RESUMO
The Rayleigh ratio for young human and cataractous lenses, having spherical particles with constant diameter embedded in a medium with a different refractive index, has been calculated as a function of concentration (volume fraction) using the theory of the small-q behaviour of the static structure factor, S(q). It involves treating the long-range forces between particles in the gel in the random phase approximation, dividing the pairwise interaction potential into a reference part and a perturbed part based on WCA model, and applying the perturbation approach of WCA to lenses obeying van der Waals' potential as a perturbative attraction over the Percus-Yevick (PY) hard sphere model. The calculated Rayleigh ratios are found in excellent agreement with experimental values, thereby showing that the present model works well for young human and cataractous lenses.