Visual Field Assessment and Disability Evaluation (2025)
Chapter: 2 How Other Selected Federal Agencies Assess Impairment Due to Visual Field Loss
2
How Other Selected Federal Agencies Assess Impairment Due to Visual Field Loss
Like the Social Security Administration (SSA), many government agencies have their own definitions of visual impairment and acceptable methods for assessing visual field loss. Assessments using these standards determine eligibility for disability benefits, eligibility for other disability-related programs, or qualification for jobs. Both definitions of visual impairment and assessment methods deemed acceptable vary between agencies.
Most agency definitions go beyond the federal definition of statutory blindness due to field loss, which requires that the widest diameter of a person’s visual field be 20 degrees or less at the visual horizon—in other words, 10 degrees in either direction from the point of central fixation. Some agencies, similarly to SSA, use statutory blindness as one of several criteria a person can meet to qualify as having a disability. Others adopt a functional definition of visual disability based on potential obstacles to engaging in relevant daily tasks. Most, however, set a specific visual field size that examinees must meet or not meet. The preferred perimeters and measurement techniques vary as well, with some permitting a broader selection of devices and techniques than others. Some of these differences are task specific and may involve stricter guidelines when safety is a concern. Stringent requirements can be found outside of occupational testing, such as in state-by-state visual requirements for driver’s licensure. However, the committee found many of these differences to be arbitrary.
The sections below review the criteria and methods used by selected federal agencies other than SSA for purposes of determining qualification for disability benefits, determining eligibility for employment in jobs that require good vision, and measuring functional vision.
DISABILITY BENEFITS
Like SSA, certain other federal and state agencies assess visual field loss to determine whether a person has a compensable disability. These agencies typically have the most rigorous and well-defined requirements for visual field measurement.
Department of Veterans Affairs
The Department of Veterans Affairs assesses the nature and severity of veterans’ service-related disabilities. These assessments result in “disability ratings,” expressed in percentages, that affect the monthly amount of a veteran’s disability compensation, as well as their eligibility for other benefits and programs.
The perimeter requirements1 of the Department of Veterans Affairs are very similar to those used by SSA for disability determination. For disability rating, visual field evaluation requires the use of manual or semiautomated kinetic perimeters, specifically “Goldmann [manual] kinetic perimetry or [semi]automated [kinetic] perimetry using Humphrey Model 750, Octopus Model 101, or later versions of these perimetric devices with simulated kinetic Goldmann testing capability.”2 These perimeters also meet SSA’s requirements for semiautomated kinetic perimetry. Also like SSA, the Department of Veterans Affairs requires that perimeters use the Goldmann III/4e stimulus. However, certain aphakic (lacking a lens) or pseudophakic (having an artificial lens implanted) veterans are allowed to use a IV/4e stimulus, which is larger. The Department of Veterans Affairs averages an individual’s remaining visual field (measured in degrees) across the eight principal meridians of the eye to determine the average concentric contraction of the visual field in each eye. Lower average concentric contractions result in higher disability ratings.
Office of Workers’ Compensation Programs
The Department of Labor’s Office of Workers’ Compensation Programs (OWCP) administers four federal workers’ compensation programs, each covering a different group of employees. Two of these—the Federal Employees’ Compensation Program and the Longshore Program—compensate employees who permanently lose limbs, organs, or their functions. For both of these programs, the loss of 80 percent or more of visual function is considered the same as completely losing the eye.3
___________________
1 CFR § 4.77
2 CFR § 4.77
3 See 5 USC § 8107(c) and 33 USC § 908(c).
The percentage loss of visual function is calculated using the American Medical Association’s (AMA’s) Guides to the Evaluation of Permanent Impairment (AMA, 2024). The sixth edition of the Guides assigns a visual field score based on the number of points along each of 10 meridians that a person can see. These meridians are different from the “eight principal meridians” referenced in SSA’s listings. The meridians in the Guides are located at 25, 65, 115, 155, 195, 225, 255, 285, 315, and 345 degrees radially around the point of fixation. The average normal visual field score is 100; a score of 20 or less corresponds to an impairment rating of 80 percent or more.
According to the Guides, tangent screen testing and confrontation testing are insufficient for assessing permanent impairment. These methods involve the manual movement of a disc against a physical background or of the physician’s finger in the air. Instead, it is suggested that examiners use either a Goldmann manual kinetic perimeter with the III/4e isopter or semiautomated kinetic perimetry with an equivalent “pseudoisopter”; this guidance is in line with SSA’s perimetry requirements, which are mentioned specifically in the Guides.
The Guides require manual or semiautomated kinetic perimetry for visual field assessment. The text notes that most static methods measure only the central 30 degrees of the visual field—that is, 30 degrees from the point of central fixation—and are therefore insufficient for the functional assessment of visual field loss, which requires measurement out to a 60-degree radius. If only larger isopters are available, they may be used with the understanding that they may underestimate field loss. Since smaller isopters would overestimate field loss, they are deemed unacceptable for impairment evaluation.
Many states also use various editions of the AMA Guides for assessing impairment in their own workers’ compensation programs (LexisNexis, 2019). However, some use their own state-developed standards. For example, New York State’s Workers’ Compensation Guidelines for Determining Impairment (Workers’ Compensation Board, 2017, p. 60) require that visual field extent be measured using “a perimetric method with a white target.” Like the Guides, the New York State Guidelines state that this method should be either a manual Goldmann kinetic perimeter with the III/4e isopter or an equivalent automated perimeter.
Federal Employees Retirement System
Another program for federal workers, the Federal Employees Retirement System (FERS), also offers disability retirement for civil servants who become disabled in a way that precludes “useful and efficient service” in their current or similar roles.4 Chapter 60 of the Civil Service Retirement
___________________
4 See 5 CFR § 844.102 “Useful and efficient service.”
System and FERS Handbook, which describes requirements and procedures for these disability annuities, include “Job Aids” that guide examining physicians in providing acceptable medical evidence (U.S. Office of Personnel Management, 1998). Section 60C1.1-10 contains such guidance for eye disorders. This section of the Handbook advises that confrontation testing is useful as a base physical examination and that perimetry may be useful as a “special study.” However, it does not require any specific perimeter or methodology.
Railroad Retirement Board
Retired railroad workers often receive a Railroad pension instead of Social Security retirement benefits. Railroad retirement benefits include a disability benefit. The Railroad Retirement Board (RRB), which manages retirement benefits for railroad workers, also manages disability evaluations and commensurate benefits. Generally, RRB impairment evaluations align with SSA’s Listing of Impairments, and while SSA disability determinations are not binding on RRB decisions, they are part of the evidence that RRB considers.5
However, the RRB also maintains its own Disability Claims Manual (DCM), which is used primarily to determine whether a person’s disability fully precludes them from railroad work as opposed to any regular work.6 The DCM prefers that visual field testing be performed using an arc perimetry device (RRB, 2021). Arc perimetry, which is typically fully manual and does not use computerized measurement, involves the movement of a disc along an arc-shaped track. This arc can be rotated to test along different angles. The device should use a 3-millimeter white disc-shaped target set at a distance of 330 millimeters from the examinee, and illumination for the test should be at least 7 foot-candles. However, a handheld arc perimeter (essentially a handheld disc) or a traditional (manual) Goldmann kinetic perimeter is also acceptable. The DCM further states that tangent screening and “various automated perimeters” are “not desirable instruments for disability determination purposes” because such devices “record an erroneously more constricted” visual field than the permitted perimeters (RRB, 2021, p. 65).
EMPLOYMENT QUALIFICATIONS
Other agencies assess visual field extent to determine eligibility for employment in roles requiring good vision. Such eligibility requirements will often define an acceptable range for visual field extent and may or
___________________
5 See 20 CFR § 220.100(b)(3) and 74 FR 63598.
6 See 20 CFR § 220.10(a). Typically, disabilities precluding any work will be evaluated using SSA’s listings and methodology for the purposes of RRB disability annuities.
may not define a preferred method for measurement. These requirements differ from SSA’s disability requirements in that they are designed to assess suitability for a specific occupation, whereas SSA’s disability determination process is meant to assess a person’s ability to hold any gainful occupation.
Federal Aviation Administration
The Federal Aviation Administration (FAA) requires that pilots obtain a medical certificate before flying. Different types of pilots need different classes of certificates. First- and second-class medical certificates, which are, respectively, necessary for airline transport pilots and other commercial pilots, require normal fields of vision.7 Air traffic controllers must also hold a second-class medical certificate.8
FAA medical certificates are granted by designated aviation medical examiners. Item 53 in the FAA’s (2025) Guide for Aviation Medical Examiners describes how aviation medical examiners test fields of vision. The FAA prefers a tangent screen test using a 2-millimeter white test object on a black-handled holder against a 50-square-inch black matte wall target. For this method, results are recorded as the distance from the fixation point, in inches, at which the examinee first identifies the target object along each radial. However, a “standard perimeter” or confrontation test is also permitted, although the Guide advises that confrontation tests vision primarily at the periphery rather than centrally. If a perimeter is used, “any significant deviation from normal field configuration will require evaluation by an eye specialist” (FAA, 2025, p. 393). No specific perimeter is mentioned as required.
Federal Railroad Administration
While the vast majority of railroads in the United States are privately owned and operated, the Federal Railroad Administration (FRA) requires that conductors and locomotive engineers have a “field of vision of at least 70 degrees in the horizontal meridian [or diameter] of each eye.”9
Beyond FRA requirements, individual railroads are given discretion to design their preferred medical assessments. As of 2018, for example, Union
___________________
7 See 14 CFR § 67.103(d) and 14 CFR § 67.203(d).
8 See 14 CFR § 65.31(c).
9 See 49 CFR § 240.121(c)(2) and 49 CFR § 242.117(h)(2). In the literature and in this report, meridian typically refers to a line from the fixation point to the edge of the visual field (i.e., a radius). While FRA’s requirements do not specify its meaning, typically the term horizontal meridian refers in the literature to a line running from the edge of the visual field nasally, through the fixation point, and to the other edge temporally (i.e., a diameter).
Pacific Railroad (2018) allowed for the use of automated perimeters such as the Humphrey Field Analyzer static automated perimeter, as well as Goldmann manual kinetic perimetry, when needed to measure full visual fields. A 2015 interim rule interpretation from FRA clarified that “the railroad must be able to cite a rigorous scientific study published in a peer-reviewed scientific or medical publication that demonstrates the scientific test is a valid, reliable, and comparable test for that visual capacity.”10 This differs from SSA guidelines, which require three clinical validation studies.
Federal Motor Carrier Safety Administration
The Federal Motor Carrier Safety Administration (FMCSA) sets regulations for drivers of commercial motor vehicles (e.g., truck drivers), such as physical qualifications. Like the FAA, FMCSA employs approved medical examiners to provide physical certification. Drivers must generally have a field of vision of at least 70 degrees horizontally in both eyes.11 Use of a specific measurement methodology is not required.
If only one eye fails to meet this standard, applicants may meet an alternative vision standard instead.12 Under this standard, both eyes must be retested, and the better eye must be verified to meet the 70-degree requirement. For this retest only, FMCSA mandates that an applicant’s visual field be tested out to 120 degrees horizontally (i.e., 60 degrees both temporally and nasally). No specific type of perimetry or perimeter is mandated.
Other Federal Agencies
Several other federal visual field standards for hiring are listed below. Note that these agencies do not require that any specific test be performed, and each specifies a total visual field extent across the combined nasal and temporal meridians:
- U.S. Merchant Mariner Medical Manual: Requires that “the horizontal field of vision should not be less than 100 degrees in each eye” for deck personnel and other crew, such as engineers, tankermen, barge supervisors, and radio officers (USCG, 2019, pp. 5-1, 5-2).
- Federal Interagency Wildland Firefighter Medical Standards: Require “peripheral vision of at least 85 [degrees] laterally in each eye” for wildland firefighters, “which is generally considered to be normal” (USDA, n.d., p. 5).
___________________
10 See 80 FR 73122.
11 See 49 CFR § 391.41(b)(10)(i). See earlier footnote on the term “horizontal meridian.”
12 See 49 CFR § 391.44.
- Commissioned Corps of the U.S. Public Health Service Medical Accession Standards (USPHS, 2022): Require at least “30 degrees in either eye; a continuous field of vision which is [at least] 140 degrees (testing both eyes together)” for both Active Duty and Ready Reserve Corps members (p. 9).
The variation in these requirements suggests that, at least occupationally, the bar for meaningful visual impairment is vocation specific.
FUNCTIONAL CRITERIA
Some federal programs define visual impairment or disability according to functional criteria. Methods for measuring and systematically defining functional vision are well documented in the literature (Colenbrander, 2010; Massof, 2022). However, federal programs using such criteria tend to leave room for broader judgment based on the visual field extent necessary for normal activities. Such definitions are most commonly seen in federal accessibility rules.
Department of Education
The Department of Education’s Office of Special Education Programs (OSEP) oversees the efforts of state and local education agencies to make education accessible for children with disabilities. These activities are authorized and regulated by the Individuals with Disabilities Education Act (IDEA). IDEA lists disabilities that make students eligible for special education services13; state and local education agencies must evaluate students according to these federal guidelines.14
On May 22, 2017, OSEP (2017) offered guidance to state and local education agencies on appropriate procedures for evaluating visual impairment. This guidance noted that for some disabilities, agencies have discretion to define certain qualifiers found in federal law. An example of an IDEA definition with such a qualifier is orthopedic impairment, defined as “a severe orthopedic impairment that adversely affects a child’s educational performance.”15 While state and local standards may not be narrower than the definitions laid out in IDEA, agencies would be allowed, in this instance, to determine what qualifies as a “severe” impairment. However, the OSEP guidance noted that IDEA’s definition of visual impairment does not include a modifier such as severe
___________________
13 See 34 CFR § 300.8.
14 See 34 CFR § 300.122.
15 See 34 CFR § 300.8(c)(8).
that could be open to interpretation. IDEA defines visual impairment including blindness as “an impairment in vision that, even with correction, adversely affects a child’s educational performance.”16 According to OSEP’s (2017) interpretation, this means that any visual impairment that adversely affects a student’s educational performance must qualify that student for special education services “regardless of significance or severity.” OSEP (2017) further advised that basing eligibility for special education solely on specific diagnostic criteria without considering the degree to which the student’s vision affects their educational performance is “inconsistent with the IDEA.” Instead, agencies must use a holistic approach that considers educational, behavioral, medical, and other factors to determine how a child’s visual impairment affects them in the classroom.
Statutes governing specific Department of Education programs are written similarly, operationalizing functional criteria. One such program assists state and local education agencies in providing accessible instructional materials for students with disabilities. Agencies must meet certain requirements to remain eligible for this assistance, including aligning their definitions for impairments with federal standards. To be an “eligible person”17 who may receive services from these programs, a student may either meet the federal definition of statutory blindness or meet criteria related to their ability to access standard educational materials.
Federal law outlines two such functional criteria, either of which is sufficient for a student’s eligibility18:
- The individual “has a visual impairment or perceptual or reading disability that cannot be improved to give visual function substantially equivalent to that of a person who has no such impairment or disability and so is unable to read printed works to substantially the same degree as a person without an impairment or disability;” or
- The individual “is otherwise unable, through physical disability, to hold or manipulate a book or to focus or move the eyes to the extent that would be normally acceptable for reading.”
Eligibility must be confirmed by one of a list of approved medical or educational experts who use their professional judgment to assess how students’ impairments will affect their ability to learn. No specific measurement or diagnosis is required.
___________________
16 See 34 CFR § 300.8(c)(13).
17 See 2 U.S. Code § 135a.
18 See 2 USC § 135a(g)(1) and 17 USC § 121(d)(3).
Equal Employment Opportunity Commission
The Equal Employment Opportunity Commission (EEOC) takes an approach similar to the of the Department of Education in enforcing the employment provisions of the Americans with Disabilities Act (ADA). Under the ADA, an impairment qualifies as a disability if it substantially limits major life activities; federal law further provides that the phrase “substantially limit” should be interpreted as broadly as possible.19
In a 2023 guidance document, EEOC (2023) further noted that, given federal law, visual impairments do not need to prevent or severely restrict vision in order to quality as a disability. The use of mitigation measures other than ordinary glasses or contacts, such as low-vision devices, to improve a person’s vision does not disqualify a person from disability protections. In general, EEOC considers visual impairments as disabilities based not on specific diagnosis but on their impacts on day-to-day life. While SSA does include functional assessment in later steps of its disability determination process (see Chapter 1), agencies such as EEOC differ by referring only to effects on an individual’s functioning.
SUMMARY AND CONCLUSION
As described in Chapter 1, SSA outlines specific requirements for visual field testing to inform disability determinations. The guidelines clarify when and how different methods, such as static automated threshold perimetry and manual or semiautomated kinetic perimetry, are to be used, ensuring that test results align with SSA standards. Like SSA, many other government agencies have their own definitions of disability and visual impairment and their accepted methods for assessing visual field loss. These assessments are used to determine eligibility for disability benefits, eligibility for other disability-related programs, or qualification for jobs. Most go beyond the federal definition of statutory blindness, which requires that the widest diameter of a person’s visual field be 20 degrees or less. Some agencies, similar to SSA, use statutory blindness as one of several medical criteria a person can meet to qualify as having a disability. Others adopt a functional definition of visual impairment, based on potential obstacles to engaging in relevant daily tasks. Most, however, set a specific visual field size that examinees must meet or not meet. The preferred perimeters and measurement techniques also differ among agencies, with some permitting a broader selection than others.
Some agencies assess visual field extent to determine eligibility for employment in roles requiring good vision. For example, the FAA requires
___________________
19 See 29 CFR § 1630.2(j)(1)(i).
that pilots obtain a medical certificate before flying, and FRA requires that conductors and locomotive engineers have a “field of vision of at least 70 degrees in the horizontal [diameter] of each eye.”20 Varied requirements in occupationally based visual assessment suggest that the bar for meaningful visual impairment is vocation specific.
Other federal programs define visual impairment or disability based on functional criteria rather than specific diagnostic measures, emphasizing the impact on activities such as education or daily living. The Department of Education’s OSEP, under IDEA, requires a holistic evaluation of how visual impairments affect a child’s educational performance, ensuring eligibility for special education services regardless of severity. Federal accessibility programs similarly define eligibility using functional criteria, such as the inability to access standard educational materials, as verified by qualified experts. EEOC, under the Americans with Disabilities Act, adopts a broad interpretation of disability, focusing on how impairments limit major life activities rather than on specific diagnoses or severity.21 This approach highlights the emphasis on functional impact over the type of objective medical criteria found in federal disability evaluations.
Based on its review of the literature, the committee reached the following conclusion:
Conclusion 2.1: Different federal government agencies have their own definitions of disability and visual impairment and their accepted methods for assessing visual field loss for a variety of purposes, including determining eligibility for disability benefits, eligibility for other disability-related programs, or qualification for certain jobs.
REFERENCES
AMA (American Medical Association). 2024. AMA guides to the evaluation of permanent impairment, 6th ed.
Colenbrander, A. 2010. Assessment of functional vision and its rehabilitation. Acta Ophthalmologica 88(2):163–173.
EEOC (U.S. Equal Employment Opportunity Commission). 2023. Visual disabilities in the workplace and the Americans with Disabilities Act. https://www.eeoc.gov/laws/guidance/visual-disabilities-workplace-and-americans-disabilities-act (accessed February 3, 2025).
FAA (Federal Aviation Administration). 2025. Guide for aviation medical examiners. https://www.faa.gov/ame_guide/media/ame_guide.pdf (accessed February 3, 2025).
LexisNexis. 2019. State-by-state use ofAMA guides. https://www.lexisnexis.com/LegalNewsRoom/cfs-file/__key/telligent-evolution-components-attachments/01-221-00-00-01-44-08-54/AMAGuidesStatebyState.pdf (accessed April 21, 2025).
___________________
20 See 49 CFR § 240.121(c)(2).
21 See 29 CFR § 1630.2(j)(1)(i).
Massof, R. W. 2022. Patient-reported measures of the effects of vision impairments and low vision rehabilitation on functioning in daily life. Annual Review of Vision Science 8:217–238.
OSEP (Office of Special Education Programs). 2017. Memorandum: Eligibility determinations for children suspected of having a visual impairment including blindness under the Individuals with Disability Education Act. U.S. Department of Education. https://sites.ed.gov/idea/files/letter-on-visual-impairment-5-22-17.pdf (accessed February 3, 2025).
RRB (U.S. Railroad Retirement Board). 2021. Disability claims manual part 4 medical evidence development and evaluation. https://www.rrb.gov/sites/default/files/2022-12/DCM_Part_4_0.pdf (accessed February 3, 2025).
Union Pacific Railroad. 2018. Medical standards for safety critical workers. https://www.up.com/cs/groups/public/@uprr/@employee/@hr/documents/up_pdf_nativedocs/cdf_up_hr_hms_med_stnrds_visio.pdf (accessed February 4, 2025).
U.S. Office of Personnel Management. 1998. Chapter 60. Disability retirement. In Civil Service Retirement System (CSRS) and Federal Employees Retirement System (FERS) handbook for personnel and payroll offices. https://www.opm.gov/retirement-center/publications-forms/csrsfers-handbook/c060.pdf (accessed April 21, 2025).
USCG (U.S. Coast Guard). 2019. Merchant mariner medical manual. https://media.defense.gov/2019/Sep/11/2002181050/-1/-1/0/CIM_16721_48.pdf (accessed February 3, 2025).
USDA (U.S. Department of Agriculture). n.d. Federal interagency wildland firefighter medical standards. https://www.fs.usda.gov/sites/default/files/federal-interagency-wildland-firefighter-medical-standards.pdf (accessed February 3, 2025).
USPHS (Commissioned Corps of the U.S. Public Health Service). 2022. CCI 221.01. Medical accession standards. https://www.usphs.gov/media/4nhfmjln/medical-accession-standards-tab-a.pdf (accessed January 28, 2025).
Workers’ Compensation Board. 2017. Worker’s compensation guidelines for determining impairment. New York State of Opportunity. https://www.wcb.ny.gov/2018-Impairment-Guidelines.pdf (accessed February 3, 2025).
This page intentionally left blank.
