NEW YORK (CNNMoney.com) -- A federal appeals court ruled Tuesday that the U.S. Treasury Department is violating the law by failing to design and issue currency that is readily distinguishable to blind and visually impaired people.

The U.S. Court of Appeals for the District of Columbia Circuit upheld a 2006 district court ruling that could force the United States to redesign its money so blind people can distinguish between values.

Suggested solutions include making bills different sizes, including raised markings or using foil printing which is a method of hot stamping that is tactically discernable.

Judge Judith Rogers, in a ruling on a suit by the American Council of the Blind, wrote that the Treasury Department's failure to design and issue paper currency that is readily distinguishable to the visually impaired violates the Rehabilitation Act's guarantee of "meaningful access."

The Rehabilitation Act of 1973 was originally designed to extend civil rights to disabled individuals and provide them a full opportunity to participate in American society.

Rogers also wrote that Treasury Secretary Henry Paulson has not met his burden to show why changing the money would impose an undue burden.

"A large majority of other currency systems have accommodated the visually impaired, and the Secretary does not explain why U.S. currency should be any different," Rogers wrote in her ruling.

The euro, for example, is one currency designed to be more readily identifiable. Each banknote has a predominant color and large numbers to make them easier to see. Also, the larger the denomination of the euro, the larger the banknote.

"We are very pleased with the ruling," said a spokeswoman for the American Council of the Blind. "We are hopeful that the Treasury Department will now get busy and come up with a plan to make paper money more readily identifiable for the visually impaired people all over the world."

The Treasury Department has been working to improve the nation's paper currency, according to Jennifer Zuccarelli, a spokeswoman for the Treasury.

"Most recently the Bureau of Engraving and Printing contracted with a research firm to conduct a comprehensive study to gather additional data, research and analysis for development of methods to help the blind and visually impaired," Zuccarelli said in an e-mail to CNNMoney.com. "The results of this study will be available by early 2009, and the Bureau will take that information under consideration when they transition in new production equipment in both printing facilities in the following years."

However, Paul Schroeder, vice president for programs and policy for American Foundation for the Blind, a nonprofit group based in New York, said he "would not be surprised" if the Treasury Department appealed the court's decision.

While Schroeder said it would be feasible to address this challenge, whatever solution is ultimately found must "work within a very substantial infrastructure" of U.S. currency.

The suit was originally filed in 2002 by the American Council of the Blind and two individuals with visual impairments, Patrick Sheehan and Otis Stephens.

The appeals court ruled 2-1, with Judge A. Raymond Randolph dissenting. Judge Thomas Griffith joined Rogers in voting to uphold the lower court ruling.