  This paper investigates the novel phenomenon of gravitational lensing
experienced by gravitational waves traveling past a Schwarzschild black hole
perturbed by a specific, first-order, polar gravitational wave. We utilize the
Gauss-Bonnet theorem, uncovering a topological contribution to the deflection
of light rays passing near the black hole. We demonstrate that the deflection
angle can be determined by analyzing a region entirely outside the light ray's
path, leading to a calculation based solely on the parameters of the perturbing
wave (Legendre polynomial order, $l$, and frequency, $\sigma$). This approach
offers a unique perspective on gravitational lensing and expands our
understanding of black hole interactions with gravitational waves.
