Purpose:The purpose of this study was to investigate the telescope use behaviors in natural daily driving of people with reduced visual acuity licensed to drive with a bioptic (a small spectacle-mounted telescope). Methods:A large dataset (477 hours) of naturalistic driving was collected from 19 bioptic drivers (visual acuity 20/60 to 20/160 without the telescope). To reduce the data volume, a multiloss 50-layer deep residual neural network (ResNet-50) was used to detect potential bioptic telescope use events. Then, a total of 120 hours of selected video clips were reviewed and annotated in detail. Results:The frequency of looking through their telescopes ranged from 4 to 308 times per hour (median: 27, interquartile range [IQR], 19-75), with each bioptic use lasting median 1.4 seconds (IQR, 1.2-1.8). Thus, participants spent only 1.6% (IQR, 0.7%-3.5%) driving time with their telescopes aiding their vision. Bioptic telescopes were used most often for checking the road ahead (84.8%), followed by looking at traffic lights (5.3%), and reading road signs (4.6%). Conclusions:In daily driving, the bioptic drivers mostly (>98% of driving time) drove under low visual acuity conditions. The bioptic telescope was mainly used for observing road and traffic conditions in the distance for situational awareness. Only a small portion of usage was for road sign reading. Translational Relevance:This study provides new insights into how the vision rehabilitation device-bioptic telescopes are used in daily driving. The findings may be helpful for designing bioptic driving training programs.

IMPORTANCEThere is scant rigorous evidence about the real-world mobility benefit of electronic mobility aids.OBJECTIVE To evaluate the effect of a collision warning device on the number of contacts experienced by blind and visually impaired people in their daily mobility. DESIGN, SETTING, AND PARTICIPANTSIn this double-masked randomized clinical trial, participants used a collision warning device during their daily mobility over a period of 4 weeks. A volunteer sample of 31 independently mobile individuals with severe visual impairments, including total blindness and peripheral visual field restrictions, who used a long cane or guide dog as their habitual mobility aid completed the study. The study was conducted from January 2018 to December 2019. INTERVENTIONSThe device automatically detected collision hazards using a chest-mounted video camera. It randomly switched between 2 modes: active mode (intervention condition), where it provided alerts for detected collision threats via 2 vibrotactile wristbands, and silent mode (control condition), where the device still detected collisions but did not provide any warnings to the user. Scene videos along with the collision warning information were recorded by the device. Potential collisions detected by the device were reviewed and scored, including contacts with the hazards, by 2 independent reviewers. Participants and reviewers were masked to the device operation mode.MAIN OUTCOMES AND MEASURES Rate of contacts per 100 hazards per hour, compared between the 2 device modes within each participant. Modified intention-to-treat analysis was used. RESULTSOf the 31 included participants, 18 (58%) were male, and the median (range) age was 61 (25-73) years. A total of 19 participants (61%) had a visual acuity (VA) of light perception or worse, and 28 (90%) reported a long cane as their habitual mobility aid. The median (interquartile range) number of contacts was lower in the active mode compared with silent mode (9.