The impact of vision loss on attitudes toward autonomous vehicles: A vision-centric analysis.

SIGNIFICANCE: Autonomous vehicles (AVs) have the promise to be an alternative transportation solution for those with vision loss. However, the impact of vision loss on the perceptions and concerns of AVs is unknown. This study therefore examined whether AVs are perceived differently by blind, visually impaired (VI), and normally sighted people. PURPOSE: This study compared the perceptions of AVs among the blind, VI, and normally sighted. METHODS: Participants' opinions on four perception measures (general opinion, trust, impact on quality of life, and intention to use AVs) and nine concerns regarding AVs were measured. The survey was administered to 51 normally sighted, 68 VI, and 65 blind participants. Analyses of covariance assessed whether the four perception measures and nine concerns varied by vision status (normal vision, VI, blind) and driving status (driver, nondriver). Univariate correlations and multiple regression analyses identified associations and predictors of AV perceptions and concerns from demographic, mood, cognition, travel behavior, and vision measures, which included visual acuity, contrast sensitivity, and visual field. RESULTS: The blind (p<0.001), VI (p<0.001), and nondrivers (p<0.001) showed a greater intention to use AVs compared with those with normal vision and drivers. Similar findings were found for the other perception measures. As visual acuity, contrast sensitivity, and visual field extent declined, positivity toward AVs increased (p<0.001). Visual field extent best predicted general opinion and trust in AVs, whereas driving measures were the best predictors of impact on quality of life and intention to use AVs. Concerns about AVs showed no differences based on vision (p=0.94) or driving (p=0.63) status. CONCLUSIONS: Individuals with vision loss expressed more acceptance of AVs despite their concerns. How positive someone is toward AVs appears to be dependent on their visual field extent and driving status.

Use and Perceptions of Advanced Driver Assistance Systems by Older Drivers With and Without Age-Related Macular Degeneration.

Purpose: Advanced driver assistance systems (ADAS) have been reported to improve the safety of elderly and normally sighted drivers. The purpose of this study was to assess exposure to, perceived safety of, comfort level with, and interest in using ADAS among drivers with age-related macular degeneration (AMD). Methods: Current drivers aged 60+ years were recruited at four US sites to complete a survey about ADAS and driving habits. Frequency of use and/or perceptions of eight ADAS were investigated. An avoidance score was generated using questions about difficult driving situations. Results: The survey was completed by 166 participants (80 with AMD vs. 86 without). Participants with AMD had worse self-rated vision than those without (34% vs. 2% poor or fair rating), and drove fewer weekly miles (median [interquartile range [IQR] 30 [15 to 75] vs. 60 [30 to 121] miles, P = 0.002). Participants with AMD reported more avoidance of difficult driving situations (P < 0.001). There was no difference in the number of ADAS used by AMD status (median [IQR for AMD = 2.5 [1 to 5] vs. 3 [2 to 4] without, P = 0.87). Greater reported number of ADAS used was associated with less avoidance of difficult situations (P = 0.02). The majority perceived improved safety with most ADAS. Conclusions: Many drivers with AMD utilize common ADAS, which subjectively improve their road safety and may help to reduce self-imposed restrictions for difficult situations and mileage. Translational Relevance: Drivers with AMD are adopting readily available ADAS, for which they reported potential benefits, such as safety and less restrictive driving.

Target position and avoidance margin effects on path planning in obstacle avoidance.

This study examined how people choose their path to a target, and the visual information they use for path planning. Participants avoided stepping outside an avoidance margin between a stationary obstacle and the edge of a walkway as they walked to a bookcase and picked up a target from different locations on a shelf. We provided an integrated explanation for path selection by combining avoidance margin, deviation angle, and distance to the obstacle. We found that the combination of right and left avoidance margins accounted for 26%, deviation angle accounted for 39%, and distance to the obstacle accounted for 35% of the variability in decisions about the direction taken to circumvent an obstacle on the way to a target. Gaze analysis findings showed that participants directed their gaze to minimize the uncertainty involved in successful task performance and that gaze sequence changed with obstacle location. In some cases, participants chose to circumvent the obstacle on a side for which the gaze time was shorter, and the path was longer than for the opposite side. Our results of a path selection judgment test showed that the threshold for participants abandoning their preferred side for circumventing the obstacle was a target location of 15 cm to the left of the bookcase shelf center.

Pupil diameter as a biomarker of effort in goal-directed gait.

Subjects' eye movement behavior related to cognitive effort during gait was measured as subjects walked to perform low and high cognitive load tasks. We found that all pupil diameter measures, fixation durations, and the proportion of blink duration changed significantly during gait as a function of task load. In contrast, the number of fixations, saccade durations and travel time did not change significantly as a function of task load. Findings showed that pupil diameter was the best predictor of task load during one's gait preceding the performance of the task. While other studies have demonstrated the importance of eye fixation characteristics during gait, our findings showed that eye measures related to pupil diameter were better at detecting cognitive load while walking to perform a task compared to eye fixation data. We also found that cognitive effort was not limited to just the performance of the task, but that it was also exerted during one's gait preceding the performance of the task. Therefore, the additional attention demand caused by an increase in task complexity may result in less attentional resources being available to adequately handle distractions (such as obstacle avoidance) while walking to perform the task. Consequently, this may increase the likelihood of falls in those individuals with lower attentional capacity.

Hierarchical goal effects on center of mass velocity and eye fixations during gait.

The purpose of this study was to determine the effect of hierarchical goal structure of a yet-to-be performed task on gait and eye fixation behavior while walking to the location of where the task was to be performed. Subjects performed different goal-directed tasks representing three hierarchical levels of planning. The first level of planning consisted of having the subject walk to a bookcase on which an object (a cup) was located in the middle of a shelf. The second level of planning consisted of walking to the bookcase and picking up the cup which was in the middle, on the right side, or on the left side of the bookcase shelf. The third level of planning consisted of walking to the bookcase, picking up the cup which was located in the middle of the bookcase shelf, and moving it to a higher shelf. Findings showed that hierarchal goals do affect center of mass velocity and eye fixation behavior. Center of mass velocity to the bookcase increased with an increase in the number of goals. Subjects decreased gait velocity as they approached the bookcase and adjusted their last steps to accommodate picking up the cup. The findings also demonstrated the important role of vision in controlling gait velocity in goal-directed tasks. Eye fixation duration was more important than the number of eye fixations in controlling gait velocity. Thus, the amount of information gained through object fixation duration is of greater importance than the number of fixations on the object for effective goal achievement.

The Mind Cannot Go Blind: Effects of Central Vision Loss on Judging One's Crossing Time.

SIGNIFICANCE: This study explored whether people with AMD can accurately judge the time they need to cross the street. The results suggest that AMD-related vision loss does not affect a person's ability to estimate his/her own street-crossing time, whereas familiarity with the street does. PURPOSE: The purpose of this study was to assess whether people with AMD could judge accurately their street-crossing time. METHODS: Fifty-one AMD subjects and 47 age-matched normally sighted subjects (controls) estimated their time to cross a single-lane, one-way street four times (pre-estimate). Then, subjects actually crossed the street four times and subsequently estimated their crossing time four additional times (post-estimate). A linear mixed model with repeated measures for subject was used to determine if the ratio between subjects' estimated and actual crossing times changed as a function of subject group (AMD vs. control) and whether estimates changed before and after actually crossing the street. Univariate correlations and multiple regression analyses were also performed to determine which of the measured experimental variables were the best predictors of a subject's ability to estimate his/her crossing time. RESULTS: No significant difference in crossing ratios were found between the AMD (average, 1.05) and control (average, 1.16) subjects (P = .11). This was true for both the pre-crossing (AMD, 1.09; controls, 1.23; P = .11) and post-crossing ratios (AMD, 1.01; controls, 1.09; P = .17). Both subject groups' crossing ratios, however, decreased significantly going from pre to post (P < .0001). Increased age, longer actual crossing time, and experience gained from previously crossing the street resulted in less overestimation of one's crossing time. CONCLUSIONS: Our data suggest that familiarity with the street as opposed to central vision loss from AMD affects a person's ability to estimate his/her crossing time.

The Effect of Simulated Central Field Loss on Street-crossing Decision-Making in Young Adult Pedestrians.

SIGNIFICANCE: This study explored the street-crossing decision-making performance of young normally sighted subjects with simulated central field loss (CFL). The results suggest that using eccentric viewing enables a person to make safe and reliable street-crossing decisions. PURPOSE: This study tested the hypothesis that, as the diameter of an experimentally induced central scotoma increases, the accuracy and reliability of street-crossing decisions worsen. METHODS: Street-crossing decisions were measured in 20 young subjects aged between 23 and 31 years while monocularly viewing a nonsignalized, one-way street for different vehicular arrival times. Using a 5-point rating scale, subjects judged whether they could cross the street before vehicular arrival with habitual vision and simulated CFL with eccentric viewing. The CFL was induced using soft contact lenses with different central opaque diameters. Using receiver operating characteristic curve analysis, we obtained subjects' accuracy (amount of time in seconds where subjects either overestimated or underestimated vehicular arrival time relative to their actual crossing time) and reliability (how quickly subjects transitioned from judging insufficient to sufficient time to cross relative to their actual crossing time). RESULTS: The centrally opaque contact lenses induced central scotomata with a mean (standard deviation) diameter of 17.12° (5.83°). No significant difference in street-crossing accuracy (P = .35) or reliability (P = .09) was found between the normal, habitual vision and simulated CFL conditions. No statistically significant correlations were found between scotoma diameter and the accuracy and reliability of subjects' street-crossing decisions (P = .83 and P = .95, respectively). CONCLUSIONS: The findings of this study suggest that adopting eccentric viewing enables a person to successfully mitigate the negative effects of an absolute central scotoma on the accuracy and reliability of their street-crossing decisions.

Prevalence of Falls and Fall-Related Outcomes in Older Adults with Self-Reported Vision Impairment.

OBJECTIVES: To determine the prevalence of falls, fear of falling (FoF), and activity limitation due to FoF in a nationally representative study of older adults with self-reported vision impairment (VI). DESIGN: Cross-sectional analysis of panel survey data. SETTING: National Health and Aging Trends Study, a nationally representative survey administered annually from 2011 to 2016 to U.S. Medicare beneficiaries aged 65 and older. PARTICIPANTS: Respondents (N=11,558) who contributed 36,229 participant observations. MEASUREMENTS: We performed logistic regression to calculate the unadjusted and adjusted prevalence of self-reported history of more than 1 fall in the past year, any fall in the past month, FoF, and activity limitation due to FoF in participants with and without self-reported VI. RESULTS: The weighted proportion of participants reporting VI was 8.6% (95% confidence interval (CI)=8.0-9.2%). The unadjusted prevalence of more than 1 fall in the past year was 27.6% (95% CI=25.5-29.7%) in participants with self-reported VI and 13.2% (95% CI=12.7-13.7%) in those without self-reported VI. In respondents with self-reported VI, the prevalence of FoF was 48.3% (95% CI=46.1-50.6%) and of FoF limiting activity was 50.8% (95%CI 47.3-54.2%), and in those without self-reported VI, the prevalence of FoF was 26.7% (95% CI=25.9-27.5%) and of FoF limiting activity was 33.9% (95% CI=32.4-35.4%). The prevalence of all fall and fall-related outcomes remained significantly higher among those with self-reported VI after adjusting for sociodemographics and potential confounders. CONCLUSION: The prevalence of falls, FoF, and activity limitation due to FoF is high in older adults with self-reported VI. This is the first study to provide nationally representative data on the prevalence of fall-related outcomes in older Americans with self-reported VI. These findings demonstrate the need to treat avoidable VI and to develop interventions to prevent falls and fall-related outcomes in this population. J Am Geriatr Soc 67:239-245, 2019.

Changes in the Properties of the Preferred Retinal Locus with Eccentric Viewing Training.

SIGNIFICANCE: This study explores whether eccentric viewing training (EVT) changes the properties of the retinal area used for fixation in subjects with bilateral macular disease. The data presented demonstrate the feasibility of conducting a randomized controlled trial on EVT. PURPOSE: Patients with bilateral central scotomas adopt other retinal area(s) called preferred retinal locus to substitute the blind fovea. EVT is offered with the goal to improve functional vision by learning how to identify and use a more useful retinal area for fixation-a trained retinal locus-and/or to improve fixation stability with their existing preferred retinal locus. An observational study was conducted to determine whether patients change and adopt a new trained retinal locus location and/or if fixation stability improves after EVT. METHODS: Seventy-six patients with bilateral central scotomas received EVT from an experienced rehabilitation therapist. Retinal locations for repeated fixations and sizes of central scotomas of the better eye were recorded before and after EVT with a scanning laser ophthalmoscope. The position and area of the 95% confidence bivariate ellipse that defines the retinal area in which 95% of fixations occur were analyzed. RESULTS: We observed no significant difference between the size of the area of the fitted ellipses before (mean [SD], 26.4° [19.7°]) and after (mean [SD], 24.8° [20.9°]) EVT (P = .54). However, we observed a shift in the preferred retinal locus location after EVT (P < .0001). The mean (SD) shift in the position of the center of fixation after EVT was 7.5° (5.2°; range, 0.45 to 23°). This mean difference was larger than would be expected from average within-subject fixation stability. CONCLUSIONS: The location of the retinal area used for fixation changes after EVT. Fixation stability does not change after EVT. These preliminary data are yet to be confirmed with the use of a control group.

Simulation of a central scotoma using contact lenses with an opaque centre.

PURPOSE: This study evaluated the feasibility of using soft contact lenses (CLs) with an opaque centre to induce absolute central scotomas that move with the eye. We examined the geometrical optics prediction that scotoma size will vary with the size of the CL's opaque centre and with ocular pupil size. We also tested the hypothesis that high environmental light levels will ensure that the ocular pupil will remain small enough, even with opaque centre CLs, to generate absolute scotomas representative of those experienced by patients with age-related macular disease. METHODS: Using an Octopus 900 Perimeter ( www.Haag-Streit.com), kinetic visual fields (VFs) were measured in five normally-sighted subjects using a V4e Goldmann target with CLs that had central opaque areas with diameters of 2.8, 3.0, and 3.2 mm. To control pupil size, VFs were measured with background perimeter bowl luminances of 10, 585, and 1155 cd m-2 . Subjects attempted to (i) fixate the bowl centre; and (ii) place the scotoma edge at the bowl fixation target (eccentric viewing). RESULTS: As predicted, there was a direct relationship between scotoma size and both luminance level and diameter of the opacity. Mean scotoma diameters were 0°, 17.6° and 22°, for the low, medium and high bowl luminances, respectively. Scotoma size was determined primarily by the difference between the diameters of CL opacity and the entrance pupil of the eye and the axial separation between them, and between-subject differences in pupil diameters contributed most to the between-subject variability in scotoma diameter at each light level (SD: 6.01°). Scotoma displacement during eccentric fixation confirmed the gaze-contingent characteristics of this experimental model. CONCLUSION: It is possible to induce a gaze-contingent absolute scotoma and hence mimic central vision loss using centrally-opaque CLs provided that the CL opacity is larger than the entrance pupil of the eye. This simulation tool will, therefore, be ineffective at low environmental light levels (as shown previously) if the entrance pupil of the eye is larger than the CL opacity.

Motion-generated optical information allows event perception despite blurry vision in AMD and amblyopic patients.

Events consist of objects in motion. When objects move, their opaque surfaces reflect light and produce both static image structure and dynamic optic flow. The static and dynamic optical information co-specify events. Patients with age-related macular degeneration (AMD) and amblyopia cannot identify static objects because of weakened image structure. However, optic flow is detectable despite blurry vision because visual motion measurement uses low spatial frequencies. When motion ceases, image structure persists and might preserve properties specified by optic flow. We tested whether optic flow and image structure interact to allow event perception with poor static vision. AMD (Experiment 1), amblyopic (Experiments 2 and 3), and normally sighted observers identified common events from either blurry (Experiments 1 and 2) or clear images (Experiment 3), when either single image frames were presented, a sequence of frames was presented with motion masks, or a sequence of frames was presented with detectable motion. Results showed that with static images, but no motion, events were not perceived well by participants other than controls in Experiment 3. However, with detectable motion, events were perceived. Immediately following this and again after five days, participants were able to identify events from the original static images. So, when image structure information is weak, optic flow compensates for it and enables event perception. Furthermore, weakened static image structure information nevertheless preserves information that was once available in optic flow. The combination is powerful and allows events to be perceived accurately and stably despite blurry vision.

How do vision and hearing impact pedestrian time-to-arrival judgments?

PURPOSE: To determine how accurate normally sighted male and female pedestrians were at making time-to-arrival (TTA) judgments of approaching vehicles when using just their hearing or both their hearing and vision. METHODS: Ten male and 14 female subjects with confirmed normal vision and hearing estimated the TTA of approaching vehicles along an unsignalized street under two sensory conditions: (1) using both habitual vision and hearing and (2) using habitual hearing only. All subjects estimated how long the approaching vehicle would take to reach them (i.e., the TTA). The actual TTA of vehicles was also measured using custom-made sensors. The error in TTA judgments for each subject under each sensory condition was calculated as the difference between the actual and estimated TTA. A secondary timing experiment was also conducted to adjust each subject's TTA judgments for their "internal metronome." RESULTS: Error in TTA judgments changed significantly as a function of both the actual TTA (p < 0.0001) and sensory condition (p < 0.0001). Although no main effect for gender was found (p = 0.19), the way the TTA judgments varied within each sensory condition for each gender was different (p < 0.0001). Females tended to be as accurate under either condition (p ≥ 0.01), with the exception of TTA judgments made when the actual TTA was 2 seconds or less and 8 seconds or longer, during which the vision-and-hearing condition was more accurate (p ≤ 0.002). Males made more accurate TTA judgments under the hearing only condition for actual TTA values 5 seconds or less (p < 0.0001), after which there were no significant differences between the two conditions (p ≥ 0.01). CONCLUSIONS: Our data suggest that males and females use visual and auditory information differently when making TTA judgments. Although the sensory condition did not affect the females' accuracy in judgments, males initially tended to be more accurate when using their hearing only.

Measurements of street-crossing decision-making in pedestrians with low vision.

PURPOSE: Crossing the street is an important but risky activity of daily living. If a pedestrian makes a poor street-crossing decision, the consequence could be serious injury or death. In order to advance our understanding of how visual and auditory information is sampled and processed to make street-crossing decisions, an accurate, reliable, and sensitive psychophysical and/or psychometric method of measurement of the street-crossing decision variable must first be developed and validated. The aim of this paper is to develop and validate a new metric for this variable. METHODS: Using a 5 point rating scale, safety ratings for eight different vehicular gap times of different durations were recorded along an unsignalized, two-lane street of one-way traffic. Safety ratings were collected from 12 normally sighted and 10 visually impaired subjects. Receiver Operating Characteristic (ROC) curves were estimated for all possible gap pairs and the discriminability (d') of the street-crossing decision variable for all gap pairs was estimated from the area under the ROC curve. RESULTS: We found that our data conform with the assumptions that the underlying distributions of the decision variable are continuous, monotonic and unbounded. Using the dissimilarity matrix of d' values for each person (which were computed for all pairings of gap times) in a one-dimensional scaling model, we estimated the means of each distribution of the decision variable relative to a center of gravity (COG) for the person. When plotting the means of the distributions against vehicular gap time, the data are best described as a non-linear function symmetric about the COG. We showed that the x-intercept (t(COG)) and slope from the non-linear function can be used to assess a person's street-crossing decision-making performance for different amounts of sensory information. Using our newly developed metrics, we found no significant difference in t(COG) (p=0.30) and in the slopes of the model (p=0.85) between normally sighted and visually impaired subjects. In addition, both subject groups centered their t(COG) close to their actual crossing time. CONCLUSIONS: A newly developed model for measuring a street-crossing decision variable functions as a valid metric that can be used to quantify street-crossing decision-making performance in pedestrians. Using this new metric, we observed that visually impaired subjects who travel independently are able to make street-crossing judgments that are comparable to those of normally sighted subjects.

Street-crossing decision-making: a comparison between patients with age-related macular degeneration and normal vision.

PURPOSE: We determined whether the street-crossing decisions of subjects with age-related macular degeneration (AMD) were as accurate and precise as those made by young and older subjects with normal vision. METHODS: Street-crossing decisions in 13 AMD subjects, and 20 young and 20 older control subjects with normal vision were measured along an un-signalized street for nine different gap times. After calculating the discriminability (d') of the street-crossing decision variable for all gap pairs and entering these d' values into a one-dimensional scaling model, the means of each distribution of the decision variable relative to a "center of gravity" were estimated and plotted against gap time. The resultant plot was a nonlinear function. Street-crossing decision accuracy was computed for each subject as the difference between the x-intercept of the nonlinear function (t(COG)) and subjects' measured street-crossing time. Street-crossing decision-making precision was computed as the value of the slope of the nonlinear function at t(COG). RESULTS: We found that all subjects were precise in their street-crossing decisions (P = 0.55). Significant differences in street-crossing accuracy were found as a function of age (P = 0.003). Compared to either the older normally-sighted (P = 0.018) or AMD (P = 0.019) subjects, the young normally-sighted subjects made the least accurate street-crossing decisions. No significant difference in accuracy was found between the AMD and age-matched normally-sighted subjects (P = 0.90). CONCLUSIONS: Our data suggested that age and mild central vision loss did not affect significantly a subject's precision in their street-crossing decisions. Age, but not mild central vision loss, significantly affected a subject's accuracy in their street-crossing decisions.

Are normally sighted, visually impaired, and blind pedestrians accurate and reliable at making street crossing decisions?

PURPOSE: The purpose of this study is to measure the accuracy and reliability of normally sighted, visually impaired, and blind pedestrians at making street crossing decisions using visual and/or auditory information. METHODS: Using a 5-point rating scale, safety ratings for vehicular gaps of different durations were measured along a two-lane street of one-way traffic without a traffic signal. Safety ratings were collected from 12 normally sighted, 10 visually impaired, and 10 blind subjects for eight different gap times under three sensory conditions: (1) visual plus auditory information, (2) visual information only, and (3) auditory information only. Accuracy and reliability in street crossing decision-making were calculated for each subject under each sensory condition. RESULTS: We found that normally sighted and visually impaired pedestrians were accurate and reliable in their street crossing decision-making ability when using either vision plus hearing or vision only (P > 0.05). Under the hearing only condition, all subjects were reliable (P > 0.05) but inaccurate with their street crossing decisions (P < 0.05). Compared to either the normally sighted (P = 0.018) or visually impaired subjects (P = 0.019), blind subjects were the least accurate with their street crossing decisions under the hearing only condition. CONCLUSIONS: Our data suggested that visually impaired pedestrians can make accurate and reliable street crossing decisions like those of normally sighted pedestrians. When using auditory information only, all subjects significantly overestimated the vehicular gap time. Our finding that blind pedestrians performed significantly worse than either the normally sighted or visually impaired subjects under the hearing only condition suggested that they may benefit from training to improve their detection ability and/or interpretation of vehicular gap times.

Visual field size criteria for mobility rehabilitation referral.

PURPOSE: To investigate evidence-based visual field size criteria for referral of low-vision (LV) patients for mobility rehabilitation. METHODS: One hundred and nine participants with LV and 41 age-matched participants with normal sight (NS) were recruited. The LV group was heterogeneous with diverse causes of visual impairment. We measured binocular kinetic visual fields with the Humphrey Field Analyzer and mobility performance on an obstacle-rich, indoor course. Mobility was assessed as percent preferred walking speed (PPWS) and number of obstacle-contact errors. The weighted kappa coefficient of association (κr) was used to discriminate LV participants with both unsafe and inefficient mobility from those with adequate mobility on the basis of their visual field size for the full sample and for subgroups according to type of visual field loss and whether or not the participants had previously received orientation and mobility training. RESULTS: LV participants with both PPWS <38% and errors >6 on our course were classified as having inadequate (inefficient and unsafe) mobility compared with NS participants. Mobility appeared to be first compromised when the visual field was less than about 1.2 steradians (sr; solid angle of a circular visual field of about 70° diameter). Visual fields <0.23 and 0.63 sr (31 to 52° diameter) discriminated patients with at-risk mobility for the full sample and across the two subgroups. A visual field of 0.05 sr (15° diameter) discriminated those with critical mobility. CONCLUSIONS: Our study suggests that: practitioners should be alert to potential mobility difficulties when the visual field is less than about 1.2 sr (70° diameter); assessment for mobility rehabilitation may be warranted when the visual field is constricted to about 0.23 to 0.63 sr (31 to 52° diameter) depending on the nature of their visual field loss and previous history (at risk); and mobility rehabilitation should be conducted before the visual field is constricted to 0.05 sr (15° diameter; critical).

Older drivers and failure to stop at red lights.

BACKGROUND: Despite sensational news reports, few studies have quantified the rates of poor driving performance among older drivers and the predictors of poor performance. We determined the rate of running red traffic lights among older drivers and the relationship of failure to stop to measures of vision and cognition. METHODS: Multiple measures of vision and cognition were collected at the baseline examination of a population of 1,425 drivers aged 67-87 years in greater Salisbury, Maryland. Each driver had real-time data collected on 5 days of driving performance at baseline and again at 1 year. Failure to stop at a red traffic light was the primary outcome. RESULTS: Overall, 3.8% of older drivers failed to stop at red traffic lights, with 15% of those who ran the light having failed 10% or more of the traffic lights they encountered. A narrowing of the attentional visual field (AVF; the extent of peripheral vision in which objects are detected while attention is also centrally fixated) was associated with failure to stop at traffic lights at baseline and predictive 1 year later (incidence rate ratio = 1.09 per degree lost, 95% confidence interval = 1.01-1.16). Persons with smaller vertical AVF were more likely to fail to stop. No demographic or vision variable was related to failure to stop. CONCLUSIONS: Failure to stop at red lights was a relatively uncommon event in older drivers and associated with reduced ability to pay attention to visual events in the vertical field of vision.

Poor sense of direction is associated with constricted driving space in older drivers.

The aims of this study were to determine whether perceived sense of direction was associated with the driving space of older drivers and whether the association was different between genders. Participants (1,425 drivers aged 67-87 years) underwent a battery of visual and cognitive tests and completed various questionnaires. Sense of direction was assessed using the Santa Barbara Sense of Direction (SBSOD) scale. Driving space was assessed by both the driving space component of the Driving Habits Questionnaire and log maximum area driven. Analyses were performed using generalized linear models. The SBSOD score was lower in women than in men and significantly associated with log driving area in women but not in men. The SBSOD score also showed a significant association with women's self-reported driving restriction. The findings emphasize the need to explore the role of psychological factors, and include gender, in driving studies and models.

Visual and cognitive deficits predict stopping or restricting driving: the Salisbury Eye Evaluation Driving Study (SEEDS).

PURPOSE: To determine the visual and other factors that predict stopping or restricting driving in older drivers. METHODS: A group of 1425 licensed drivers aged 67 to 87 years, who were residents of greater Salisbury, participated. At 1 year after enrollment, this group was categorized into those who had stopped driving, drove only within their neighborhood, or continued to drive beyond their neighborhood. At baseline, a battery of structured questionnaires, vision, and cognitive tests were administered. Multivariate analysis determined the factors predictive of stopping or restricting driving 12 months later. RESULTS: Of the 1425 enrolled, 1237 (87%) were followed up at 1 year. Excluding those who were already limiting their driving at baseline (n = 35), 1.5% (18/1202) had stopped and 3.4% (41/1202) had restricted their driving. The women (odds ratio [OR], 4.01; 95% confidence interval [CI], 2.05-8.20) and those who prefer to be driven (OR, 3.91; 95% CI, 1.91-8.00) were more likely to stop or restrict driving. Depressive symptoms increased likelihood of restricting or stopping driving (OR, 1.08; 95% CI, 1.009-1.16 per point Geriatric Depression Scale). Slow visual scanning and psychomotor speed (Trail Making Test, Part A: OR, 1.02; 95% CI, 1.01-1.03), poor visuoconstructional skills (Beery-Buktenica Test of Visual Motor Integration: OR, 1.14; 95% CI, 1.05-1.25), and reduced contrast sensitivity (OR, 1.15; 95% CI, 1.03-1.28) predicted stopping or reducing driving. Visual field loss and visual attention were not associated. The effect of vision on changing driving behavior was partially mediated by cognition, depression, and baseline driving preferences. CONCLUSIONS: In this cohort, contrast sensitivity and cognitive function were independently associated with incident cessation or restriction of driving space. These data suggest drivers with functional deficits make difficult decisions to restrict or stop driving.

Cognitive and vision loss affects the topography of the attentional visual field.

PURPOSE: The attentional visual field (AVF), which describes a person's ability to divide attention and extract visual information from the visual field (VF) within a glance, has been shown to be a good predictor of driving performance. Despite this, very little is known about the shape of the AVF and the factors that affect it. The purposes of this study were to describe the AVF in a large sample of older drivers and identify demographic, cognitive, and vision factors associated with AVF performance and shape. METHODS: Registered drivers between 67 and 87 years of age, residing in Greater Salisbury, Maryland, were recruited to participate in the study. Participants underwent a battery of visual and cognitive assessments and completed various questionnaires for demographics, medical history, and history of depression. The AVF was assessed using a divided-attention protocol within the central 20 degrees radius along the four principal meridians. The shape of the AVF was classified as either symmetric or one of two asymmetric shape profiles. RESULTS: Symmetrically shaped AVFs were found in just 34% of participants. AVF performance was significantly better along the horizontal (15.3 degrees ) than the vertical (11.3 degrees ) meridian (P < 0.05). After adjusting for AVF area, we found that poorer cognitive and vision performance was associated with a symmetric AVF shape. Overall AVF extent was predicted by vision and cognitive measures as well as various demographic factors. CONCLUSIONS: Good vision and cognitive ability appear to be associated with having an asymmetric as opposed to a symmetric AVF shape profile.