During a ceremony last week, more reporters spent their time looking at President Reagan's right ear than listening to what he was saying about illiteracy. The presidential hearing aid had finally debuted, and as the reporters scribbled, across the country people with hearing loss applauded.

Until last week, the little pieces of plastic--like the hearing impairment they remedy--were hardly popular subjects of conversation. Auditory handicaps themselves have typically been shrouded in personal embarrassment, despite public-service ad campaigns in which celebrities like actor Lorne Green, singer Nanette Fabray and Sen. Charles Percy (R-Ill.) openly discuss their hearing losses and hearing aids.

"Usually hearing impairment is associated with age, with degeneration," says Joseph Rizzo, executive director of the Better Hearing Institute, a national public-education organization.

"It's a stigma. So when someone as successful and strong and virile as the president comes out with his hearing aid, it is a great help.

"I think the man ought to be congratulated. We are so delighted that he has gone public with his hearing aid, because what it will do is encourage a lot of other people to explore the different forms of treatment.

"People will see that he wasn't afraid to come out and wear a hearing aid. They are going to say, 'If the president can do it, so can I.' "

It is estimated that only 3 million of the nearly 17 million Americans with hearing loss wear hearing aids. More than 11 million Americans suffer from uncorrected hearing handicaps; ignorance and what Rizzo calls the "stigma" have kept many from seeking help.

"That's the tragedy," he says. "People just don't realize they can be helped."

Along with expressions of enthusiasm, Howard Stone, president of Self Help for Hard of Hearing Inc., has asked Reagan to do even more. "I've drafted a letter to the president making him an honorary member of our organization.

"Not commiserating with him over becoming a member, but suggesting that now that he has gone public he might like to make a statement--keeping his problem in perspective-- to educate the people about the condition.

"For the last several years we had individual members from all over the country who were writing to him. They were urging him to do for hearing aids what Betty Ford did for drugs and alcohol and mastectomy--to bring the subject to the attention of the nation."

A retired government employe, Stone has been what he chooses to call "hard of hearing" since age 19. He established the Institute in 1979, and the organization now has nearly 3,500 members who meet monthly in small self-help groups.

"By and large our society is becoming more and more aware of the problems faced by people with hearing loss," says Stone.

"In the past the deaf only about 5 percent of the hearing impaired are legally deaf got all the publicity, and they've gotten all the resources. They need it and deserve it, but our organization is aiming at a much larger segment of the population."

President Reagan, 72, has said that his hearing loss stems from the accidental explosion of a gun shot close to his head while he was making a film in the late 1930s, in which he played Secret Service agent "Brass Bancroft."

Noise and aging are the two most common causes of hearing loss. Rizzo hopes the president's hearing aid will prompt more popular discussion of hearing loss due to noise, since that is the most easily preventable cause.