Abstract
Purpose :
The purpose of this study was to compare self-reported estimates of driving exposure to objective estimates made using naturalistic recording devices in drivers with central vision impairment who use bioptic telescopic spectacles (BTS) to drive and normally-sighted controls. Estimates of driving exposure are useful for assessing the rate of collisions and associated factors.
Methods :
Visual acuity was measured for each eye individually and through the BTS. Contrast sensitivity testing was performed with the Mars chart. Driving exposure and difficulty were assessed using the Driving Habits Questionnaire (Owsley et al.). A commercially available GPS tracking device (Azuga) was installed in the OBD-II port of drivers’ own cars. Drivers were monitored for a minimum of six weeks, and average weekly mileage and trips were calculated for the recording period. Driver characteristics and exposure were compared using Mann-Whitney U tests.
Results :
Seventeen licensed drivers were enrolled (11 bioptic drivers with low vision and 6 normally-sighted control drivers). Bioptic drivers were older than controls (median (IQR) = 55 (15) years for bioptic drivers vs 47 (18.75) years for controls; P=0.02). Control drivers had better visual acuity (logMAR -0.08 (0.13)) than visually impaired drivers (logMAR 0.70 (.12) with carrier lenses, P<0.001). Log contrast sensitivity was worse in bioptic drivers (1.44 (0.28) vs 1.82 (0.06), P<0.001). Median objective weekly mileage for bioptic drivers over the observation period was 183 (207). There was no significant difference in objective weekly mileage between bioptic drivers and controls (P = 0.525). A strong correlation was observed between DHQ-reported average weekly mileage and average weekly mileage from the GPS tracking devices over six weeks (Spearman rho = 0.791, P = 0.004) for bioptic drivers.
Conclusions :
Bioptic drivers’ objectively recorded mileage was about the same as that of normally-sighted control drivers, and there was a high correlation between subjective and objective estimates of exposure. These results suggest that exposure estimates for bioptic drivers obtained with the Driving Habits Questionnaire can be useful in studies of bioptic driving performance and safety.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.