Our eyes are very delicate organs that need protection. Tears kill the invading germs. Eyelids, eyelashes and eyebrows help to keep other harmful objects away. On an average, we blink our eyes once in every six seconds. This means that in the course of a lifetime our eyes blink about 250 million times. The blinking of the eyes is an automatic action and we are not even aware of it. In the process of blinking, eyelids move up and down. This activates the tear glands under the upper eyelids. As we close our eyes, these glands produce a salty fluid. This fluid lubricates the eyes and prevents them from getting dry. When this fluid is secreted in large quantities it takes the shape of tears. When some irritating substance, such as particles of dirt, enters the eye, the lids automatically blink. This action produces larger amounts of tears, which wash out the eye and protect it against the irritant and any other infection. These tears drain into our nose through tear ducts or the tiny tubes at the inner corner of each eyelid. When the tears are too many to drain through tear ducts, the ducts become flooded and tears run down our cheeks. Blinking also protects the eyes against the bright light. In the bright light, eyelids close automatically and prevent the entry of light into the eyes and thus, the adverse effects of bright light are minimised.