This study focuses on the effect of polyethylene oxide (PEG) on the elastic properties of the micellar nematic formed in cesium perfluorooctanoate (CsPFO) water mixtures. We used PEO with molecular weights of 100,000 and 300,000 and prepared samples with CsPFO concentrations of 49 wt% in water containing small amounts of PEG. The weight fractions of PEO in water were 0.0, 0.25, 0.60, and 1.0%. We determined the splay and bend elastic constants by analyzing the optical response of surface aligned films to magnetic fields. The splay constants, compared at corresponding temperatures, are nearly independent of the PEO concentration. The birefringence decreases slightly. The bend elasticity which depends on the smectic coherence length shows the strongest effects.