Washington ? The government discriminates against blind people by printing money that all looks and feels the same, a federal judge said Tuesday in a ruling that could change the face of American currency.

U.S. District Judge James Robertson ordered the Treasury Department to come up with ways for the blind to tell bills apart. He said he wouldn’t tell officials how to fix the problem, but he ordered them to begin working on it.

The American Council of the Blind has proposed several options, including printing bills of differing sizes, adding embossed dots or foil to the paper or using raised ink.

“Of the more than 180 countries that issue paper currency, only the United States prints bills that are identical in size and color in all their denominations,” Robertson wrote. “More than 100 of the other issuers vary their bills in size according to denomination, and every other issuer includes at least some features that help the visually impaired.”

Robertson said the government was violating the Rehabilitation Act, which prohibits discrimination on the basis of disability in government programs. The opinion came after a four-year legal fight.

Electronic devices are available to help blind people differentiate between bills, but many complain that they are slow, expensive and unreliable. Visually impaired shoppers frequently rely on store clerks to help them.

“It’s just frankly unfair that blind people should have to rely on the good faith of people they have never met in knowing whether they’ve been given the correct change,” said Jeffrey A. Lovitky, attorney for the plaintiffs in the lawsuit.

The Treasury Department had no comment on the ruling Tuesday. The government has 10 days to decide whether to appeal.

U.S. bills have not always been the same size. In 1929, the government standardized the size and shrank all bills by about 30 percent to lower manufacturing costs and help distinguish between genuine and counterfeit notes.

In court documents, government attorneys said changing the way money feels would be expensive. Cost estimates ranged from $75 million in equipment upgrades and $9 million annual expenses for punching holes in bills to $178 million in one-time charges and $50 million annual expenses for printing bills of varying sizes.