More than 3 million Americans have glaucoma and half of them don't even know it. The disease will steal your vision without warning and without symptoms.

Once a person's vision is lost, it can't come back. An early diagnosis is crucial to stop glaucoma in its tracks, reported WDIV-TV in Detroit.

Kenneth Hamilton, 67, of Detroit has always been good about getting his eyes examined. He's worn glasses for more than 30 years, but suddenly, his vision was fading. He started having trouble seeing colors.

"My wife would have to help me get dressed," Hamilton said. "She said, 'That tie doesn't go with that suit.'"

He was especially self-conscious about reading.

"I'm a deacon at my church," he said. "And I have to read the Bible, and I just really couldn't read it."

When he decided to get an eye exam, doctors found he had glaucoma. His eyes weren't draining properly, causing a buildup of pressure that leads to vision loss.

"It's one of the more common causes of blindness in this country and around the world," said Dr. Mark Rubinstein, of the Michigan Eyecare Institute.

Experts have found that glaucoma is six times more common in blacks than in whites. Those most at risk are people over 60, diabetics and people who are severely nearsighted.

It can't be cured, but it can be controlled with medication. Still, many patients are not compliant and say they forget to use the prescription.

"If I had a busy day, I'd forget about them," said Hamilton.

The more he forgot the medication, the worse his vision became. So Hamilton is undergoing a simple procedure with a difficult name: selective laser trabeculoplasty.

Using a combination of frequencies of light, a doctor applies a laser, reducing the pressure without destroying any tissue.

"The click noise you hear is the actual fire of the laser," said Rubinstein. "Every time it fires, it delivers the energy and causes a photochemical reaction. Over the course of the next few weeks, tissue is remodeled -- and the eye calms down."

The procedure is successful 90 percent of the time, eliminating most patients' need for drops, said Rubinstein.

Hamilton can't understand why anyone would avoid the surgery.

"I would say that's the biggest mistake in life they can make," Hamilton said. "It's simply painless."

But the results are not permanent. Hamilton may have to undergo the same one-minute procedure several times.