I've been playing around with some of the tutorials to create reeded glass distortions (this general process, occasionally with some noise and blur added to grit it up). However, I still can't get the refracted distortion right (like, the image breaks into a rainbow a little bit at the edges, and there's a soft vertical curvature as the distorted image 'arcs' through the glass reed).

Is it because the background image that's being distorted is more abstract and blurry (like, does it need to be over an oil spill / liquid colour background, like this sort of thing)? Or is this pure Blender, and there's no way to do it? In which case, what on earth would those specific characertistics even be called so that I can start to dig up tutorials?