New Estimates Show Over 4 Million People in the U.S. Have Glaucoma

—
Black adults roughly twice as likely as white adults to be affected

by
Randy Dotinga, Contributing Writer, MedPage Today
October 17, 2024

An estimated 4.22 million people in the U.S. had glaucoma and 1.49 million people had vision-affecting glaucoma in 2022, with Black adults approximately twice as likely as white adults to be affected, according to a meta-analysis.

The prevalence of glaucoma was 1.62% among people ages 18 and older and 2.56% among people ages 40 and older, while the prevalence of vision-affecting glaucoma was 0.57% and 0.91%, respectively, said Joshua R. Ehrlich, MD, MPH, of the University of Michigan in Ann Arbor, and colleagues.

Black adults had a prevalence of 3.15% compared with 1.42% among white adults, while Hispanic adults and those in all other racial and ethnic categories combined had a prevalence of 1.56%, they reported in JAMA Ophthalmology.

“Glaucoma remains an important threat to vision, and [its prevalence] is likely increasing over time, at least due to changes in the U.S. population,” Ehrlich told MedPage Today.

Glaucoma is the leading cause of irreversible blindness in the world, and more than half of glaucoma cases in the U.S. are undiagnosed, the authors noted.

Ehrlich said that “theories regarding the higher prevalence among the Black population include a higher prevalence of other eye conditions that increase the risk of glaucoma, lesser access to eye care and appropriate treatments to slow the disease, and possible genetic factors. It is important to remember that none of these causes can be conclusively linked to higher rates of glaucoma in this population.”

As for how these findings can be useful, Ehrlich explained that public health officials at the national, state, and local levels could use these data to “understand the burden of glaucoma across populations of interest and use the data to plan public health strategies to address the problem.”

In an accompanying commentary, Rohit Varma, MD, MPH, of Southern California Eye Institute at CHA Hollywood Presbyterian Medical Center in Los Angeles, and Xuejuan Jiang, PhD, of USC Roski Eye Institute at the University of Southern California in Los Angeles, called the new estimates “an important contribution.”

However, they noted that the meta-analysis lacked representation of people ages 80 and up, didn’t explore urban-rural divides, and failed to dig into numbers in ethnic/racial groups other than Black adults. (Ehrlich said a lack of data prevented further analyses.)

For instance, American Indian and Asian-American adults are especially affected by primary angle-closure glaucoma, which poses a higher risk of blindness than open-angle glaucoma, they noted.

They also pointed out that policy changes over the past 20 years such as the expansion of healthcare coverage “likely improved glaucoma detection and outcomes for some vulnerable or low-income populations.” As a result, the data “may not fully capture the current burden of glaucoma.”

For this meta-analysis, Ehrlich and team drew on several sources including the National Health and Nutrition Examination Survey (NHANES) from 2005-2008, Medicare fee-for-service claims from 2019, IBM MarketScan commercial insurance claims from 2016, population-based studies of eye disease from 1985-2003, and 2022 population estimates from the U.S. Census Bureau.

PubMed was also searched for population-based studies of glaucoma prevalence published from 1991 to 2016.

The NHANES survey was the most important resource, Ehrlich said. “Out of necessity, we did assume that prevalence of glaucoma stayed the same within each stratified population group (race and ethnicity group, by gender and by age) as measured during the time of these studies. Had newer data been available, we would have used them.”

Glaucoma in NHANES was defined by fundus photograph grading. The authors transformed the polytomous grade into a probability, setting possible to 10% and probable to 90%. Vision-affecting glaucoma was defined as glaucoma and a visual field abnormality.

Prevalence of glaucoma among people ages 18 and up ranged from 1.11% in Utah to 1.95% in Mississippi.

The authors pointed to limitations to their study, such as the difficulty of defining glaucoma and reliance on old data. “Although diagnostic criteria varied among data sources, we considered all definitions equivalent,” they wrote.