Simulated Visual Impairment Research Articles

The influence of simulated visual impairment on distance stereopsis.

The intricate interrelationships between visual acuity (VA) and stereopsis depend on an array of factors, incorporating the nature of vision impairment, its manifestation (monocular versus binocular), and the classification of stereopsis test symbols used. The objectives of this study were to methodically dissect these multifaceted interactions by simulating a diverse range of vision loss conditions. Thirty medical students with normal vision were subjected to simulated vision loss through opacification and blurring methodologies. Stereopsis was assessed at a distance using both contour-based and random-dot-based symbols under equal binocular and varied monocular VA conditions. In this study, opacification consistently affected stereopsis more than blurring at equivalent VA reductions. However, this difference was absent in contour-based symbols under binocular vision impairment conditions. Significant differences in stereopsis emerged between monocular and binocular vision within the opacification contour-based groups. These differences were less evident in the opacification and blurring groups using random-dot-based patterns. In terms of symbols, the contour-based test demonstrated superior results to the random-dot-based test, particularly under decreased VA. In sum, the method of VA reduction and the choice of stereogram significantly impact distance stereopsis outcomes. This understanding can guide clinical assessments of stereopsis in individuals with varying visual impairments.

Exploring Upper Limb Kinematics in Limited Vision Conditions: Preliminary Insights from 3D Motion Analysis and IMU Data

This study examined upper limb kinematics under simulated visually impaired conditions. By investigating how upper limb movements adapt in these circumstances, we aimed to gain insights that may prove valuable for both healthy populations and those with clinical conditions. Data, including 3D marker-based motion capture and accelerometer readings, were collected from seven healthy volunteers walking on a treadmill at 1.5 m/s under two conditions: without glasses (NG) and with stroboscopic glasses (G). Each walking condition lasted 2 minutes, and two 10-second recordings were analyzed from the midpoint of each session. Contrary to our hypothesis, simulated visual impairment with stroboscopic eyewear at 6Hz did not statistically affect upper limb kinematics, specifically in terms of wrist acceleration and hand distance in the frontal plane. Future research should explore varied visual impairment conditions, extend task durations, and investigate the relationship between subjective gait difficulties and biomechanical data.

Effects of Simulated Visual Impairment Conditions on Movement and Anxiety during Gap Crossing.

This study investigated the effects of visual conditions associated with progressive eye disease on movement patterns and anxiety levels during gap-crossing tasks. Notably, 15 healthy young adults performed crossover platforms with a 10 cm gap at three different heights, namely equal (0 cm), raised (+15 cm), and lowered (-15 cm) levels, under four vision conditions, namely normal or corrected eyesight, 10° tunnel vision, 5° tunnel vision, and 5° tunnel vision with 0.04 occlusion. Leg movements during gap crossing were analyzed using three-dimensional motion analysis. The results highlighted a distinct motion pattern in the trajectories of participants' legs under the different visual conditions. Specifically, at the point where the gap-crossing movement began (D1), the normal or corrected eyesight conditions resulted in further separation between the steps compared with the other visual conditions. The highest point of the foot during movement (D2) did not differ between the visual conditions, except for the 0 cm step. Furthermore, anxiety levels, as quantified by the State-Trait Anxiety Inventory (STAI-S) questionnaire, were exacerbated under conditions of restricted visual information. In conclusion, visual impairments associated with progressive ocular diseases may perturb complex motor movement patterns, including those involved in gap-crossing tasks, with heightened anxiety potentially amplifying these disturbances.

Changes in Physical Stability of Simulated Visual Impairment according to Gaze Distance

Changes in Physical Stability of Simulated Visual Impairment according to Gaze Distance

The effects of simulated vision impairment on performance in football

ABSTRACT Footballers with vision impairment (VI) are eligible to compete in the Para sport if they meet a minimum impairment criteria (MIC) based on measures of their visual acuity (VA) and/or visual field. Despite the requirements of the International Paralympic Committee Athlete Classification Code that each sport uses an evidence-based classification system, VI football continues to use a medical-based system that lacks evidence to demonstrate the relationship between impairment and performance in the sport. The aim of this study was to systematically simulate vision loss to establish the minimum level of impairment that would affect performance in futsal. Nineteen skilled sighted players completed tests of individual technical skill and anticipation performance under six levels of simulated blur that decreased both VA and contrast sensitivity (CS). VA needed to be reduced to a level of acuity that represents worse vision than that currently used for inclusion in VI football before meaningful decreases in performance were observed. CS did not have a clear effect on football performance. These findings produce the first evidence for the minimum impairment criteria in VI football and suggest a more severe degree of impairment may be required for the MIC.

Preparation of 3D Models of Cultural Heritage Objects to Be Recognised by Touch by the Blind—Case Studies

Providing access to and the protection of cultural goods—intangible and tangible heritage—is carried out primarily by institutions such as museums, galleries or local cultural centres where temporary exhibitions are shown. The international community also attempts to protect architectural objects or entire urban layouts, raising their status by inscribing them on the UNESCO World Heritage List. Contemporary museums, however, are not properly prepared to make museum exhibits available to the blind and visually impaired, which is confirmed by both the literature studies on the subject and the occasional solutions that are put in place. The development of various computer graphics technologies allows for the digitisation of cultural heritage objects by 3D scanning. Such a record, after processing, can be used to create virtual museums accessible via computer networks, as well as to make copies of objects by 3D printing. This article presents an example of the use of scanning, modelling and 3D printing to prepare prototypes of copies of museum objects from the Silk Road area, dedicated to blind people and to be recognised by touch. The surface of an object has information about it written in Braille before the copy-making process is initiated. The results of the pilot studies carried out on a group of people with simulated visual impairment and on a person who is blind from birth indicate that 3D models printed on 3D replicators with the fused filament fabrication technology are useful for sharing cultural heritage objects. The models are light—thanks to which they can be freely manipulated, as well as having the appropriate smoothness—which enables the recognition of decorative details present on them, as well as reading texts in Braille. Integrating a copy of an exhibit with a description about it in Braille into one 3D object is an innovative solution that should contribute to a better access to cultural goods for the blind.

The effects of simulated and actual visual impairment on the Montreal Cognitive Assessment

ABSTRACT Many cognitive assessments include a visual component; however, adults may experience a decline in visual acuity with age. Scores on cognitive assessments of adults with visual impairments are typically lower than adults with normal vision, however, it is unclear if these lower scores are a consequence of cognitive or visual impairment. We measured the impact of simulated visual impairment on a cognitive screening measure. Undergraduate students were administered the Montreal Cognitive Assessment (MoCA) under three vision conditions (20/20, simulated 20/80, simulated 20/200). We found a main effect of vision condition on test performance such that there is a statistically significant difference between scores on the 20/20 and 20/80 conditions and 20/200. However, no differences were observed between 20/80 and 20/200. Participants’ performance decreased with simulated impairments. A secondary between-subject analysis was conducted on a sample of older adults with and without vision impairment; no differences were found.

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

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.

How Is Jump Performance Affected in Male Athletes when Completed with a Visual Impairment?

High-, long-, and triple-jump athletic events may need to consider whether it is appropriate to group vision-impaired athletes in the same classification with loss of different visual functions, and a greater emphasis may need to be placed on the visual field (VF) within the current classification system used. Athletes with vision impairment are grouped, based on their visual function, into one of three different classes (B1, B2, and B3, with B1 being the most severe). Athletes in class B2 have loss in visual acuity (VA; range, 1.50 to 2.60 logMAR) or VF (constricted to a diameter of <10°). The current study investigated how loss of different visual function (VA or VF) within the same class impacts jumping performance, a fundamental component in long-, triple-, and high-jump athletic events. Ten subelite male athletes (age, 21.6 ± 0.96 years; height, 178.8 ± 2.97 cm; mass, 82.2 ± 10.58 kg) with normal vision who participate in athletics were recruited. Participants completed drop jumps in four vision conditions: habitual vision condition (Full), VA no better than 1.60 logMAR (B2-VA), VF restricted to <10° (B2-VF), and VA no better than 1.30 logMAR (B3-VA). Meaningful differences were observed between Full and B2-VF conditions. After rebound, vertical velocity at take-off was highest in Full condition (2.84 ± 0.35 m · s-1; 95% confidence interval [CI], 2.68 to 2.99 m · s-1) and was lowest in B2-VF condition (20% reduction; 2.32 ± 0.29 m · s-1; 95% CI, 2.16 to 2.48 m · s-1). Peak vertical jump height was highest in Full (0.42 ± 0.10 m; 95% CI, 0.38 to 0.46 m) and reduced by 40% in B2-VF (0.28 ± 0.07 m; 95% CI, 0.24 to 0.32 m). Minimal differences were found between Full and B2-VA, or B3-VA conditions. Jump performance is compromised in athletes with simulated vision impairment. However, decrements in performance seem specific to those with severely constricted VF. Those with reduced VA (in B2-VA and B3-VA classes) seem to produce performance comparable to those with normal vision.

Getting a grip on the resilience to blur: The impact of simulated vision loss on a visually guided combat sports interaction

Research has shown that performance in highly visually demanding sports can be resilient to substantial levels of blur. This raises the question whether the need for high visual clarity might be reduced even more in less visually demanding sports such as combat sports, where athletes compete at relatively close distances. The aim of this study was to examine the resilience to blur in the grip fighting phase of judo as an exemplar of a visually guided combat sports task. The results were particularly relevant for the purposes of Paralympic judo for athletes with vision impairment (VI judo), because athletes are currently allowed to compete with a visual acuity (VA) of 1.0 logMAR or worse (i.e., 6/60 or 20/200 vision), suggesting this is the presumed level of impairment that decreases performance in able-sighted judo. We let 28 able-sighted judo athletes compete in pairs in a series of grip fighting tasks under increasing levels of simulated vision impairment. Visual function was tested in each condition by measuring VA and contrast sensitivity (CS). We found that VA was a better predictor than CS of grip fighting performance. VA needed to be reduced to at least 1.3 logMAR before a decrease in performance was found, with approximately twice as much blur needed to be applied when compared to visually demanding tasks such as cricket batting, but less than what has been found in static tasks such as basketball free-throw shooting and golf putting. These findings hold implications for VI judo regulations, suggesting that a more severe degree of impairment should be required to participate than is currently the case.

The Effects of Age, Distraction, and Simulated Central Vision Impairment on Hazard Detection in a Driving Simulator.

Despite similar levels of visual acuity and contrast sensitivity reductions, simulated central vision impairment increased response times to a much greater extent in older than in younger participants. Driving is crucial for maintaining independence in older age, but age-related vision impairments and in-vehicle auditory distractions may impair driving safety. We investigated the effects of age, simulated central vision impairment, and auditory distraction on detection of pedestrian hazards. Thirty-two normally sighted participants (16 younger and 16 older) completed four highway drives in a simulator and pressed the horn whenever they saw a pedestrian. Pedestrians ran toward the road on a collision course with the approaching vehicle. Simulated central vision impairment was achieved by attaching diffusing filters to a pair of laboratory goggles, which reduced visual acuity to 20/80 and contrast sensitivity by 0.35 log units. For drives with distraction, subjects listened to an audiobook and repeated out loud target words. Simulated central vision impairment had a greater effect on reaction times (660-millisecond increase) than age (350-millisecond increase) and distraction (160-millisecond increase) and had a greater effect on older than younger subjects (828- and 492-millisecond increase, respectively). Simulated central vision impairment decreased safe response rates from 94.7 to 78.3%. Distraction did not, however, affect safety because older subjects drove more slowly when distracted (but did not drive more slowly with vision impairment), suggesting that they might have perceived greater threat from the auditory distraction than the vision impairment. Older participants drove more slowly in response to auditory distraction. However, neither older nor younger participants adapted their speed in response to simulated vision impairment, resulting in unsafe detections. These results underline the importance of evaluating safety of responses to hazards as well as reaction times in a paradigm that flexibly allows participants to modify their driving behaviors.

Effects of simulated visual impairment on orientation, shape, and emotion perception

Effects of simulated visual impairment on orientation, shape, and emotion perception

An augmented reality sign-reading assistant for users with reduced vision.

People typically rely heavily on visual information when finding their way to unfamiliar locations. For individuals with reduced vision, there are a variety of navigational tools available to assist with this task if needed. However, for wayfinding in unfamiliar indoor environments the applicability of existing tools is limited. One potential approach to assist with this task is to enhance visual information about the location and content of existing signage in the environment. With this aim, we developed a prototype software application, which runs on a consumer head-mounted augmented reality (AR) device, to assist visually impaired users with sign-reading. The sign-reading assistant identifies real-world text (e.g., signs and room numbers) on command, highlights the text location, converts it to high contrast AR lettering, and optionally reads the content aloud via text-to-speech. We assessed the usability of this application in a behavioral experiment. Participants with simulated visual impairment were asked to locate a particular office within a hallway, either with or without AR assistance (referred to as the AR group and control group, respectively). Subjective assessments indicated that participants in the AR group found the application helpful for this task, and an analysis of walking paths indicated that these participants took more direct routes compared to the control group. However, participants in the AR group also walked more slowly and took more time to complete the task than the control group. The results point to several specific future goals for usability and system performance in AR-based assistive tools.

Effects of simulated vision impairment and auditory distraction on the detection of hazards while driving

Effects of simulated vision impairment and auditory distraction on the detection of hazards while driving

Detecting Cheating when Testing Vision: Variability in Acuity Measures Reveals Misrepresentation.

In certain scenarios, it is advantageous to misrepresent one's ability and "cheat" on vision tests. Our findings suggest that increased variability when testing visual acuity holds promise as a novel means to help detect this cheating and may generalize to other subjective tests of visual function. People who cheat on vision tests generally do so to make their vision appear better than it actually is (e.g., for occupational or driving purposes). However, there are particular settings in which it is advantageous for their vision to appear to be worse than is the case (e.g., to qualify for benefits available to people with low vision). Therefore, a method to help detect cheating in these scenarios is desirable. The aim of this study was to investigate whether the intentional underrepresentation of vision could be detected when testing visual acuity. We tested the visual acuity of 13 participants with simulated vision impairment using the Berkeley Rudimentary Vision Test. Participants were tested in an honest condition when providing their best effort and in a cheating condition when attempting to make their visual acuity appear to be markedly worse. We also tested visual acuity of 17 participants with a wide range of vision impairments. Participants were successfully able to "cheat" on the tests; however, their responses were significantly more variable when cheating (P < .001). Although the variability in visual acuity was larger in individuals with actual vision impairment compared with those providing honest answers with simulated impairment (P < .01), their responses remained significantly less variable than those for individuals in the cheating condition (P = .01). The variability in the estimations of vision provides a promising novel means of detecting the intentional underrepresentation of vision and could help to minimize the chance of successfully cheating on tests of vision.

Three-dimensional binocular eye-hand coordination in normal vision and with simulated visual impairment.

Sensorimotor coupling in healthy humans is demonstrated by the higher accuracy of visually tracking intrinsically-rather than extrinsically-generated hand movements in the fronto-parallel plane. It is unknown whether this coupling also facilitates vergence eye movements for tracking objects in depth, or can overcome symmetric or asymmetric binocular visual impairments. Human observers were therefore asked to track with their gaze a target moving horizontally or in depth. The movement of the target was either directly controlled by the observer's hand or followed hand movements executed by the observer in a previous trial. Visual impairments were simulated by blurring stimuli independently in each eye. Accuracy was higher for self-generated movements in all conditions, demonstrating that motor signals are employed by the oculomotor system to improve the accuracy of vergence as well as horizontal eye movements. Asymmetric monocular blur affected horizontal tracking less than symmetric binocular blur, but impaired tracking in depth as much as binocular blur. There was a critical blur level up to which pursuit and vergence eye movements maintained tracking accuracy independent of blur level. Hand-eye coordination may therefore help compensate for functional deficits associated with eye disease and may be employed to augment visual impairment rehabilitation.

The design and efficiency of a physical education program to promote attitudinal changes towards people with visual impairments

The main goal of this study was to design, and confirm the efficiency of, a formative Physical Education program with the purpose of improving schoolchildren’s attitudes towards people who have a visual impairment. The participants were 910 students aged 9 to 13 years old from the region of Castilla-La Mancha (Spain). Participants simulated visual impairment during eight Physical Education sessions within the context of play and a sports-based learning environment. They completed an attitudinal questionnaire both pre and post the intervention. The author’s (2018) aim was to evaluate children’s attitudes toward both visual impairment and integrated Physical Education CAIPE-R (Block, 1995). Both a descriptive and comparative analyses, as well as ANOVA, were conducted. The results indicated a significant improvement in children’s attitudes toward those with visual impairment. Therefore, this program would be efficacious when applied in schools in the future in order to promote a better attitude toward inclusion.

Effects of simulated visual impairment on orientation and shape perception

Effects of simulated visual impairment on orientation and shape perception

The effect of magnification and contrast on reading performance in different types of simulated low vision

Low vision therapy, such as magnifiers or contrast enhancement, is widely used. Scientific evidence proving its efficacy is scarce however. The objective of this study was to investigate whether the benefits of magnification and contrast enhancement depended on the origin of low vision. For this purpose we measured reading speed with artificially induced low vision in 12 healthy subjects in conditions of a simulated central scotoma, blurred vision and oscillopsia. Texts were either blurred, set in motion or blanked at the gaze position by using eye tracking and gaze contingent display. The simulated visual impairment was calibrated such that all types of low vision caused equal reading impairment. We then tested the effect of magnification and contrast enhancement among the different types of low vision. We found that reading speed improved with increasing magnification and with higher contrast in all conditions. The effect of magnification was significantly different in the three low vision conditions: The gain from magnification was highest in simulated blur and least in central scotoma. Magnification eventually led to near normal reading speed in all conditions. High contrast was less effective than high magnification and the effect of contrast enhancement was similar in all low vision conditions. From these results we conclude that the type of low vision determines the benefit that can be expected from magnification. Contrast enhancement leads to similar improved reading speed in all low vision types. We provide evidence that supports the use of low vision aids.

The effects of simulated vision impairments on the cone of gaze.

Detecting the gaze direction of others is critical for many social interactions. We explored factors that may make the perception of mutual gaze more difficult, including the degradation of the stimulus and simulated vision impairment. To what extent do these factors affect the complex assessment of mutual gaze? Using an interactive virtual head whose eye direction could be manipulated by the subject, we conducted two experiments to assess the effects of simulated vision impairments on mutual gaze. Healthy subjects had to demarcate the center and the edges of the cone of gaze-that is, the range of gaze directions that are accepted for mutual gaze. When vision was impaired by adding a semitransparent white contrast reduction mask to the display (Exp. 1), judgments became more variable and more influenced by the head direction (indicative of a compensation strategy). When refractive blur was added (Exp. 1), the gaze cone shrank from 12.9° (no blur) to 11.3° (3-diopter lens), which cannot be explained by a low-level process but might reflect a tightening of the criterion for mutual gaze as a response to the increased uncertainty. However, the overall effects of the impairments were relatively modest. Elderly subjects (Exp. 2) produced more variability but did not differ qualitatively from the younger subjects. In the face of artificial vision impairments, compensation mechanisms and criterion changes allow us to perform better in mutual gaze perception than would be predicted by a simple extrapolation from the losses in basic visual acuity and contrast sensitivity.