Computers are such a visual medium that it might be hard to understand how a person with vision impairment can use them.

But, indeed, screen readers, magnifiers and a variety of other devices enable people with vision problems to use the Internet, read and write documents, and do other types of electronic tasks at work and at home.

In fact, just like other types of technology, these adaptive products are developing at such a rapid pace that it is a challenge to keep current, said Spero Pipakis, coordinator of the Computer Access Technology Center at Blind & Vision Rehabilitation Services in Homestead.

Mr. Pipakis and his staff work with about 150 clients per year to improve their computer technology skills. All instructors in the program, including the coordinator, have vision impairment.

Most clients are older teens and adults who have lost or are losing their vision. Many enroll because of personal employment or education goals. Increasingly, the center is working with veterans from the Iraq war as well as senior adults with degenerative vision problems.

The computer center is one of several services offered at Blind & Vision Rehabilitation Services, a 100-year-old agency that's been located in the former Homestead Hospital since 2005. Most computer technology students are from Western Pennsylvania, but because the facility is nationally known and can offer short-term residential accommodations, there is consistent enrollment of people who live much farther away.

Brian Persons, 45, a current client from Avon, Mont., completely lost his vision after a serious car accident 11 years ago. He's a former cow roper and "cow boss," as well as an avid dancer who was his state's jitterbug champ for three years running in the early 1980s.

In his current clerical position at the Montana state library in Helena, Mr. Persons types 35 words per minute with 98 percent accuracy. That's quite acceptable, but he wants to improve his typing speed to 70 words per minute and learn computer shortcuts that will position him for a new career in ranch management. His job counselor in Montana recommended the extended training at the center.

"I've learned more here in two weeks than I learned in six months on the job," said Mr. Persons. "It's a first-class place, and the help is first-class."

Computer access for people who are blind or have low vision falls into a few categories: screen readers that vocalize what's on the screen, screen magnifiers that enlarge the image, personal desktop assistants with speech or Braille display, closed-circuit TV, Braille printers and displays, and optical character recognition software and scanners.

About 10 million people in the United States are blind or have vision impairment, according to the American Foundation for the Blind. Of that number, a little more than half -- 5.5 million -- are over age 65.

A 1999 study showed that only about 10 percent of teens and adults with blindness or vision impairment regularly used the computer and the Internet. Today, computer skills are much more essential to this population, said Mr. Pipakis. Moreover, children who have vision problems are often as computer-savvy as their nondisabled peers. These children learn to use adaptive technology in their schools.

When the center does get a question from a youngster, it's usually a doozy, said Mr. Pipakis -- like how to marry a screen reader to an iPod.

That mixing and matching of adaptive technology to the needs of clients is the heart of the work, he says. "It's a real high when we figure out something for somebody. What we do here can change someone's life."