State mandated vision screenings conducted to determine driving ability unnecessarily prevent the mobility of older individuals, according to research published in Ophthalmology. This is due to a weak association between vision impairment and motor vehicle collisions (MVCs).
Researchers conducted a population-based study of 2000 licensed drivers (mean age 77.2±4.9 years, 56.5% men, 82% White). The team collected participant demographics and medical history and measured the following visual functions: visual acuity, contrast sensitivity, useful field of view, motor free visual perception test, and visual field sensitivity. They surveyed participants on an annual basis for a period of 3 years, obtaining data regarding their driving status through follow-up phone calls. The team also monitored MVC involvement during the study period.
At baseline, researchers noted that nearly 75% of participants drove at least five days per week. Less than 10% of individuals had impaired visual acuity or contrast sensitivity, and slightly more than 10% of individuals had useful field of view impairment.
A total of 359 collisions occurred by the conclusion of the study and approximately 16% of individuals had at least 1 collision.
Visual function measures indicated poor discrimination (area under the curve values only slightly above 0.5%) and low sensitivity, despite high specificity. Risk ratios (RRs) with clinical cut points were not statistically significant. The researchers concluded that the inadequate specificity and sensitivity of these measures made them inadequate screening tools, according to the report.
“Visual risk factors for older drivers’ MVCs are not effective visual screening measures for the general population,” according to the researchers. “They fail to meet the high standard of sensitive and specific screening tests, needlessly removing many older drivers from the road who are not threats to safety.”
Limitations of the study included possible failure to obtain MVC data in cases not involving the completion of an accident report.
McGwin G Jr, Owsley C. Vision screening for motor vehicle collision involvement among older drivers. Ophthalmol. Published online April 25, 2022. doi:10.1016/j.ophtha.2022.04.013