Tears are useful. They telegraph all kinds of feelings. They help you see clearly. They wash debris from your eyes.

Here you’ll discover everything you need to know about tears, Cleveland Clinic reports. Why they taste salty. Why women cry more than men. Why you get dry eye. And more.

These are 3 kinds of tears:

1. Basal, your basic tears. The eyes roll around in them all day. Contain oil, mucuse, water and salt and help to fight infections. The oil keeps your tears in place and prevents them from evaporating into the atmosphere.

2. Irritant. Eyewash tears. Come gushing out of glands under the eyebrows, when you peel onions, vomit or get dust in your eye. 

3. Psychic tears. Gush in response to strong emotions, like sadness, grieve, joy or anger. Contain more hormones and natural painkillers than other tears.

Why salt?

We evolved from creatures that lived in salt water. Our blood, sweat, and tears are all salty in the proportion. It's an evolutionary hold-over.

Why cry?

Emotional reasons, makes you feel better. Releases tension. Gives a psychic reboot.

Physical reasons – May wash out stress-related toxins, communicates distress, sincerety, attraction, aversion- depnding on context.

Do women cry more often than men?

About 60% more. Nobody knows why. But a chemical and psychic tears is associated with production of breast milk. Men also have smaller tear ducts.

Too many  teardrops – The tiny openings in the corner of your eyelids are drains. When you cold, they can swell and get blocked. Then tears often flow onto your face. If you have this problem, talk to your doctor. There are treatments.

Dry eyes – Your eyes can temporarily dry out because of atmospheric conditions. But they can also dry out from disease. Some medications and cancer treatments can cause dry eye. Drug store carry different types of artificial tears to treat dry eye. But if this sort of things goes on, see your doctor.

Uncontrollable tears – There's a neurological condition called pathological laughing and crying. It's caused by Alzheimer's, stroke and other brain diseases.

True or false? – If the first tear comes from the right eye, it's happiness, if it comes from left eye – sadness.