• Question: what are eyes made of?

    Asked by paige to Kylie, Matt, Bex, RobB, Sam on 12 Jun 2016.
    • Photo: Sam Briggs

      Sam Briggs answered on 12 Jun 2016:

      Hi Paige,

      What a cracking question – seriously – mostly water, they are a fascinating substance called a hydrogel. Now I’m sure that I will get shouted at by medics, but I think I’ll just talk about the chemistry bit of how you get a liquid to stay in a given shape.

      A hydrogel is a network of long chains of molecules that associate with one another through a variety of forces, in effect electrostatic interactions, chemical interactions or hydrogen bonding. This creates a highly viscous, think honey, not wine in terms of runny-ness, and that lets you make things that have certain physical or optical properties, both of which are required for the eye.

      Thinks there is some muscle and nerve tissue in there too. Contact lenses are made from hydro gels too!

      Hope that helps?

    • Photo: Matt Dunn

      Matt Dunn answered on 13 Jun 2016:

      Hi Paige,

      Eyes are a super complex organ, and as such are made of many different materials. The simple answer would be cells, as everything in your body is made up of cells!

      But what different types of cells? The front part of the eye is called the cornea, and is a transparent lens which allows you to see. At the back of the eye it gets more complicated: a nerve connecting the eye to the brain (the optic nerve, the eye cannot see without the brain processing the information first), muscles (which let the eye rotate and look around, as well as focus on objects near to you and far away), blood vessels (which supply all the cells with oxygen from the blood, and also mean that your eyes can appear red due to the blood vessels). At the side of your eyes are also your tear ducts. It’s an amazing organ, all in all!

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