Glaucoma diagnosis may be mistaken in some younger Chinese people

Many young and middle-aged people of Chinese ancestry told they are at risk of going blind from glaucoma may be getting incorrect information, say researchers at the Stanford University School of Medicine.

After following a cluster of 16 such patients for seven years and observing more than 100 others, the researchers have concluded that there's a new syndrome occurring in the Chinese population, and it may be less likely to lead to severe vision loss or blindness than typical glaucoma. Their results are published in the March issue of Ophthalmology.

Glaucoma is a condition that occurs from accumulating damage to cells whose fibers make up the optic nerve, which transmits information from the eye to the brain. This disease is the second-leading cause of blindness worldwide, affecting one in 200 people over the age of 50, but is less common in younger people.

So when Kuldev Singh, MD, MPH, professor of ophthalmology, began seeing a number of young Chinese males 15 years ago who had been diagnosed with glaucoma, he became suspicious that perhaps they had another syndrome.

"I started to see a lot of Chinese men with advanced glaucoma at a young age," said Singh. "Many of them were terrified. Most were otherwise healthy and active and thus were surprised that they had this disease."

Singh noticed that not only were these patients young Chinese males, but almost all were nearsighted and many had normal eye pressure. Most glaucoma patients have high eye pressure, which is thought to lead to optic nerve damage. To see so many similar patients including many with normal pressure was unusual.

"It would be equivalent to someone having a heart attack when they have normal cholesterol," he said.

The combination of similarities among the patients led Singh to question whether these individuals, including some as young as 25, had glaucoma rather than another syndrome. So instead of the normal, aggressive course of treatment for young glaucoma patients - including surgery - Singh kept most of the patients on low doses of pressure-lowering eye drops as a precaution. As he suspected, none of the patients progressed toward blindness during the course of the study.

Singh began sharing his experience with doctors around the world and found he was not the only one with patients with these symptoms. Frequently, he said, a doctor in an online forum would describe a puzzling case of a young man with unexplained glaucoma. Singh would respond, "Is he nearsighted and is he Chinese?" and the doctor would respond, "How did you know?"

Singh said he thinks that optic nerve damage in these patients is caused by their nearsightedness, and that others have reported that nearsightedness is increasing in the Chinese population.

Nearsightedness is caused by a lengthening of the eye, and Singh and colleagues suggested in the paper that stretching the eye can damage the optic nerve. Since nearsightedness rarely gets worse in people after their 30s, the optic nerve damage may ultimately slow or stabilize in such patients.