A recent epidemiological literature review of glaucoma and those it affects suggests more interventions are needed to lighten the burden posed by this irreversible disease. Glaucoma is the second leading cause of blindness in the world and is estimated to affect approximately 76 million people today and as many as 111.8 million in the next 20 years.

The study found that 57.5 million people are affected by primary open-angle glaucoma (POAG) worldwide. In Europe, POAG affects 7.8 million people. The team’s findings shed light on a potential genetic component of POAG.

East Asians under the age of 40 are more likely to be affected by primary angle-closure glaucoma (PACG) than European and Afro-Caribbean people. Those of the Igbo tribe of Nigeria—a very homogenous ethnic group—have the highest prevalence of glaucoma in the world.

“The severity of glaucoma begins at an earlier age and at a more aggressive course in Black people than in white people and Asians,” the researchers noted in their study. However, this may not be due entirely to genetic factors, but partially “a result of a lack of early diagnosis and poor access to treatment,” they added. They noted that one study indicated that glaucoma service is affected by socioeconomic differences or inequalities.

Glaucoma’s prevalence in those over 40 is highest among Black people, at 5.7% compared with 2.2% in white people. The prevalence of the disease generally increases with age, and POAG is strongly correlated with age; the investigators reported higher prevalences of glaucoma in older Hispanic and Latinx (18%), Black (15%), white (7%) and Asian (5%) individuals. They also found that males are 36% more likely to develop glaucoma than females. Males are at higher risk for POAG, while females are at higher risk for PACG.

Reporting rates of glaucoma in African countries tend to be lower since “surveys in African countries may have a limited diagnostic capacity.” Overall, West Africa tends to have a higher prevalence than in South Africa, which has a higher prevalence than in East Africa. Glaucoma prevalence in Nigeria is higher than that of Brazil, Iran, Qatar and the indigenous populations in Australia.

By 2040, most of those with glaucoma will be of Asian and African ethnicities, according to the review. Europeans, North Americans and Oceanians will contribute to only a small number of the increase in POAG and PACG cases. Individuals from Africa will see a projected 130.8% increase in cases from 2013 to 2040. Those in Asia will see a 79.8% POAG increase and a 58.4% PACG increase in that same timespan. Stateside, one study estimated that Georgia’s population, which is heavily Black, will have about 254,047 cases of glaucoma among those aged 40 and older by 2050.

The economic burden of glaucoma in the United States is $2.9 billion. Studies reported that glaucoma patients incur, on average, an additional $2,903 in annual total healthcare costs and higher outpatient costs by $2,599 compared with those without glaucoma. Treating and preventing glaucoma is approximately $5.8 billion per year in the United States, and this number is expected to rise to $12 billion by 2032 and $17.3 billion by 2050. Prescription drugs are the main reason for the high cost.

“Detection at earlier stages is vital to prevent the progression of glaucoma,” the study authors concluded in their paper. They suggest a number of interventions, including teleglaucoma (especially for rural areas), regular glaucoma screening, genetic testing, a stronger educational push, more medication/surgery studies and more diverse healthcare providers.

Allison K, Patel K, Alabi O. Epidemiology of glaucoma: the past, present and predictions for the future. Cureus. November 24, 2020. [Epub ahead of print].