Tear contains enzymes which could protect your eyes and nasal mucosa from bacterial infection. It is a self-defense method of your body. When you feel some emotion impact, the tear gland will receive the order from brain, the tears will be produced. When people feel agitate or other feeling, the capillaries will congestion by blood, the muscles around eyes will contrast, the tear is the by-products of this movement. It is normal and let it be; the tear will take away most of the pressure on your emotion, and keep your emotional health. However, if you always feel anxious and embarrass, it may be the no relation with the eyes but your emotion, you can go to psychologist for check.