A New Interpretation of Thomas Young Refractive Index Law n=c/v

The Thomas Young refraction law established in 1807 needs a new evaluation. So far this law, simple in its formulation n=v/c, has been applied only when light passes from low refractive index medium like air to a high refractive index medium like glass and never when light exits back to air. New developments like the slowing down of light up to 17 ms ^-1 by Lene Hau and others, and the widespread use of optic fibers to transmit a huge amount of all kind of information and the Internet around the world, mandates the new evaluation. The matter at hand is whether we apply this law when light exits from glass to air, or we need a new formulation of the Thomas Young law for its new application.