This chapter presents a summary of the physiological processes that support key visual functional capabilities such as visual acuity, contrast sensitivity, and field of view. The chapter also considers some of the most common causes of visual dysfunction and their impact on the visual capabilities that are necessary for successful interaction with contemporary computer systems, particularly for access to the World Wide Web (the Web). The chapter then outlines some of the key steps that have been taken in the last few years to promote the appropriate access to the World Wide Web by users who might have restrictions in their visual functionalities, as described.
