March 2009

 

OPHTHALMOLOGY NEWS

 

Fewer fatalities for older drivers


by Maxine Lipner Senior EyeWorld Contributing Editor

 

 

Study looks at effect of Florida vision screening law on drivers over age 80

A new Florida law requiring vision screening for drivers over the age of 80 has resulted in a dip in related fatalities. Recent study results published in the November 2008 issue of Archives of Ophthalmology indicate that death rates from motor vehicle accidents for this population fell by 17% after the law was passed, according to Gerald McGwin, Ph.D., associate professor of ophthalmology, University of Alabama at Birmingham, Birmingham, Ala.

The study was launched in response to the public’s concerns about what the law would mean for older drivers. “When this law was getting ready to come out after it had been passed, there were all these newspaper articles,” Dr. McGwin said. “People were up in arms about the fact that it was going to take all these older drivers off the road and how they were going to get around.” In an attempt to quantify what this would mean Dr. McGwin launched this study, as well as an earlier one centering on older drivers’ experiences with the new re-screening process.

Renewal experiences

In the first study, which was published in the March/April 2008 issue of Ophthalmic Epidemiology, investigators contacted 1,000 drivers over the age of 80 to delve into their experiences with the renewal process. “What we were interested in finding out was how many of them couldn’t renew their licenses as a result of the new law,” Dr. McGwin said. “Many groups were up in arms about how this was going to impede mobility and we wanted to put a number on that.” Results here indicated that almost all who sought to renew their licenses were able to do so. “What we found was that of those who sought renewal, 93% were able to get their licenses renewed,” Dr. McGwin said. “There were, however, a fairly decent number of people who, because of the law, didn’t even bother attempting to renew their licenses.”

He sees this as potentially coloring the interpretation of the more recent study centering on fatalities and vision screening. In this study, investigators looked at motor vehicle-related fatalities involving Florida residents over age 80. Investigators here found that while car-related fatalities rose by 6% from 2004 to 2006, related deaths for those over age 80 fell by 17% after passage of the law.

“One of the explanations for the reduced fatality rate is that (the older) drivers who are on the road had better vision than they did previously,” Dr. McGwin said. “They went in (for renewal), found out they didn’t have adequate vision, they got their vision fixed, and now they’re driving around with better vision.” He sees another possible scenario here. “The other possibility is that the group of people who didn’t even bother to have their licenses renewed was removed from the driving environment,” he said. Investigators don’t know which is true or whether both may be contributing here.

Dr. McGwin was surprised by the dramatic decrease in fatalities for older drivers. “We had done the first study and had found that a fairly small proportion of people didn’t get their licenses renewed. I felt that since so few people were removed from the road, I couldn’t imagine that it was going to have an effect on the crash rate,” he said. “But we were wrong.”

Investigators are still unsure as to exactly why the fatality rate dropped. “Is it because people were taken off the road?” Dr. McGwin asked. “Is it because people who were on the road had better vision?” It’s hard to determine which may be true. As a result, this may make it a bit murkier for other like-minded states to pass similar laws. “This makes it difficult in terms of translating the law for general public safety for the state of Oregon, for the state of Maine, for the state of Texas,” Dr. McGwin said. While others can certainly put into place similar laws, he thinks that it would be nice if they did so knowing whether it was the vision screening part that curtailed fatalities or whether it was the fear of failing the test that was ultimately at play.

Dr. McGwin sees the study as a helpful one. “I think that it provides us with the insight that these screening laws may be effective,” he said. “We just have to determine what it is about them that make them effective.”

Currently 18 states including Florida have some sort of license renewal provision for older drivers. Dr. McGwin thinks that more states are likely to enact these. “I can definitely see states moving in this direction,” he said. However, relying upon traditional Snellen acuity screening may be a mistake. “The problem is that there has never been any research to suggest that visual acuity is related to crash involvement,” Dr. McGwin said. “But there are other tests that demonstrate a stronger relationship.” Potentially partnering these laws with other vision tests like contrast acuity may ultimately improve the effectiveness of the laws, he believes.

Editors’ note: Dr. McGwin has no financial interests related to his comments.

Contact information

McGwin: 205-325-8117, Gerald.McGwin@ccc.uab.edu

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