This is a modified version of Looki's shader (which is also included in the zip file) that will use a supplied image to derive the lens effect which is applied only to the object, layer or frame it is assigned to as opposed to the combined background image. This shader is useful when you want to localise a lens effect to something specific. The lens image can be edited in MMF.
Note that as this uses an image, you can not modify the lens at runtime other than changing the parameters. Looki's background lens object should be used when you need to apply the effect to the entire background or when you want to be able to modify the lens image while the game is running.