• Question: I tried the 'who can open there eyes the longest challenge' today at school, my eyes started to ache. Why is this?

    Asked by The Ge Ni U S to Andrew, Jessica on 26 Jun 2015.
    • Photo: Jessica Wade

      Jessica Wade answered on 26 Jun 2015:


      We’ve spoken lots about tears forming now- they happen to keep our eyes from drying out. Little tear glands near our eyes produce fluid that keeps our eyes wet. When we’re on our laptops or reading we don’t blink so often, because we’re focussing so much on netflix or I’m a Scientist that we don’t put any energy into our eyes. That means our eyes get dry. When we don’t blink, our eyes get something called ‘eye fatigue’ or ‘eye strain’. The Greek name is aesthenopia.

      What’s going on in your eye is that a little muscle known as the ciliary muscle gets a bit tighter. The ciliary muscle is in the middle of the eye and controls the shape of the lens in the eye. It’s really small, but so are all the muscles around our eye. That means our eye becomes irritated and uncomfortable. If you try to focus your sight on something far away, it should help a bit (try that later?!).

      Other great blinking facts- a blink only lasts 0.1 s! If we close our eyes for 1 second, scientists call this a ‘micro sleep’. Babies don’t blink so much, because they don’t need to keep their little eyes as wet. They only blink one or two times a minute.

    • Photo: Andrew Fensham-Smith

      Andrew Fensham-Smith answered on 26 Jun 2015:


      You’re eyes are covered in a very thin layer of molecules called a membrane, and this needs to be kept wet so that your eyes don’t dry out. When you keep your eyes open for a long time, your tears dry off from this really thing membrane and your eyes start to hurt because of this.

      Also, if you’re forcing yourself to keep your eyes open, you’re probably straining the muscles around your eyelids, and making them work harder than normal. Because of this, you’re muscles probably get tired and start to ache for this reason too!

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