This paper describes the development of a holographic instrument designed to take the place of the test glass in testing lens surfaces. The objective was to produce an instrument giving similar results as the test glass, while preserving its simplicity. The research performed in this project resulted in a very simple system wherein a single hologram contains a complete interferometer supplying both the illumination source and the reference. The instrument is designed to be used on lens surfaces without the need to remove them from the mandrel of the polishing machine. It is simply placed on the optical surface, contacting it at three points. Fringes similar to those obtained with a test glass are seen on a screen on the instrument. Each lens design requires a hologram specifically made to test its particular curvature. Since the holograms can be made cheaply and rapidly, considerable cost savings should result, since no precision test glasses need be made.