H Wilhelm1, B Endres. 1. Abt. für Pathophysiologie des Sehens und Neuroophthalmologie, Universitäts-Augenklinik, Tübingen. wilhelm@uni-tuebingen.de
Abstract
PURPOSE OF THE STUDY: To examine bicycling habits of visually handicapped people in order to learn about the visual requirements. MATERIAL AND METHODS: Survey of patients (age range: 14-60 years) suffering from macular or tapetoretinal degeneration with no additional relevant handicap using a questionnaire. RESULTS: A total of 232 questionnaires were returned (62% of the questionnaires received by the participants). The results showed that if visual acuity dropped below 0.1, only 15% of the patients were able to ride a bicycle without accidents or near-accidents. This percentage increased for higher acuities between 33% (<0.2 > or = 0.1) and 67% (> or = 0.2 < or = 0.4). For visual field diameters <60 degrees and > or = 20 degrees approximately 18% were able to ride a bicycle safely and only 8% if the visual field diameter was below 20 degrees. For visual fields larger than 60 degrees diameter approximately 40% were able to ride a bicycle without problems. With a central scotoma of more than 10 degrees diameter only 21% of the patients could cycle safely, whereas with a central scotoma of 10 degrees and less this percentage increased to 47%. CONCLUSIONS: A visual acuity of less than 0.1 is not sufficient to ride a bicycle, and a visual acuity of less than 0.2 leads to a higher accident rate. A visual field diameter of less than 60 degrees or a central scotoma of more than 10 degrees diameter for the vast majority of patients does not allow safe cycling
PURPOSE OF THE STUDY: To examine bicycling habits of visually handicapped people in order to learn about the visual requirements. MATERIAL AND METHODS: Survey of patients (age range: 14-60 years) suffering from macular or tapetoretinal degeneration with no additional relevant handicap using a questionnaire. RESULTS: A total of 232 questionnaires were returned (62% of the questionnaires received by the participants). The results showed that if visual acuity dropped below 0.1, only 15% of the patients were able to ride a bicycle without accidents or near-accidents. This percentage increased for higher acuities between 33% (<0.2 > or = 0.1) and 67% (> or = 0.2 < or = 0.4). For visual field diameters <60 degrees and > or = 20 degrees approximately 18% were able to ride a bicycle safely and only 8% if the visual field diameter was below 20 degrees. For visual fields larger than 60 degrees diameter approximately 40% were able to ride a bicycle without problems. With a central scotoma of more than 10 degrees diameter only 21% of the patients could cycle safely, whereas with a central scotoma of 10 degrees and less this percentage increased to 47%. CONCLUSIONS: A visual acuity of less than 0.1 is not sufficient to ride a bicycle, and a visual acuity of less than 0.2 leads to a higher accident rate. A visual field diameter of less than 60 degrees or a central scotoma of more than 10 degrees diameter for the vast majority of patients does not allow safe cycling