Abstract
The data provided in this study can inform resource allocation, workforce development, and entry-level occupational therapy education to address the ongoing needs of older adults with visual impairment, which limits meaningful participation in daily living.
In the United States, visual impairment (VI) affects more than 9 million adults age 65 yr and older (Centers for Disease Control and Prevention [CDC], 2022); this rate is expected to double by 2050 because the prevalence of VI increases with age (Varma et al., 2016.). In the United States, those age 65 yr and older make up 16% of the population (U.S. Census Bureau, 2021); it is estimated that by 2034, this percentage will increase to 23.4% (U.S. Census Bureau, 2018). Rates of VI increase from 0.9% to 2.2% for those ages 65 to 69 yr and from 10.5% to 20.0% for those age 80 yr and older (National Eye Institute [NEI], 2016). This rate also varies by racial subgroup. The prevalence rates of VI as a result of cataract, glaucoma, diabetic retinopathy, and uncorrected refractive error are elevated for Black, Hispanic, and multiracial people compared with White people (NEI, 2022a, 2022b; Zhang et al., 2012). Those at most risk for developing macular degeneration are White women older than age 80 yr (National Institute for Health and Care Excellence, 2018; Zambelli-Weiner et al., 2012).
Functionally, VI among older adults can influence the ability to complete daily tasks. Vision is important for most activities, such as grooming, clothing identification, smartphone use, and household management. Specifically, reading is required for many daily activities, such as financial management, meal preparation, and medication adherence. The loss of functional vision can lead to dependence in the performance of daily activity, depression, social isolation, increased assistance from care providers, and disengagement from community and society.
Because of the increasing prevalence of VI among the U.S. population and the resulting functional limitations, VI should be considered a public health priority. One strategy for addressing the needs of adults with VI in the United States is ensuring sufficient occupational therapy practitioners with adequate training in vision rehabilitation. Occupational therapy practitioners promote participation in daily life activities that enhance overall health and well-being. Prior research supports occupational therapy interventions for older adults with VI—including training in the use of problem solving, use of assistive technology and adaptive devices, use of visual skill training, education, environmental modifications, and linkages to community resources (Kaldenberg & Smallfield, 2020)—that can enhance the performance of daily activities.
Although all occupational therapy practitioners have general knowledge and skills to evaluate and provide proficient services to older adults with VI, practitioners specializing in this area can seek advanced training or certification. Many adults with VI require referral to occupational therapy practitioners with advanced training, especially for interventions such as technology and visual skill training. Given the importance that occupational therapy practitioners with specialized training in vision rehabilitation have in addressing the health and well-being of adults with VI, it is critical to understand (1) whether a sufficient number of practitioners with specialized training in vision rehabilitation are in the United States and (2) whether the geographic distribution of practitioners with specialized training in vision rehabilitation matches the geographic distribution of older adults with VI.
Prior research has provided population-level estimates of the prevalence of people with VI at the state and county level for all ages (CDC, 2022). However, those most affected by VI are those age 65 yr and older. To understand the current needs of those with VI throughout the United States, researchers need to document the prevalence of VI at a community or county level. In this study, we calculated the prevalence of VI by U.S. county and quantified and located the existing occupational therapy practitioners with certification in vision rehabilitation. On the basis of this information, we then identified whether enough adequately trained practitioners were present to meet the demand for vision rehabilitation services among older adults with VI.
Method
Design
A quantitative descriptive research design was used. Specifically, synthetic estimation was used to calculate the prevalence of VI among those age 65 yr and older in the United States by county. Synthetic estimation refers to combining data from multiple sources to produce estimates for a small-area population that are otherwise unavailable through an existing source of data (Sakshaug & Raghunathan, 2010). Synthetic estimation is often used in situations when it is difficult to acquire data for a small geographic area; it has also been used to assess health issues such as smoking prevalence (Szatkowski et al., 2015), psychological distress (McDaniel et al., 2020), drug use (Rhodes, 1993), and other topics. Moreover, geographic information systems (GIS) mapping was used to illustrate the prevalence of VI and availability of occupational therapy practitioners with specialized training in vision rehabilitation by U.S. town. GIS are computer-based tools that facilitate analyzing geospatial data and that can be used to answer questions about how disease or disability varies by location (CDC, 2019).
Data Sources
Two data sources were used to perform the synthetic estimation of those age 65 yr and older with VI by U.S. county: (1) U.S. census data regarding the annual county resident population estimates by age, sex, and race (U.S. Census Bureau, 2021) and (2) the NEI’s (2016) VI prevalence rates by age and race. Occupational therapy practitioners were defined as having specialty training in vision rehabilitation if they had completed one of the following items: (1) specialty certification in low vision from the American Occupational Therapy Association (AOTA, 2022), (2) certification as a low vision therapist from the Academy for Certification of Vision Rehabilitation and Education Professionals (ACVREP), or (3) completion of a graduate certificate in low vision. Currently, two graduate certificate programs are established in the United States, located at the University of Alabama at Birmingham and Salus University. These specialty trained occupational therapy practitioners were identified from four data sources: (1) AOTA’s specialty certification (AOTA, 2022); (2) ACVREP’s certification as a low vision therapist (Orli Weisser-Pike, personal communication, April 12, 2022); (3) University of Alabama’s low vision rehabilitation graduate certification program (Elizabeth Barstow, personal communication, May 20, 2022); and (4) Salus University’s low vision rehabilitation advanced clinician certificate (Caitlyn Foy, personal communication, July 22, 2022).
Procedures and Analysis
Occupational Therapy Practitioner Data Analysis
Occupational therapy practitioners with specialty training in vision rehabilitation were recorded in an Excel spreadsheet and organized by state and town to be used for GIS mapping.
Synthetic Estimation
A two-step process was used to generate synthetic estimates of VI by U.S. county. First, an Excel spreadsheet was created that listed the population age 65 yr and older by racial and age subgroups of each U.S. county with data from the U.S. Census Bureau’s (2021) county population characteristics data set. Racial subgroups were White, Black, Hispanic, and Asian, and age subgroups were ages 65 to 75 yr, 75 to 84 yr, and ≥85 yr. NEI estimates of the prevalence of VI for each demographic subpopulation were then used. The number of people in a demographic subcategory was multiplied by the prevalence of VI for that demographic subgroup to arrive at an estimated prevalence of VI for a particular U.S. county (for national prevalence rates based on age and race estimates, refer to Table 1).
National Prevalence Rates Based on Age and Race Estimates
Note. Data for national prevalence rates are from the National Eye Institute (2016).
An example of the synthetic estimation can be found in Table 2 for Broward County, Florida. Each age group was stratified by racial subgroup. National prevalence data for that age- and race-specific subgroup were then applied to calculate the estimated number of adults with VI in each category.
Synthetic Estimation of Broward County, Florida
Note. VI = visual impairment.
Geographic Information Systems Mapping
GIS mapping provides a visual display of data in relation to a location, in this case the United States. GIS mapping was performed with QGIS (Version 3.22.4; https://qgis.org/fr/site/). A database was created that included U.S. counties, parishes, and boroughs as the units of analysis. Variables for each geographic region included estimated prevalence rates for VI and the identified number of occupational therapy practitioners with specialized training in vision rehabilitation. After VI prevalence by county was calculated and existing practitioners were identified by the longitude and latitude of each city, GIS mapping was carried out. Prevalence by county was mapped with the obtained prevalence rates, represented by the gradient. Available occupational therapy practitioners were geocoded with longitude and latitude, and symbols were used to identify the practitioners with specialty training in vision rehabilitation (Table 3).
Number of Occupational Therapy Practitioners With Specialty Certification by State
Results
A GIS map was created to display the prevalence rate of VI by county and the number of occupational therapy practitioners with specialty training in vision rehabilitation by city within the United States. The map illustrates occupational therapy services available throughout the United States. The map can be used to identify high and low resourced communities.
Communities with high concentrations of older adults with VI were not distributed evenly throughout the United States (Figure 1). These communities were located primarily in southern Florida and the center of the United States, although some counties on the coasts have high concentrations, including Massachusetts, California, and the Long Island area of New York (see Figure 1).
Prevalence of visual impairment among adults age 65 yr and older and number of OTPs with specialty training in vision rehabilitation.
Occupational therapy practitioners with specialty training in vision rehabilitation are primarily located on the east coast of the United States, on both Florida coasts, in selected cities and towns in Texas and California, and in western Pennsylvania; a large concentration is also present in Alabama. No occupational therapy practitioners with advanced training or certification in vision rehabilitation are present in Delaware, Rhode Island, and Wyoming (see Table 3).
Discussion
This study has uncovered two important problems. First, few occupational therapy practitioners possess specialty training in vision rehabilitation. Second, the practitioners with specialty training are not evenly distributed throughout the United States. In fact, multiple states have five or fewer occupational therapy practitioners with specialty training. Thus, the availability of practitioners with specialty training in vision rehabilitation does not match the apparent need for services among older adults with VI. There may be mismatch between prevalence of VI and available vision rehabilitation services. Thus, although current health services in this area of practice may be sufficient, this study has identified a potential serious gap in health services availability.
Overall, communities with aging populations have the highest prevalence of VI and are located in suburban or rural areas in the center of the United States. Conversely, the greatest number of occupational therapy practitioners with specialty training in vision rehabilitation are found in larger urban communities and along the coasts. This finding is consistent with previous studies that revealed that rural communities had increased barriers to basic and specialty eye care services (MacLennan et al., 2014; Overbury & Wittich, 2011).
Limitations
In this study, synthetic estimation with population estimates was used, which may not represent the true population. Older adults may differ from the national sample; however, efforts were made to stratify the data by age and race to decrease potential error. The prevalence rates used for the synthetic estimation are reflective of 2016 data, whereas data for occupational therapy practitioners with specialized training were collected in 2022. In addition, specialty practitioners were identified from certifying bodies and university graduate certificate programs, which may not include all practitioners with specialized training in vision rehabilitation. Currently, few formal mechanisms (i.e., microcredentials, badges) recognize the professional development of occupational therapy practitioners with expertise obtained through other mechanisms. Finally, the reach of occupational therapy service provision was not addressed in this study.
Implications for Occupational Therapy Practice
Given the prevalence of VI among older adults in the United States, occupational therapy practitioners working with older adults are encountering adults with VI regardless of setting. Thus, all practitioners need to be prepared with the knowledge and skills to assess and provide interventions that support the visual needs of their clients. This objective can be obtained either by training currently licensed occupational therapy practitioners (workforce development) or through curricular development to ensure entry-level competency in vision rehabilitation. The current standards for occupational therapy education include only one criterion that specifically addresses VI intervention (Accreditation Council for Occupational Therapy Education, 2018). Academic curricula should incorporate vision specific assessment and intervention to develop competent clinicians to address the visual needs of the aging population in any practice setting.
Areas for continued research include analysis of service effectiveness provided within communities, sustainability, and evaluation of current entry-level occupational therapy education for those with VI. With the aging of the population, both prevalence and available services will be important factors to consider when identifying future health care resources.
Conclusion
Because the majority of VIs are progressive and chronic, the data provided in this study can inform resource allocation and program development to address the ongoing needs of people with VI. The GIS map is a useful tool to identify and prioritize efforts for new service provision, outreach to underserved populations, and education campaigns to improve awareness of vision rehabilitation services throughout the United States. Key findings indicate that an uneven distribution exists between older adults with VI and occupational therapy practitioners who can provide the needed vision rehabilitation. Occupational therapy can have a considerable impact on the functional independence of those with VI; however, access is limited. Ongoing professional development and advancement in vision rehabilitation education in entry-level occupational therapy programs can help bridge the gap in access and support the occupational performance of older adults with VI.
Footnotes
Acknowledgments
We thank Orli Weisser-Pike, Elizabeth Barstow, and Caitlyn Foy for their assistance in obtaining data regarding occupational therapy practitioners with specialty training in vision rehabilitation.