Increasing the contrast of tread edge highlighters improves stair descent safety in older adults with simulated visual impairment

Marko Bjelica; Iris C Levine; Alison C Novak

doi:10.1016/j.apergo.2021.103525

Increasing the contrast of tread edge highlighters improves stair descent safety in older adults with simulated visual impairment

Appl Ergon. 2021 Nov:97:103525. doi: 10.1016/j.apergo.2021.103525. Epub 2021 Jul 10.

Authors

Marko Bjelica¹, Iris C Levine², Alison C Novak³

Affiliations

¹ KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 13-000, 550 University Avenue, Toronto, Ontario, M5G 2A2, Canada; Rehabilitation Sciences Institute, University of Toronto, 500 University Avenue, Toronto, Ontario, M5G 1V7, Canada.
² KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 13-000, 550 University Avenue, Toronto, Ontario, M5G 2A2, Canada.
³ KITE Research Institute, Toronto Rehabilitation Institute - University Health Network, 13-000, 550 University Avenue, Toronto, Ontario, M5G 2A2, Canada; Rehabilitation Sciences Institute, University of Toronto, 500 University Avenue, Toronto, Ontario, M5G 1V7, Canada; Department of Occupational Science and Occupational Therapy, University of Toronto, 500 University Avenue, Toronto, Ontario, M5G 1V7, Canada; Faculty of Kinesiology and Physical Education, University of Toronto, 55 Harbord Street, Toronto, Ontario, M5S 2W8, Canada. Electronic address: Alison.novak@uhn.ca.

PMID: 34256320
DOI: 10.1016/j.apergo.2021.103525

Abstract

Falls during stair descent are dangerous and costly. Contrasting tread edge highlighters improve measures of stair safety, however the necessary contrast level of these interventions has not been investigated. Thirteen older adults (67.7 ± 5.5 years) completed stair descent trials under normal (300lx) and low (30lx) lighting conditions, blurred and normal vision, and four different contrast levels (0%, 30%, 50%, 70%) between the tread edge highlighter and the neighbouring tread surface. Cadence and heel clearance decreased for 0% contrast compared to 50% and 70% contrast conditions, but contrast had no effect on foot overhang. Blurred vision was observed to be a greater factor influencing biomechanical measures of fall risk than low ambient lighting. Results suggest higher contrast highlighters improve measures of safety, even more so during simulated vision impairment, and that at least 50% contrast difference provides adequate visual information for safer stair ambulation.

Keywords: Built environment; Contrast; Fall prevention; Stair descent; Visual impairment.

MeSH terms

Accidental Falls / prevention & control
Aged
Biomechanical Phenomena
Gait*
Humans
Vision Disorders
Walking*