Mechanics of ocular lens accommodation consistent with the classical Helmholtz theory

A mathematical model is derived to account for the classical Helmholtz theory of accommodation mechanics. By treating the lens capsule as the only elastic deformable component of the ocular lens and the lens fibre as an incompressible liquid capable of supporting a hydrostatic pressure, the mechanical response of a lens subject to equatorial tensile by the zonules is found. The results are consistent with Helmholtz that a stretched or unaccommodated lens possesses a reduced curvature along the optical pole. The model is compared with an alternative model recently built by Chien et al.