I see a blue outline on the left of the head and a red outline on the right when I do that. I'm guessing that's some edge case for your lighting model?
You know, some time ago, I half-jokingly put forth the idea to some friends, that chromatic aberration will become the new lens flare, i.e. an effect to make rendered 3D graphics look like a movie shot with a cheap camera by an inexperienced cameraman on purpose. I get really sad each time I see one of these effects - they make the graphics worse on purpose to make them look like a bad movie and it wastes processing power.
If you do want to simulate a camera lens, I'm not going to stop you and wish you luck. However, if you want to render 3D images for humans to look at, I'd suggest putting in effects that are observable with a naked eye and not through a glass lens. Stuff like bright light blinding you, eye adjustment to varying light intensity and motion blur. I realise it's a bit harder to implement these effects, since you can't take a reference photo and compare, but I would really like to see someone try to render images as seen by a human and not a camera.
