Compensatory behaviour of visually impaired cyclists in everyday settings

This study investigated whether visually impaired cyclists, compared to cyclists without visual limitations, take other, potentially safer routes to destinations in their own living environment and whether they ride at a lower speed. In total, 19 matched pairs of a visually impaired cyclist and a normally sighted peer from the same neighbourhood recorded their everyday bicycle rides, using GPS action cameras. In addition, they completed an 'assigned ride', a ride for which only a starting and an ending point were provided by the researcher. A risk-assessment procedure showed that the route taken by visually impaired cyclists during this assigned ride was not less risky than the route taken by the normally sighted cyclists. Analysis of the everyday rides showed that, on average, cyclists with a visual impairment more frequently (i.e. for longer periods) cycled at a speed below 10 km/h compared to cyclists without visual impairment. Also, the visually impaired participants' cruising speed was 1.4 km/h lower than that of their normally sighted counterparts. In conclusion, no evidence was found that visually impaired cyclists compensate strategically by taking different, potentially safer routes than normally sighted cyclists when riding in their own environment. They may (unconsciously) compensate tactically for their visual function limitations by riding at a lower speed when necessary. Mobility trainers in vision rehabilitation as well as road designers could apply these findings to optimise the cycling mobility of visually impaired people

Vision-related fitness to drive mobility scooters:A practical driving test

Objective: To investigate practical fitness to drive mobility scooters, comparing visually impaired participants with healthy controls. Design: Between-subjects design. Subjects: Forty-six visually impaired (13 with very low visual acuity, 10 with low visual acuity, 11 with peripheral field defects, 12 with multiple visual impairment) and 35 normal-sighted controls. Methods: Participants completed a practical mobility scooter test-drive, which was recorded on video. Two independent occupational therapists specialized in orientation and mobility evaluated the videos systematically. Results: Approximately 90% of the visually impaired participants passed the driving test. On average, participants with visual impairments performed worse than normal-sighted controls, but were judged sufficiently safe. In particular, difficulties were observed in participants with peripheral visual field defects and those with a combination of low visual acuity and visual field defects. Conclusion: People with visual impairment are, in practice, fit to drive mobility scooters; thus visual impairment on its own should not be viewed as a determinant of safety to drive mobility scooters. However, special attention should be paid to individuals with visual field defects with or without a combined low visual acuity. The use of an individual practical fitness-to-drive test is advised

The Introduction of Bioptic Driving in the Netherlands

Background: In many US states, people with moderately reduced visual acuity (eg, 20/50–20/200) can legally drive with the aid of a small, spectacle-mounted (“bioptic”) telescope.We conducted a demonstration project to assess the viability of implementing bioptic driving in the Netherlands. In this article, we describe the framework of the project from conception through to realization of our primary objective—the introduction of bioptic driving as a legal option for visually impaired people in the Netherlands. Methods: The project was based on bioptic driving programs in the United States, which were adapted to fit into current driving training and assessment practices in the Netherlands. The project convened a consortium of organizations including the Netherlands Bureau of Driving Skills Certificates, service organizations for the visually impaired, and research departments at universities investigating driving and vision. All organizations were educated about bioptic driving and participating professionals were trained in their specific aspects of the project. Media publicity led to significant interest and helped recruitment that enabled the screening and selection of potential participants. Outcomes: The project demonstrated that people with moderately reduced visual acuity can be trained to achieve an adequate level of proficient and safe driving (as assessed by the local official driving licensing professionals) when using a bioptic telescope for the road conditions in the Netherlands. Based on the successful project outcomes, a request was made to the minister to allow bioptic driving in the Netherlands. This request has been accepted; the legal procedures for implementation are in process

Driving slow motorised vehicles with visual impairment—A simulator study

Purpose: To compare different driving parameters between visually impaired people and normal sighted controls in a mobility scooter and microcar driving simulator. Materials and methods: A mobility scooter and microcar driving simulator and different virtual environments were developed for the purpose of this experiment. Participants completed 4 drives in the microcar driving simulator and 8 drives in the mobility scooter driving simulator. Driving performance was compared between visually impaired and normal sighted participants, using the parameters speed, lateral position, time-to-collision, and number and type of collision. Results: Visually impaired participants did not differ significantly from normal sighted controls with regard to speed and overall lateral position. In contrast, number of collisions was higher in visually impaired participants in almost all drives. Time-to-collision differed in some, but not all of the drives. Small obstacles with low contrast posed the highest risk of collision for impaired drivers. Conclusions: The present findings showed that visually impaired participants were able to maintain a steady position on the street, but showed more difficulties in traffic situations that included obstacles and other traffic participants. Familiarity with the driving tasks seemed to improve performance, however, further research is necessary to confirm this observation

Specificity of the effects of compensatory scanning training for patients with homonymous visual field defects

A compensatory training program has been developed aimed at improving visual scanning in patients with homonymous visual field defects. This is the first randomized controlled trial looking into the effects of a compensatory scanning training based on a top-down, systematic horizontal scanning strategy. Performances were compared for patients receiving training, patients on a waiting list and healthy control participants. Visual functions tests, a dot counting test, visual search tests, a hazard perception tests, an obstacle course, reading tests, and questionnaires on experienced difficulties in daily life were assessed. Positive effects of training on self-reported vision-related quality of life were found and these effects were still present at half year follow-up. Furthermore, training improved detection of peripheral stimuli in mobility and dual task situations. No effects of training were found for visual functions, dot counting, visual search or reading. We will discuss how different training exercises and training methods appear to affect different types of visual tasks and activities