A new study has revealed that a decrease in vision function prompts older drivers to shun their car keys.
The study, conducted by researchers affiliated with Johns Hopkins University, looked at changes in vision, cognition and the general health status of more than 1,200 licensed drivers aged 67-87 in Salisbury, MD, a community with limited public transportation.
Researchers found that after a year, 1.5 percent of the drivers had given up driving, and another 3.4 percent had restricted their driving.
The most common predictors of stopping or decreasing driving were slow visual scanning, psychomotor speed and poor visuo-constructional skills, as well as reduced contrast sensitivity.
"These skills are important for safe and confident driving where objects are moving at rapid speeds in relation to each other, and timely and accurate judgments are required," the researchers said.
In the study, researchers also found that women were four times more likely than men to stop or restrict their driving.
Also, drivers who had higher depression scores on the initial test were more likely to have given up or restricted their driving after a year.
"The decision to stop or limit driving to one's own neighbourhood has major implications for personal independence - but it is an important way to maintain the safety of older drivers and those who share the road," said researcher Lisa Keay, PhD.
"As a society, we would like to think that when a driver recognizes that his or her functions related to vision or cognition are declining, they make that crucial decision," she added.
The study was recently published in Investigative Ophthalmology and Visual Science.