WHEN DAVID Hartman was a medical student, his wife, Cheri, sometimes read to him to supplement the recorded medical texts from which he studied. Now that he's a doctor, taking a residency in psychiatry at the University of Pennyslvania's Veterans' Administration Hospital, she's had to speak for him - because he's too heavily scheduled to take a few minutes to talk about his career.

Hartman's determination to become a doctor, in spite of his having been blinded from glaucoma at age 8, was documented in "Journey from Darkness," a television movie. His attitude, helped from childhood by a father who always said, "You'll never know until you try," is not that anyone can become a doctor, but that such a handicap should not hold back anyone who is determined to do so.

Last month, Hartman completed his first year of residency in "physiatry," a combination of physical medicine and rehabilitation. After three years of residency in psychiatry, he plans to do two more years of physiatry and become a psyshiatrist specializing in the problems of the disabled. He was graduated in 1976 from Temple University School of Medicine.

His own problems as a disabled doctor are not difficult ones, Cheri Hartman said. "He can do physical examinations and histories by taking and by touch," she said. "The one thing he has a problem with is ears, eyes and throat and then he may call in a nurse or a consultant to see if there's any gross abnormality."

His fellow residents have served as readers when he needed to look something up, but she feels that he may eventually have to hire a reader to work with him.

And they both feel he has solved the problem of dealing with patients made nervous by the doctor's own disability.

"Dave's main feeling is that they trust him to the extent he conveys confidence in himself," his wife said. "With the first patient he was fairly insecure, as all interns are. it was a quadraplegic who told him he'd rather be in his own position, without the use of any of his limbs, than be in Dave's.He felt he couldn't deal with blindness." That patient happened to be trusted to another hospital a week later, and by that time, Dr. Hartman was ready with an answer to the next who asked, "You're blind - what can you do for me?"

His answer is "I can do this and this and this and this," whatever was needed. The first patient had challenged him by saying he wouldn't be able to recognize bedsores; by the second patient, Dr. Hartman realized that, of course, he would be able to feel bedsores.

Cheri Hartman is a candidate for a doctorate in educational psychology who plans a teaching career. They met when they took the same class in psychological statistics at Gettysburg College.

When he does have rare time free from the hospital and patients, they listen together to recordings of novels, riotly historical novels, by the Free Library for the Blind or Reading for the Blind, which supplied his medical textbooks on tape.

And this summer, they started going to baseball games. They take along a radio so he can follow the action, but she enjoys watching and they both like "just being there in the midst of it."