Using the Gauss-Bonnet theorem, we compute and examine the deflection angle
of light rays by rotating regular black holes with a cosmological constant. By
the help of optical geometries, we first deal with the Hayward black holes with
cosmological contributions. Then, we reconsider the study of the Bardeen
solutions. We inspect the cosmological constant effect on the deflection angle
of light rays. Concretely, we find extra cosmological correction terms
generalizing certain obtained findings. Using graphical analysis, we provide a
comparative discussion with respect to the Kerr solutions. The results confirm
that the non-linear electrodynamic charges affect the space-time geometry by
decreasing the deflection angle of light rays by such cosmological black holes.Comment: latex, 16 pages, 4 figures. Accepted for publication in Chin. J. Phys
202