Gravitational lensing effect at higher order under weak field approximation
is believed to be important to distinguish black holes and other compact
objects like wormholes. The deflection angle of a generic wormhole is difficult
to solve analytically, thus approximation methods are implemented. In this
paper, we investigate the weak-field deflection angle of a specific wormhole,
the Ellis-Bronnikov wormhole (EBWH), up to the 1/b^4 order. We use different
approximation formalism, study their precision at 1/b^4 order by a comparison
to a purely numerical result, and finally rank these formalism by their
accuracy. Moreover, we find that certain formalism are sensitive to the choice
of coordinate system, when the corresponding deflection angle approaches 0 in
the negative-mass branch of universe.Comment: Comments are welcome