TY - JOUR
T1 - Luminance contrast preferences of people with a vision impairment for elements in the built environment
AU - Manandhar, Sarita
AU - Lukman, Aldyfra
AU - Dain, Stephen J.
AU - Bridge, Catherine E.
AU - Relf, Mark
AU - Boon, Mei Ying
N1 - Publisher Copyright:
© 2022 - IOS Press. All rights reserved.
PY - 2022/12/13
Y1 - 2022/12/13
N2 - BACKGROUND: Standards for building elements recommend a minimum luminance contrast of 30%. The basis of this value and the metric originally used is not known. OBJECTIVE: To begin to provide an evidence base for the specification of minimum contrast in building elements. METHODS: Subjects with and without a vision impairment were characterized by visual acuity, contrast sensitivity, visual fields and color vision. On an iPad they rated the visibility, as a function of contrast, of simulated door frames, door handles, light switches and stair nosings as 'not visible at all', 'poorly visible', 'easily visible' and 'extremely easily visible'. RESULTS: The contrasts for each level of visibility were highly correlated with visual acuity and contrast sensitivity. A principal component analysis also verified the importance of visual acuity, contrast sensitivity and visual fields in rating visibility of simulations of building elements. The required contrast for door handles, light switches and stair nosings to attain the same ratings of visibility were very similar but less contrast was required for door frames. CONCLUSIONS: 30% Michelson contrast for building elements renders building elements only poorly visible for those with severe vision impairments. 65% luminance contrast is necessary for all elements to be 'easily visible'. Some increase (not a decrease) on the present 30% requirement and encouragement to exceed this requirement would seem appropriate. The use of simulated objects facilitates a systematic examination of the effect of contrast, but the applicability of the results to real-life remains to be demonstrated.
AB - BACKGROUND: Standards for building elements recommend a minimum luminance contrast of 30%. The basis of this value and the metric originally used is not known. OBJECTIVE: To begin to provide an evidence base for the specification of minimum contrast in building elements. METHODS: Subjects with and without a vision impairment were characterized by visual acuity, contrast sensitivity, visual fields and color vision. On an iPad they rated the visibility, as a function of contrast, of simulated door frames, door handles, light switches and stair nosings as 'not visible at all', 'poorly visible', 'easily visible' and 'extremely easily visible'. RESULTS: The contrasts for each level of visibility were highly correlated with visual acuity and contrast sensitivity. A principal component analysis also verified the importance of visual acuity, contrast sensitivity and visual fields in rating visibility of simulations of building elements. The required contrast for door handles, light switches and stair nosings to attain the same ratings of visibility were very similar but less contrast was required for door frames. CONCLUSIONS: 30% Michelson contrast for building elements renders building elements only poorly visible for those with severe vision impairments. 65% luminance contrast is necessary for all elements to be 'easily visible'. Some increase (not a decrease) on the present 30% requirement and encouragement to exceed this requirement would seem appropriate. The use of simulated objects facilitates a systematic examination of the effect of contrast, but the applicability of the results to real-life remains to be demonstrated.
KW - Accessibility standards
KW - safe navigation
KW - universal design
KW - visibility assessment
KW - visual detection
UR - http://www.scopus.com/inward/record.url?scp=85144590019&partnerID=8YFLogxK
U2 - 10.3233/WOR-210997
DO - 10.3233/WOR-210997
M3 - Article
C2 - 36093666
AN - SCOPUS:85144590019
SN - 1051-9815
VL - 73
SP - 1265
EP - 1278
JO - Work
JF - Work
IS - 4
ER -