Florida Vision Test of Elderly Drivers Appears to
Reduce Deaths, But No One Knows How
Importance of driving to older adults suggests that
isolating the true mechanism responsible for the decline is in fact
important
Nov. 10, 2008 - A vision screening law targeting
Florida drivers age 80 and older appears to be associated with lower
death rates from motor vehicle collisions in this age group., It is
somewhat of a mystery, however, because there is little evidence of an
association between vision and car crashes, according to a report in the
November issue of Archives of Ophthalmology, one of the JAMA/Archives
journals.
"Older drivers represent the fastest-growing
segment of the driving population," the authors write as background
information in the article.
"As this segment of the population expands, so too
have public safety concerns, given older drivers' increased rate of
motor vehicle collision involvement per mile driven. Research has
suggested that this increase may be partly attributed to medical,
functional and cognitive impairments."
Little evidence links visual acuity to involvement
in motor vehicle collisions. However, in January 2004, Florida
implemented a law requiring all drivers 80 years and older to pass a
vision test before renewing their driver's licenses.
Gerald McGwin Jr., M.S., Ph.D., and a team at the
University of Alabama at Birmingham used data from the National Highway
Traffic Safety Administration and the U.S. Census Bureau to study rates
of motor vehicle collision deaths among all drivers and older drivers in
Florida between 2001 and 2006. They also compared these rates to those
in Alabama and Georgia, neighboring states that did not change their
legal requirements during this time period.
Overall death rates from motor vehicle collisions
in Florida increased non-significantly between 2001 and 2006, but showed
a linear decrease in drivers age 80 and older.
When comparing the period before the law (2001 to
2003) to the period after the law (2004 to 2006), the fatality rate
among all drivers increased by 6 percent (from 14.61 per 100,000 persons
per year to 14.75 per 100,000) while fatality rates among older drivers
decreased by 17 percent (from 16.03 per 100,000 persons per year to
10.76 per 100,000).
Death rates among older drivers did not change in
Alabama or Georgia during the same time period.
Several potential reasons exist for the decline in
Florida, the authors note. "Perhaps the most apparent reason is that the
screening law removed visually impairment drivers from the road," the
authors write. "However, in reality, the situation is significantly more
complex."
About 93 percent of individuals who sought a
license renewal were able to obtain one, suggesting that only a small
percentage of drivers were removed from the road for failing to meet the
vision standards.
Another possibility is that the vision screening
requirement improved visual function overall, because many of those who
do not pass the test on the first try seek vision care and then return
with improved vision.
Finally, those who believe they have poor vision
may have been discouraged from renewing their license at all,
voluntarily removing themselves from the road.
"Ultimately, whether the vision screening law is
responsible for the observed reduction in fatality rates because of the
identification of visually impaired drivers or via another, yet related,
mechanism may be inconsequential from a public safety perspective," the
authors write.
"However, the importance of driving to the
well-being of older adults suggests that isolating the true mechanism
responsible for the decline is in fact important." Future research
identifying this mechanism would allow states to implement laws that
accurately target high-risk drivers while allowing low-risk older
drivers to retain their mobility.
Keep up with the latest news for senior citizens, baby
boomers
Nov. 10, 2008 - A vision screening law targeting
Florida drivers age 80 and older appears to be associated with lower
death rates from motor vehicle collisions in this age group., It is
somewhat of a mystery, however, because there is little evidence of an
association between vision and car crashes, according to a report in the
November issue of Archives of Ophthalmology, one of the JAMA/Archives
journals.