Theoretical analysis of peculiarities of light propagating and scattering in smectic-A liquid crystals is carried out. The optical anisotropy of the medium is incorporated in the analysis. The model takes into account distortion of the layer structure as well as of the field of the directors. The intensity of the light scattered on the director fluctuations is calculated for arbitrary directions of the incident and scattered light. Peculiarities of the angle dependence of intensity are analyzed in detail. All geometries of the optical experiment, which permit separate observation of the two fluctuation modes of the director, are obtained. The extinction coefficients of the ordinary and extraordinary rays far from the smectic-A-nematic phase transition as well as its vicinity are calculated. As a result, we obtain that, contrary to nematic liquid crystals, outside the nearst vicinity of the phase transition point, the extinction coefficients of the ordinary and extraordinary rays possess a similar angle dependence and are of the same order.