Purpose
To provide a state-level prediction of the future burden of visual impairment and its causes in adults in the state of Georgia through 2050, accounting for age and race demographics.
Design
A population prevalence projection study.
Methods
Population data were obtained from the Georgia Governor’s Office of Planning and Budget, stratified by age and race and applied to the Prevent Blindness America eye disease prevalence values. Prevalence of overall vision impairment and of blindness were calculated, in addition to the most common diseases.
Results
In Georgia in 2050, there will be an estimated 226,000 visually impaired persons, and nearly 100,000 will be blind. Of those who are visually impaired or blind, 65% will be age 80 or older. There will be a greater than 350% projected increase in visual impairment in those 80 and older by 2050. A projected 1.7 million cases of cataract, 2.3 million of refractive error, over 250,000 cases of glaucoma, and 117,000 cases of macular degeneration will be present. The total caseload of diabetic retinopathy in adults age 40 and older is expected to increase by 150% between 2015 and 2040.
Conclusion
The aging population and racial demographics impact projections for future eye disease burden, causing state-level projections to vary from national levels. As the demand for eye services increases, states must have individualized projections to evaluate the unique challenges they will face and prepare for enhanced service delivery, educational campaigns, and advocacy that match the need for their state.
Visual impairment and blindness currently burden millions of Americans. As of 2012, Prevent Blindness America estimates that 2.91 million Americans are visually impaired, with best-corrected visual acuity worse than 20/40 but better than 20/200. An additional estimated 1.29 million are blind, with best-corrected visual acuity equal to or worse than 20/200, or visual field extent less than 20° in diameter. Visual impairment and blindness are associated with negative physical and mental effects. Numerous studies have shown an association between visual impairment and a reduced quality of life, difficulties performing activities of daily living, and higher rates of depression. Furthermore, visual impairment and blindness are a major economic burden, costing an estimated $16.2 billion in direct medical costs and $8 billion in productivity losses for adults in the United States.
Owing to the impact of visual impairment on quality of life, the economy, and health services, it is important to understand the current and future prevalence of visual impairment, blindness, and associated eye diseases. Current prevalence estimates have established disparities in vision loss among age groups, racial groups, and sex. The prevalence of these diseases is expected to outpace the rate of population growth owing primarily to the aging population, shifting demographics, and increasing prevalence of diabetes.
Current and future projections of visual impairment exist on a national level, but to our knowledge there are currently very few, if any, state-based projections that delineate predictions by eye disease and demographic factors. These state-specific projections fill an important gap, as states vary widely in their demographic makeup, predicted growth rate, and rate of obesity and diabetes, all of which directly affect projections for visual impairment. Specifically, states with larger African-American populations, such as Georgia, will need to prepare for an increased burden of glaucoma and those faced with the growing obesity and diabetes epidemic, such as in the South, will have increased diabetic retinopathy (DR). Because of the racial demographics and the current and predicted high prevalence of diabetes, we expect the state of Georgia to be particularly affected by visual impairments and blindness in the future. Additionally, Georgia is demonstrating more rapid population growth than most other states and is in the top 10 fastest-growing states in the country. This is primarily owing to Georgia having a larger than average rate of birth (ranked eighth in 2018 census data) and net migration (ranked seventh). This paper aims to close that gap and provide approximate estimations for the state of Georgia that will enable appropriate planning and budgeting for the future. Additionally, we hope to make the case for and encourage other states to evaluate what the future of vision health looks like for their state and begin discussions on what will be needed to ensure a healthy, prospering population.
We will include the current (2013) and projected future prevalence (2050) of visual impairment, blindness, primary open-angle glaucoma (OAG), DR, cataract, age-related macular degeneration (AMD), and refractive error for the state of Georgia in this paper.
Methods
Definitions
Both visual impairment and blindness are defined using the US definitions. Specifically, visual impairment is defined as best-corrected visual acuity worse than 20/40 but better than 20/200 in the better-seeing eye, and blindness is defined as best-corrected visual acuity in the better-seeing eye of worse than or equal to 20/200, or a visual field extent of less than 20° in diameter. For disease prevalence the definition included a single person meeting the diagnostic criteria in either eye. Refractive error is classified as myopia or hyperopia, including both corrected and uncorrected; myopia is defined as a spherical equivalent of -1.0 diopter (D) or less, and hyperopia is defined as a spherical equivalent of +3.0 D or more. AMD is defined as either nonexudative AMD with geographic atrophy or exudative AMD with neovascularization. Prevalence estimates of cataract include a definition of cortical cataract that affect 25% or more of the lens, posterior subcapsular cataract of 1 mm or larger, or nuclear cataract that is equal to or greater than the second-highest grade in the grading system used (in the Lens Opacities Classification System II, commonly a grade of NII or NIII). Prevalence estimates of DR include retinopathy of grade 14 or higher on the ETDRS final scale based on fundus photographs, involving macular edema, definite nonproliferative retinopathy, or proliferative changes. Primary OAG was defined as cases that had optic nerve damage and/or reproducible visual field loss.
Statistical Methods
To obtain projections of an eye disease’s prevalence through 2050, the following statistical modeling strategy and methods were used: (1) we needed to obtain the joint race-sex-age distribution of the population through 2050; and (2) for each specific age-race-sex demographic, we needed to estimate/have the prevalence rate of the given eye disease for that specific group. For step 1, we modeled the joint race-sex-age distribution of population as a product of the marginal distribution of age with the joint race-sex distribution of the population. The marginal distribution of age in the population was based on the Georgia state population projections and demographic data as described below. And the joint race-sex distribution of population was based on the current population demographic stratifications.
Population projections and demographic data were obtained from the Georgia Governor’s Office of Planning and Budget. Per the Governor’s website the current population data comes from the US Census and the projections were “prepared using the standard cohort component demographic methodology, relying upon recent historical fertility, migration, and age data.” We used the population projections to 2050 stratified by age group to account for the aging population and applied the current population demographic stratifications to these projections, under the assumption that the race and sex stratifications will not significantly change between now and 2050 in Georgia and that aging will affect different races and sexes to the same extent. This assumption was necessary given the limitations of data available and unknown migration patterns.
For step 2 we used Prevent Blindness America prevalence value for each eye disease within a specific age, race, and sex demographic to calculate the projected prevalence of visual impairment, blindness, OAG, cataract, and AMD, using the assumption that within each demographic category, the incidence of each disease would remain stable and not significantly change between now and 2050. To compare our results to the overall US data, we used the published data from Prevent Blindness America’s “The Future of Vision” report.
For DR, we used the 2017 International Diabetes Federation Atlas on the projected prevalence of diabetes (2015 and 2040) and applied this to our Georgia census data. We then used 2008 CDC data on the prevalence of DR among those with diabetes, and applied age-specific DR prevalence values to the corresponding age groups among those with diabetes in 2015 and 2040. These methods assume that the prevalence of DR among those with diabetes would not significantly change between now and 2050. This captures the future prevalence of DR while accounting for the increase in diabetes prevalence as well as the aging population.
Results
Current estimates for the burden of eye disease in the state of Georgia in 2013 include 71,000 people with visual impairment, with an additional 32,000 blind individuals. The most common cause of visual impairment is presence of (both corrected and uncorrected) refractive error, affecting over 1.4 million people. Cataract is the next most common cause, with nearly 677,000 cases in the state in 2013. Glaucoma and AMD affect 100,000 and 43,000 people, respectively.
Georgia’s Governor’s Office anticipates a 47% increase in the population by year 2050. In Georgia in 2050, there will be a projected 226,000 visually impaired persons, and nearly 100,000 will be blind. A total of 65% of those who are visually impaired or blind will be aged 80 or older. There will be 1.7 million cases of cataract and 2.3 million of refractive error. Additionally, there will be over 250,000 cases of glaucoma and 117,000 cases of AMD. Full results for the projected cases of visual impairment, blindness, and its major causes are outlined in Table 1 .
| Age Group | Blindness (SD) | Visual Impairment (SD) | AMD (SD) | Glaucoma (SD) | Cataract (SD) |
|---|---|---|---|---|---|
| 40-49 | 2,553 (50) | 3,037 (55) | N/A | 15,694 (125) | 46,630 (213) |
| 50-59 | 4,270 (65) | 7,001 (83) | 9,128 (95) | 28,312 (167) | 144,410 (364) |
| 60-69 | 8,750 (93) | 19,277 (138) | 14,183 (119) | 48,745 (216) | 346,616 (523) |
| 70-79 | 18,603 (135) | 50,483 (220) | 26,626 (161) | 69,612 (255) | 556,012 (571) |
| 80+ | 64,318 (244) | 146,601 (353) | 67,353 (245) | 91,683 (288) | 619,940 (483) |
| Total | 98,494 (306) | 226,350 (449) | 117,291 (330) | 254,047 (488) | 1,713,608 (1006) |
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