Abstract: A method and apparatus for scoring a slot through one surface of an article by a scoring light beam confocally determines the remaining depth in the article between the bottom of the slot and an opposed second surface to automatically control the application of the scoring light beam at a particular point in the slot to maintain a constant depth between the bottom of the slot and the opposed second surface along the entirety of the slot despite any surface dimensional variations in the article. In one aspect, a detecting laser beam is directed into the slot formed by the scoring laser beam during formation of the slot, with only light reflected from a confocal plane established at the predetermined bottom depth of the slot being reflected to a detector.