  We investigate the gravitational lensing effect around a spherically
symmetric black hole, whose metric is obtained from the Einstein field equation
with electric charge and perfect-fluid dark matter contributing to its
energy-momentum tensor. We do the calculation analytically in the weak field
limit and we assume that both the charge and the dark matter are much less
abundant (only give rise to the next-leading-order contribution) in comparison
to the black hole mass. In particular, we derive the light deflection angle and
the size of the Einstein ring, where approximations up to the next-leading
order are done with extra care, especially for the logarithmic term from
perfect-fluid dark matter. We expect our results will be useful in the future
to relate the theoretical model of perfect fluid dark matter with observations
of celestial bodies immersed in thin dark matter.
