The elastic scattering cross sections for the reactions Cd-110,Cd-116(alpha,alpha)Cd-110,Cd-116 at energies above and below the Coulomb barrier are presented to provide a sensitive test for the alpha-nucleus optical potential parameter sets. Additional constraints for the optical potential are taken from the analysis of elastic scattering excitation functions at backward angles which are available in literature. Moreover, the variation of the elastic alpha scattering cross sections along the Z = 48 isotopic and N = 62 isotonic chain is investigated by the study of the ratios of the Cd-106,Cd-110,Cd-116(alpha,alpha)Cd-106,Cd-110,Cd-116 scattering cross sections at E-cm approximate to 15.6 and 18.8 MeV and the ratio of the Cd-110(alpha,alpha)Cd-110 and Sn-112(alpha,alpha)Sn-112 reaction cross sections at E-cm approximate to 18.8 MeV, respectively. These ratios are sensitive probes for the alpha-nucleus optical potential parametrizations. The potentials under study are a basic prerequisite for the prediction of alpha-induced reaction cross sections (e.g., for the calculation of stellar reaction rates in the astrophysical p or gamma process).