Historically, rehabilitation clinicians who work with people who are visually impaired (that is, are blind or have low vision) have relied on subjective checklists and clinical assessments to document the capacity of individuals to perform various tasks, including mobility, and to assess the impact of rehabilitation. Numerous instruments have been developed to measure functional outcomes and the quality of life of people who are visually impaired. The continued development and implementation of such instruments represents a major achievement in the coordination and standardization of measurements of functional outcomes. This article highlights a unique, objective method for assessing the mobility of clients who are visually impaired by using a combination of GPS (Global Positioning System), and accelerometer technologies. The use of these technologies facilitates a highly objective and reliable measurement of both indoor (accelerometer) and outdoor (GPS and accelerometer) mobility and travel patterns.