While it may be widely known that the risk of vision loss increases with age, Americans may be less aware that one’s ancestry and ethnicity can play a significant role in increasing odds.
In fact, a recent study published in the journal Ophthalmology has shown a link between African ancestry in Latino-Americans and increased intraocular pressure, a major risk factor for the eye disease glaucoma. This is one of the latest examples of a growing body of research showing that certain minority groups are at greater risk for serious eye conditions that can cause vision loss and blindness if left untreated.
Common Eye Health Issues for Hispanic Americans
Cataract – Cataract is the clouding of the eye’s naturally clear lens. The leading cause of blindness worldwide, cataract is also more common among Hispanics. Additional risk factors for cataract include age, gender (more common among women) and cumulative UV exposure.
Glaucoma – Often known as the silent thief of sight – because it leads to permanent vision loss, often without warning – glaucoma is the leading cause of blindness among Hispanics.
Studies suggest that open-angle glaucoma affects Hispanics at comparable rates to African Americans, and at much higher rates compared to non-Hispanic whites.
Hispanics may be particularly susceptible to damage from poor blood flow to the optic nerve because there is a high prevalence in this population of diseases that affect the blood vessels, such as diabetes.
As with African Americans, thinner corneas also increased the risk of glaucoma in Hispanics.
Pterygia – A pterygium is a non-cancerous growth of the clear, thin tissue over the white part of the eye. While the cause is unknown, prevalence is significantly higher among Hispanic Americans. Other risk factors include extended exposure to UV and wind.
Diabetes – Diabetes disproportionately affects Hispanics in the U.S. – and Hispanics are more likely to get it at an earlier age. Diabetes can lead to serious vision problems, including diabetic retinopathy. Since signs of diabetes can be seen in the eye, getting regular eye exams is one of the best ways to prevent further damage to the body and eye.
Hypertension – While high blood pressure is more common among Hispanics, as many as half don’t know they have it. Over time, hypertension can lead to serious vision problems or blindness. Because signs of hypertension are visible in the eye, regular eye exams are critical in overall health management.
Common Eye Health Issues for African Americans
Cataract – Cataract is the clouding of the eye’s naturally clear lens. African Americans are 1.5 times more at risk for developing cataract compared to the general population, and are five times more likely to develop related blindness. Additional risk factors for cataract include age, gender (more common among women) and cumulative UV exposure.
Glaucoma – Glaucoma causes gradual degeneration of the cells that make up the optic nerve, leading to vision loss. It is more common with age. African Americans are five times more likely than whites to develop glaucoma and four times more likely to suffer related blindness.
Glaucoma is about 3 to 4 times more common in African American populations than in people of European ancestry.
African Americans have thinner corneas than those of European descent. Thin corneas are a known risk factor for glaucoma.
Americans of African ancestry had larger optic nerves. This may be important as people with larger nerves are often misdiagnosed with glaucoma.
Americans of African descent have more rapid progression in vision loss
Diabetes – African American adults are twice as likely as non-Hispanic white adults to be diagnosed with diabetes, and are also twice as likely to develop and die from diabetes-related complications. Diabetes can lead to serious vision problems, including diabetic retinopathy. Since signs of diabetes can be seen in the eye, getting regular eye exams is one of the best ways to prevent further damage to the body and eye.
Hypertension – African Americans are significantly more likely to have high blood pressure, yet less likely to have it under control.5 Untreated, hypertension can lead to serious vision problems and even vision loss. Signs of hypertension can sometimes be seen in the eye, making regular eye exams important for disease management.
HIV/AIDS – African Americans face the most severe burden of Human Immunodeficiency Virus (HIV) infection and Acquired Immunodeficiency Syndrome (AIDS) of all racial and ethnic groups. Despite representing only 14 percent of the U.S. population in 2009, African Americans accounted for 44 percent of all new HIV infections that year.6 HIV/AIDS can lead to retinal detachment and blindness within two to six months.
Common Eye Health Issues of Asian Americans
Myopia – Myopia, or trouble seeing far away, affects upwards of 80 percent of Asian Americans. While myopia can usually be treated easily with eyewear, 40 percent of Asian Americans don’t see their eye doctor when experiencing this problem – and an additional 40 percent believe that wearing glasses will make their vision get worse.
Glaucoma – Asian Americans are more likely than the general population to develop glaucoma, with new research showing rates similar to Hispanic populations. Rates of narrow-angle glaucoma – which occurs when excess fluid becomes blocked and pressure builds up in the eye – are higher in Asian Americans than any other racial group, and are particularly high among Chinese and Vietnamese Americans.
Other forms of glaucoma, including normal tension glaucoma and open-angle glaucoma, are higher among Japanese Americans.
For example, Vietnamese Americans, Pakistani Americans, and Chinese Americans have been found to have a greater risk of narrow angles compared to other Asian American populations.
Thus far we have been discussing the most common form of glaucoma in the U.S., namely primary open-angle glaucoma. However, for primary angle-closure glaucoma (PACG) there are also differences among various ethnic groups. In some ways, PACG could be considered a more aggressive form of glaucoma and accounts for 90% of blindness in China.
It is difficult to know why Asian Americans have higher rates of PACG but it likely has to do with the anatomy of the eye, which likely reflects some genetic contribution. Narrow angles are much less common in African American and Hispanic populations.
One study demonstrated that the prevalence of primary open-angle glaucoma (POAG) in Asian Americans was similar to that of Hispanics, and greater than for Caucasian Americans.
Normal-Tension Glaucoma
Along the spectrum of POAG, there is also a form in which the eye pressure is not elevated, so-called normal tension glaucoma (NTG). What is interesting is that NTG has been found to be more common in Japanese Americans. American Indian and Alaskan Native populations also have a higher prevalence of NTG. This can be a particularly insidious form of glaucoma because the eye pressure is never elevated.
Pseudo exfoliation glaucoma is another form of open-angle glaucoma that occurs in different ethnic groups at varying rates. It is more common in patients with heritage from Scandinavian countries, although it is found in all populations to varying degrees. In a U.S. study, the prevalence of pseudo exfoliation glaucoma was much higher in Caucasian Americans than African Americans. A genetic association has been found with the lysyl oxidase-like 1 gene (LOXL1) but the interesting thing is that even many patients without pseudo exfoliation glaucoma have changes in this gene. This suggests that genetic factors are not the only contributing factor, and that the environment could be playing a very important role.
Diabetes – Asian Americans are more likely than whites to develop type 2 diabetes – but because they are less likely to be overweight, they may not be diagnosed as early as they could be.3 Diabetes can lead to serious vision problems, including diabetic retinopathy. Since signs of diabetes can be seen in the eye, getting regular eye exams is one of the best ways to prevent further damage to the body and eye.
Tuberculosis – The world’s leading infectious cause of death, Tuberculosis (TB) is 13 times more common among Asian Americans. Over time, TB can lead to a number of serious complications throughout the body and eye. Untreated, these problems can lead to permanent vision loss or blindness.
The Academy recommends that adults of all ethnicities have a baseline comprehensive eye exam with an ophthalmologist – a physician specializing in medical and surgical eye care – ideally when they turn 40. This is when age-related eye changes often begin to occur.
People who are 65 and older should get an eye exam every one to two years. Those with chronic conditions such as diabetes or high blood pressure or known eye diseases may need to go more often.
Sources:
http://www.aao.org/eye-health/news/ethnicity-eye-disease-risk-reminder-asian-african-
http://www.aao.org/eye-health/news/ethnicity-eye-disease-risk-reminder-asian-african-
http://www.visionproblemsus.org/downloads/2167_MultiCultiCompanion_v08_web.pdf
http://www.brightfocus.org/glaucoma/article/how-glaucoma-affects-different-ethnic-groups