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Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

1
INTRODUCTION

The problem of visual loss is recognized as a significant issue by the American public. The federal government recognized the potential disability associated with visual loss when it incorporated Aid to the Blind into the Social Security Act of 1935 (Koestler, 1976, p.45). Thus, the issue of the appropriate determination of disability for individuals with visual impairment is an important one for the Social Security Administration (SSA).

This report assesses the existing disability determination process used by SSA to identify individuals with visual impairments in the context of current scientific knowledge and clinical practice. The charge of the Committee on Disability Determination for Individuals with Visual Impairments was to:

  • Evaluate current scientific understanding of the visual demands of everyday tasks, including information that can be obtained from quality-of-life measures.

  • Examine the adequacy of the current tests of central visual acuity and visual field as measures of the capacity to work.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×
  • Explore other existing tests of visual function as means of simply and reliably estimating visual capacity, alone or in combination with other tests.

  • Examine the potential value of new measures and procedures for estimating visual disability.

  • Identify where more work might be required to better characterize visual impairments, to better estimate functional capacity, and to better characterize the visual requirements of work and everyday tasks.

This report is the committee’s response to these challenges.

ISSUES THAT PROMPTED THE STUDY

SSA administers benefits programs for people with long-lasting disabilities that severely affect their ability to work or, for children, to perform everyday activities like their peers. Under Title II of the Social Security Act, workers covered by Social Security may qualify for benefits called Social Security Disability Insurance (SSDI, often referred to as DI). Under Title XVI, adults and children who are not eligible for DI may qualify for Supplemental Security Income (SSI) benefits, which are means-tested disability benefits. For each person who comes to SSA to request disability benefits (formally referred to as a “claimant”), SSA must determine whether he or she is eligible under the program regulations that implement the laws Congress has enacted for Social Security disability benefits.

SSA was concerned that, while its criteria are intended to identify claimants whose visual impairment severely reduces their ability to work, the agency has little information about the relationship between performance on medical tests of vision and performance of vision-dependent tasks on the job. The SSA Office of Disability is also aware that the criteria it uses are based on old medical practices and that new and refined methods of testing visual function are being used in the medical and rehabilitation communities.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

Predicting Performance in the Workplace

The overall goal of disability assessment is to establish functional capacity (fitness for work). The committee examined how best to do that, whether through the use of simple tests of visual function, such as acuity and visual fields, or through testing more complex, visually dependent skills, such as reading and driving, or even through the direct measurement of visual performance in the workplace.

A good deal is now known about the visual requirements of work-related tasks like reading and mobility, as well as about the visual capabilities most missed by people with impaired vision. Much work has also been done to assess the impact of different degrees of visual impairment on a person’s quality of life, by using questionnaires and by observation of behavior in different everyday contexts. Although the measurement of overall performance has been a major focus of research on people with low vision and has become central to the assessment of disability in children (discussed below), it has not been systematically examined as a means of assessing visual disability in adults.

Adequacy of Current Tests

The SSA disability determination process uses basic tests of visual acuity and visual fields that were standardized in the 1950s. The SSA regulations specify quite precisely some conditions under which tests should be administered but provide little guidance on others, particularly those for the measurement of acuity. Understanding of what the tests measure has advanced greatly since the SSA regulations were formulated, and the instruments used for measurement have been much improved, offering the prospect of more refined and reliable assessment.

Recognizing this, in 1994 SSA sought advice from the National Research Council’s Committee on Vision on the testing and scoring procedures that should be used to obtain reliable measures of central visual acuity and visual fields. The resulting report (National Research Council,

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

1994) noted that the current standards have important weaknesses, in addition to making recommendations about how tests should be administered in ways that conform to the standards. That report served as a point of departure for the current study, and its findings informed our investigation of visual disability determination methods.

Limited Range of Visual Functions Tested

The tests of central visual acuity and visual fields described in SSA’s medical listings assess key aspects of visual performance, but they do not touch on other dimensions of vision that may be relevant to overall functioning in everyday life and the workplace. In its 1994 report, the Committee on Vision commented on some of these, which we mention here.

An important element of normal vision is the capacity to distinguish small differences in the brightness of adjacent regions in a scene. The better one’s spatial contrast sensitivity, the better one can distinguish an object from similar surroundings, and the better one can distinguish fine detail. Contrast sensitivity has been studied systematically since the 1960s, and its potential importance in clinical assessment has only recently been recognized. Impaired contrast sensitivity can result in poor vision that is not readily detected by such measures as visual acuity.

Other visual capabilities that are potentially important include binocular vision, which is the use of two eyes to provide normal vision. Disruptions of binocular vision can lead to double vision and impaired capacity to distinguish small differences in depth. The SSA criteria take no account of impairments of binocular vision other than those that might arise through paralysis of the eye muscles.

Impairments of color vision, both congenital and acquired, are not uncommon, especially among males. These generally result in one’s being unable to distinguish colors that are readily distinguished by people with normal color vision. The SSA criteria take no account of the weaknesses of color vision, either as isolated impairments or in conjunction with others.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

There are at least two issues related to the brightness or darkness of the environment in which a person is trying to see: adaptation and glare. The normal visual system is able to adjust its sensitivity rapidly (adapt), so that one can see well over the very wide range of light intensities encountered in normal life. Impairments of adaptation can leave one unable to see well at low or high light levels. The SSA criteria do not touch on impairments of light or dark adaptation.

Light from a bright source in the field of view can be scattered within the eye. This scattering, known as glare, reduces the contrast in the retinal image. Some people are very susceptible to glare and their vision can be much impaired by it. The SSA criteria do not provide for the measurement of susceptibility to glare.

Visual search is another aspect of visual function that may be important in everyday life and work. It allows one to locate and select objects of importance in the environment, in order to respond appropriately to them. This function is not now part of the testing for disability determination.

PREVALENCE AND SIGNIFICANCE OF VISUAL IMPAIRMENTS

Estimates of Visual Loss

There are many different estimates of the number or prevalence rates of people in the United States with visual impairments, all supporting the assertion that this population is significant, is likely to be greater in underserved populations, and increases markedly with age. The variation among estimates is in part due to differences among the surveys in the assessment of vision (self-report of vision loss versus loss based on standard visual testing), differences in definitions of blindness and visual impairment, and differences in the age, socioeconomic status, and racial/ethnic mix of the populations studied.

The committee reviewed several population-based studies that included detailed examination of visual status, not all of them based

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

on U.S. populations. They include the Baltimore Eye Survey (Rahmani et al., 1996; Tielsch et al., 1990), the Beaver Dam Eye Study (Klein et al., 1991), the Rotterdam Study (Klaver et al., 1998), the Blue Mountains Eye Study (Attebo et al., 1996), the SKI study (Brabyn et al., 2000), Proyecto VER, a study of Hispanic populations in Arizona (Munoz et al., 2002; Rodriguez et al., 2002) and the Salisbury Eye Evaluation Study (Rubin et al., 1997). Because visual loss is strongly dependent on age, most of these studies are based on older population samples, ranging from age 40 and older in the Baltimore study to age 65 and older in the Salisbury study. Each of these studies except one examined sample sizes of 2,500 or more subjects, with four each having over 4,000 subjects. Table 1-1 shows their reported rates for blindness and measured visual impairment, according to the study definitions. Rates cannot be directly compared, however, because the actual age structure may differ among study populations.

The rates of blindness and visual impairment as reported in the age-specific analyses in these studies suggest that blacks and Hispanics have more vision loss than whites. The data are difficult to summarize for several reasons: the studies used different definitions of visual loss, the age distributions are different (e.g., the Hispanic population age 40 and older is much younger than other populations age 40 and older), some studies are decades older than others and are affected by the rise in the rate of cataract surgeries, and the age ranges vary from 40 and older to 65 and older. Overall, the prevalence of blindness varied from 0.3 percent in a population age 40 and older to greater than 1.7 percent in a black population age 65 and older. Blindness rates in the populations less than age 65 are unstable because vision loss is rare; most studies report rates of less than 0.3 percent.

The studies in which detailed ophthalmological examinations have been carried out to determine causes of visual loss were most informative as to major causes of vision impairment in adults. These causes will change with age, as cataract, glaucoma, and age-related macular degeneration (AMD) assume more prominence in the older age groups. There are also shifting trends over time related to changes in medical practice, as cataract surgery has become more frequent in the past 15 years, leading to less cataract blindness and visual loss over time.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

The ranking of causes is quite different in the 40 to 65 age group than in the older group, with AMD and cataract, disorders commonly related to age, accounting for much less of the total impairment in the younger age group. Diabetic retinopathy and other causes of visual loss were much more important at younger ages. AMD was the leading cause of blindness among whites, and cataract, glaucoma, and diabetic retinopathy the leading causes among blacks. For Hispanics, the leading cause of blindness was glaucoma; the leading cause of visual loss was cataract, followed by diabetic retinopathy and AMD.

The committee recognizes that many people with visual impairments have other impairments as well. We considered this in our evaluation of tests, noting when particular tests require capabilities in addition to vision, such as motor skills or literacy. We have given the most attention to this issue in the discussion of tests for infants and children, for whom multiple impairments are especially important (Chapter 4). We have not, however, considered how the results of tests for visual impairments might be combined with those for other impairments to produce composite disability scores. This issue is beyond the scope of work the committee was asked to perform.

Self-Reported Visual Problems

In addition to actual ophthalmological determination of visual loss are people’s perceptions of visual problems and the self-reported impact on function that such problems may cause. Various health surveys have used different phrases, such as “cannot see at all,” when asking respondents whether they are blind. One estimate of the numbers of persons with disability due to self-reported visual impairments1 is based on the 1992 National Health Interview Survey

1  

The committee prefers to use the term “impairment” only to refer to measured loss of visual function, and to refer to self-reported losses as vision “problems” or “limitations.” However, the NHIS questionnaire and datasets use the term “impairment” for such self-reported losses, so we have used it in that way in reference to NHIS data only.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

TABLE 1-1 Rates of Visual Impairment (VI) and Blindness in Population-Based Studies

Authors

Population

Beaver Dam

White (one city in Wisconsin)

Baltimore:

White (inner city)

 

Black (inner city)

Blue Mountain

White (Australian city)

Rotterdam

White (one district in city, Holland)

VER

Hispanic (2 cities, Arizona)

Salisbury

Eye Evaluation

White (city in Maryland)

 

Black (city in Maryland)

*This definition of visual impairment is more lenient than that of the other studies; it includes those with acuity of 20/40, whereas others defined impairment as acuity worse than 20/40.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

Age Range

Definitions

Data

43+

VI *: ≤20/40

Blind: ≤20/200

VI: 5.2%

Blind:0.5%

40+

VI: <20/40

(white):2.2%

(black): 3.9%

 

Blind: ≤20/200

(white): 0.76%

(black): 1.75%

49+

VI: <20/40

Blind: ≤20/200

4%

0.7%

55+

VI: <20/40

Blind: ≤20/200

3.8%

0.75%

40+

VI: <20/40

Blind: (20/200

1.9%

0.3%

65+

VI: <20/40

(white):2.7%

(black): 5.3%

 

Blind: ≤20/200

(white): 0.5%

(black): 1.7%

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

(LaPlante & Carlson, 1996). Visual impairment was estimated as the “main cause of activity limitation” for 558,000 people of all ages in the United States in 1992, with “blindness in both eyes” accounting for 189,000 of these. Reported visual impairments were the main condition causing work limitation for 256,000 people ages 18 to 69, and were one of “all conditions” causing work limitations for 580,000 people in this age range.

The employment and economic well-being of those reporting serious visual limitations is substantially affected, as the following section shows.

Visual Limitations and the Workplace

Unambiguous data on the prevalence of visual limitations among the population covered by the SSDI and SSI programs—working-age people ages 18-64, and children 0-17—do not exist. Nor do data on the employment and economic well-being of those populations.

Quite detailed objectively reported data on the visual limitations of subpopulations in the United States and other countries are available based on professional evaluations by clinicians, as reviewed above. But most of these studies have relatively small sample sizes and focus on older populations that contain a relatively large share of men and women age 65 and older who are not actively seeking employment, are not eligible for Social Security disability benefits, and are unlikely to be representative of the younger populations that these programs cover. We found no clinically based samples drawn from random samples of the children and the working-age populations eligible for SSI or SSDI benefits.

We were able to find nationally representative data on children and the working-age population, but these data, while rich in socioeconomic information, based all of their information about visual limitations on self-reports. Also, the questions asked were quite extreme in their attempt to identify visual limitations—for example, “Are you blind in both eyes?” Finally, because “blind in both eyes” and other serious visual limitations are relatively rare, even in quite

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

large nationally representative samples, only a small number of people is actually identified, and hence it is difficult to obtain reliable estimates for subpopulations with these impairments—children, working-age population, men, women, etc.

An analysis of such self-reported data shows that there is substantial heterogeneity in the working-age population with disabilities. A study commissioned by the committee and included in Appendix A offers an approximation of the prevalence of visual limitations in the working-age population in the United States (ages 25-61) as well as their employment and economic well-being (Houtenville, 2001). Houtenville uses a random one-sixth sample of the working-age population reporting visual impairments (and other severe impairments), as well as a sample of the entire working-age population of the National Health Interview Survey (NHIS). Respondents were first asked if they had a health-based work limitation, and only then were they asked about the kind of impairment that limited their work (this procedure is referred to here as the choice-based sample). Because visual impairments are relatively rare in the working-age population, Houtenville pooled cross-sectional data from the NHIS for the years 1983-1996.

For the one-sixth random sample for all years, Houtenville found that 0.17 percent of working-age men and 0.17 percent of working-age women reported being “blind in both eyes.” A larger percentage of men (4.89) and women (2.38) in this age range reported “some visual impairment.” For the sample of working-age men and women who are asked about their impairments only if they first report that they have a work limitation, the percentage of men (0.10) and women (0.08) reporting being blind in both eyes fell dramatically. The same situation was found for men (0.67) and women (0.39) reporting some visual impairment. Houtenville shows that choice-based samples that ask only those who first report a work limitation about their impairment reported a significantly lower prevalence of these impairments in the working-age population. Nevertheless, his prevalence findings using the one-sixth random sample are still somewhat lower than those found in the population-based studies reported in Table 1-1. This is of course in large part likely to be caused by the much younger average working-age population he considered.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

Using the random sample, Houtenville found that 49.4 percent of working-age men who report being blind in both eyes have worked over the past two weeks, but only 32.4 percent of a choice-based sample have done so. Of the other impairment categories he considered, only men with mental retardation or paraplegia, hemiplegia, or quadriplegia have significantly lower employment rates. In the choice-based sample, only those with paraplegia, hemiplegia, or quadriplegia have significantly lower employment rates. For women, no other group has significantly lower employment rates. In contrast, those with other visual impairments have significantly higher employment rates than do those who are blind in both eyes in both samples.

Overall, Houtenville (2001) found that men and women who are blind in both eyes are consistently less likely to be employed and more likely to receive SSDI or SSI and to live in lower-income households than those without visual impairment. In addition, he found that this is also true when those who are blind in both eyes are compared with all but the most serious impairment groups. However, he also found that those with vision impairments other than blindness in both eyes are significantly more connected to the labor force and live in higher-income households than those who are blind in both eyes.

Few studies have looked at the employment of working-age people with visual impairment from a national perspective. Houtenville (2001) compared his findings with those of Trupin et al. (1997) and Kirchner et al. (1999). While the definition of serious vision impairment varies across the three studies, the employment rates found in these studies are approximately the same for similarly defined populations.

In summary, Houtenville found considerable heterogeneity in the severity of impairments in the population with disabilities both across and within impairment groups. Those with severe visual impairments—that is, blindness in both eyes—have significantly lower employment rates and a higher prevalence of SSDI and SSI receipt than those with other visual impairments. While household income of those who are blind in both eyes is closer to that of the average household income of other impairment groups, it is still relatively low.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

This suggests that those who are blind in both eyes and those with other serious visual impairments, as well as those with other serious impairments (e.g., mental retardation, paraplegia, hemiplegia, quadriplegia, cerebral palsy), are appropriate beneficiaries of SSDI and SSI benefits.

Houtenville’s analysis of the NHIS data reported above is strongly suggestive of the importance of good vision for employment. The actual visual requirements in the workplace are extremely variable and not well documented. The committee turned to two major sources for information on the visual demands of the work environment: (1) O*NET, a job analysis database currently being developed by the U.S. Department of Labor and (2) the dataset associated with the Position Analysis Questionnaire (PAQ), a proprietary job analysis system. These are discussed in more detail in Chapter 3. Our analyses point out the importance of several key activities in the workplace for which visual input to performance is highly important: reading, mobility, social participation, and the use of tools. The committee specifically focused attention on these four activities to evaluate the possibilities for using performance-based tests of function in these domains to determine disability.

Children and Visual Impairments

Children, especially young children, present a special set of issues for disability determination because they often cannot be tested using the same methods used with adults. Moreover, it is difficult to find reliable information on the number of children with visual impairments in the United States. Because of the reporting requirements for federal programs mandating educational services for children with impairments, statistics are available on the number of children with various impairments served by programs funded under the federal Individuals with Disabilities Education Act (IDEA). The figures quoted here are taken from the 22nd annual report to Congress on the implementation of the Individuals with Disabilities Education Act by the Department of Education (U.S. Department of Education, Office of Special Education Programs, 2000).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×
Limitations of the Data

The 2000 IDEA report makes clear that, especially for infants and toddlers served by IDEA Part C and for preschoolers served under Part B, the proportion of children in the population served by these programs has not yet peaked and may vary widely from state to state. “Child-finding” efforts may be more successfully implemented in some areas than in others. In addition, in a few states, changes in methods of reporting have led to large year-to-year changes in the number of children reported as receiving services under IDEA. This report provides figures for children with visual impairments and for children categorized as deaf-blind. However, more children with visual impairments are served by these programs than are included in those two categories, since an unknown number of visually impaired children are included in the “multiple disabilities” category.

School-Age Children

Table 1-2 shows statistics for children with visual impairments taken from Table AA18 of the IDEA report (U.S. Department of Education, Office of Special Education Programs, 2000). Year-to-year changes could be the result of changes not only in the prevalence of visual impairments but also in the proportion of such children being deemed eligible and being served through these programs.

The table shows a slow but steady increase in the number of children with visual impairments served over the 10-year period, from 24,499 in 1989-1990 to 27,741 (a bit over 13 percent increase) in 1998-1999. The report estimates that the population of the United States and its territories for this age group grew from 56.5 to 63.35 million over the period 1988-1999 (no 1989 figures are given), an increase of about 12.1 percent. Thus the proportion of the population ages 6-21 served by the programs for visually impaired and deaf-blind children increased very slightly over the period of the report.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×
Infants, Toddlers, and Preschoolers

The statistical tables in the Department of Education 2000 report do not break out numbers by types of disabilities for children under age 6. Table AH5 of the report provides the number of infants and young children receiving services under Part C of IDEA, which serves infants and toddlers up to age 3. The table is sorted by type of services provided, as listed on the Individualized Family Service Plans developed for these youngest children. “Vision services” were provided to 8,846 infants and toddlers in 1997, the year reported in the 2000 report. This report does not provide figures for preschool children (ages 3-5) by type of services provided. The report includes some early findings from the National Early Intervention Longitudinal Study (NEILS), now under way, which should provide more detailed information on early childhood programs when it is completed.

Significant Public Health Problem

The SSA caseload under current program regulations suggests the magnitude of this problem. As of June 2001, there were 250,340 people receiving benefits on the basis either of blindness or of disability on the basis of visual impairment: 148,745 under Title II and 101,595 under Title XVI. Figure 1-1 shows an age-group breakdown for these beneficiaries. It is clear that the number of beneficiaries rises steeply with age within the working-age range. This is noteworthy, as the age distribution of the working-age population has already begun to shift toward older workers.

Over the past five years, SSA has received about 20,000 to 22,000 claims annually in the DI program and 17,000 to 20,000 in the SSI program from people claiming disability from visual impairments including blindness. In 2000, 57 percent of SSDI claims and 51 percent of SSI initial claims for visual impairments were allowed. Over the five years, the proportion of SSDI initial claims allowed has risen steadily from 49 percent in 1996 to 57 percent in 2000, with a growing number meeting the statutory blindness criteria, and

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

TABLE 1-2 Number of Children Served Under IDEA by Disability and Age Group, During the 1989-1990 Through 1998-1999 School Years

 

Year

Age Group

Category

1989-

1990

1990-

1991

1991-

1992

1992-

1993

6-11

 

Visual

Impairments

10,956

11,347

11,635

11,210

Deaf-Blind

684

651

608

554

Total

11,640

11,998

12,243

11,764

12-17

 

Visual

Impairments

9,980

10,350

10,530

10,641

Deaf-Blind

624

587

594

599

Total

10,604

10,937

11,124

11,240

18-21

 

Visual

Impairments

1,930

1,985

1,918

1,693

Deaf-Blind

325

286

225

241

Total

2,255

2,271

2,143

1,934

All

6-21

 

Visual

Impairments

22,866

23,682

24,083

23,544

Deaf-Blind

1,633

1,524

1,427

1,394

Total

24,499

25,206

25,510

24,938

 

Source: U.S. Department of Education, Office of Special Education Programs, (2000: Table AA18).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

Year

1993-

1994

1994-

1995

1995-

1996

1996-

1997

1997-

1998

1998-

1999

 

 

11,723

11,557

11,870

11,843

12,088

12,135

564

524

547

508

562

646

12,287

12,081

12,417

12,351

12,650

12,781

 

 

11,357

11,445

11,864

12,072

12,033

11,991

585

600

619

559

679

718

11,942

12,045

12,483

12,631

12,712

12,709

 

 

1,724

1,711

1,756

1,847

1,910

2,006

220

207

221

193

219

245

1,944

1,918

1,977

2,040

2,129

2,251

 

 

24,804

24,713

25,490

25,762

26,031

26,132

1,369

1,331

1,387

1,260

1,460

1,609

26,173

26,044

26,877

27,022

27,491

27,741

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

FIGURE 1-1. SSA Visually impaired and statutorily blind beneficiaries by age, June 2001.

declining numbers meeting the disability criteria without being statutorily blind.2

For SSI, the total percentage approved increased from 41 percent in 1997 to 51 percent in 1998 and has stayed at about that level. The 1998 figures show a large increase in the number of claims allowed for all categories of visual impairment, with much of the increase attributable to an increase in the number of claimants over 60 years of age. For this age group, the percentage of claims allowed ranges from 68 to 77 percent. In general, the proportion of claims allowed increases with the claimant’s age, as would be expected when age is included as a vocational factor in the determination. The total number of claimants rose substantially between 1989 and 1996. Changes in eligibility rules in 1996 have resulted in slight declines thereafter.

2  

These figures are taken from various SSA data files and were prepared for the committee by staff of Social Security Administration Office of Disability, Division of Disability Program Information and Studies (DMAB1).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

These data on the magnitude of the problem of blindness and visual impairment point to a significant public health issue in the United States, with evidence of a negative impact on the economic and employment status of the individuals affected. Good vision appears to be an important component of jobs in the workplace, although certainly people with visual loss are not irretrievably excluded from the labor force, especially if a supportive physical and social environment exists. Maximizing the abilities of those with visual impairments through rehabilitation and training can also influence performance and participation in the workplace.

Nevertheless, there are circumstances in which visual impairment can severely reduce the ability of an individual to obtain employment, resulting in the need for a humane society to provide an economic safety net. The criteria used for determining such disability will naturally shift with the acquisition of knowledge about the functioning of the visual system, new tests and procedures, and changes in the conceptual framework of disability. The issues raised in this section provide the context for the work the committee undertook in preparing this report.

THE SOCIAL SECURITY CONTEXT

When children and adults apply for disability benefits and claim that a visual impairment has limited their ability to function, SSA is required to determine their eligibility for blindness and disability benefits (see Appendix C for a glossary of terms used in reference to SSA disability programs). To ensure that these determinations are made fairly and consistently, SSA has developed criteria for eligibility and a process for assessing each claimant against the criteria. The criteria are designed to make the determination process as objective as possible, but to leave some room for considering individual circumstances. The criteria include duration and severity of the disabling condition, employment and income (and assets for SSI), “medical listings” of conditions that are presumptively disabling, and such vocational factors as age, education, and work experience.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

In the case of people with visual impairments, SSA has medical listings criteria that parallel other federal and state agencies’ definitions of statutory blindness, based on Snellen visual acuity and visual fields, with some allowance for combinations of less severe impairments. These criteria are identical for SSDI and SSI benefits. For people who do not meet the medical listings criteria, additional tests of vision may be used in the evaluation of functional capacity, but there are no clear guidelines at present for evaluating visual impairments that do not meet the medical listing criteria.

SSDI is funded by the same trust fund as the well-known SSA retirement program. It is a contributory plan; that is, one must have worked under and contributed to the Social Security tax program (FICA) to be eligible for these benefits. SSDI covers only working-age adults and their dependents. At retirement age, SSDI beneficiaries transition to the retirement benefits program.

SSI is a means-tested program for old-age assistance, aid to the blind, and aid to permanently and totally disabled adults. Blind and disabled children from families with limited income and resources are also covered under this program. The program considers both income and assets in its means-testing. SSI blindness and disability determinations are made using the same process and criteria as the SSDI program. SSI children who are 18 and under are evaluated using a different process and criteria. Funding for this program is not from the Social Security Trust Fund; SSI is primarily funded through congressional appropriations. Adult eligibility for entitlement under both the SSI and SSDI programs is based on demonstrating that a disabling, medically determinable impairment is present in an individual whose labor earnings capacity has fallen below a set limit, termed substantial gainful activity (SGA). This labor earnings limit is set higher for claimants with blindness than it is for claimants with disability. Neither SSDI nor SSI has provisions for variable benefits based on severity of impairment; the claimant either meets the disability criteria or does not.

SSI is the only SSA program that covers children with blindness or disability. Although the definition of blindness is the same for children, the definition of disability for children is somewhat different

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

than that for adults. The definition of childhood disability has been changed more than once in recent years in response to court cases and legislation. Currently, if children do not meet the specifically listed medical criteria defining blindness and disability, they must be considered under an equivalence standard. The equivalence of their impairment to the specifically listed medical criteria must be evaluated by its medical or functional consequences; that is, it can medically equal a listed criterion or, using the functional domains cited in the SSA regulations, it can be judged functionally equivalent to the intent of the listings. The methodology used to make this decision is discussed below.

Procedures for Determining Disability

SSA reviews all claims for blindness and disability benefits using its sequential evaluation process. For adults, the process has five steps; for children, a three-step process is used.

Adults

For adults covered by SSDI and for adult SSI claimants, the disability determination process follows the steps shown in Figure 1-2. The first step of the sequential evaluation process requires that SSA determine whether the claimant is engaged in substantial gainful activity. Each year the SSA formally establishes an average monthly earnings level that serves to define SGA. The earnings limit is higher for blindness than it is for disability. For 2002, the monthly SGA limit is $780 for disabled claimants and $1,300 for blind claimants. If the claimant is determined not to be performing SGA, the case goes on to Step 2 of the sequential evaluation process. If the claimant is determined to be performing SGA, she or he is found ineligible for benefits at this step.

At Step 2, the claimant must document through a report or medical records provided by an acceptable medical source that a medically determinable impairment is present that significantly limits his or her

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

FIGURE 1-2. Disability decision flow for adults.

physical or mental ability to do basic work activities. Furthermore, medical evidence must support a judgment that the limitations imposed by the impairment have lasted or can be expected to last for at least 12 months or are expected to lead to the claimant’s death. If these criteria are satisfied, the claim progresses to Step 3. If the criteria are not satisfied, the claimant is found ineligible for benefits at this step.

Step 3 of the sequential evaluation process uses medical criteria as a screening test to identify claimants who are obviously blind or disabled. In this step, SSA must decide whether the claimant’s medically determinable impairment(s) meets or equals in severity the specific medical criteria listed in 20CFR Part 404, Subpart P, Appendix 1. This decision requires concurrence of a medical or psychological consultant. If the claimant has an impairment that is determined to meet or equal the listed criteria and that level of impairment severity has been demonstrated to have lasted or is expected to last for at least

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

12 months or to end in death, the claimant is found eligible for benefits. If not, the process continues to the consideration of vocational factors in Steps 4 and 5.

At this point in the process, the adjudicative team assesses the residual functional capacity of the claimant. Form SSA-4734-BK, called “Physical Residual Functional Capacity Assessment,” is used for physical impairments, and Form SSA 4734 is used when a mental impairment has been identified. These are assessments of what the claimant can do in spite of any physical and mental impairment over a 12-month period of time. The forms require assessment of exertional, postural, manipulative, visual, communicative, and environmental limitations. The visual functions listed include near and far acuity, depth perception, accommodation, color vision, and field of vision.

In Step 4, the decision makers must determine whether any of the claimant’s physical and mental limitations cited in the evaluations of residual functional capacity precludes the performance of “past relevant work.” If the claimant is found able to perform past relevant work in spite of cited physical and mental limitations, he or she is found ineligible for benefits. If the claimant is found unable to perform past relevant work, the claim goes to Step 5.

In Step 5, the SSA uses a defined set of profiles and rules that consider the claimant’s age, education, and work experience or skills. A decision is made whether the claimant is capable of performing any work in the U.S. economy. A so-called vocational grid is used as a decision aid, embodying the rules for determining disability. The grid combines the vocational factors and recommends findings for various combinations. Constructed in 1979 based on information from the Dictionary of Occupational Titles (Social Security Advisory Board, 2001b), it reflects SSA’s evaluation of the existence of work in the national economy. It was designed to be used in cases of limitations of strength and stamina, for example, to consider whether a claimant is able to perform “sedentary,” “light,” “medium,” or “heavy” work. It is not useful for other functional limitations, for which the assessment must be based on professional judgment.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

If the claimant is found to have a disability under the rules of Step 5, he or she is eligible for benefits. If he or she is found not to have a disability, benefits are denied. If a claimant disagrees with SSA’s decision, several levels of appeal are available.

Children

For children (covered under SSI only), a slightly different set of steps is followed, as shown in Figure 1-3.

Steps 1 and 2 are the same as for adults. Step 3 for children is initially the same as for adults. If a child is determined to have an impairment that meets or medically equals the criteria cited in the listings, and that impairment is expected to last for 12 months or to end in death, the child is eligible for SSI blindness or disability benefits. Since Steps 4 and 5 for adults are not appropriate for children, an additional

FIGURE 1-3. Disability decision flow for children.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

decision point has been added to Step 3 of the process for children. Under new rules that took effect January 2, 2001, when a child is found to have a medically determinable impairment that does not meet or medically equal a listed criterion, SSA must make a determination of whether the child’s impairment(s) functionally equals the intent of the listings.

The fundamental decision to be made is whether the effects of the impairment(s) are “marked and severe.” This is judged mainly on the child’s ability to perform in specific functional domains compared with normative data based on the ability of an unimpaired child of the same age, as discussed in Chapter 4. The new regulations specify the functional domains to be considered and give examples of age-appropriate levels of functioning for various age groups (20CFR §416.924-926a). The regulations state that “marked” limitation “is the equivalent of the functioning we would expect to find on standardized testing with scores that are at least two, but less than three standard deviations below the mean” (20 CFR §416.926a, (e) (ii)). “Extreme” limitation is described in a subsequent section as equivalent to at least three standard deviations below the mean.

If the child meets the functional equivalence criteria, which may be satisfied by showing marked limitations in two or more domains or extreme limitation in one domain, she or he is judged medically eligible for benefits. If not, she or he is ruled ineligible. All children who receive benefits must have their eligibility reviewed when they reach age 18, based on the adult SSI criteria.

Current Disability Criteria for Vision

In the discussion of Step 3 of the sequential evaluation process, we mentioned the listing of impairments found in Appendix 1 of subpart P of 20CFR Part 404. The vision listings deal principally with impairments of central visual acuity and visual fields. The vision listings are unique because the SSA statute includes a specific definition of blindness that is different from the definition of disability. People often refer to visual impairments that meet the

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

legislative and SSA definition of blindness as “statutory blindness.” We use the term here because it is important to understanding the SSA’s determination process and criteria, although the committee recognizes that most people who meet the statutory definition of “blindness” have useful vision.

Statutory Blindness

A person is considered to be statutorily blind under the following conditions:

  • Central visual acuity is 20/200 or worse in the better eye or

  • The visual field extends to less than 10° from the fixation point, or its greatest diameter is less than 20°.

Some of the vision listings deal with blindness and some deal with disability. Listing 2.02 defines a visual acuity loss that meets the statutory definition of blindness. Listing 2.03 addresses visual field impairments and includes criteria that define statutory blindness and other criteria that define disability. Listing 2.04 provides for a finding of disability based on overall loss of visual efficiency resulting from both visual acuity and visual field impairments in the better eye.

Central Visual Acuity

Visual acuity is the capacity to distinguish fine detail. It is generally best in the center of the visual field, the region a person uses when reading, for example. The listing stipulates that acuity should be measured in this region of (normally) highest acuity. Reduced visual acuity may be caused by refractive error in the eye’s optical system, which results in a blurred image on the retina. In most cases, reduced acuity is readily restored to normal by optical correction that compensates for the eye’s refractive error. The determination of the appropriate correction, undertaken separately for each eye, is called refraction. Acuity measured after correction is the best-corrected acuity.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

The listing stipulates that central visual acuity must be measured after best correction. Visual acuity loss that persists after best refractive correction can be a cause of blindness or disability under the SSA guidelines.

Most people without ocular pathology or amblyopia have best corrected visual acuities better than 20/20. The standard for blindness is a best-corrected central visual acuity in the eye with better acuity of 20/200 or worse.

Field of Vision

The visual field is the range of directions extending left, right, up, and down from the line of sight, over which the eye is sensitive to light. The normal field of vision can be reduced through contraction, resulting in the world’s being seen as if through a tube, or through the development of a blind region or scotoma, leaving unimpaired vision surrounding the region. Sometimes sighted regions exist as islands in an otherwise blind visual field.

For the purpose of determining blindness or disability on the basis of visual field impairment, the SSA listings measure the size of the visual field in the better eye under specified conditions. The extent of the contracted visual field is represented by the sum of its angular extents along eight directions from the line of sight (up, down, left, right, and the intermediate diagonals). For the normal visual field, this sum is considered to be 500°. The definition of blindness on the basis of contraction of the visual field is a visual field that extends to less than 10° from the point of fixation or, alternatively, a field with its greatest diameter less than 20°.

Loss of Visual Efficiency

Impaired visual acuity or an impaired visual field, which alone would not be severe enough to meet the standard for blindness or disability, may nevertheless in combination be determined to be disabling. SSA

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

TABLE 1-3 Percentage of Central Visual Efficiency Corresponding to Central Visual Acuity Notations for Distance in the Phakic and Aphakic Eye (Better Eye)

Snellen

Percent Central Visual Efficiency

English

Metric

Phakic

Aphakic

Monocular

Aphakic

Binocular

20/20

6/6

100

50

75

20/40

6/12

85

42

64

20/80

6/24

60

30

45

20/160

6/48

30

22

20/200

6/60

20

 

Source: Social Security Administration (2001: Table 1).

uses the term “visual efficiency” to represent the fraction of visual capacity that remains after losses are accounted for. It is derived by calculating “central visual efficiency” (acuity) and “visual field efficiency” separately, then combining them according to an SSA-provided algorithm. Listing 2.04 provides for the weighted combination of impairments, following the method set forth by Snell and Sterling (1925). Central visual efficiency for acuity is computed as

0.2 (MAR-1)/9

and expressed as a percentage (see the section on visual acuity in Chapter 2 for a definition of MAR). Table 1-3 shows how this measure of visual efficiency is related to Snellen acuity.

The standard for severe visual acuity listing-level impairment (20/200 or worse) is equivalent to a central visual efficiency of 20 percent or less in the better eye.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

The visual field efficiency of the contracted field is calculated as:

(sum of extents [in degrees from fixation point] along 8 meridia)/500

and expressed as a percentage. The standard for disability based on visual field impairment is a visual field efficiency of 20 percent or less.

The aggregate measure of visual efficiency is calculated by combining the measurements of less-than-listing-level impairments of visual acuity and visual field that are present in the same eye. It is calculated as:

central visual efficiency × visual field efficiency

and expressed as a percentage. Listing-level impairment is met when the overall visual efficiency of the better eye is 20 percent or less. For example, a claimant with central visual acuity of 40 percent and visual field efficiency of 50 percent would just meet this criterion (40 percent times 50 percent = 20 percent).

A person is not considered statutorily blind if the standard for disability is met only through loss of visual efficiency.

Criteria for Children

The listings include special provisions for the evaluation of children. Visual acuity of listing-level severity is the same as for adults (20/200 or worse), but SSA recognizes that conventional Snellen charts may not be suitable for very young children and admits other “appropriate” methods of measurement.

Quoting from the SSA regulations, for children younger than 3 years, the standard is met if the child shows (Social Security Administration, 2001, p. 147):

  1. Absence of accommodative reflex (except for infants under 6 months, plus any months of prematurity); or

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×
  1. Retrolental fibroplasia3 with macular scarring or neovascularization; or

  2. Bilateral congenital cataracts with visualization of the retinal red reflex only or when associated with other ocular pathology.

The visual field listing criteria are the same for children as for adults.

As noted above, a child’s impairments are considered to be functionally equivalent to the intent of the listings if he or she has “marked” limitations in two broad domains of function—cognition/ communication, social functioning, personal/behavioral functioning, and task completion—or an “extreme” limitation in one domain.

THE COMMITTEE’S APPROACH

The conceptual model underlying disability determination has been undergoing changes over the past several years, especially since the passage of the Americans with Disabilities Act (ADA) in 1990. The newer conceptualization follows a social model of disability, which postulates that factors both within the individual and in his or her physical and social/cultural environment combine to influence performance and participation in everyday life situations.

This model replaces the earlier stress on disability or handicap, and the negative aspects of an individual’s situation, emphasizing instead the person’s remaining capabilities and how they can best be supported to permit full economic and social participation. The ADA, based on the social model, represents a commitment in the United States to help individuals with disabilities to participate as fully as possible in the society and the economy.

3  

This is now more commonly referred to as retinopathy of prematurity. The International Classification of Diseases, Ninth Revision (ICD-9) allows for the use of either term.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

The social model also underlies the approach now taken by the World Health Organization toward disability and handicap. Whereas the International Classification of Impairment, Disability, and Handicap (ICIDH) (World Health Organization, 1980) established definitions for these terms, the new International Classification of Functioning, Disability and Health (ICF) (World Health Organization, 2001) is an attempt to fully account for the interactions between the individual and the physical and social environment in determining the participation of an individual with a disability.

Generic Concepts and Terms as Applied to Vision

The committee carefully considered the social model as it applies to those with visual impairment, recognizing that a diagnosis of a visual disorder (or even the measured severity of visual impairment) does not inevitably predict a person’s disability or handicap. However, this model does pose a dilemma for using the measurement of impairment as a surrogate for determining level of disability. In reviewing data on visual testing and functional status, the committee’s paradigm was deceptively simple: visual loss, by some measure, is associated with increasing inability to carry out activities associated with employment or, in the case of children, age-appropriate activities. The data bearing on this issue present a more complicated picture, because the same level of visual loss can result in a wide spectrum of disability level, depending on such diverse factors as education, age, presence of other comorbid conditions, and social and environmental support. Thus, there is substantial variation in functional status for any given level of visual loss.

The committee also carefully evaluated the fourth and fifth editions of the American Medical Association’s (AMA) Guides to the Evaluation of Permanent Impairment: Vision (American Medical Association, 1993, 2001). These guides are used in many workers’ compensation disability determination procedures and represent a more traditional quantitative approach to evaluating the disability resulting from specific levels of impairment.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

The committee has chosen a framework that recognizes a continuum from disorder to handicap: as one progresses from disease or disorder to impairment, and then to disability and to handicap, many variables within the individual and in his or her environment interact to determine the level of function. Figure 1-4, adapted from a document prepared as background for the 2001 AMA guides (International Society for Low Vision Research and Rehabilitation, 1999) illustrates this continuum. Instead of the term “functional vision,” we use “visual task performance,” which in our view more clearly expresses the intended meaning: performance of real-world tasks using vision.

At the left of the box are features of the organ (or organ system) and its function. Diseases, disorders, injuries, or other structural or physiological changes in an organ or organ system often lead to the outcomes we call disabilities, but they do not directly or unconditionally cause disabilities. Diseases or disorders affect the functioning of the organ system; in the case of the visual system, these are visual functions. Visual functions are measured using quantitative clinical tests, such as tests of acuity, visual fields, or contrast sensitivity. When we speak of visual functions we are referring to the performance of the visual system, more or less in isolation, under standardized measurement conditions.

An organ system function that fails to meet some agreed-on criterion of normal status is said to be impaired. Impairment refers to a measurable deficit in what the organ system is able to do, compared with its normal function. It may be expressed in such terms as “systolic blood pressure of 180 mmHg” or “visual acuity of less than 20/60 on a Snellen chart.”4

The right side of Figure 1-4 describes the capabilities and performance of the whole person in the environment. It starts with skills and abilities, meaningful things the person can do, like reading, driving,

4  

The ICIDH (World Health Organization, 1980) definition: “In the context of health experience, an impairment is any loss or abnormality of psychological, physiological, or anatomical structure or function” (p. 27).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

 

The Organ

The Person

Aspects:

Structural change, anatomical change

Functional change at the organ level

Skills, abilities of the individual

Social, economic consequences

Neutral Terms:

Health condition

Organ function

Skills, abilities

Social participation

Loss, limitation:

Disorder, injury

Impairment

Disability

Handicap

ICIDH—80:

Disorder

Impairment

Disability

Handicap

ICF:

Structural change

Functional change, impairment

Activity + performance code

Participation + performance code

Application to Vision:

 

Visual functions

--Measured quantitatively, e.g, visual acuity

Functional vision *

--Described qualitatively,e.g., reading ability

 

*Visual task performance in our framework

FIGURE 1-4. Aspects of vision loss.

Source: Adapted from International Society for Low Vision Research and Rehabilitation (1999).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

keyboarding, crossing the street, or identifying birds. Generally, abilities are described more qualitatively than the raw visual functions, although this report examines some quantitative measures of visual task performance that might be considered by SSA. From the concept of ability, it is a short step to the concept of disability, a reduction in or loss of an ability. Examples of visual disabilities include difficulty reading normal size print and using tools or small machinery. As noted above, disability is recognized as a complex interplay between the individual, the complexity of the task, and the surrounding environmental and social supports.5

The term handicap, in modern practice, refers to the result of an interaction between a person and the environment. We use it only to refer to the negative result of the interaction between a person’s impaired abilities and the environment in which she or he is attempting to function. Thus a disability that prevents a person from climbing stairs imposes a handicap when that person must live, work, or otherwise participate or obtain services in a structure that has stairs and lacks wheelchair ramps, elevators, or other assistive devices. Although the disability may be real and permanent, it need not result in a handicap if the person has a suitably designed supportive environment in which to live and work or is able to use assistive technology.6

SSA uses “disability” or “disabled” as a term that applies to those who are deemed eligible for disability benefits as a result of the formal determination process. The agency uses the terms to describe the relationship of the person to the criteria for its programs, not

5  

The ICIDH (World Health Organization, 1980) definition: “In the context of health experience, a disability is any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being” (p. 28).

6  

The ICIDH (World Health Organization, 1980) definition: “In the context of health experience, a handicap is a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual” (p. 29).

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

necessarily as a description of his or her personal functional status. The SSA disability determination process (already described) follows a path starting with a medical model, embodied in the listings of impairments, through Step 3 of the decision process; it then proceeds to a model that implicitly accounts for some social and physical environmental factors in the later steps, in which vocational factors are considered. The listed medical conditions are assumed to produce impairments so severe that individuals are disabled by the mere presence of the condition, as determined by physical diagnostic markers. For persons whose conditions meet or equal the listings and who are not engaged in substantial gainful activity, SSA does not require that functional capacity be evaluated to determine eligibility for benefits.

For those whose conditions do not meet or equal the medical listings, SSA switches to an evaluation of functional capacity in relation to the work environment (based on a simplistic model of work). The process evaluates the claimant’s ability first to perform recent relevant employment and then to perform any work in the U.S. economy. The vocational grids mentioned earlier are used as decision aids when the impairment is in the ability to perform physical labor, but for other work, the guidance is sparse at best. The decision maker considers the claimant’s age, education, and work experience, and, by implication, transferable skills. At this time, SSA prescribes no formal tests or evaluation protocols to determine what the claimant actually can do, no formal method for determining what disability might result from an individual’s impairments in the living and work environments, nor what the mitigating effects of environmental accommodations or assistive technology might be.

Vision-Specific Concepts and Terms

As explained above, visual functions are measured using quantitative clinical tests. When we speak of visual functions we are referring to the performance of the visual system, more or less in isolation, under standardized measurement conditions. The specific visual functions considered in this study are:

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×
  • visual acuity,

  • visual fields,

  • contrast sensitivity,

  • color vision,

  • binocular function,

  • visual search.

The committee also examined environmental conditions that may exacerbate visual impairments, chiefly extremes of lighting (glare, high or low luminance) and transitions between high and low luminance conditions. Full definitions of these visual functions are given in Chapter 2, which treats each of them in detail.

The committee selected four task or activity domains as exemplars of everyday and work functions in which vision is an important contributor to performance capability. The committee sought to identify categories of tasks that are important across a wide range of daily life and work situations, that may be reasonable surrogates for visually intensive job tasks, that are of moderate complexity, and for which data are available in the research literature. The selection process is discussed in more detail in Chapter 3. After considerable discussion of candidate task domains, the committee chose the following:

  • Reading and other sustained near tasks (e.g., computer use);

  • Mobility, including both ambulatory and driving situations;

  • Social participation, including visual communication;

  • Tool use and manipulation, including hand-eye coordination.

These domains were used as organizing concepts in our examination of the scientific evidence on relationships between visual functions and visual task performance.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

Lines of Inquiry

For the purposes of the SSA benefit programs, disability is defined by “the inability to engage in any substantial gainful activity, by reason of any medically determinable physical or mental impairment(s)” (Social Security Administration, 2001). SSA is required to document the disability of each claimant in the process of deciding whether he or she is eligible for disability benefits. Because disability represents the outcome of interactions between the person and his or her environment (both physical and social), there are many possible avenues for determining whether any individual claimant has a disability.

The first and most obvious variable is the measurement of the physical (in this case, visual) impairment. The committee examined how this is now done by SSA and also examined evidence on best practices for current tests and on new or emerging ways to test visual functions. We established psychometric and other criteria that vision tests should meet if they are to be recommended for use in SSA disability determination. We also gave careful consideration to what visual functions should be measured, evaluating evidence both for the importance of the functions for task performance and for the availability of tests that met our criteria. Finally, the committee reviewed ways in which to combine test results into a composite index of visual impairment.

Because disability occurs at the interface of visual ability and task demands, the next obvious area of inquiry was the determination of whether disability from visual causes could be determined by judging performance on a set of standardized tasks. In order to approach this issue, the committee selected a set of tasks or activity domains that represent common, visually intensive, job tasks. The committee pursued research on available survey-based job task taxonomies and datasets that include information on the visual requirements of jobs or job categories, which may serve to inform SSA policies or practices.

The committee considered the utility of directly measuring performance on these surrogate tasks, seeking information on instruments available for this purpose. Other information sources were questionnaire instruments that gather self-reports of

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

performance abilities from individuals, notably health-related quality of life instruments. Such instruments that have been developed specifically for people with visual disorders have been used to demonstrate a relationship between visual impairment and task performance limitations, and we examined these carefully.

The committee’s final line of inquiry was the examination of data on the employment and economic consequences of visual impairment. We commissioned studies of datasets generated by the National Health Interview Survey and the National Health and Nutrition Evaluation Survey, both nationally representative surveys conducted by the federal government that include information on self-reported disabilities and economic and employment status.

Information Sources and Standards

The committee and staff conducted literature searches in the peer-reviewed and technical literature (e.g., government-sponsored reports) on vision-related topics, testing, disability determination, disability programs, and other topics. For vision and vision testing, the peer-reviewed research and clinical literature was the predominant source, although many other sources were also tapped.

Standards for Evidence

Peer-reviewed scientific literature was the most desirable source of information for this study, and when it was available it was used. Committee members applied their professional judgment in evaluating the methodology of studies they reviewed, rejecting studies that appeared to be poorly designed, executed, or analyzed. Technical reports and other information sources, such as analyses of survey datasets, were evaluated for acceptability, with special attention to the data sources used in preparing the reports and to the methodology used. The committee often discussed the strengths and weaknesses of particular evidence in its deliberations.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
×

When weaknesses were found but a report or study was deemed worthy of inclusion, the weaknesses are discussed along with the evidence in this report. The committee is especially careful to note the limitations of epidemiological and survey-based studies that could be used to infer characteristics of populations. Often the findings are worth discussing, but only limited inferences can be drawn because of the size or other characteristics of the study sample. In some cases, the committee commissioned specialists to perform data analyses, to ensure that the analyses were done by people who knew well the idiosyncrasies and limitations of the source data.

Public Forum

In the committee’s view, it was important to obtain input for this study from organizations providing services to people with visual impairments and advocating for their interests. The committee therefore organized a public forum to gather input from these communities. Representatives of national and regional organizations and others were invited to make presentations. A list of organizations invited to nominate speakers and a list of speakers and major topics appear in Appendix B.

ORGANIZATION OF THE REPORT

Three chapters follow this introduction. Chapter 2 lays out the committee’s findings on tests of visual function. Each function is examined in detail, and tests of the function are evaluated for their potential value in disability determination, with detailed rationale for the conclusions that we reached and the recommendations we made. Chapter 3 presents our findings on the relationships between visual functions and the tasks of everyday life. It discusses the four task domains found to be important, as well as evaluations of health-related quality of life studies and occupational analysis methods and datasets. Chapter 4 covers the special issues that affect how children’s visual function can and should be tested.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
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Each of these chapters includes recommendations for SSA actions on visual disability determination, as well as for research that will improve visual disability determination. The recommendations cover what aspects of vision should be tested, how the tests should be conducted, and how to combine results of tests if warranted. Suggestions are provided for future research to address issues that remain unresolved.

Appendixes A through D provide the full text of one commissioned paper, the details of the public forum, a glossary of SSA terms, and brief biographical sketches of the committee members.

Suggested Citation:"1. Introduction." National Research Council. 2002. Visual Impairments: Determining Eligibility for Social Security Benefits. Washington, DC: The National Academies Press. doi: 10.17226/10320.
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Visual Impairments: Determining Eligibility for Social Security Benefits Get This Book
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When children and adults apply for disability benefits and claim that a visual impairment has limited their ability to function, the U.S. Social Security Administration (SSA) is required to determine their eligibility. To ensure that these determinations are made fairly and consistently, SSA has developed criteria for eligibility and a process for assessing each claimant against the criteria. Visual Impairments: Determining Eligibility for Social Security Benefits examines SSA's methods of determining disability for people with visual impairments, recommends changes that could be made now to improve the process and the outcomes, and identifies research needed to develop improved methods for the future. The report assesses tests of visual function, including visual acuity and visual fields whether visual impairments could be measured directly through visual task performance or other means of assessing disability. These other means include job analysis databases, which include information on the importance of vision to job tasks or skills, and measures of health-related quality of life, which take a person-centered approach to assessing visual function testing of infants and children, which differs in important ways from standard adult tests.

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