Abstract: Surface inhomogeneities of a piece of glass are detected by disposing the glass piece in interfacial relation to an optical medium and reflecting light at a predetermined angle of incidence from the glass surface - optical medium interface along a scan path, through at least a portion of the optical medium. The optical medium is selected to have a refractive index equal to the bulk refractive index of the piece of glass. The intensity of the light reflected from the glass along the scan path is monitored to indicate surface inhomogeneities and the location thereof on the glass surface.