a given situation. If the eyes are perfectly normal, they will blink; suppression of the act ofblinking shows a tendency to become abnormal.b. The action of the eyelids in blinking is most essential to normal eyes and sight. The fluid thatkeeps the eyes moist is produced by a small gland called the lacrimal gland under the outerportion of the upper lid. When one blinks, this fluid is washed down and over the eyeball andkeeps the eye moist.