The release of an esoteric plug-in for a twenty-year-old piece of software normally doesn't merit much attention... except when the software is the ubiquitous Microsoft Word, and the add-on could have a major positive effect on the 1.5 million blind or visually impaired Americans who use computers, millions more like them around the globe, and, potentially, tens or hundreds of millions of people worldwide with developmental disabilities or reading problems.

Earlier this week, Microsoft announced the availability of a plug-in (downloadable from openxmlcommunity.org) that lets users of Word 2007, 2003 and XP easily save documents in the DAISY (Digital Accessible Information SYstem) XML format.

DAISY XML is the latest iteration of a decade-old standard developed by the DAISY Consortium, a leading nonprofit group serving the vision-impaired, to be the most accessible format for blind computer users.

Hidden structures

Why DAISY, when screen readers and text-to-speech tools already let blind computer users hear HTML Web pages and Word or PDF documents recited aloud?

For one, the experience, as illustrated in an April feature on computing for the blind, remains intensely frustrating Narrator, the screen reader built into Windows XP and Vista, is so crude that even Microsoft admits that it is not suitable for daily use.

Meanwhile, popular third-party readers, such as JAWS, are expensive. The standard version of JAWS, for instance, costs US$895; another package, EasyConverter from Dolphin Computer Access Ltd., weighs in at US$5,200. And the experience with JAWS and others remains, according to Curtis Chong, president of the National Federation of the Blind in Computer Science, uneven or poor. "If something is coded up wrong, your screenreader sees nothing," Chong said.

Why so bad? The problem is that for the blind, the most important parts of a page are the parts even the sighted can't perceive -- invisible metadata embedded in the document. What's missed isn't the stylistic metadata that sighted users usually think about, such as font, size, or color, but attributes such as paragraph marks, table structures, and headings, which determine a document's actual structure.

Good structural metadata lets a blind user nimbly navigate, browse and search a document. Word and PDF weren't built from the ground up to support that. DAISY was.

"DAISY is a fantastic format due to its flexibility," said Sam Ogami, an assistive-technology expert for the California State University system's chancellor's office. "From DAISY, you can easily move to other accessible formats, such as Braille or large print, in addition to audio, with little to no extra work."