The aqueous humour is a transparent water-like fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary body, a structure supporting the lens. It fills both the anterior and the posterior chambers of the eye, and is not to be confused with the vitreous humour, which is located in the space between the lens and the retina, also known as the posterior cavity or vitreous chamber.  From [Wikipedia](https://en.wikipedia.org/wiki/Aqueous_humour) under [CC BY 3.0](https://creativecommons.org/licenses/by/3.0/) license.