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A. L. Doherty, A. R. Bowers, E. Peli; Monocular Bioptic Telescopes May Not Be a Hazard When Driving. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3624.
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Magnification causes a blind area (ring scotoma) around the telescopic view that has been suggested as a danger potentially impairing detection of traffic hazards when driving with bioptics. We evaluated the ability of the fellow (non-telescope) eye to detect stimuli in the area of the ring scotoma (bi-ocular multiplexing) when using a monocular bioptic. We investigated the effect of background complexity, viewing task, and experience using a bioptic on this ability.
To date, 14 subjects have completed the study: 9 experienced and 5 naïve bioptic users. All subjects used a monocular 3x bioptic telescope (Ocutech Mini or Designs for Vision) for the experiment. A dichoptic computerized perimeter (Woods et al, J Biomedical Optics, in press) was used to measure central visual fields with and without the bioptic; a suprathreshold stimulus was used for all tests. To avoid ceiling effects, contrast of the stimuli were adjusted so that the detection rate without bioptic was <90%. The bioptic ring scotoma was mapped presenting the stimulus to the telescope eye only. Each subject then performed a series of detection tasks under binocular viewing with stimuli presented to only the fellow eye within the area of the ring scotoma. Fellow-eye detection rates were determined with and without the bioptic on simple plain grey and more visually-complex noise image backgrounds in passive (looking at fixation cross) or active (reading letters) viewing tasks.
There were no significant differences in fellow-eye detection rates with and without the bioptic (means 79% and 80%; p=0.731); this was true for the two backgrounds (p=0.161) and both experienced and naïve users (p=0.824). As expected, there was a significant reduction in detection rates on the noise background compared to the grey background (71% and 88%, p < 0.001) and with the active task compared to the passive task (75% and 84%, p = 0.006).
Preliminary analyses suggest that both naïve and experienced bioptic users are able to use the fellow eye to detect stimuli in the ring scotoma on a complex background while actively viewing through a monocular bioptic. These results appear promising for monocular bioptic drivers.
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