Grim reality of what yellow ‘sleep’ in your eyes when you wake up actually is

There's nothing better than a good night's sleep - you wake up feeling rested, refreshed and ready for the day ahead.

However, I'm sure many of us are quick to notice that goop in the corners of our eyes when we first take a peek in the mirror in the morning.

It's a bodily function we seemingly all have - but what on earth is that yellowy 'sleep' crust and why do we get it?

What is that 'sleep' we get in our eyes after waking up? (Maria Korneeva / Getty Images)

Well, one TikToker has come to the rescue to answer the age-old mystery.

"If you have ever woken up in the morning and you have some crust on your eyes," Andrew Huberman explained.

"And you know that crust, that kind of yellowy stuff, sometimes it's yellow, I know this is kind of gross."

He continued: "That's actually dead bacteria that your eyes have successfully defeated during your night's sleep.

"So when you wipe those away, you're taking the casualties of a war that you won during your night's sleep and you're whisking those away."

Yep, the eye produces a small amount of mucus and oils to stay moist and, as you don't blink when you get some shut-eye, the discharge can collect in the corners.

That crust you get after sleeping is actually 'dead bacteria'. (JulPo / Getty Images)

It can take many different forms with the most common being crusty, sticky, thick, thin, white, clear, or slightly yellow.

Now, eye discharge - what a phrase - is totally normal and no cause for concerns but you should be wary that an eye with lots of sticky yellow pus on the eyelashes can be a symptom of conjunctivitis.

The eye condition, also known as red eye, is caused by infection or allergies and while it usually gets better in a couple of weeks without treatment - it's still a right pain to deal with.

It usually affects both eyes and makes them red, burn or feel gritty, produce pus that sticks to lashes, itch and water.

Not ideal.

The NHS advises that there are things you can do to help ease the symptoms of conjunctivitis, which is highly contagious, yourself:

• Wash your eyelids with clean water. Boil the water and let it cool down, then gently wipe your eyelashes with a clean cotton wool pad to clean off crusts (1 piece for each eye).
• Hold a cold flannel on your eyes for a few minutes to cool them down.

The NHS also warns to not contact lenses until your eyes are better.