Book excerpt: Foundations of Low Vision: Clinical and Functional Perspectives, the ground-breaking text that highlighted the importance of focusing on the functional as well as the clinical implications of low vision, has been completely updated and expanded in this second edition. The revised edition goes even further in its presentation of how best to assess and support both children and adults with low vision and plan programs and services that optimize their functional vision and ability to lead productive and satisfying lives, based on individuals' actual abilities. Part 1, Personal and Professional Perspectives, provides the foundations of this approach, with chapters focused on the anatomy of the eye, medical causes of visual impairment, optics and low vision devices, and clinical low vision services, as well as psychological and social implications of low vision and the history of the field. Part 2 focuses on children and youths, providing detailed treatment of functional vision assessment, instruction, use of low vision devices, orientation and mobility, and assistive technology. Part 3 presents rehabilitation and employment issues for working-age adults and special considerations for older adults.