Devices systems, and methods can measure, diagnose and/or characterize an eye of a patient, including physiologic and optical properties, such as hydration and tear volume in relation to an optical surface of the eye, including topography of a corneal surface of the eye and/or a wavefront elevation map...http://www.google.com/patents/US7520609?utm_source=gb-gplus-sharePatent US7520609 - Non-invasive measurement of tear volume systems and methods
