Amazon says it will make the Kindle DX easier to use for visually-impaired individuals by summer 2010.

The eReader will be outfitted with an audible menu system and the inclusion of extra large font to allow users who are blind or have limited sight the ability to access books without assistance. The new font will be twice as large as the Kindle’s current largest font.

“With some key modifications, we believe Kindle can be a breakthrough device for the blind, and the team is excited about making these enhancements,” said Ian Freed, vice president of Amazon Kindle, in a statement.

The announcement came one month after the National Federation of the Blind and two universities criticized the device for its inaccessibility to blind users. The University of Wisconsin-Madison and Syracuse University in New York told Amazon they wouldn’t consider wide-scale launches of the device until it was made more usable to blind and visually impaired students as part of their nondiscrimination policy.

The $489 Kindle DX is especially suited for use by educational institutions. The device features a 9.7-inch diagonal e-ink screen, compared to the 6-inch screen of the regular Kindle. The Kindle DX also features auto rotation and can hold up to 3,500 books.