How Visible Are Steps and Stairs for People with Low Vision?
by Maureen Duffy
As many readers know, I am a vision rehabilitation therapist (VRT) and a low vision therapist (LVT) with a lifelong professional interest in assessing and modifying indoor and outdoor environments for people who are blind or have low vision. One of my particular interests is steps and stairs: How easy – or difficult – are they to see, decipher [i.e., step up or step down], and navigate safely?
Thus, I have been following – with great interest – the core research team of Gordon E. Legge, Christopher S. Kallie, Tiana M. Bochsler, and Rachel Gage, from the University of Minnesota. For several years, they have been investigating the visual accessibility of ramps and steps, specifically for people with low vision. Following is a brief summary of their ongoing and developing research.
2010: The Journal of Vision
Visual Accessibility of Ramps and Steps was published in the September 9, 2010 online edition of the Journal of Vision, a digital, open-access, peer-reviewed journal devoted to all aspects of visual function, published by the Association for Research in Vision and Ophthalmology (ARVO).
The study investigated the impact of two factors in the recognition of steps and ramps by persons with low vision: (a) visual texture [or patterns] on the ground and (b) the role of walking/moving about in providing information. The researchers constructed a "test sidewalk" with ramps and steps, which 48 sighted subjects viewed through "blurring" goggles that simulated vision impairment.
As a result of this experimentation, they discovered the following:
- A step up is usually more visible than a step down, and failing to see a step down is usually more dangerous than failing to see a step up. This [difference] in visibility is primarily due to the [lighting] contrast between the riser of a step up and [the step's flat surface].
- Subtle changes in the edge contours of a walkway provide [low vision/visual] cues for steps and ramps, dependent upon the viewing distance and the contrast between the walkway and its background.
- Future studies will expand the research to people with low vision.
2011: ARVO Conference Presentation
This conference presentation, entitled Recognition of Ramps and Steps by People with Low Vision, built upon their prior work, this time asking whether previous results with sighted "goggle-wearing" subjects would also apply to subjects with low vision. Participants included nine subjects with low vision and a comparison group of sighted subjects with "blurring" goggles.
The results of this expanded research were as follows:
- A step up was more recognizable than a step down for both groups.
- Both groups performed best at a middle (10-foot) distance.
- The effects of distance, lighting, and target type [i.e., ramp or step] were similar for sighted and low vision subjects.
2012: Optometry and Vision Science
Seeing Steps and Ramps with Simulated Low Acuity: Impact of Texture and Locomotion in the September 2012 edition of Optometry and Vision Science, the official journal of the American Academy of Optometry.
Similar to their previous work, this study investigated the impact of (a) visual texture on the ground and (b) the role of walking in generating visual cues. The 24 sighted subjects used "blurring" goggles. In the texture experiment, the subjects viewed steps and ramps on a surface with a coarse black-and-white checkerboard pattern. In the walking experiment, the subjects moved along the sidewalk toward the ramp or step before making judgments.
The results were as follows:
- A coarse texture pattern on the ground surface can interfere with contrast and hinder the visibility of ramps and steps.
- [Walking] toward ramps and steps does enhance their visibility.
- If the results also apply to people with low vision, the findings may prove helpful in designing spaces to enhance visual accessibility.
- The findings may also be helpful for rehabilitation specialists who can inform their low vision clients about the possible interfering effects of surface patterns and the advantages of movement and walking in the visual exploration of their surroundings.
Recognition of Ramps and Steps by People with Low Vision has been published online ahead-of-print in Investigative Ophthalmology & Visual Science, the official journal of the Association for Research in Vision and Ophthalmology (ARVO).
The research goal was to assess the impact of viewing conditions and environmental factors on the recognition of [ramps and steps] by people with low vision. Sixteen subjects with low vision viewed a sidewalk interrupted by one of five targets: a single step up or down; a ramp up or down; or a flat continuation of the sidewalk. Researchers compared the performance of the low vision subjects with a group of sighted subjects wearing "blurring" goggles.
The results were the following:
- Performance was significantly better at shorter distances and after walking, compared with stationary viewing.
- The effects of distance, target type [i.e., ramp or step], and walking/movement were similar for both groups.
- The effects of lighting and background contrast were only significant for the sighted subjects wearing "blurring" goggles.
Real-Life Steps and Ramps
So what does this mean? How do stairs, steps, and ramps look to someone who has low vision? To better illustrate the problems that people with low vision encounter, here are some photographs I've taken at locations around the world:
Descending outdoor steps in Sydney, Australia:
The same set of steps, this time ascending. See the difference?
What about this set of steps? The shadow pattern changes your perception, doesn't it?
Are these steps or a ramp leading to the parking lot? Or both?
Do you have real-life situations, photos, or experiences to share? please leave a note in the comments section. I'm interested to hear from you!
Re: How Visible Are Steps and Stairs for People with Low Vision?Posted by susangayle on 12/20/2012 at 9:08 AM
When we built an addition onto our outside deck, we made it two-leveled (i.e. one half of the deck was at a lower level than the other half.) As the contractor was finishing up, I noticed that there was no discernable contrast between the upper half and the lower half, which made it very difficult for my mother, who is severely visually impaired, to tell where the drop was onto the lower level. I asked the contractor if he could place a darker colored slat of wood at the very end of the drop off, running along the edge of the drop off. He did, and the problem was solved. What we needed was the contrast.
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