- Driving performance under nighttime conditions was significantly degraded by modest visual impairment; but these effects were greatest for a (simulated) cataract condition.
- Recognition of volunteer pedestrians was greatly enhanced when pedestrians wore reflective markings on the clothing covering arms and legs, highlighting their body movements.
This study investigated the effects of simulated visual impairment on nighttime driving performance and pedestrian recognition under real-road conditions.
Nighttime driving performance (closed road) was measured for 20 young visually normal participants (M = 27.5 ± 6.1 years) under three visual conditions: normal vision, simulated cataracts, and refractive blur that were incorporated in modified goggles. The visual acuity levels for the cataract and blur conditions were matched for each participant. Driving measures included sign recognition, avoidance of low contrast road hazards, time to complete the course, and lane keeping. Pedestrian recognition was measured for pedestrians wearing either black clothing or black clothing with retroreflective markings on the moveable joints to create the perception of biological motion (“biomotion”).
Simulated visual impairment significantly reduced participants’ ability to recognize road signs, avoid road hazards, and increased the time taken to complete the driving course (p < 0.05); the effect was greatest for the cataract condition, even though the cataract and blur conditions were matched for visual acuity. Although visual impairment also significantly reduced the ability to recognize the pedestrian wearing black clothing, the pedestrian wearing “biomotion” was seen 80% of the time.
The study found that driving performance under nighttime conditions was significantly degraded by modest visual impairment; these effects were greatest for the cataract condition. Pedestrian recognition was greatly enhanced by marking limb joints in the pattern of “biomotion,” which was relatively robust to the effects of visual impairment.
Optometry & Vision Science: June 2010 – Volume 87 – Issue 6 – pp 379-386 – doi: 10.1097/OPX.0b013e3181d95b0d