Optical glass is one of the most difficult-to-cut brittle materials due to its high brittleness and high hardness. In this work, an experimental study was conducted to diamond-cut glass SF6 in ductile mode. Nano-indentation analysis was performed for understanding the material deformation behavior in practical cutting process. The effect of process conditions, i.e. conventional turning and ultrasonic vibration assisted cutting, on the tool wear and surface quality was discussed based on the observations of the tool wear zone microstructure and the machined surface topography. The investigation presents the feasibility of achieving optical quality surfaces on glass with the application of ultrasonic vibration cutting technology. The tool life and surface finish were improved significantly by applying ultrasonic vibration to the cutting tool.