When I made that shader, years ago, the client wanted reflections. and not much "refraction".

So feel free to turn off reflectivity if you want


However, to get the background to "distort" depends on a lot of things to get the look you are after.

In Maya, and to a more complicated sense in real life, this is called REFRACTION.

In a shader, this is controlled in the "Raytrace Options" attribute list.

The number/attribute that you'll want to mess with to get different results, is the "refractive index".

Refractive Index determines how much a ray of light will bend when it passes through an object.

This attribute only works if:

-your object is "ripply, or curved, so as to reflect & refract the environ.
-your material is partially or completely transparent (see the Transparency attribute)
-refractions are turned on (see the Refractions attribute)
-and you are rendering using Ray Tracing. (See Render Globals)

If the Refractive Index is set to 1.0, then light does not bend when it passes through the object.

FYI: Here are some other useful REAL-WORLD values for Refractive Index:

Air: 1.0
Water: 1.33
Gasoline: 1.45
Crystal: 2.00
Glass: 1.5
Ice: 1.309
Quartz: 1.6
Ruby: 1.77
Sapphire: 1.77
Salt: 1.54
Alcohol: 1.329
Emerald: 1.57
Polystyrene: 1.55

Note:If you make an object transparent, objects that are seen through it will be refracted only if their Visible In Refractions attribute is turned on.