New York ? Gary Bergman bounds onto the stage, hopping backward down a short flight of stairs — a dangerous move, even for the most agile. George Ashiotis enters more cautiously, feeling his way across a complex set that is new to him.

Both men are actors, rehearsing the Agatha Christie play “Ten Little Indians.” And both are blind.

It’s the first time they’ve rehearsed on this stage, and director Ike Schambelan is concerned.

Crucial parts of the set — newel posts and banisters that would help the performers locate themselves on stage — are not yet in place. So besides the usual details — learning lines perfectly, quick costume changes, pouring drinks, lighting and smoking cigarettes on cue — the actors must take care not to bump into one another on stage at the Blue Heron Arts Center.

After running through the opening scene several times, the actors coast about the set with remarkable ease. Schambelan has placed folding chairs on platforms where the posts and railings will be. No one falls.

Schambelan, 62, who is not blind, created Theater by the Blind in 1979. Each year, the troupe of vision-impaired and sighted actors puts on two plays in New York. Last year, Theater by the Blind produced “Brecht on Brecht” and “Murder in Baker Street.”

TBTB, one of the few professional repertory companies for blind actors in the world, survives mostly on grants and contributions to make its $260,000 annual budget. It also puts on readings and workshops.

“My grandma was blind,” Schambelan says. “We are not trying to hide blindness. My real hope is that some of my actors will get jobs with other companies.”

Special needs

The company’s latest play is a nifty whodunit based on Christie’s novel, “And Then There Were None.” The play is set on an island estate where a mysterious host keeps killing his guests at an alarming rate. During the drama, which Schambelan has compressed into two acts, each character’s story emerges.

Like any production, preparation begins with the reading of the play. But these actors have special needs — the script must be prepared in various forms, including tapes, large-type editions and Braille.

director Ike schambelan talks with his cast during a break in dress rehearsal for the play Ten

It is just the first of the adjustments that must be made in the production, which runs through Feb. 16.

On this rehearsal evening, the theater is empty, and only the cast and crew are witnesses to the art of blind stagecraft.

At one point, Ashiotis fumbles around a tabletop bar stacked with glasses and bottles. “Where are the ashtrays?” he shouts. Ashiotis, 55, the company’s co-artistic director, is almost totally blind, capable of seeing some light and shadows. He also is an actor of great precision.

“I need props to be where they’re supposed to be,” he says. “It’s essential not to have anything out of place.”

Yet he demands more from himself than he does from the prop manager.

“My nightmare is that I’ll be criticized on how well I, a blind actor, pull off playing a sighted character, rather than how well I perform the role,” he says.

Nick Viselli is one of the company’s sighted members, and to some degree he is there because of Ashiotis. Some years ago, he saw the troupe perform another Christie play, “The Unexpected Guest,” and he was amazed to watch as Ashiotis “walked across the stage in one scene and flawlessly lit the cigarette of an actress.”

“I was blown away,” Viselli says.

Bergman, 35, portrays a playboy with a penchant for fast cars. He sees shapes but with little detail. To get around the stage so briskly, he uses what he calls “cheats” — a rug that warns him as he approaches the stairs, light colored banisters set off against the dark floor that help his entrance, a white pillow on a chair makes it stand out.

“It’s all about contrast,” he says.

A triumph

By the day of the dress rehearsal, the set designed by Merope Vachlioti has taken on the appearance of the parlor in an old manor house. Bright edges make the steps stand out. Getting the performers safely off stage in the dark between scenes is the only real problem left. Sighted actors help some of the visually impaired change costumes, cutting seconds off the switch-over.

Now, the actors can get into the subtleties of their roles: a gesture, a touch, an arm around the shoulders. “I just steer them,” says Schambelan.

And when opening night comes, the first performance is a triumph.

Ashiotis stumbles at one point and sends some dishes to the floor. But the crowd loves the show, and there is much applause.

After the audience trickles out, the cast gathers on the stage to celebrate with a large bottle of champagne. Then they head home, some in groups, one with a guide dog and others with striped canes moving carefully into the darkness.