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We investigate potential $\gamma-\gamma$ absorption of gamma-ray emissionfrom blazars arising from inhomogeneities along the line of sight, beyond thediffuse Extragalactic Background Light (EBL). As plausible sources of excess$\gamma-\gamma$ opacity, we consider (1) foreground galaxies, including casesin which this configuration leads to strong gravitational lensing, (2)individual stars within these foreground galaxies, and (3) individual starswithin our own galaxy, which may act as lenses for microlensing events. Wefound that intervening galaxies close to the line-of-sight are unlikely to leadto significant excess $\gamma-\gamma$ absorption. This opens up the prospect ofdetecting lensed gamma-ray blazars at energies above 10 GeV with theirgamma-ray spectra effectively only affected by the EBL. The most luminous starslocated either in intervening galaxy or in our galaxy provides an environmentin which these gamma-rays could, in principle, be significantly absorbed.However, despite a large microlensing probability due to stars located inintervening galaxies, gamma-rays avoid absorption by being deflected by thegravitational potentials of such intervening stars to projected distances("impact parameters"') where the resulting $\gamma-\gamma$ opacities arenegligible. Thus, neither of the intervening excess photon fields consideredhere, provide a substantial source of excess $\gamma-\gamma$ opacity beyond theEBL, even in the case of very close alignments between the background blazarand a foreground star or galaxy.

How gravitational lensing helps gamma-ray photons avoid $\gamma - \gamma$ absorption