Available on the CDC's website is an interactive map displaying crude and adjusted visual impairment prevalence rates reported in each county across the US. To see how your county stacks up against the rest, simply click on its spot on the map, which can be found here.

Available on the CDC's website is an interactive map displaying crude and adjusted visual impairment prevalence rates reported in each county across the US. To see how your county stacks up against the rest,  simply click on its spot on the map, which can be found here. Click image to enlarge.

Skipping eye exams is known to be a significant risk factor for poor vision and eye health. In areas where optometrists and ophthalmologists are more scarce, as well as in areas of higher poverty, patients are less likely to receive adequate vision care, which can lead to worse clinical outcomes. A team of researchers recently published data from two studies showing that county-level prevalence of visual acuity loss and blindness prevalence in the United States is positively correlated with the percentage of a county’s population living below the federal poverty line. They drew several conclusions from their analysis of the nationwide data.

The researchers reported that the crude (unadjusted) prevalence of visual acuity loss or blindness at the county level ranged from 0.75% in Douglas County, CO, to 13.16% in Kalawao County, HI, while the standardized prevalence (adjusted for demographic factors) ranged from 0.99% in Cumberland County, ME, to 10.88% in Clay County, KY. Not surprisingly, more rural, nonmetropolitan counties were shown to have a lower density of ophthalmologists (2.19 per 100,000 persons) than metropolitan counties (6.29 per 100,000 persons). In this study, conducted in 2020, optometrist density was not taken into account (a similar work done in 2015 included both ODs and OMDs). Additionally, the proportion of counties that didn’t have a single ophthalmologist was shown to be higher in nonmetropolitan counties (67%) compared with metropolitan counties (35%), but still not as high as in rural counties, where a whopping 97% lacked an ophthalmologist.

The researchers suspect that a large reason why those living in poverty may have higher rates of visual impairment is because of the lack of available eyecare providers. They noted in their research letter on the study, “Previous research found the odds of receiving an eye examination in the past year were lower in counties with the highest prevalence of persons with poor vision and eye health.” Individuals living in rural counties with higher rates of poverty may especially face challenges finding doctor availability in addition to transportation to a clinic. The researchers wrote that the 2015 study reported “71.1% of counties in the south were in one of the bottom two quartiles of ophthalmologist and optometrist availability; the south had the lowest number of providers per capita.”

There are other potential reasons for the demonstrated correlation between visual impairment and poverty, according to the study authors (a group of health policy experts from the CDC, the University of Washington and the University of Chicago). “It could be due to lower rates of having health insurance and vision insurance among people with lower incomes,” they explained in response to an inquiry for elaboration. “Another important factor could be the higher prevalence of certain risk factors like diabetes among people living below the federal poverty level. Additionally, people with severe vision impairment or blindness are at higher risk of being unemployed, which can lead to conditions of poverty.” 

The authors suggested one possible step that could be taken to improve the rate of positive visual outcomes, particularly in low-income populations. “Public health and clinical interventions can help those at risk to manage chronic disease risk factors like diabetes, receive timely eye examinations for early detection of eye diseases and access routine eyecare for the prevention of long-term vision loss,” they noted.

The researchers did point out that their “results are limited by the lack of county-level measurement of the relative prevalence of visual acuity loss vs. blindness.” Still, they argue that the data identifies geographic variation in visual impairment occurrence that demands a call to action. “We hope that the results of this study, which show prominent geographic disparities in the county-level prevalence of visual acuity loss and blindness, can be used to identify those at greatest risk and prioritize public health resources for the prevention of vision loss,” the researchers concluded.

Lundeen EA, Flaxman AD, Wittenborn JS, et al. County-level variation in the prevalence of visual acuity loss or blindness in the US. JAMA Ophthalmol. July 7, 2022. [Epub ahead of print].