It’s because Parker, who is legally blind, does not have a driver’s license, a requirement for many workers who make home visits.

Parker was one of nearly 100 job seekers who attended a jobs fair yesterday that was sponsored by the Massachusetts Commission for the Blind and other organizations at Perkins School for the Blind. It was the first event of its kind in Massachusetts.

People with limited eyesight face many unique challenges when entering the workforce, including online applications they can’t read, a need for software that converts text to speech, and assumptions that a person with limited vision can’t do the work.

Such perceptions are among the reasons the unemployment rate for visually impaired people in Massachusetts is 37 percent, compared to 7.4 percent for all workers. It is the job seeker’s responsibility to prove them wrong, said keynote speaker Kareem Dale.

“We need to continue to be two times better than the next employee,’’ said Dale, a member of the Obama administration’s Office of Public Engagement who is partially blind. “We have to demonstrate to the employer that if you hire us, this isn’t about sympathy. . . . This is about doing something that’s going to help your business.’’

Twenty companies turned out to talk to prospective candidates at the newly opened Grousbeck Center for Students and Technology, which was packed with blind job seekers using white canes or guide dogs, as well as people with partial vision who strolled between tables unaccompanied.

At one table, Randy Johnson, vice president of sales and customer service at the employee benefits and incentive company Edenred USA in Watertown, looked over Richard O’Driscoll’s resume. O’Driscoll, 56, dressed in a gray pinstripe suit with a German shepherd service dog at his feet, has been unemployed since his customer service job at Appleseed’s, a women’s clothing company in Beverly, was outsourced three years ago.

Johnson was impressed by O’Driscoll’s experience and pointed out the blind man next to him, Edenred salesman James Duffy, who was just promoted.

“Jim sells 120 new accounts a year, and none of them know that he’s blind,’’ Johnson said.

Looking for work is often a challenge for people with disabilities, but the recession has made it even more discouraging, said O’Driscoll, who is from Chelsea.

“You go to a regular job fair, where there are people waiting outside in line to get in,’’ he said. “What chance do I have over 1,000 people that have been looking for a handful of jobs?’’

In the middle of the room, TD Bank recruiter Brian Lefort talked to William Timberman, a 30-year-old from Boston wearing a blue sport coat. Timberman, who realized his vision was failing when, as a child, he could no longer hit a baseball, said his job search has been frustrating.

“Nobody wants to train you,’’ he said. “It’s just easier to hire someone that they think is more capable.’’

But TD Bank has visually impaired employees who use the same enlarging software and hand-held magnifiers that Timberman uses, and the two men agreed to continue their conversation via e-mail.

“You’d do well in retail banking,’’ Lefort told him.

Some employers assume that hiring a blind person means making a big investment in new technology, but the Massachusetts Commission for the Blind provides free job site evaluations. Depending on the size of the company, it sometimes provides the technology for free, as well.

“If employers are making the commitment to hire our consumers, we partner together to find a way to make that happen,’’ said the agency’s commissioner, Janet LaBreck, who is blind.

That commitment includes an understanding that people with visual impairments work differently - particularly those who use software that converts text to speech, said Jonathan Gale, a coordinator at the Disability Law Center Inc. who was on a panel discussion at the jobs fair.

“What might take a sighted person three minutes because it’s look, point, and click takes the blind person a lot longer because it’s listen, listen, listen,’’ he said.

Parker, the social worker, uses this software at her job for the Gloucester Council on Aging, where she has worked part time for 18 years. She has been looking for a second job since 2007, when her part-time case manager position at a Salem homeless shelter was eliminated.

If Parker’s potential employers had not turned her away when they learned she doesn’t drive, she could have explained that she can visit clients by taking a train or taxi or by using the MBTA’s transportation service for disabled travelers.

“When I’m applying for jobs, a lot of them say you have to have a driver’s license,’’ she said. But, she added, “I have a social work license.’’

Katie Johnston can be reached at kjohnston@globe.com. Follow her on Twitter @ktkjohnston.