Download Refractive Shader FREE Unity. 

This shader emulates light refraction as it passes through media with different refractive indices.

However, the effect is purely artistic/cosmetic as the method of distortion is not based on physical model of refraction.

Update 1.3 – Added new Lit and Unlit shader with:
– Masking parameters for refraction
– Alpha blending
– Sample count based quality tuning
– More Physically correct looking distortion

Update 1.2
– Added unlit distortion shader
– Added a simple particle distortion shader