This application seeks support for exploratory research to develop a user interface (UI) specifically designed for moderate to severe low vision, that will allow improved access to structured documents such as those written in hypertext markup language (HTML) or extensible markup language (XML). The UI will incorporate intelligent, well-accepted principles and empirical knowledge from vision and rehabilitation sciences, and will be initially embodied in a web browser for low vision. With an emphasis on simplicity and ease of use, the configurable features of the UI will be limited to those that have the highest impact on legibility and reading performance, and will be designed so that once configured, no adjustments will be needed, regardless of what document the user is viewing. The UI will allow users simultaneous access to both the global features of web documents as the author intended, along with enlarged text tailored to the user's needs;this will allow access to all web pages without requiring that sites have special markup or authoring. The design will be motivated by the corpus of existing of health sciences based psychophysical research in low vision, and will utilize recent software engineering advances including XML-based User Interface Language (XUL) and eXtensible Application Markup Language (XAML), eXstensible Style Sheet Language (XSL) and XSL-Transform, the Document Object Model (DOM), and the general trend toward separation of content and structure in electronic documents. The technology and research developed in this project is expected to lead to general user interfaces for low vision that might be incorporated into operating system design, as well as electronic books and web documents. The broader impact of this project is that it can help close the digital divide for millions of users with moderate and severe vision loss who are at a relative disadvantage in access to information. In addition, the technology can, if widely adopted, alleviate the failure of most authors of structured documents to comply with best practices for authoring accessible content, because document pages with reduced visual accessibility can now be more easily appreciated. This project is intended to enhance web and document accessibility to the growing number of older visually impaired people who are reluctant to learn to use large, feature-laden software. Since the technology can be easily extended to any language, such solutions can, assuming computers, electronic documents and web access are available, enhance the lives of tens of millions of users worldwide.