Second-order contribution to the gravitational deflection of light

We calculate the gravitational deflection of light to second order in the Newtonian constant $G$. For a light ray passing the Sun with impact parameter $b$, the deflection in general relativity is $\left(\frac{4G{M}_{\odot }}{b{c}^2}\right)\times [1+(\frac{15\pi }{16}\left)\right(\frac{G{M}_{\odot }}{b{c}^2}]$ radians.