Not Gravitational Lensing, but Medium Lensing

According to the General Theory of Relativity the gravity curves the spacetime and everything overthere follows a curved path. The space being curved near massive cosmic bodies is just a metaphor, not a fact. We dough that gravity is only geometry. The deflection of light (Gravitational Lensing) near massive cosmic bodies is not due because of a ``curved space'', but because of the medium composition (medium that could be formed by waves, particles, plasma, dust, gaseous, fluids, solids, etc.), to the medium density, to the medium heterogeneity, and to the electromagnetic and gravitational fields contained in that medium that light passes through. This medium can deviate the light direction, because of the interactions of photons with other particles. The space is not empty, as Theory of Relativity says. It has various nebulae and fields and corpuscles, etc. Light bends not only because of the gravity. Light bends because of the medium gradient and refraction index, similarly as light bends when it leaves or enters a liquid, a plastic, a glass, or quartz. The inhomogeneous medium may act as an optical lens such that its refractive index varies in a fashion. We talk about a Medium Lensing, which means that photons interact with other particles in the medium.