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Validating a model of architectural hazard visibility with low-vision observers

ABSTRACT: Pedestrians with low vision are at risk of injury when hazards, such as steps and posts, have low visibility. This study aims at validating the software implementation of a computational model that estimates hazard visibility. The model takes as input a photorealistic 3D rendering of an architectural space, and the acuity and contrast sensitivity of a low-vision observer, and outputs estimates of the visibility of hazards in the space. Our experiments explored whether the model could predict the likelihood of observers correctly identifying hazards. In Experiment 1, we tested fourteen normally sighted subjects with blur goggles that simulated moderate or severe acuity reduction. In Experiment 2, we tested ten low-vision subjects with moderate to severe acuity reduction. Subjects viewed computer-generated images of a walkway containing five possible targets ahead—big step-up, big step-down, small step-up, small step-down, or a flat continuation. Each subject saw these stimuli with variations of lighting and viewpoint in 250 trials and indicated which of the five targets was present. The model generated a score on each trial that estimated the visibility of the target. If the model is valid, the scores should be predictive of how accurately the subjects identified the targets. We used logistic regression to examine the correlation between the scores and the participants’ responses. For twelve of the fourteen normally sighted subjects with artificial acuity reduction and all ten low-vision subjects, there was a significant relationship between the scores and the participant’s probability of correct identification. These experiments provide evidence for the validity of a computational model that predicts the visibility of architectural hazards. It lays the foundation for future validation of this hazard evaluation tool, which may be useful for architects to assess the visibility of hazards in their designs, thereby enhancing the accessibility of spaces for people with low vision.

SUBMITTER: Liu S

PROVIDER: S-EPMC8608317 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:PurposeLow vision reduces text visibility and causes difficulties in reading. A valid low-vision simulation could be used to evaluate the accessibility of digital text for readers with low vision. We examined the validity of a digital simulation for replicating the text visibility and reading performance of low-vision individuals.MethodsLow-vision visibility was modeled with contrast sensitivity functions (CSFs) with parameters to represent reduced acuity and contrast sensitivity. Digital filtering incorporating these CSFs were applied to digital versions of the Lighthouse Letter Acuity Chart and the Pelli-Robson Contrast Sensitivity Chart. Reading performance (reading acuity, critical print size, and maximum reading speed) was assessed with filtered versions of the MNREAD reading acuity Chart. Thirty-six normally sighted young adults completed chart testing under normal and simulated low-vision conditions. Fifty-eight low-vision subjects (thirty with macular pathology and twenty-eight with non-macular pathology) and fifteen normally sighted older subjects completed chart testing with their habitual viewing. We hypothesized that the performance of the normally sighted young adults under simulated low-vision conditions would match the corresponding performance of actual low-vision subjects.ResultsWhen simulating low-vision conditions with visual acuity better than 1.50 logMAR (Snellen 20/630) and contrast sensitivity better than 0.15 log unit, the simulation adequately reduced the acuity and contrast sensitivity in normally sighted young subjects to the desired low-vision levels. When performing the MNREAD test with simulated low vision, the normally sighted young adults had faster maximum reading speed than both the Non-macular and Macular groups, by an average of 0.07 and 0.12 log word per minute, respectively. However, they adequately replicated the reading acuity as well as the critical print size, up to 2.00 logMAR of both low-vision groups.ConclusionA low-vision simulation based on clinical measures of visual acuity and contrast sensitivity can provide good estimates of reading performance and the accessibility of digital text for a broad range of low-vision conditions.

Project description:Visual information is key to how many animals interact with their environment, and much research has investigated how animals respond to colour and brightness information in the natural world. Understanding the visibility of features in anthropogenic environments, and how animals respond to these, is also important, not least for the welfare and safety of animals and the humans they co-exist with, but has received comparatively less attention. One area where this is particularly pertinent is animal sports such as horseracing. Here there is a need to understand how horses see and respond to obstacles, predominantly fences and hurdles, as this has implications for horse and rider safety, however obstacle appearance is currently designed to human perception. Using models of horse colour and luminance (perceived lightness) vision, we analysed the contrast of traditional orange markers currently used on fences from 11 UK racecourses, and compared this to potential alternative colours, while also investigating the effect of light and weather conditions on contrast. We found that for horses, orange has poor visibility and contrast against most surroundings. In comparison, yellow, blue, and white are more conspicuous, with the degree of relative contrast varying with vegetation or background type. Results were mostly consistent under different weather conditions and time of day, except for comparisons with the foreground turf in shade. We then tested the jump responses of racehorses to fences with orange, fluorescent yellow, bright blue, or white takeoff boards and midrails. Fence colour influenced both the angle of the jump and the distances jumped. Bright blue produced a larger angle of takeoff, and jumps over fluorescent yellow fences had shorter landing distances compared to orange, with bright blue fences driving a similar but non-significant trend. White was the only colour that influenced takeoff distances, with horses jumping over white fences having a larger takeoff distance. Overall, our results show that current obstacle coloration does not maximise contrast for horse vision, and that alternative colours may improve visibility and alter behavioural responses, with the ultimate goal of improving safety and welfare.

Project description:BackgroundLow vision affects over 300 million people worldwide and can compromise both activities of daily living and quality of life. Rehabilitative training and vision assistive equipment (VAE) may help, but some visually impaired people have limited resources to attend in-person visits at rehabilitation clinics to receive training to learn to use VAE. These people may be able to overcome barriers to care through remote, Internet-based consultation (i.e. telerehabilitation).ObjectivesTo compare the effects of telerehabilitation with face-to-face (e.g. in-office or inpatient) vision rehabilitation services for improving vision-related quality of life and near reading ability in people with visual function loss due to any ocular condition. Secondary objectives were to evaluate compliance with scheduled rehabilitation sessions, abandonment rates for VAE devices, and patient satisfaction ratings.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 6); Ovid MEDLINE; Embase.com; PubMed; ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any language restriction or study design filter in the electronic searches; however, we restricted the searches from 1980 onwards because the Internet was not introduced to the public until 1982. We last searched the electronic databases on 24 June 2019.Selection criteriaWe planned to include randomized controlled trials (RCTs) or controlled clinical trials (CCTs) in which participants diagnosed with low vision were undergoing low vision rehabilitation using an Internet, web-based technology compared with an approach involving in-person consultations.Data collection and analysisTwo review authors independently screened titles and abstracts and then full-text articles against the eligibility criteria. We planned to have two review authors independently abstract data from the included studies. Any discrepancies were resolved by discussion.Main resultsWe identified two ongoing studies, but did not find any completed RCTs and CCTs that met the inclusion criteria for this review. We did not conduct a quantitative analysis. We discussed review articles on telemedicine for facilitating communication with elderly individuals or for providing remote ophthalmological care.Authors' conclusionsWe did not find any evidence from RCTs or CCTs on the efficacy of using telerehabilitation for remote delivery of rehabilitation services to individuals with low vision. Given the disease burden and the growing interest in telemedicine, the two ongoing studies, when completed, may provide evidence in understanding the potential for telerehabilitation as a platform for providing services to people with low vision.

Project description:SignificanceWe assessed the number of referrals for low vision (LV) services to determine if establishing an LV program at a large academic medical center impacted referral rates. Visual acuity (VA), referral outcome, location, and specialty were examined as factors that could impact referrals.PurposeThis study aimed to identify gaps in the referral process to LV services.MethodsElectronic medical records of patients were reviewed to ascertain the referral rate among those who qualified for services, both before (2014 to 2016) and after (2017 to 2019) the establishment of an LV program. The medical records were further subdivided into two categories based on VA in the better-seeing eye: 20/70 to 20/200 and 20/200 to worse vision.ResultsA total of 2014 patient records with VA qualifying for LV services were reviewed. The proportion of patients who had a VA of 20/70 to 20/200 inclusive in their better eye was 91.7%. A majority (89.8%) of patients with VA of 20/70 to 20/200 and 74.4% of patients with VA worse than 20/200 were never referred. Before establishing an LV program, only 2.2% of patients with VA of 20/70 to 20/200 were referred for services on their first visit, which improved to 8% after the program was established (odds ratio [OR], 3.88; 95% confidence interval [CI], 2.37 to 6.33; P < .001). Also, before the program's establishment, 12.5% of patients with VA worse than 20/200 were referred on their first visit, which increased to 31.9% after the program's establishment (OR, 3.29; 95% CI, 1.50 to 7.19; P = .002). Patients with VA worse than 20/200 were more likely to be referred (before: OR, 6.34 [95% CI, 3.03 to 13.28; P < .001]; after: OR, 5.38 [95% CI, 3.09 to 9.37; P < .001]). Our data also showed that 10.3% of patients in this study declined referral to LV services.ConclusionsReferral rates to LV services are low among patients who qualify. The establishment of an LV program at the medical center significantly increased referral rates. However, more improvement is necessary to connect patients to LV services.

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Validating a model of architectural hazard visibility with low-vision observers

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