Tears

What are tears?

Tears are the clear, salty fluid that the glands above your eyes produce and release. They’re made up of water, oil and mucus. Tears have several important functions. They:

• Keep your eyes lubricated. Tears help keep the surface of your eyes wet and healthy.
• Protect your eyes. Tears wash away dirt and germs and repel bacteria. They also protect your corneas.
• Help with your vision. Tears help focus outside light so you can see clearly.
• Help soothe your emotions. Emotional tears contain neurotransmitters like acetylcholine.
• Help communicate your feelings. Crying can be a normal behavior that can be caused by a variety of reasons, including sadness or happiness.

You may not think about your tears very often, but they’re an important part of your eye health. They’re not just for crying. If you have an issue with your tears, it can lead to several different conditions and disorders that can affect your eyes. If you have dry or watery eyes, don’t wait to see an eye care specialist. They can help determine what’s going on with your eyes and provide the appropriate treatment.

What do tears do?

Your eyes produce three types of tears: basal tears, reflex tears and emotional tears. Each type has a different function.

• Basal tears. Basal tears are responsible for keeping your eyes lubricated. Your eyes constantly release small quantities of them to nourish and protect your corneas. They’re baseline tears that are present all the time and should never leave your eye. Basal tears help keep dirt and debris washed away from your eyes. They also help you see clearly.
• Reflex tears. Physical triggers cause reflex tears to form. They help wash away harmful irritants like dust, smoke or onion fumes. Reflex tears contain antibodies to help fight bacteria.
• Emotional tears. Strong emotions like sadness, joy or grief cause your body to produce emotional tears. Scientists are still studying the exact purpose of emotional tears, but they may help release stress hormones and promote social bonding.

What are tears made of?

Tears have a similar structure to saliva. While they’re made up mostly of water, they also contain electrolytes, lipids, enzymes and more. Each tear your eye produces has three different layers, which together, make up the tear film:

• Outer oily layer. This layer keeps the surface of the tear smooth so you can see through it. It keeps the other layers of tear film from drying up too fast.
• Middle watery layer. This layer is made mostly of water and is the thickest layer. It keeps your eyes moist and supports your eye tissue. It also keeps bacteria out and protects your corneas.
• Inner mucus layer. This layer helps the whole tear film stick to the surface of your eye.

Why are tears salty?

Tears are salty because they contain electrolytes, or salt ions, like sodium, potassium, calcium and magnesium. Each of your tears contains about 0.3 milligrams (mg) worth of salt.

Where do tears come from?

Tears come from your meibomian glands, goblet cells and lacrimal glands. You can find these exocrine glands at the upper outside corner of your eyes. That’s why the medical term for shedding tears is “lacrimation.” When you blink, tears move across your eyes. They then drain into your tear ducts that empty into the back of your nose. There, they’ll either evaporate or be reabsorbed.

What are the common conditions and disorders that affect your tears?

Conditions that can affect your tears usually cause you to produce too few or too many tears. Or tears might drain too quickly or too slowly from your eyes. Conditions that affect tears include:

• Dry eye. If you have dry eye, it might feel like there’s something in your eye that won’t come out. This can be a gritty, scratchy or sandy sensation. You may also feel burning, stinging or a sensitivity to light.
• Blocked tear duct. Symptoms of a blocked tear duct can include watery eyes and gooey or crusty buildup on your eyelids or in your eyelashes. You might frequently rub your eye or face around the blocked duct, causing redness and swelling.
• Epiphora (watery eyes). You may notice tears running down your face or building up in your eyes when you’re not crying or laughing. Epiphora can be a temporary condition, but it can also be a sign of a serious eye infection or a blockage in your tear ducts.
• Dacryocystitis. Symptoms of dacryocystitis can include eye pain, swelling around your eye and redness or skin darkening.

Common tests to check the health of your eyes

An eye care specialist will give you a thorough eye exam. Other tests they may use include:

• Slit lamp exam. Providers use a slit lamp exam to determine the amount of tears your eyes produce. They’ll shine a light into your eyes and use a microscope to examine your eyes.
• Schirmer’s test. The Schirmer’s test also measures your tear production. Your provider will place a small sliver of paper right along the edge of your eyelid and leave it there for a few minutes. Your eye will produce tears in response, and your provider will measure those tears by looking at how much of the paper they cover.
• Tear breakup time (TBUT) test. The TBUT test lets your provider see how quickly your tears evaporate. They’ll put a dye into your eye and use a microscope to see how long your tear film remains stable.

Common treatments for tear conditions

There are many possible treatment options for conditions that affect your tears. These range from eye drops to antibiotics to surgery. Your healthcare provider is the best person to tell you what treatment options are best for you and your condition.

How can I keep my eyes moist and healthy?

You should see an ophthalmologist regularly to keep up to date on your eye health. But there are many other things you can do to help keep your eyes well-lubricated and healthy, including:

• Protect your eyes in windy areas. If you live or spend a lot of time in a windy area, wear a pair of wraparound sunglasses. This can help reduce your risk of wind blowing into your eyes and drying them out.
• Avoid cigarette smoke. Cigarette smoke can irritate dry eyes. Smoking also increases your chances of developing dry eye.
• Rest your eyes often and remember to blink. Working at a computer, reading or watching TV a lot can dry your eyes out because you don’t blink as often as you normally do. Make sure to take frequent breaks to rest your eyes. Blinking helps your eyes regain some of the moisture they’ve lost.
• Use artificial tears. You can get artificial tears without a prescription and use them as often as you need to help keep your eyes nourished and lubricated.
• Take care of your eyelids. Try putting a warm compress on your eyes to help release oil in your eyelids’ glands. This can help improve the quality of your tears.