  Gravitational light deflection is known as one of three classical tests of
general relativity and the angle of deflection may be computed explicitly using
approximate or exact solutions describing the gravitational force generated
from a point mass. In various generalized gravity theories, however, such
explicit determination is often impossible due to the difficulty with obtaining
an exact expression for the deflection angle. In this work, we present some
highly effective globally convergent iterative methods to determine the angle
of semiclassical gravitational deflection in higher- and infinite-derivative
formalisms of quantum gravity theories. We also establish the universal
properties that the deflection angle always stays below the classical Einstein
angle and is a strictly decreasing function of the incident photon energy, in
these formalisms.
