Did you know that rubbing your eyes is a natural reaction tied to feeling sleepy? Another reason is to rid our eyes of rheum, or ‘sleepy dust’, that has developed overnight. But what is this sleepy dust and why do we get it every night?

The Sandman

The origins of calling it sand come from the mythological character of Mr Sandman. We know him as a benevolent person who sprinkles sand in our eyes, so that we sleep well at night and have lovely dreams. However, his origins are a great deal more sinister.

Image of Mr Sandman

Mr Sandman comes from the tale of ‘Der Sandmann’, a German folk legend. The tale goes that he is a wicked man who throws sand in the eyes of children who won’t sleep. He then puts their eyes in his bag before feeding them to his children! This legend was deemed necessary to encourage children to sleep, so that they would be well rested to help with chores.

Times change, however, and thankfully the story has taken a much less macabre twist!

What is rheum?

Spoiler alert: sleepy dust doesn’t come from Mr Sandman at all! Whatever you call it, we can all recognise this debris in our eyes. Resembling white-yellow gunk, this bodily product is composed of an array of different materials. This includes bacteria, oils, dust, discarded cells and mucus. If you wear eye makeup such as mascara it’s likely that the sleep in your eyes will absord the colour and appear darker.

Image of woman cleaning sleepy dust from eyes

How is sleepy dust made?

Our eyes close from the outside in, meaning debris on eyes surface is pushed into the inner corner. When we’re awake this debris is blinked away, meaning the surface of our eyes is kept fresh. However, when we’re asleep it all accumulates into the corner of our eyes.

Read more: How To Avoid The Worst Sleeping Habits

If you wear contact lenses you may experience more of this debris, as your eyes will be driven to cleanse the surface of the eyes more often. If your contact lens hasn’t been fit particularly well to your eye, then you will almost certainly produce more mucus. This is because the gap between the lens and your eye will trap more materials such as pollen and dust. This extra accumulation of foreign objects in your eyes needs to be cleaned away. This means you may suffer from extra rheum in your eyes as a result.

Should you worry about sleepy dust?

The presence of rheum in your eyes is normal, but that doesn’t mean you shouldn’t pay attention to it if it changes colour or consistency. Trouble opening your eyelashes in the morning, because your eyes have become matted and crusted together, is a sign of blepharitis. This inflammation of the eyelid is easy enough to treat but can be worrisome.

Image of young girl with sore eye

Green discharge from the eye, however, can be a sign of a sinus infection. Other strange types of sleep in your eye include a stringy discharge, which could be a sign of allergy, and excess rheum partnered with eye redness and/or pain or sensitivity to light. If you experience these types of symptoms, it’s recommended that you go and see a doctor. They can inform you of the best course of action to take.

What term have you always know sleepy dust by? Let us know in the comments section.