Visual acuity and factors influencing automobile driving status in 1,000 patients age 60 and older

Abstract

Background: The objective of this prospective observational study was to evaluate the number of people driving in accordance with common legal standards, measured through far binocular visual acuity, and to identify variables associated with driving habits outside of legal standards.

Methods: Subjects aged 60 years and older were recruited at a tertiary referral center (University Hospital of Mont-Godinne, Yvoir, Belgium). Ophthalmological examination was conducted in all subjects by an ophthalmologist. Visual acuity was measured with the modified Early Treatment Diabetic Retinopathy charts at a distance of 4 m on each eye for far binocular visual acuity, defined as equal or better than 20/40, according to the European legal driving requirements. Details on demographic, socioeconomic, and medical characteristics were obtained from all participants by questionnaires. Numerical variables were compared with the Wilcoxon rank sum test. Categorical and ordinal parameters were compared with the Chi-square test or the Cochran test respectively.

Results: One thousand subjects (447 women and 553 men) were enrolled in the study over a period of 7 months (mean age: 71.3 ± 8.8 years), of whom 810 were current drivers. Among the 810 current drivers, 732 (90.4 %) had a far binocular visual acuity equal or better than 20/40 (mean 0.89), and 78 (9.6 %) did not (mean 0.36). Among the 190 non-drivers, 94 (49.5 %) never drove; 47 (24.7 %) had stopped driving because of their impaired vision; and 49 (25.8 %) had stopped driving for other reasons. A logistic regression was performed to identify the variables statistically associated with the practice of driving among licensed drivers without minimal visual requirements, which revealed that a non-recent ophthalmological examination (p < 0.001), the subject's non-perception of impaired vision (p = 0.001), and non-access to stores without a car (p < 0.001) were influencing factors.

Conclusions: In our study, 81 % of subjects aged 60 years and older were still driving, of whom 10 % did not meet the European legal driving requirements set at equal or better than 20/40. The variables associated with driving status were the time of last examination, non-perception of a visual impairment, and limited access to stores without a car.