Jack Lebby's favorite customers are the ones who don't pay him a cent.

Each year, right before the beginning of the school year, the optometrist opens his office doors to children for free vision screenings.

For four hours, he sees one school-aged kid after another.

Through the years, that's added up to more than 1,600 Coachella Valley children.

“What I see in the chair doesn't surprise me anymore,” says Lebby, who has been holding the screenings for the past 14 years at Advanced Optometry inside Westfield Palm Desert.

Some of them have such poor sight, they can't make out the big “E” on the eye chart.

In some cases, the children lost their glasses a while back and have been squinting ever since.

Many don't realize the world shouldn't be fuzzy.

About 20 percent of the kids screened by Lebby need some kind of treatment, which is better than the national statistic.

About one in four children have a vision problem, according to the American Optometric Association.

Studies also indicate that 60 percent of children identified as “problem learners” actually suffer from undetected vision problems.

“The parents need to be vigilant, because the children don't know any better,” he says. “They don't know when their eyesight goes bad, because they have nothing to compare it with.”

Lebby, a slight man with an unassuming manner, has been working with apt pupils for more than 40 years. He jokes that he thought about becoming a dentist but didn't want to hurt people.

There are moments when it's easy to see just how well Lebby relates to youngsters.

When this reporter described her childhood glasses — hideous oversized mauve and gold frames, tinted pink lenses with an engraved unicorn on the side — Lebby's voice takes on a sing-song, Mr. Rogers cadence.

“A unicorn!” he says. “That's very personal, isn't it? You really made those glasses your own. They must have been very special.”

The free screenings are his favorite time of the year, he says.

Lebby is humble about how he helps these kids; he shrugs it off as a community service.

“If a child can't see, they can't learn,” he says.

Maggie Downs is a features reporter for The Desert Sun. She can be reached at 778-6435 or maggie.downs@thedesertsun.com.