• Question: Why do we get crust in our eyes when we wake up?

    Asked by Resh@science to Hayley, Jimi on 18 Mar 2016.
    • Photo: Hayley Moulding

      Hayley Moulding answered on 18 Mar 2016:

      When we are sleeping, our eyes either are quite still or move about a lot. As you are laying (quite) still for a long time, all the bits of dust and grit which have got in your eyes during the day will be pooled into the little ducts of your eyes. Your eyes are cleaning themselves to get all these little bits away from the eyes and because we have our eyes shut during sleep, the eyes are able to clean them better and get rid of the stuff in it!!

    • Photo: Jimi Wills

      Jimi Wills answered on 18 Mar 2016:

      You blink your eyes a lot when you’r awake, which helps wipe them clean, but when you’re asleep dirt can accumulate, and bacteria can grow.

      If you have crusties in your eyes, some of it is dried salt, but some of it is the immune cells that come from the tear ducts to kill the bacteria that grow in your eye at night.

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