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Shirin E Hassan; Does Loss of Vision Impact a Pedestrian's Ability to Estimate their Own Street Crossing Time?. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© ARVO (1962-2015); The Authors (2016-present)
To determine how well a visually impaired person can estimate their street crossing time.
The actual street crossing time of 129 visually impaired subjects (64 subjects self-reporting “difficulty crossing the street” and 65 subjects self-reporting “no difficulties”) was measured four times along a street that was two lanes of one-way traffic. Subjects also estimated their street crossing time four times by imagining themselves crossing the same street. Subjects said “start” and “stop” when they imagined themselves stepping off the curb and reaching the other side of the street respectively. The time interval between “start” and “stop” was recorded and street crossing estimates were measured both before and after subjects actually crossed the street. A linear mixed model with repeated measures for subject was used to determine if the ratio between subjects’ estimated and actual crossing times changed as a function of subject group (with and without self-reported difficulties) and before and after actually crossing the street.
No significant difference was found in the ratio between subjects with (ratio=1.02) and without (ratio=0.96) self-reported difficulties in crossing the street (p=0.16). Overall, subjects’ estimates of their crossing time decreased significantly (on average by 8%) after they had the experience of crossing the street (p=0.0006). The reduction in the ratio before and after crossing was significant for the subjects who self-reported difficulties (p=0.002) but not for the subjects who self-reported no difficulties in crossing the street (p=0.08).
Our data suggests that reporting having difficulties crossing the street does not affect a visually impaired pedestrian’s ability to judge their own crossing time. Familiarity with the street significantly reduces a visually impaired pedestrian’s estimate of the time they think they need to cross the street.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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