Purpose
In more than 40 US states, drivers who cannot meet vision standards with conventional optical correction are permitted to use bioptic telescopic spectacles to obtain licensure. There are few studies comparing risk of motor vehicle collisions (MVC) for bioptic drivers with that of normally-sighted drivers. This study compared the MVC rate of bioptic drivers to normally-sighted control drivers and examined the effect of previous, non-bioptic driving experience on rates.
Methods
A retrospective study of patients identified as having received an initial daylight bioptic examination at the College of Optometry at the Ohio State University was conducted. Data were collected on vision and demographics, and driving records from the Ohio BMV were obtained. BMV driving records were also obtained for a control group of age, sex, and population density matched Ohio drivers in order to compare MVC rates. Rate ratios for MVC were calculated using the total number of MVC over the total time since last license renewal for both bioptic and control drivers.
Results
186 bioptic drivers who had an exam for the daylight bioptic program and 3001 matching control drivers were identified. Age ranged from 21 to 84 years (mean = 49±14 years) in both groups. Mean logMAR visual acuity OU at initial exam for bioptic drivers was 0.77±0.12 (20/115) and mean log letter contrast sensitivity was 1.55±0.23. 16% of the bioptic drivers were involved in at least one MVC since the last license renewal (mean licensure time = 22 months). The mean±SD number of MVC per year for bioptic drivers without previous experience (n = 76) was 0.16±0.41, and 0.084±0.25 for those with previous experience. The MVC rate ratio [95% CI] for all bioptic drivers compared to controls was 3.0 [2.2, 4.3]. The ratio for inexperienced bioptic drivers was 3.4 [2.1, 5.4], and the ratio for experienced bioptic drivers was 2.8 [1.7, 4.7].
Conclusions
The MVC rate of bioptic drivers was elevated compared to matched controls, though less so in bioptic drivers with previous driving experience. The increased risk of MVC for bioptic drivers in this study is comparable to that shown previously for drivers with other medical restrictions (Janke, 1983).
Keywords: 584 low vision •
464 clinical (human) or epidemiologic studies: risk factor assessment