Would it be possible to have a volume shader refract light?

I want to know if I could make a material that refracts not just on the surfaces, but also internally.

I think you'd need to put an object inside of that object to make it refract, I mean.. most 3d objects don't really have an inside as they are basically hollow so for example if you had a glass then you could but a cylinder (tube) in and apply the refractive properties to it.. just a thought, don't know if this is directly relevant to what you're asking and I could be way off the mark.

Yes, I've tried that of course but it's cumbersome and eats up a lot of rendertime.

Volumes have density and they are quite fast so I thought that perhaps we can piggyback refraction calculations somehow but I don't quite understand how their shaders differ from normal surface shops, soooo…. :?: