The second graders from Horace Mann Elementary School in Northwest scrambled like any group of fidgety 8 year olds into the converted U.S. Air DC8 and fumbled with its reclining seats.

But the questions they asked the teaching ophthalmologists aboard the Orbis flying eye hospital at National Airport last week reflected an understanding of blindness that was anything but childlike.

"He's removing the cornea, isn't he?" asked Adam Rhodes, watching a cataract operation magnified on a color television screen.

The Orbis doctors and nurses, dressed in navy blue uniforms similar to those of pilots and flight attendants, explained the operation, much as they have during the airplane's world tours to such places as China, Abu Dhabi and Indonesia.

While Orbis exports ophthalmological science and services to developing countries at jet speed, Mary Ann Barnes' class is exploring its own educational frontiers with classroom studies on blindness.

Her 25 students have been studying blindness in a special class project that culminated in a tour of Orbis May 24. They were met there by Barbara Bush, wife of the vice president.

Their studies were aided by consultant Harold Krents, whose son Jamie is in the class. Krents, a lawyer, works as a promoter for Orbis, which is funded by private grants and the U.S. Agency for International Development. Krents himself was blinded at age 8 in a football accident.

Krents said he wanted the tour to be more than "window dressing." So he addressed the class the day before the tour, sharing personal experiences to familiarize the class with the world of the blind.

"The questions they asked were incredible," Krents said. "I think discomfort with the blind or with any handicapped person is something we acquire in our lives. Children are so much more up front."

He said the children asked "how I managed to get through school, how I felt not being able to see what my son looked like, how I could go to work."

At the airport, the effect of Krents' anecdotes on the children was evident, and they were clearly impressed with technological advances in aiding the blind.

"We learned about a lot of new things," Jake Sargent said as they waited for Bush in the wind-swept terminal. One of those things, a machine that "runs over paper and tells you what's on it," he thought had "kind of a Swedish voice."

"No, it sounds more like the Muppets," Alexandra Keeling said. "You know the cook on the Muppets? That's what it sounds like."

They were talking about the computer-operated reader for the blind, which reads aloud books, newspapers and other printed material in a computer-like voice.

The children said they also had studied blindness prevention and had been cautioned not to play with forks or have pencil fights. "Most accidents only take three seconds," Rhodes noted.

Aboard the jet, the surgeons and nurses took the children through the operating room and allowed Sargent to undergo a mock operation.

"What a brave young man," Bush commented as Secret Service agents jostled photographers, surgeons and youngsters trying to watch the mock operation in the cramped cabin.

Rhodes, asked how he imagines it feels to be blind, said, "It must be terrible. I think seeing is your most important sense."

Krents, however, disagreed. "I'd say a sense of humor is far more important," he said.