January is glaucoma awareness month.

Dr. Kevin Jones with Family EyeCare Center in Pella says glaucoma is a group of diseases that cause slow, undetectable changes in vision.

“These changes happen in a way that the patient is unaware that the changes are happening,” he says. “It’s not until the patient has lost approximately 40% of their vision before they start to notice that they’re actually having some vision loss–this vision loss is a permanent loss as well.”

Jones says eye doctors review patient history and regular eye exams can help them detect changes in eyes and properly diagnose glaucoma and treat it better.

Currently, more than three million people in the United States have glaucoma. The National Eye Institute projects this number will reach 4.2 million by 2030, a 58 percent increase. There is no cure, but Jones says they can treat symptoms to slow the damage done and onset of blindness.