I think what David Caruso is using what we call in the biz, a special effect...
I have trouble seeing anything else when he's in a scene, what with him chewing all the scenery to bits...Sorry, can't stand his acting or his characterizations.

I love seeing what I call the X Files flashlights in the various cop shows. It's amazing what a little bit of artificial smoke can do to a beam of light.

JohnE