Blur the screen sides for mobile. Is it possible without huge performance impact?

Hello Guys,

I need to blur the screen sides. For example like in Limbo game:

I’ve tried many shaders. Including the:
Unity Image Effects (Vignetting, TiltShift Eris mode),
free shader from asset store,
IndieEffects and some other radial blur shaders.
All of them have a huge performance impact for mobile devices. For example they reduce the FPS to 5-15 on android Galaxy s3 for the almost empty scene.

Is it possible to achive this effect on mobile devices with Unity3D so that it could be used (without huge performance impact)? Is there any way to cheat or mobile optimized solution for such blur?

i ran into the same issue – spent a few days trying to work it out.

http://forum.unity3d.com/threads/dof-on-ios-how-we-did-it-mini-post-mortem.143887/

this was the best solution for me, for now. it’s not ideal, because i’m using screen space - camera, and need to reassign the render camera for each ui element, every time i blur/unblur the ui.