Abstract
Purpose :
To assess the impact of wearing bioptic telescopes (BTS) on the visual recognition of traffic signs, traffic lights and hazards in the on-road driving environment in individuals with central visual impairment (VI).
Methods :
Eleven individuals (mean age 38.6 ± 17.9 years) with central VI, who had been trained to use BTS, participated in a repeated measures design on–road experiment. Participants, seated in the front passenger seat of a sedan car, were instructed to report aloud all signs, lights and hazards seen along a route that included suburban roads and highways. Video cameras were used to capture the driving scene, participants’ viewing behaviour and their verbal commentary. Participants completed the route for two viewing conditions, with and without the BTS; the order of BTS wear was randomized. Three signs were selected where the driver could drive at a constant speed; the distance at which those signs were recognised was calculated based on the video footage. Non-peak hour driving periods were selected.
Results :
Mean high contrast visual acuity was 0.74 ± 0.16 logMAR, which improved to 0.27 ± 0.1 logMAR with BTS. Wearing the BTS resulted in 2.7x longer identification distances (45.9 ± 23.25 m vs 17.1 ± 11.87 m, t10=5.3, p<0.001). There was no significant difference in the percentage of signs identified when wearing (53.7 ± 4.54 %) and not wearing the BTS (51.32 ± 14.03 %), (paired-t10=1.7, p=0.11). Most traffic lights and hazards were identified for both experimental conditions and there was no significant effect of BTS wear (Wilcoxon signed-rank test; traffic lights Z=1.6, p=0.11 and hazards Z=0.178, p=0.86).
Conclusions :
While the percentage of signs, traffic lights and hazards correctly identified was not significantly affected by BTS wear, traffic signs were identified at 2.7X longer distances when wearing the BTS. This confirms that BTS have a positive impact on the visual recognition of objects within the driving scene.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.