The results of the static light scattering (SLS) from oil-rich microemulsions was reported for sodium bis(2-ethylhexyl) phosphate system, in which cylindrical W/O aggregates were formed. A model was proposed to relate the SLS intensity to the cylindrical aggregates found from the SAXS. The model takes into account the dependence of the refractive index of the aggregates on their lengths. This dependency arose from the penetration of organic solvent molecules into the surfactants monolayer coating the spherical caps. The observed Rayleigh ratios were well explained by the model when considering the solvent penetration significantly affects the refractive index of the aggregates. It was indicated that the surfactants monolayer coating the spherical caps contains a much larger amount of solvent molecules than the monolayer coating the cylindrical (central) part.