Rights: University of Waikato. All Rights Reserved. Published 14 March 2012 Size: 71 KB

The Helmholtz theory of accommodation claims that, as the ciliary muscle contracts, the zonules become loose and the lens becomes rounder. The Schachar theory claims that the zonules become tighter to distort the centre of the lens into a more steeply rounded shape.

The University of Waikato acknowledges the work of Dr R Schachar in creating this diagram.