In this paper, a recently developed light-section techniqzie is deiriunstmted as u z~iable technique for the ineusiireinmt of the topography of tnoziing szi yfuces. The sensitizdy und precision of this technique are stutically und iiynatizically e71aluateJ for surnples of diffi'rent roughness. It is sho7im that an optical system using the light-section inethod is not only precise biit ulso inirniine to the effects of perpendicular and luteral niotion ofthe slitface. It is therefore 7 c d l suited to on-line tnonitoring of the change of profile l$nzoziing siiyfaces. The technique, with its ability to nieasiire the topography of rtzoziing suyfices withoiit contuct, proi.hhi u most gfectizie tool for the study of 7uear and lirbrication inechanisrris under partial elustohydrodynuniic lubrication.