Water effect on camera lens

I am curious if it is possible to have a water refraction effect on the camera view, like in the first few minutes of Bioshock, where it looks like water comes off of the camera lens, or like water coming off of glasses?

I've looked and looked, and it seems the only way to do it would be via a shader, and I don't know shaders very well.

If you look in the Pro Standard Assets, there's an FX-Refractive material that uses a shader called FX/Glass/Stained BumpDistort that should be very similar to something you'd want.

I have been trying to pull this effect of for a couple of days now with no or partial success.

The way I`m doing it is to put a plane in front and as child of the camera, and apply a texture with the translucid water stains on it.

This shader mentioned above gave it almost the right effet, but not it is not quite there.

If someone already have achieved it and could spare the time to post a guide to it, would be very helpful to me.

Thanks in advance.