TY - JOUR
T1 - Seeing steps and ramps with simulated low acuity
T2 - Impact of texture and locomotion
AU - Bochsler, Tiana M.
AU - Legge, Gordon E.
AU - Kallie, Christopher S.
AU - Gage, Rachel
PY - 2012/9
Y1 - 2012/9
N2 - PURPOSE.: Detecting and recognizing steps and ramps is an important component of the visual accessibility of public spaces for people with impaired vision. The present study, which is part of a larger program of research on visual accessibility, investigated the impact of two factors that may facilitate the recognition of steps and ramps during low-acuity viewing. Visual texture on the ground plane is an environmental factor that improves judgments of surface distance and slant. Locomotion (walking) is common during observations of a layout, and may generate visual motion cues that enhance the recognition of steps and ramps. METHODS.: In two experiments, normally sighted subjects viewed the targets monocularly through blur goggles that reduced acuity to either approximately 20/150 (mild blur) or 20/880 Snellen (severe blur). The subjects judged whether a step, ramp, or neither was present ahead on a sidewalk. In the texture experiment, subjects viewed steps and ramps on a surface with a coarse black-and-white checkerboard pattern. In the locomotion experiment, subjects walked along the sidewalk toward the target before making judgments. RESULTS.: Surprisingly, performance was lower with the textured surface than with a uniform surface, perhaps because the texture masked visual cues necessary for target recognition. Subjects performed better in walking trials than in stationary trials, possibly because they were able to take advantage of visual cues that were only present during motion. CONCLUSIONS.: We conclude that under conditions of simulated low acuity, large high-contrast texture elements can hinder the recognition of steps and ramps, whereas locomotion enhances recognition.
AB - PURPOSE.: Detecting and recognizing steps and ramps is an important component of the visual accessibility of public spaces for people with impaired vision. The present study, which is part of a larger program of research on visual accessibility, investigated the impact of two factors that may facilitate the recognition of steps and ramps during low-acuity viewing. Visual texture on the ground plane is an environmental factor that improves judgments of surface distance and slant. Locomotion (walking) is common during observations of a layout, and may generate visual motion cues that enhance the recognition of steps and ramps. METHODS.: In two experiments, normally sighted subjects viewed the targets monocularly through blur goggles that reduced acuity to either approximately 20/150 (mild blur) or 20/880 Snellen (severe blur). The subjects judged whether a step, ramp, or neither was present ahead on a sidewalk. In the texture experiment, subjects viewed steps and ramps on a surface with a coarse black-and-white checkerboard pattern. In the locomotion experiment, subjects walked along the sidewalk toward the target before making judgments. RESULTS.: Surprisingly, performance was lower with the textured surface than with a uniform surface, perhaps because the texture masked visual cues necessary for target recognition. Subjects performed better in walking trials than in stationary trials, possibly because they were able to take advantage of visual cues that were only present during motion. CONCLUSIONS.: We conclude that under conditions of simulated low acuity, large high-contrast texture elements can hinder the recognition of steps and ramps, whereas locomotion enhances recognition.
KW - locomotion
KW - low acuity
KW - low vision
KW - mobility
KW - ramps
KW - steps
KW - texture
KW - visual accessibility
KW - visual recognition
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U2 - 10.1097/OPX.0b013e318264f2bd
DO - 10.1097/OPX.0b013e318264f2bd
M3 - Article
C2 - 22863792
AN - SCOPUS:84865732988
SN - 1040-5488
VL - 89
SP - E1299-E1307
JO - Optometry and Vision Science
JF - Optometry and Vision Science
IS - 9
ER -