The Problem: In the United States, motor vehicle–related accidents are the leading cause of death for all people under the age of 34. In 2000, motor vehicle crashes cost roughly $230 billion. CDC: Motor vehicle safety. The number of licensed drivers over the age of 65 has increased dramatically over the last decade. Drivers ages 80 and over have a higher rate of fatal crashes per miles driven than all other demographic groups except teenagers. The impact of aging on vision, cognitive functions, and other physical capacities has been identified as a contributing factor in motor vehicle crashes. CDC Website - Older Adult Drivers: Fact Sheet.
The Law: State transportation and safety laws require different procedures and apply different standards in screening the vision of older drivers. For instance, to renew a license in California, an individual must have visual acuity of 20/40 with both eyes together and at least 20/40 in the stronger eye and 20/70 in the weaker eye, California Department of Motor Vehicles, CA Vehicle Code §12805; in Arizona, a minimum of 20/40 in one eye is required. Arizona Administrative Code: R17-4-502, R17-4-503. The age at which vision tests are required for renewal also varies (e.g., 40 years in Maryland (Maryland Transportation Code 16-115(h)) to 80 years in Virginia. VA Code Ann. § 46.2-46.2-330 (C). For another example of a state law requiring vision screening for individuals above a specified age, see FL Rev. State 322.18(5) (Florida).
The Evidence: A Cochrane Collaboration Task Force attempted to conduct a systematic of studies assessing the impact of vision screenings for older drivers on motor vehicle crashes, but did not find any studies meeting its criteria. Subzwari S et al. Vision screening of older drivers for preventing road traffic injuries and fatalities. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.:CD006252. The task force accordingly concluded that there is insufficient evidence to determine whether vision screening programs for individuals above a specified age are effective in reducing crashes among older adults.
The Bottom Line: In the judgment of a Cochrane Collaborative expert panel, laws requiring vision screening are a plausible means of reducing crashes involving older drivers, but there is insufficient evidence to rigorously assess their effectiveness at this time.
Additional Information: The Physician’s Guide to Assessing and Counseling Older Drivers, created by the American Medical Association (AMA) with support from the National Highway Traffic Safety Administration (NHTSA), is available online and provides substantial information about state policies regarding vision screening.
The International Council of Opthalmology provides online access to a table of vision requirements for the fifty US states.