Why Do We Blink?

Why Do
We Blink?

By Kate Wilkinson-Brindle
Illustrated by Amy Robinson

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What is Blinking?

Blinking is the fast movement of your eyelids opening and closing.
There are three different types of blink:

Spontaneous. This is the sort of blink that happens without you
thinking about it. This type of blink happens about 12 times in
one minute.

Reflex. This type of blink happens when something gets near to
your eyes, and so you blink to protect them.

Voluntary. This is a blink that you think about and mean to do
because your eyes may feel gritty, or you may need to take a
break from looking at something.

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Why Do We Blink?

Blinking prevents your eyes from drying out. Each time you blink,
you cover the surface of your eyes with a thin layer of tears.
Blinking washes away any dust or dirt that shouldn’t be there – like
a shower for the eyes!
Blinking also allows the eyelashes to catch dust and dirt before it
reaches the eye.

What Are Tears?

The tear glands above your eyes make three types of tears (see
diagram on page 1). Tears are made of water, salt, oil and mucus.
They also have chemicals in them that help prevent eye infections.

Basic tears. These tears are made in small amounts, just
enough to cover the eye with each blink.
Reflex tears. These tears are made if something gets in
your eye, like dust or onion vapour.
Happy or sad tears. These tears are made in larger amounts
when we feel strong emotions and cry.

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Babies and Blinking

Babies blink less often than adults. In fact, babies only blink twice
in one minute, and adults blink 12–15 times in one minute. Nobody
really knows why, but it is possibly because babies sleep more than
adults, so their eyes don’t dry out as much. As babies grow older,
they gradually begin to blink more often.

Did you know?
Babies cry a lot when they are very small, but
they don’t make tears until after they’re one
month old.

Animals That Blink

Some types of geckos can’t blink. They keep their eyes clean by
licking them with their long tongue!
Rabbits don’t blink often. This is most likely because they’re
watching for predators.
Hamsters only blink one eye at a time – like they’re winking!
Frogs blink to help swallow their food.

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