An original experimental set up was designed combining a Couette flow system and an optical sensor measuring the light flux multiple scattered from a flowing suspension. The method was used to study shear- or time-dependent microstructural changes to a concentrated suspension of monodispersed latex spheres (diameter 170 rim) for particle volume fraction ranging from 1% up to 48%. Microstructural changes were caused either by shear forces acting upon stabilized latex particles or by the addition of carboxymethylcellulose polymer chains inducing reversible depletion flocculation of latex spheres.