Four-year study results reveal higher glaucoma rate among Latinos

Study advocates community screening programs for this growing segment of the U.S. population.

Issue: September 25, 2012

The incidence of primary open-angle glaucoma among Latinos who are at least 40 years old is more than double that observed among non-Hispanic whites and less than or comparable to that in Afro-Caribbeans, according to 4-year follow-up data from the ongoing Los Angeles Latino Eye Study.

“I believe this relatively higher incidence is mostly due to a genetic predisposition in the Latino population,” lead study author Rohit Varma, MD, MPH, director of Glaucoma Service at Doheny Eye Institute in Los Angeles, told Ocular Surgery News. “Latinos may also have some other risk factors, such as a longer axial length or myopia, that contribute to the higher incidence of glaucoma.”

OAG, OHT

The study, which was published in the American Journal of Ophthalmology, involved 3,939 participants with a mean age of 54.7 years who were assessed for both open-angle glaucoma (OAG) and ocular hypertension (OHT).

At 4 years, the incidence of OAG was 2.3% (87 subjects). This compares with rates of 1.1% and 1.8%, respectively, at 5 years in two representative studies of non-Hispanic whites.

Rohit Varma

For OHT, the incidence was 3.5% (124 subjects) at 4 years. Varma said that the challenge of comparing OHT results is that there are few population-based studies for this condition.

Notably, subjects who had OAG in one eye at baseline were five times more likely to develop OAG in the fellow eye at 4 years than those without OAG in either eye at baseline.

“We did not know how large the number would be,” Varma said. “But the fact that it was five times higher is mind-boggling. … I believe this population is genetically predisposed to OAG. So if OAG is detected in one eye, you really have to pay attention to the other eye.”

In participants with OHT in one eye at baseline, the 4-year risk for developing OHT in the fellow eye was even greater: 10 times as high as the risk for those without OAG in either eye at baseline.

“This was also a surprise, but patients with OHT do not have any vision loss or any permanent irreversible damage,” Varma said. “If needed, the high pressure can always be lowered with eye drops, so the clinical implications of OHT are not nearly as grave as for OAG.”

The long-term study, which is being funded by the National Institutes of Health, also found that the rates of OAG and OHT were higher among older Latinos compared to younger Latinos.

Screenings necessary

The authors advocated community screening programs for both OAG and OHT.

“However, screening programs are not easy to implement and they are expensive,” Varma said. “They have been done, but not very well. Still, I think they are essential because glaucoma, particularly primary open-angle glaucoma, is a silent disease. You don’t have any symptoms, you don’t have pain or redness. … Most of the vision loss early on in glaucoma is peripheral, so you don’t pay very much attention to it until it is too late. But the benefits of identifying people early through screening programs are probably well worth it.”

Glaucoma is one of the leading causes of blindness in the U.S. and around the world, Varma said.

“It also causes irreversible vision loss, so it is important to identify people who have this disease early in the course and treat them so you can prevent the disability that is associated with vision loss,” he said.

In addition, Latinos are the fastest growing segment of the U.S. population.

“Given these high incidence rates, it is critically important that we implement early screening and treatment programs for this particular ethnic group,” Varma said.

The study’s 8-year follow-up data on OAG and OHT will likely be published in about 2 years, Varma said.

“I hope that the new data will not show rates that are even higher,” he said. “We expect that the data will validate the current findings.” – by Bob Kronemyer

Reference:

Varma R, Wang D, Wu C, et al; Los Angeles Latino Eye Study Group. Four-year incidence of open-angle glaucoma and ocular hypertension: the Los Angeles Latino Eye Study. Am J Ophthalmol. 2012;154(2):315-325.

For more information:

Rohit Varma, MD, MPH, can be reached at Doheny Eye Institute, 1450 San Pablo St., Suite 4900, Los Angeles, CA 90033; 323-442-6411; email: rvarma@usc.edu.
Disclosure: Varma has no relevant financial disclosures.