DRY EYES
Tears normally coat the surface of the eyes to keep them moist and comfortable. When tears are poor in quantity or quality, it causes dry eyes. Dry eyes usually present with gritty sensation, burning, redness and discomfort in the eyes. Ironically watering of eyes is also a symptom of dry eyes. This occurs because the dry surface of the eyes stimulates the nerves to reflexly cause tearing..
Normally when we blink, the eyelids close and replenish the normal tear film by draining away the old tear film. Also on blinking, around 30 to 40 glands located in the eyelids secrete oily secretions to stabilize the tear film. The average blink rate in an infant is around 8 to 12 blinks a minute and as we age the blink rate drops to around 4 to 6 blinks per minute. In between blinks, when the eye remains exposed to the atmosphere, the tear film dries up resulting in symptoms of dry eyes.