Mechanical response of the vitreous gel in our eyes: Results from an inhomogeneous two-fluid model*

The vitreous gel is a viscoelastic gel present between the eye lens and the retina. It is made up of a composite network of stiff collagen fibers and softer hyaluronic acid (HA) polymers, and water. Its mechanical properties are critical to proper functioning of the eye, and undergo changes with aging and disease. We study rheological properties of this gel by simulating it as a two-fluid model made of an inhomogeneous polymer network interacting with a fluid. Our results relate the time-varying mechanical response of the gel to the composition of the network, the material properties of the network and the fluid, and the strength of the coupling of between the network and the fluid. These results may provide insights into changes in mechanical-structure function properties of the vitreous gel in vitreous disorders.