While there are strict federal vision standards for commercial licensing, there are no such international standards, and there are no federal standards for unrestricted noncommercial passenger vehicle drivers’ licenses in the United States. Individual states and the District of Columbia have their own vision requirements for initial and renewal licensing. These requirements can vary widely .
Defining Visual Disability
The World Health Organization lists several categories of visual disability. Low vision is defined as visual acuity between 20/60 and 20/200 or corresponding visual field loss to less than 20 degrees in the better eye with best possible correction. Blindness is defined as visual acuity of less than 20/400 or corresponding visual field loss to less than 10 degrees in the better eye with the best possible correction .
The Social Security Administration of the United States declares a taxpayer disabled for economic purposes and eligible for supplemental security income when the best corrected visual acuity is 20/200 or worse in the better eye, the visual field is limited to 20 degrees or less in the better eye, or both .
The generally accepted testing parameters are: uncorrected visual acuity in each eye, best corrected visual acuity (BCVA) in each eye, and binocular or monocular horizontal visual fields. Some states ask about monocularity, diplopia, impaired night vision, and a history of retinitis pigmentosa or other possibly progressive deteriorating eye disease.
An unrestricted license allows its owners to drive without corrective lenses, in any location and for any distance, in all light conditions, both day and night, on any road, at any legal speed, and in any normally equipped vehicle, without additional or special mirrors. By far the most common restriction is that requiring the use of corrective lenses when driving.
Restrictions based on vision testing vary from state to state and include mandated use of corrective lenses, limiting driving to sunrise to sunset only, prohibiting freeway driving, restricting the area in which driving is allowed, and requiring additional mirrors (left and right outside, wide-angle, panoramic, and fender-mounted). Montana issues an area-restricted license, specifying, for example, home to grocery store, driving for medical needs, or driving to church. Most states have provisions that allow drivers to use telescopic lenses and to demonstrate competency with other visual assistance devices when necessary.
The testing parameter that varies least from state to state is visual acuity. All states have visual acuity requirements for licensure, and all but 3 have set the minimum best corrected visual acuity (BCVA) requirement at 20/40 in the better eye. Georgia requires a BCVA of at least 20/60 in at least one eye; for New Jersey and Wyoming the requirement is 20/50.
Horizontal visual field requirements are more varied. Sixteen states have no required visual field testing unless the individual has been referred to an eye care practitioner after failing a visual acuity test or because the visual acuity test was passed using special telescopic lenses. For the 34 states with a binocular horizontal visual field requirement, 15 stipulate 140 degrees; for the other 19 states, the range is from 105 degrees to 130 degrees; Maine requires 150 degrees. Several states list the horizontal dimension of the visual field of applicants with only one useful eye; this ranges from 55 degrees (Kansas) to 105 degrees (Arkansas). Some states, including North Carolina and Texas, will not issue any driver’s license to a person with a homonymous hemianopia (loss of vision in the right halves or the left halves of both eyes).
Only Kentucky has a vertical visual field requirement: 25 degrees above and below the fixation point.
Some states list the ages at which routine vision testing must begin; in some states repeat testing starts as early as age 62, but is more commonly age 65 or 70. The frequency of follow-up testing is variable. In Illinois, at age 87, applicants must start taking annual vision (and road) tests.
Unique State Restrictions
Massachusetts has a color vision requirement: “Drivers must be able to distinguish the colors red, green, and amber. If applicants or licensees cannot distinguish the colors red, green, and amber a license is not possible.” In Mississippi, applicants who fail the eye care specialist’s depth perception test are restricted to a maximum speed of 45 mph. Ohio requires that applicants referred with vision restrictions go to an eye care specialist affiliated with the Ohio State University School of Optometry or Vision Rehabilitation of Akron and, if needed, attend training and evaluation at one of those two institutions. In Utah, applicants who fail all parameters of vision testing may not be issued a license “except in meritorious circumstances.”
While it stands to reason that drivers with poor visual acuity, limited visual fields, or both would be more prone to motor vehicle accidents, there have been no published reports to substantiate that contention. Nevertheless, establishing strict national vision and vision testing standards for noncommercial passenger vehicle driver licensing would eliminate state-to-state inconsistencies, simplify the comparison of accident rates in different states, and may, if adequately established and strictly enforced, help eliminate poor vision as a cause of motor vehicle accidents.
The physician’s duty to report potential physical and mental conditions that may impair a patient’s ability to drive has been a subject of interest for some time. In 1997, the Council on Ethical and Judicial Affairs of the American Medical Association studied the issue and recommended that physicians assess driving risk in cases of concern and have open discussions with patients and their families about any risk of damage to self and others . In some cases, negotiating a workable driving plan with patients can render reporting unnecessary. In those situations where clear evidence of substantial driving impairment implies a strong threat to patient and public safety, and where physicians’ advice to discontinue driving privileges is disregarded, physicians have an ethical duty to notify the state department of motor vehicles of the patient’s safety-related medical condition. This duty exists even when reporting impaired drivers is not mandated by law .
Macular Degeneration Support. State vision screening and standards for licenses to drive. Summary of Medical Advisory Board Practices,June 2003. http://www.mdsupport.org/drivingsummary.pdf. Accessed November 16, 2010.
World Health Organization. Change the definition of blindness. http://www.who.int/blindness/Change%20the%20Definition%20of%20Blindness.pdf. Accessed November 17, 2010.
US Social Security Administration. If you are blind or have low vision—how we can help. Social Security Online. http://ssa.gov/pubs/10052.html. Accessed November 16, 2010.
American Medical Association. Opinion 2.24 Impaired drivers and their physicians. Code of Medical Ethics. Chicago, IL: American Medical Association; 2010. http://www.ama-assn.org/ama/pub/physician-resources/medical-ethics/code-medical-ethics/opinion224.shtml. Accessed November 17, 2010.