Figure 8. .

The age-dependence of lens membrane conductances and the effective extracellular resistivity determined from curve-fitting impedance data with an equivalent circuit model of the lens. (A) The surface cell membrane conductance normalized to a unit area of lens surface. (B) The fiber cell membrane conductance per area of fiber cell membrane. (C) The effective extracellular resistivity, which depends on the volume fraction and tortuosity of the extracellular spaces within the lens. (D) The input resistance. The input resistance depends on size, specific membrane conductances, and the effective resistivity of the extracellular spaces within the lens. Many of these parameters are changing with age, leading to no systematic overall effect. The dashed lines in all of the panels are our arbitrary assessment of the general trend of age-dependent changes in each parameter.