Vision impairment and older drivers: who's driving?

Effect of additional tasks on the reaction time of braking responses in simulated car driving: beyond the PRP effect

The presentation of one task increases the reaction time on a subsequent task, if stimulus onset asynchrony (SOA) between tasks is short. This psychological refractory period (PRP) effect is typically leveling off as SOA approaches 1 s, which has been documented both in classical laboratory paradigms and in simulated car driving. Here we report a more persistent effect on the subsequent task that goes well beyond the typical duration of the PRP effect. In a driving simulator, 120 healthy older participants followed a lead car that mostly drove at a constant speed. They had to maintain a regular distance from the lead car and had to brake when the lead car braked. Participants also engaged in several additional tasks during driving (two types of tasks: typing three-digit numbers, stating arguments on public issues). SOA between the braking task and the last preceding additional task was 11.49 s ± 1.99 (mean and standard deviation). In a control condition, the braking task was administered without additional tasks. Main performance outcome was Braking Reaction Time (RT, in s), as the interval between onset of brake lights of the lead car and the moment participants released the gas pedal. Additionally, foot movement time (MT, in s), i.e., the difference between gas pedal release and brake pedal onset, was considered for possible compensation behavior. Inter-vehicle distance to the lead car (in m) was taken into account as a moderator. We found that RT averaged 0.77 s without additional tasks, but averaged 1.45 s with additional tasks. This RT difference was less pronounced at smaller inter-vehicle distances, and was not compensated for by faster MT from the gas pedal to the brake pedal. We conclude that detrimental effects of additional tasks on subsequent braking responses can be more persistent than suggested by the PRP effect, possibly because of maintaining multiple task sets, requiring increased executive control. We further conclude that potential detrimental effects can be ameliorated at small inter-vehicle distances by mobilizing extra cognitive resources when response urgency is higher. As a practical implication of our study, distracting stimuli can have persisting detrimental effects on traffic safety.

United States Population Disparities in Ophthalmic Care: Blindness and Visual Impairment in the IRIS® Registry (Intelligent Research in Sight)

PURPOSE

To evaluate associations of patient characteristics with United States eye care use and likelihood of blindness.

DESIGN

Retrospective observational study.

PARTICIPANTS

Patients (19 546 016) with 2018 visual acuity (VA) records in the American Academy of Ophthalmology's IRIS® Registry (Intelligent Research in Sight).

METHODS

Legal blindness (20/200 or worse) and visual impairment (VI; worse than 20/40) were identified from corrected distance acuity in the better-seeing eye and stratified by patient characteristics. Multivariable logistic regressions evaluated associations with blindness and VI. Blindness was mapped by state and compared with population characteristics. Eye care use was analyzed by comparing population demographics with United States Census estimates and proportional demographic representation among blind patients versus a nationally representative US population sample (National Health and Nutritional Examination Survey [NHANES]).

MAIN OUTCOME MEASURES

Prevalence and odds ratios for VI and blindness; proportional representation in the IRIS® Registry, Census, and NHANES by patient demographics.

RESULTS

Visual impairment was present in 6.98% (n = 1 364 935) and blindness in 0.98% (n = 190 817) of IRIS patients. Adjusted odds of blindness were highest among patients ≥ 85 years old (odds ratio [OR], 11.85; 95% confidence interval [CI], 10.33-13.59 vs. those 0-17 years old). Blindness also was associated positively with rural location and Medicaid, Medicare, or no insurance vs. commercial insurance. Hispanic (OR, 1.59; 95% CI, 1.46-1.74) and Black (OR, 1.73; 95% CI, 1.63-1.84) patients showed a higher odds of blindness versus White non-Hispanic patients. Proportional representation in IRIS Registry relative to the Census was higher for White than Hispanic (2- to 4-fold) or Black (11%-85%) patients (P < 0.001). Blindness overall was less prevalent in NHANES than IRIS Registry; however, prevalence in adults aged 60+ was lowest among Black participants in the NHANES (0.54%) and second highest among comparable Black adults in IRIS (1.57%).

CONCLUSIONS

Legal blindness from low VA was present in 0.98% of IRIS patients and associated with rural location, public or no insurance, and older age. Compared with US Census estimates, minorities may be underrepresented among ophthalmology patients, and compared with NHANES population estimates, Black individuals may be overrepresented among blind IRIS Registry patients. These findings provide a snapshot of US ophthalmic care and highlight the need for initiatives to address disparities in use and blindness.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Associations between vision impairment and vision-related interventions on crash risk and driving cessation: systematic review and meta-analysis

OBJECTIVES

To systematically investigate the associations between vision impairment and risk of motor vehicle crash (MVC) involvement, and evaluate vision-related interventions to reduce MVCs.

DESIGN

Medline (Ovid), EMBASE and Global Health electronic databases were systematically searched from inception to March 2022 for observational and interventional English-language studies. Screening, data extraction and appraisals using the Joanna Briggs Institute appraisal tools were completed by two reviewers independently. Where appropriate, measures of association were converted into risk ratios (RRs) or ORs for meta-analysis.

PARTICIPANTS

Drivers of four-wheeled vehicles of all ages with no cognitive declines.

PRIMARY AND SECONDARY OUTCOMES

MVC involvement (primary) and driving cessation (secondary).

RESULTS

101 studies (n=778 052) were included after full-text review. 57 studies only involved older drivers (≥65 years) and 85 were in high-income settings. Heterogeneity in the data meant that most meta-analyses were underpowered as only 25 studies, further split into different groups of eye diseases and measures of vision, could be meta-analysed. The limited evidence from the meta-analyses suggests that visual field defects (four studies; RR 1.51 (95% CI 1.23, 1.85); p<0.001; I2=46.79%), and contrast sensitivity (two studies; RR 1.40 (95% CI 1.08, 1.80); p=0.01, I2=0.11%) and visual acuity loss (five studies; RR 1.21 (95% CI 1.02, 1.43); p=0.03, I2=28.49%) may increase crash risk. The results are more inconclusive for available evidence for associations of glaucoma (five studies, RR 1.27 (95% CI 0.67, 2.42); p=0.47; I2=93.48%) and cataract (two studies RR 1.15 (95% CI 0.97, 1.36); p=0.11; I2=3.96%) with crashes. Driving cessation may also be linked with glaucoma (two studies; RR 1.62 (95% CI 1.20, 2.19); p<0.001, I2=22.45%), age-related macular degeneration (AMD) (three studies; RR 2.21 (95% CI 1.47, 3.31); p<0.001, I2=75.11%) and reduced contrast sensitivity (three studies; RR 1.30 (95% CI 1.05, 1.61); p=0.02; I2=63.19%). Cataract surgery halved MVC risk (three studies; RR 0.55 (95% CI 0.34, 0.92); p=0.02; I2=97.10). Ranibizumab injections (four randomised controlled trials) prolonged driving in persons with AMD.

CONCLUSION

Impaired vision identified through a variety of measures is associated with both increased MVC involvement and cessation. Cataract surgery can reduce MVC risk. Despite literature being highly heterogeneous, this review shows that detection of vision problems and appropriate treatment are critical to road safety.

PROSPERO REGISTRATION NUMBER

CRD42020172153.

Inefficient frontal and parietal brain activation during dual-task walking in a virtual environment in older adults

Walking while performing an additional cognitive task (dual-task walking; DT walking) is a common yet highly demanding behavior in daily life. Previous neuroimaging studies have shown that performance declines from single- (ST) to DT conditions are accompanied by increased prefrontal cortex (PFC) activity. This increment is particularly pronounced in older adults and has been explained either by compensation, dedifferentiation, or ineffective task processing in fronto-parietal circuits. However, there is only limited evidence for the hypothesized fronto-parietal activity changes measured under real life conditions such as walking. In this study, we therefore assessed brain activity in PFC and parietal lobe (PL), to investigate whether higher PFC activation during DT walking in older adults is related to compensation, dedifferentiation, or neural inefficiency. Fifty-six healthy older adults (69.11 ± 4.19 years, 30 female) completed three tasks (treadmill walking at 1 m/s, Stroop task, Serial 3's task) under ST and DT conditions (Walking + Stroop, Walking + Serial 3's), and a baseline Standing task. Behavioral outcomes were step time variability (Walking), Balance Integration Score BIS (Stroop), and number of correct calculations S3_corr (Serial 3's). Brain activity was measured using functional near-infrared spectroscopy (fNIRS) over ventrolateral and dorsolateral PFC (vlPFC, dlPFC) and inferior and superior PL (iPL, sPL). Neurophysiological outcome measures were oxygenated (HbO₂) and deoxygenated hemoglobin (HbR). Linear mixed models with follow-up estimated marginal means contrasts were applied to investigate region-specific upregulations of brain activation from ST to DT conditions. Furthermore, the relationships of DT-specific activations across all brain regions was analyzed as well as the relationship between changes in brain activation and changes in behavioral performance from ST to DT. Data indicated the expected upregulation from ST to DT and that DT-related upregulation was more pronounced in PFC (particularly in vlPFC) than in PL regions. Activation increases from ST to DT were positively correlated between all brain regions, and higher brain activation changes predicted higher declines in behavioral performance from ST to DT. Results were largely consistent for both DTs (Stroop and Serial 3's). These findings more likely suggest neural inefficiency and dedifferentiation in PFC and PL rather than fronto-parietal compensation during DT walking in older adults. Findings have implications for interpreting and promoting efficacy of long-term interventions to improve DT walking in older persons.

Improving the conspicuity and safety of pedestrians and cyclists on night-time roads

The visual limitations of drivers at night are a key contributing factor to the relatively high crash involvement of vulnerable road users including pedestrians, roadworkers and cyclists on night-time roads. Making vulnerable road users more conspicuous (recognisable, rather than simply visible) to oncoming drivers, is one approach to increasing their safety and has been a particular focus of my research. This review highlights the experimental approaches that our multidisciplinary research team have adopted to explore these issues, involving both closed and open road studies at night. One effective strategy to increase night-time conspicuity of vulnerable road users is clothing that includes retro-reflective materials on the moveable joints which, when illuminated in the headlight beam of oncoming vehicles, creates a strong sense of 'biological motion' or 'biomotion'. Our studies demonstrated that this basic visual perception allows drivers to accurately perceive the presence of a person, such as a pedestrian or cyclist, at much longer distances than when retro-reflective materials are positioned on the torso, as in high visibility vests. Subsequent studies demonstrated that the benefits of biomotion clothing are evident in cluttered environments, in the presence of glare, and for drivers of different ages and visual characteristics. Evidence gathered in these studies was instrumental in changing Australian and New Zealand standards governing high visibility clothing for roadworkers to include retro-reflective strips in the biomotion configuration. Ongoing studies are exploring how to make biomotion clothing attractive to vulnerable road users exercising at night, and how to ensure that the limitations of night-time vision and the importance of increasing night-time conspicuity are better understood. This body of research has involved collaborators from a range of disciplines who have been essential to understanding and addressing the visual challenges of night-time roads and assisted in translating this research into tangible benefits for night-time road safety.

Effective refractive error coverage in adults aged 50 years and older: estimates from population-based surveys in 61 countries

BACKGROUND

In 2021, WHO Member States endorsed a global target of a 40-percentage-point increase in effective refractive error coverage (eREC; with a 6/12 visual acuity threshold) by 2030. This study models global and regional estimates of eREC as a baseline for the WHO initiative.

METHODS

The Vision Loss Expert Group analysed data from 565 448 participants of 169 population-based eye surveys conducted since 2000 to calculate eREC (met need/[met need + undermet need + unmet need]). A binary logistic regression model was used to estimate eREC by Global Burden of Disease (GBD) Study super region among adults aged 50 years and older.

FINDINGS

In 2021, distance eREC was 79·1% (95% CI 72·4-85·0) in the high-income super region; 62·1% (54·7-68·8) in north Africa and Middle East; 49·5% (45·0-54·0) in central Europe, eastern Europe, and central Asia; 40·0% (31·7-48·2) in southeast Asia, east Asia, and Oceania; 34·5% (29·4-40·0) in Latin America and the Caribbean; 9·0% (6·5-12·0) in south Asia; and 5·7% (3·1-9·0) in sub-Saharan Africa. eREC was higher in men and reduced with increasing age. Global distance eREC increased from 2000 to 2021 by 19·0%. Global near vision eREC for 2021 was 20·5% (95% CI 17·8-24·4).

INTERPRETATION

Over the past 20 years, distance eREC has increased in each super region yet the WHO target will require substantial improvements in quantity and quality of refractive services in particular for near vision impairment.

FUNDING

WHO, Sightsavers, The Fred Hollows Foundation, Fondation Thea, Brien Holden Vision Institute, Lions Clubs International Foundation.

Vision Impairment and On-Road Driving

Good vision is important for safe driving. The impact of vision impairment associated with common eye diseases on driving performance, and the association between vision measures and driving performance, are discussed. Studies include those where participants drove a real vehicle on a closed road or on public roads. Closed-road studies include evaluation of both simulated and true vision impairment and day- and night-time driving. Collectively, the findings provide important insights into the impact of refractive conditions, cataracts, glaucoma, age-related macular degeneration, and hemianopic field loss on driving; however, study results show varying impacts on driving performance and are often limited by small sample sizes. Vision measures including motion sensitivity, contrast sensitivity, and useful field of view have stronger associations with driving performance than do visual acuity or visual fields, with studies suggesting that some drivers with field loss can compensate for their field defects through increased eye and head movements.

Prevalence of Reduced Vision among UK Elderly Drivers: The Bridlington Eye Assessment Project (BEAP)—A Cross-Sectional Study

Self-assessment of driving fitness is mandatory in the United Kingdom. A paucity of data on visual function among drivers exists. We report prevalence of elderly drivers below legal visual acuity (VA) standard from a population study (The Bridlington Eye Assessment Project (BEAP)) conducted from 2002 to 2006. All residents aged ≥65 years were invited, 3459 undergoing structured interviews/ophthalmic examinations. Driving status was recorded, VA measured, and visual field (VF) testing performed. Outcomes were prevalence and characteristics of drivers below VA legal standard and prevalence of bilateral VF defects. Conditions causing reduced VA were explored and those with treatable conditions allowing visual improvement identified. Duration since last optometry review was recorded. Associations were explored using unpaired t-tests for continuous and chi-squared for discrete variables. Logistic regression was used for multivariate analysis and to determine odd ratios in the final adjusted model. Statistical analysis was performed using Stata 14.0 (Stata Corp, Tx). Within this sample, 7.1% (95% CI 6.0–8.3) of drivers fell below the VA legal driving standard (6/12) in their better eye, with 20% not having seen an optometrist for 2 years, including 8.2% who had not attended for over 5 years. The percentage of drivers falling below the VA minimum increases with age reaching 22.8% (95% CI 13.7–35.3) among those aged 85–89 years. 7.2% (95% CI 6.2–8.6) of drivers had bilateral visual field defects. 93% of drivers with reduced VA below legal standard had a cataract, refractive error or both in at least one eye. Significant numbers of elderly drive with VA below legal standard, most having easily correctable causes. Poor attendance with optometrists appears commonplace. Public education raised awareness of legal driving standards and encouraged compliance are required. Regular eye tests, appropriate refractive correction, and cataract surgery when needed should be encouraged.

Refractive errors among commercial drivers

Purpose

To determine the pattern of refractive error among commercial drivers in north India.

Methods

Descriptive study with convenient sampling conducted among commercial drivers of north India.

Results

A total of 213 (75.8%) heavy-vehicle and 68 (24.2%) light-vehicle drivers were screened for eye diseases. Refractive error for distance was reported in 44 (15.7%; 95% CI: 11.6-20.4) drivers. Hyperopia was reported in 23 (8.2%; 95% CI: 5.2-12) drivers, followed by myopia in 15 (5.3%; 95% CI: 3-8.6) drivers and astigmatism in six (2.1%; 95% CI: 0.7-4.5) drivers. Presbyopia was reported in 157 (55.8%) drivers. Dry eye was reported in 70 (24.9%), stereo deficiency in 77 (27.4%), and color vision deficiency in 11 (3.9%) drivers. Three drivers were diagnosed with cataract, and two were referred for retina evaluation.

Conclusion

Hyperopia in both eyes was the most common refractive error. Dry eye disease and color vision deficiency were also reported. Most of the drivers were not using spectacles for refractive error correction. Due to their mobile nature, drivers with cataract and retina diseases did not turn up for follow-up.

Inability of the Mini-Mental State Exam (MMSE) and high-contrast visual acuity to identify unsafe drivers

BACKGROUND/OBJECTIVES

To examine the validity of high-contrast visual acuity and the Mini-Mental State Exam (MMSE) as tools for identifying at-risk older drivers.

DESIGN

Prospective multi-site observational cohort study.

SETTING

Community sample drawn from cities of Brisbane and Canberra, Australia.

PARTICIPANTS

560 licensed drivers aged 65-96 years recruited between 2013 and 2016, from the community, an optometry clinic and driver referral service.

MEASUREMENTS

50-minute standardized on-road driving test conducted on a standard urban route in a dual-brake vehicle with a driver trained Occupational Therapist assessor masked to participants' cognitive, visual and medical status.

RESULTS

Of 560 participants who completed the on-road test, 68 (12%) were classified as unsafe. Binary logistic regression models adjusted for age, gender, site, comorbidity and driving exposure indicated that a 1-point decrease in MMSE score was associated with a 1.35 (95%CI: 1.12-1.63) increase in odds of unsafe driving, and for each line reduction in binocular visual acuity (increase of 0.1 logMAR) was associated with 1.39 (95%CI: 1.07-1.81) increased odds of unsafe driving. However, Receiver Operating Characteristic (ROC) analysis showed low discriminative power for both measures (MMSE: AUC = 0.65 (95%CI: 0.58-0.73), visual acuity: AUC = 0.65 (95%CI: 0.59-0.72)) and typical cut-offs were associated with very low sensitivity for identifying unsafe drivers (MMSE <24/30: 2%; visual acuity worse than 6/12 Snellen (logMAR >0.30): 3%).

CONCLUSION

The MMSE and high-contrast visual acuity tests do not reliably identify at-risk older drivers. They have extremely low sensitivity for detecting unsafe drivers, even when used together, and poor prognostic properties relative to validated screening instruments that measure cognitive, vision and sensorimotor functions relevant to driving. Clinicians should select alternate validated driver screening tools where possible.

Impact of vision disorders and vision impairment on motor vehicle crash risk and on-road driving performance: A systematic review

Vision is important for safe driving, but there is limited understanding regarding the impact of vision disorders on driving ability and safety. This systematic review evaluated and summarized evidence on the impact of vision disorders and impairment on motor vehicle crash (MVC) risk and on-road driving performance across seven databases, was prospectively registered with PROSPERO (CRD42020180135), and study quality rated using a standard tool. Forty-eight studies met the inclusion criteria for MVC risk (N = 36), on-road performance (N = 9), and both MVC risk and on-road performance (N = 3). Of these studies, less than half were rated as 'good' quality. Due to the small number of studies and often conflicting findings, it was not possible to draw firm conclusions for most vision disorders. However, evidence from several 'good' and 'fair' quality studies suggested increased MVC risk with binocular visual field impairment. There was mixed evidence regarding the impact of cataract, glaucoma, age-related macular degeneration and homonymous field loss on MVC risk and no evidence of increased MVC risk with mild VA impairment. This review highlights the need for well-designed future studies to further explore the impact of vision disorders and impairment on driving outcomes to inform evidence-based policy and fitness to drive guidelines.

Vision, Driving Exposure, and Collisions in Bioptic Drivers

SIGNIFICANCE

Lack of knowledge regarding the mileage driven by drivers with low vision who use bioptic telescopes could obscure the relationship between vision and road safety. This study provides data suggesting that worse vision is correlated with less mileage driven but more collisions per mile in bioptic drivers.

PURPOSE

The purpose of this study was to determine whether vision or demographic factors predict mileage driven in bioptic drivers and per-mile motor vehicle collision rate and also to compare the collision rate of bioptic drivers with previous estimates for the general population.

METHODS

Driver data were collected retrospectively from clinic records. Collision data were collected from the Ohio Bureau of Motor Vehicles database. Subjects were also asked to estimate their yearly mileage. Regression models were used to investigate relationships between vision and collision rates.

RESULTS

Seventy-three licensed Ohio bioptic drivers (36 male) were included. Mean ± standard deviation age was 51 ± 16 years. Mean logMAR visual acuity was 0.67 (approximately 20/100). Mean log contrast sensitivity was 1.57. Mean reported annual mileage was 9746. Age, sex, and previous (nonbioptic) driving experience were not associated with mileage. LogMAR visual acuity was inversely related to mileage (P = .02), and contrast sensitivity (P = .01) and horizontal visual field (P = .02) were directly associated with mileage. Visual acuity (P = .02) and visual field (P = .005), but not contrast sensitivity (P = .19), were associated with number of collisions.

CONCLUSIONS

Visual acuity, visual field, and contrast sensitivity were associated with driving exposure in bioptic drivers (with drivers with poorer vision reporting lower annual mileage), and poorer visual acuity and visual field were associated with more collisions. The per-mile collision rate for bioptic drivers was within the range of that previously reported for fully sighted drivers, although higher than would be expected for fully sighted drivers of similar age distribution.

Licensure and Driving Status among Visually Impaired Persons

PURPOSE

This study aimed to determine what proportion of visually impaired patients continue driving despite falling short of the legal cutoffs described in state licensure laws.

METHODS

We created a driving habits survey and administered it to 335 consecutive adult low vision patients presenting for their initial evaluation at the Vanderbilt Eye Institute. We measured visual acuity and contrast sensitivity as part of the clinical evaluation and accounted for historic visual field results where indicated. We compared self-reported licensure and driving status against the vision criteria for licensure in each subject's home state.

RESULTS

Two hundred fifty-seven subjects (76.7%) possessed an unexpired license. One hundred forty-one (54.9%) of these demonstrated vision, which would meet their home state's licensure criteria. Ninety-five of 134 current drivers (70.9%) met their home state's licensure criteria. Thirty-nine current drivers (29.1%) were driving outside the bounds of licensure criteria in their state. Among licensed subjects, being a current driver was associated with younger age (P < .001), better visual acuity (P < .001), and better contrast sensitivity (P < .001).

CONCLUSIONS

Many drivers do not possess adequate vision for licensure based on their home state's current standards. Changes to licensure qualification and renewal procedures may be advisable.

Distracting tasks have persisting effects on young and older drivers' braking performance

It is well established that car driving performance suffers when the driver concurrently engages in a distracting activity, such as talking on a cell phone. The present study investigates whether the effects of driver distraction are short-lived, or rather persist for some time. Age-related differences are evaluated as well. Sixty-three young and 61 older adults were tested in a driving simulator. They were asked to follow a lead car that drove at a constant speed, and to concurrently engage in a pseudorandom sequence of distracting tasks (typing, reasoning, memorizing). When the lead car braked, participants had to brake as well to prevent a collision. The stimulus onset asynchrony between the braking task and the last preceding distraction was 11.49 ± 1.99 s. Each person was tested once in a multitasking condition (as described above), and once in a control condition without distracting tasks. Outcome measures quantified distance keeping and lane keeping while participants braked to the lead car. We found that braking responses differed significantly between conditions; this difference could be interpreted as a combination of performance deficits and compensatory strategies in the multitasking condition compared to the control condition. We also found significant differences between age groups, which could be interpreted similarly. Differences between age groups were less pronounced in the multitasking than in the control condition. All observed effects were associated with participants' executive functioning. Our findings confirm that distractions have an impact on braking responses, and they document for the first time that this impact can persist for about 11.5 s. We attribute this persistence to a task set effect, and discuss the practical relevance of our findings.

Driving specialist's ratings of on-road performance and naturalistic driving crashes and near-crashes

BACKGROUND

This study aimed to evaluate the association between a Certified Driving Rehabilitation Specialist's (CDRS) ratings of on-road driving performance by older drivers and at-fault crash and near-crash involvement using naturalistic driving techniques where crashes and near-crashes are recorded in everyday driving through in-vehicle instrumentation.

METHODS

This is a cohort study of 144 drivers aged 70 years and over who were recruited due to a recent ophthalmology clinic visit at the University of Alabama at Birmingham. Baseline measurements consisted of demographics, visual status, and other health variables. At-fault crashes and near-crashes over 6 months were identified through instrumentation placed in their personal vehicle that recorded vehicle kinematics and video. After 6 months, a CDRS completed an on-road assessment and provided a composite rating on specific driving behaviors and a global score.

RESULTS

Rate ratios examining the association between older drivers with worse CDRS composite scores and rates of at-fault crashes, at-fault near-crashes, and combined at-fault crashes and near-crashes were significantly higher compared to drivers with better scores. Results were similar for the CDRS global score.

CONCLUSIONS

Motor vehicle administrations use CDRS ratings to make decisions about licensure, and in clinical programs such as those based at rehabilitation clinics use them to make recommendations about fitness to drive and rehabilitation. This study suggests that these decisions and recommendations are valid from a safety standpoint.

Benefits of Higher Cardiovascular and Motor Coordinative Fitness on Driving Behavior Are Mediated by Cognitive Functioning: A Path Analysis

Driving is an important skill for older adults to maintain an independent lifestyle, and to preserve the quality of life. However, the ability to drive safely in older adults can be compromised by age-related cognitive decline. Performing an additional task during driving (e.g., adjusting the radio) increases cognitive demands and thus might additionally impair driving performance. Cognitive functioning has been shown to be positively related to physical activity/fitness such as cardiovascular and motor coordinative fitness. As such, a higher fitness level might be associated with higher cognitive resources and may therefore benefit driving performance under dual-task conditions. For the first time, the present study investigated whether this association of physical fitness and cognitive functioning causes an indirect relationship between physical fitness and dual-task driving performance through cognitive functions. Data from 120 healthy older adults (age: 69.56 ± 3.62, 53 female) were analyzed. Participants completed tests on cardiovascular fitness (cardiorespiratory capacity), motor coordinative fitness (composite score: static balance, psychomotor speed, bimanual dexterity), and cognitive functions (updating, inhibition, shifting, cognitive processing speed). Further, they performed a virtual car driving scenario where they additionally engaged in cognitively demanding tasks that were modeled after typical real-life activities during driving (typing or reasoning). Structural equation modeling (path analysis) was used to investigate whether cardiovascular and motor coordinative fitness were indirectly associated with lane keeping (i.e., variability in lateral position) and speed control (i.e., average velocity) while dual-task driving via cognitive functions. Both cardiovascular and motor coordinative fitness demonstrated the hypothesized indirect effects on dual-task driving. Motor coordinative fitness showed a significant indirect effect on lane keeping, while cardiovascular fitness demonstrated a trend-level indirect effect on speed control. Moreover, both fitness domains were positively related to different cognitive functions (processing speed and/or updating), and cognitive functions (updating or inhibition), in turn, were related to dual-task driving. These findings indicate that cognitive benefits associated with higher fitness may facilitate driving performance. Given that driving with lower cognitive capacity can result in serious consequences, this study emphasizes the importance for older adults to engage in a physically active lifestyle as it might serve as a preventive measure for driving safety.

Lifetime Outcomes of Anti-Vascular Endothelial Growth Factor Treatment for Neovascular Age-Related Macular Degeneration

Importance

Neovascular age-related macular degeneration (nAMD), the largest single cause of irreversible severe vision loss in high-income countries, can now be treated with vascular endothelial growth factor (VEGF) inhibitors, but to our knowledge, no data on lifetime outcomes are available.

Objective

To determine visual acuity (VA) outcomes of anti-VEGF treatment for nAMD in both eyes for patients' remaining lifetime.

Design, Setting, and Participants

Multistate modeling using real-world cohort data of 3192 patients with nAMD (>67 000 visits) treated in routine eye clinics in Australia, New Zealand, and Switzerland. Data were analyzed between 2007 and 2015.

Exposures

Intravitreal anti-VEGF treatment at the treating physician's discretion and prospective data collection in standardized registry.

Main Outcomes and Measures

Visual acuity in both eyes over the remaining lifetime.

Results

For the mean remaining lifetime of 11 years, an estimated 12% (n = 371; 95% CI, 345-400) of the sample retained driving VA and an estimated 15% (n = 463; 95% CI, 434-495) reading VA in at least 1 eye. At that time, an estimated 82% of the sample (n = 2629; 95% CI, 2590-2660) had dropped out. Younger age at baseline and more injections during the first year of treatment were associated with better long-term outcomes.

Conclusions and Relevance

Anti-VEGF treatment was associated with preserved useful visual acuity in almost 20% of patients over their average remaining lifetime. More than 80% of patients will cease treatment over that time, having likely experienced a deterioration of vision beforehand. This is a remarkable outcome compared with outcomes without intervention, which lead to legal blindness within 3 years of disease onset in 80% of those affected. These findings underline the public health necessity of providing anti-VEGF treatment to persons in need.

Differential interactions of age and sleep deprivation in driving and spatial perception by male drivers in a virtual reality environment

We determined the effects of age and sleep deprivation on driving and spatial perception in a virtual reality environment. Twenty-two young (mean age: 22 years, range: 18-35) and 23 old (mean age: 71 years, range: 65-79) participants were tested after a normal night of sleep and a night of sleep deprivation. The participants drove a virtual car while responding to uni- and bilateral visual and auditory stimuli. Driving errors (crossing the lane borders), reaction times and accuracy to visual and auditory stimuli, performance in psychological tests, and subjective driving ability and tiredness were measured. Age had no effect on the number of driving errors, whereas sleep deprivation increased significantly especially the number of left lane border crossings. Age increased the number of stimulus detection errors, while sleep deprivation increased the number of errors particularly in the young and in the auditory modality as response omissions. Age and sleep deprivation together increased the number of response omissions in both modalities. Left side stimulus omissions suggest a bias to the right hemispace. The subjective evaluations were consistent with the objective measures. The psychological tests were more sensitive to the effects of age than to those of sleep deprivation. Driving simulation in a virtual reality setting is sensitive in detecting the effects of deteriorating factors on both driving and simultaneous spatial perception.

Driving exposure, patterns and safety critical events for older drivers with and without mild cognitive impairment: Findings from a naturalistic driving study

OBJECTIVE

The aim of the study is to compare driving exposure, patterns and factors associated with safety critical events between drivers with MCI and a comparison group without cognitive impairment.

DESIGN, SETTING, PARTICIPANTS

Naturalistic driving data using an in-vehicle monitoring device were collected from 36 older drivers with MCI and 35 older drivers without cognitive impairment over a two-week period in Western Australia.

MEASUREMENTS

Naturalistic driving exposure, patterns (eg. night-time trips, peak-hour trips) and safety critical events (harsh acceleration, harsh braking and harsh cornering).

RESULTS

Drivers with MCI had a lower number of safety critical events (mean = 7.20, SD = 11.44) compared to drivers without cognitive impairment (mean = 10.89, SD = 23.30) however, this was not statistically significantly. There were also no statistically significant differences between drivers with and without MCI for measures of driving exposure or any of the driving patterns including weekday trips, night-time trips and trips on highways/freeways. The results of the multivariable modelling found only binocular contrast sensitivity was associated with the rate of safety critical events. For every increase of 0.1 log units in contrast sensitivity (better contrast sensitivity) the rate of safety critical events significantly decreased by 30 % (IRR = 0.70, 95 % CI = 0.50-0.98, p = 0.04).

CONCLUSION

Drivers with MCI were found to have similar driving exposure and patterns compared to older drivers without cognitive impairment, however drivers with better contrast sensitivity experienced fewer safety critical events. Future research should consider a longitudinal study design with an extended driving monitoring period and a larger sample with a clinical diagnosis of MCI to assess changes in cognition and its impact on driving.

Eye-head coordination and dynamic visual scanning as indicators of visuo-cognitive demands in driving simulator

Driving is an everyday task involving a complex interaction between visual and cognitive processes. As such, an increase in the cognitive and/or visual demands can lead to a mental overload which can be detrimental for driving safety. Compiling evidence suggest that eye and head movements are relevant indicators of visuo-cognitive demands and attention allocation. This study aims to investigate the effects of visual degradation on eye-head coordination as well as visual scanning behavior during a highly demanding task in a driving simulator. A total of 21 emmetropic participants (21 to 34 years old) performed dual-task driving in which they were asked to maintain a constant speed on a highway while completing a visual search and detection task on a navigation device. Participants did the experiment with optimal vision and with contact lenses that introduced a visual perturbation (myopic defocus). The results indicate modifications of eye-head coordination and the dynamics of visual scanning in response to the visual perturbation induced. More specifically, the head was more involved in horizontal gaze shifts when the visual needs were not met. Furthermore, the evaluation of visual scanning dynamics, based on time-based entropy which measures the complexity and randomness of scanpaths, revealed that eye and gaze movements became less explorative and more stereotyped when vision was not optimal. These results provide evidence for a reorganization of both eye and head movements in response to increasing visual-cognitive demands during a driving task. Altogether, these findings suggest that eye and head movements can provide relevant information about visuo-cognitive demands associated with complex tasks. Ultimately, eye-head coordination and visual scanning dynamics may be good candidates to estimate drivers' workload and better characterize risky driving behavior.

Driving Skills Tested on Simulator After Strabismus Surgery: A Prospective Study

Purpose

The sense of vision is responsible for 90% of the information obtained by the motorist. Improvement in binocular visual acuity (VA) and visual field (VF) achieved after strabismus surgery could have beneficial effects on driving. Our study sought to identify functional improvements (VA and VF) and improvements in driving ability following strabismus surgery.

Methods

In a prospective cohort study, the following parameters are analyzed before and 3 months after strabismus surgery: simulated driving performance (including eye movements and actions on vehicle control), binocular VA, binocular VF, and self-confidence during driving.

Results

Twenty patients participated in the study. The mean preoperative logMAR binocular VA and stereopsis do not significantly differ from the postoperative. The mean Esterman VF score increases from 91.3 (±17.2) preoperatively to 96.9 (±13.9) postoperatively (P = 0.045). The mean self-confidence directed at driving scores decreases from 20.5 (±10.3) points before surgery to 11.0 (±6.0) points after surgery (P < 0.001). The distance at which the road signs are identified is significantly higher after surgery. The average speed of the vehicle and the speed near the targets (30 m) increase significantly after strabismus surgery. A significant decrease in ocular movements near targets is also observed. The number of brake pedal depressions and the rate of brake pedal depressions slightly decrease after surgery.

Conclusions

This study demonstrates the potential beneficial effects of strabismus surgery on driving ability, with significant improvements in self-confidence during driving, VF, and driving on a simulator.

Translational Relevance

This was the first study to use a driving simulator in strabismus.

Are Your Eyes "on the Road"? Findings from the 2019 National Study on Vision and Driving Safety in Spain

Background: Vision is an undisputable contributor to the explanation of many human-factor related traffic crashes happening every day. The Inland Transport Committee (ITC), the United Nations regulatory platform, included on 1st April 2020 special action on the vision of road users inside the ITC Recommendations for Enhancing Road Safety Systems. The results of this wide-scale study on drivers’ vision health conducted in Spain perfectly illustrates the need of global action and its potential impact on the public health figures and the burden of potentially preventable traffic causalities. Objective: The aim of this study was to assess three key visual health issues (i.e., visual acuity, visual field campimetry and glare recovery) among Spanish drivers, in order to formulate implications and possible guidelines to enhance road safety. Methods: This cross-sectional study examined the visual health of a representative sample of 3249 drivers (70% females and 30% males) with a mean age of 41 (SD = 13) years, gathered from all the 17 autonomous communities of Spain. Results: The tests performed allowed to determine that 15% of Spanish drivers have a poor photopic vision, while 38% of them present an inadequate mesopic vision. Further, 23% of drivers have deficiencies in peripheric visual field campimetry, and the average time for full-vision recovery after a 10-s glare was 27 s. Sex, age and driver type (professional vs. non-professional) differences were found for the study variables. Conclusions: The findings of this study support the idea that certain demographic-based population groups of drivers present several unaddressed deficiencies and impairments in visual health. Overall an estimated 29.5% of Spanish drivers present visual issues, that need to be attended in order to enhance the prevention of driving crashes and the road safety of all road users.

The effects of simulated acuity and contrast sensitivity impairments on detection of pedestrian hazards in a driving simulator

Driving is a highly visual task, yet the vision requirements for driving licensure vary widely. All US states have a threshold for visual acuity (e.g. most use 20/40 for an unrestricted license). Contrast sensitivity (CS) is not measured for licensure, despite evidence that it may be a better predictor of crash risk than visual acuity (VA). Two experiments were conducted to investigate how simulated reductions in VA and CS affect the detection of pedestrians in a driving simulator during the daytime in a highway setting. Young normally-sighted current drivers wore goggles simulating different levels of VA and CS loss (within a range that would meet licensing criteria) and pressed the horn as soon as they saw a pedestrian. The proportion of pedestrians detected and driving speed was not different between the conditions. Reducing VA alone did not significantly reduce reaction time or the deceleration needed to stop before the collision point. However, adding a CS loss to a VA deficit increased both reaction time and the deceleration required to stop before the collision point. These results suggest that an individual's CS should be considered when determining visual fitness to drive, especially in the early stages of ocular disease, such as cataract, where CS may be impaired while high contrast VA is still relatively unimpaired.

Structure of executive functions in young and in older persons

INTRODUCTION

Using factor analysis, several studies reported that higher-order cognitive control involves separable executive functions. However, the number and definition of the purported functions differed between studies. One possible explanation for this discrepancy is that executive functions don't exhibit a clear factorial structure, i.e., there is no clear dichotomy between executive function tests which are well-correlated (representing a common factor) and those which are poorly correlated (representing distinct factors). We scrutinize this explanation separately in data from young and from older persons.

METHODS & RESULTS

Young and older volunteers completed cognitive tests of the purported executive functions shifting, updating, inhibition and dual-tasking (two tests per function). Confirmatory and exploratory factor analyses yielded, for either age group, factorial structures that were within the range reported in literature. More importantly, when correlations between tests were sorted in ascending order, and were then fitted them by piecewise linear regression with a breakpoint, there was no evidence for a distinct breakpoint between low and high correlations in either age group. Correlations between tests were significantly higher in older compared to young participants, and the pattern of test pairs with high and with low correlations differed between age groups.

DISCUSSION

The absence of a breakpoint indicates that executive function tests don't segregate into well-correlated and poorly correlated pairs, and therefore are not well suited for factor analyses. We suggest that executive functions are better described as a partly overlapping rather than a factorial structure. The increase of correlations in older participants supports the existence of age-related dedifferentiation, and the dissimilarity of correlations in the two age groups supports the existence of age-related reorganization.

The effects of auditory satellite navigation instructions and visual blur on road hazard perception

The distracting effects of mobile telephone use while driving are well known, however the effects of other sources of distraction, such as auditory navigation devices, are less well understood. Whether the effects of auditory distraction might interact with other sensory impairments, such as vision impairment, is of interest given that visual impairment is relatively common within the population, particularly as a result of uncorrected refractive error. In this experiment, 20 current drivers (mean age of 29.4 ± 3.2 years), binocularly viewed video recordings of traffic scenes presented as part of the Hazard Perception Test and responded to potential hazards within the traffic scenes. Half of the presented scenes included auditory navigation instructions as an auditory distractor. Additionally, some of the scenes were viewed through optical lenses to induce different levels of refractive blur (+0.50 DS, +1.00 DS and +2.00 DS). Hazard perception response times increased significantly (p < 0.05) with increasing blur. Participants were significantly slower in reacting to hazards for the +1.00 DS and +2.00 DS blur conditions compared to the control condition (with no blur). There was also a significant increase in response times to hazards in the presence of the auditory navigation instructions. The combined effect of blur and auditory instructions was additive, with the worst performance being in the presence of both blur and auditory instructions. These results suggest that the delivery of auditory navigation guidance for those with visual impairments, such as blur, which are relatively common in the population, should be further investigated.

Assessment of physical inactivity and locomotor dysfunction in adults with visual impairment

To evaluate the association between vision-related quality of life (QoL), physical inactivity, and locomotor dysfunction in subjects with visual impairment.This cross-sectional study included 215 visually impaired subjects recruited from six ophthalmology departments in Japan. The physical inactivity and locomotor dysfunction associated with their visual impairment was investigated. The physical activity level was assessed using the short form of the International Physical Activity Questionnaire and classified as high, moderate, or low. Locomotor function was evaluated with the Geriatric Locomotive Function Scale. Vision-related QoL was evaluated using the 25-item National Eye Institute Visual Function Questionnaire. Background data, including for age, sex, best-corrected visual acuity for each eye, causative eye diseases, systemic comorbidities, and body mass index, were also collected.The average patient age was 69.6 (range, 20-93 years; standard deviation, 14.5 years) and 118 patients (54.9%) were men. Multivariate analysis showed that vision-related QoL and best-corrected visual acuity in the worse eye were significantly associated with physical inactivity and that vision-related QoL, female sex, age, and presence of systemic comorbidity were significantly associated with locomotor dysfunction. Vision-related quality of life is associated with physical inactivity and locomotor dysfunction.

Multitasking During Simulated Car Driving: A Comparison of Young and Older Persons

Human multitasking is typically studied by repeatedly presenting two tasks, either sequentially (task switch paradigms) or overlapping in time (dual-task paradigms). This is different from everyday life, which typically presents an ever-changing sequence of many different tasks. Realistic multitasking therefore requires an ongoing orchestration of task switching and dual-tasking. Here we investigate whether the age-related decay of multitasking, which has been documented with pure task-switch and pure dual-task paradigms, can also be quantified with a more realistic car driving paradigm. 63 young (20–30 years of age) and 61 older (65–75 years of age) participants were tested in an immersive driving simulator. They followed a car that occasionally slowed down and concurrently executed a mixed sequence of loading tasks that differed with respect to their sensory input modality, cognitive requirements and motor output channel. In two control conditions, the car-following or the loading task were administered alone. Older participants drove more slowly, more laterally and more variably than young ones, and this age difference was accentuated in the multitask-condition, particularly if the loading task took participants’ gaze and attention away from the road. In the latter case, 78% of older drivers veered off the road and 15% drove across the median. The corresponding values for young drivers were 40% and 0%, respectively. Our findings indicate that multitasking deteriorates in older age not only in typical laboratory paradigms, but also in paradigms that require orchestration of dual-tasking and task switching. They also indicate that older drivers are at a higher risk of causing an accident when they engage in a task that takes gaze and attention away from the road.

Cognitive-Motor Interference in an Ecologically Valid Street Crossing Scenario

Laboratory-based research revealed that gait involves higher cognitive processes, leading to performance impairments when executed with a concurrent loading task. Deficits are especially pronounced in older adults. Theoretical approaches like the multiple resource model highlight the role of task similarity and associated attention distribution problems. It has been shown that in cases where these distribution problems are perceived relevant to participant's risk of falls, older adults prioritize gait and posture over the concurrent loading task. Here we investigate whether findings on task similarity and task prioritization can be transferred to an ecologically valid scenario. Sixty-three younger adults (20–30 years of age) and 61 older adults (65–75 years of age) participated in a virtual street crossing simulation. The participants' task was to identify suitable gaps that would allow them to cross a simulated two way street safely. Therefore, participants walked on a manual treadmill that transferred their forward motion to forward displacements in a virtual city. The task was presented as a single task (crossing only) and as a multitask. In the multitask condition participants were asked, among others, to type in three digit numbers that were presented either visually or auditorily. We found that for both age groups, street crossing as well as typing performance suffered under multitasking conditions. Impairments were especially pronounced for older adults (e.g., longer crossing initiation phase, more missed opportunities). However, younger and older adults did not differ in the speed and success rate of crossing. Further, deficits were stronger in the visual compared to the auditory task modality for most parameters. Our findings conform to earlier studies that found an age-related decline in multitasking performance in less realistic scenarios. However, task similarity effects were inconsistent and question the validity of the multiple resource model within ecologically valid scenarios.

Cross-sectional study assessing the addition of contrast sensitivity to visual acuity when testing for fitness to drive

OBJECTIVES

The aim of this study is to quantify the importance of loss of contrast sensitivity (CS) and its relationship to loss of visual acuity (VA), driving restrictions and daytime, on-road driving evaluations in drivers aged 70+.

DESIGN

A predictive cross-sectional study.

SETTING

Volunteer participants to a drivers' refresher course for adults aged 70+ delivered by the Swiss Automobile Club in western Switzerland from 2011 to 2013.

PARTICIPANTS

162 drivers, male and female, aged 70 years or older.

CLINICAL PREDICTORS

We used a vision screener to estimate VA and the The Mars Letter Contrast Sensitivity Test to test CS.

OUTCOMES

We asked drivers to report whether they found five driving restrictions useful for their condition; restrict driving to known roads, avoid driving on highways, avoid driving in the dark, avoid driving in dense traffic and avoid driving in fog. All participants also underwent a standardised on-road evaluation carried out by a driving instructor.

RESULTS

Moderate to severe loss of CS for at least one eye was frequent (21.0% (95% CI 15.0% to 28.1%)) and often isolated from a loss of VA (11/162 cases had a VA ≥0.8 decimal and a CS of ≤1.5 log(CS); 6.8% (95% CI 3.4% to 11.8%)). Drivers were more likely (R²=0.116, P=0.004) to report a belief that self-imposed driving restrictions would be useful if they had reduced CS in at least one eye. Daytime evaluation of driving performance seems limited in its ability to correctly identify difficulties related to CS loss (VA: R²=0.004, P=0.454; CS: R²=0.006, P=0.332).

CONCLUSION

CS loss is common for older drivers. Screening CS and referring for cataract surgery even in the absence of VA loss could help maintain mobility. Reduced CS and moderate reduction of VA were both poor predictors of daytime on-road driving performances in this research study.

Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis

BACKGROUND

Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global estimates, trends, and projections of global blindness and vision impairment.

METHODS

We did a systematic review and meta-analysis of population-based datasets relevant to global vision impairment and blindness that were published between 1980 and 2015. We fitted hierarchical models to estimate the prevalence (by age, country, and sex), in 2015, of mild visual impairment (presenting visual acuity worse than 6/12 to 6/18 inclusive), moderate to severe visual impairment (presenting visual acuity worse than 6/18 to 3/60 inclusive), blindness (presenting visual acuity worse than 3/60), and functional presbyopia (defined as presenting near vision worse than N6 or N8 at 40 cm when best-corrected distance visual acuity was better than 6/12).

FINDINGS

Globally, of the 7·33 billion people alive in 2015, an estimated 36·0 million (80% uncertainty interval [UI] 12·9-65·4) were blind (crude prevalence 0·48%; 80% UI 0·17-0·87; 56% female), 216·6 million (80% UI 98·5-359·1) people had moderate to severe visual impairment (2·95%, 80% UI 1·34-4·89; 55% female), and 188·5 million (80% UI 64·5-350·2) had mild visual impairment (2·57%, 80% UI 0·88-4·77; 54% female). Functional presbyopia affected an estimated 1094·7 million (80% UI 581·1-1686·5) people aged 35 years and older, with 666·7 million (80% UI 364·9-997·6) being aged 50 years or older. The estimated number of blind people increased by 17·6%, from 30·6 million (80% UI 9·9-57·3) in 1990 to 36·0 million (80% UI 12·9-65·4) in 2015. This change was attributable to three factors, namely an increase because of population growth (38·4%), population ageing after accounting for population growth (34·6%), and reduction in age-specific prevalence (-36·7%). The number of people with moderate and severe visual impairment also increased, from 159·9 million (80% UI 68·3-270·0) in 1990 to 216·6 million (80% UI 98·5-359·1) in 2015.

INTERPRETATION

There is an ongoing reduction in the age-standardised prevalence of blindness and visual impairment, yet the growth and ageing of the world's population is causing a substantial increase in number of people affected. These observations, plus a very large contribution from uncorrected presbyopia, highlight the need to scale up vision impairment alleviation efforts at all levels.

FUNDING

Brien Holden Vision Institute.

Effects of Light Scatter and Blur on Low-Contrast Vision and Disk Halo Size

PURPOSE

To investigate the individual effects of forward light scatter (FLS) and refractive blur on low-contrast vision and the size of the disk halo produced in response to an external glare source.

METHODS

Monocular disk halo radius, high- and low-contrast distance visual acuity (HCVA, LCVA), and contrast sensitivity (CS) were determined in 25 eyes of 25 healthy subjects under normal, FLS, and blur conditions. FLS was induced using the filter Black ProMist 2 to simulate an early cataract. Blur was induced using a +1.00 diopter lens to simulate an uncorrected refractive error.

RESULTS

Similar significant mean increases in halo radius were observed for the FLS (0.32 ± 0.10 log arc min; P < .0001) and refractive blur (0.40 ± 0.18 log arc min; P < .0001). Under induced blur, 3 lines of HCVA (0.32 ± 0.15 logMAR; P < .0001) and 4 lines of LCVA (0.39 ± 0.16 logMAR; P < .0001) were lost. FLS had a minimal (but significant) effect on HCVA, but worsened mean LCVA by more than 1 line (0.13 ± 0.10 logMAR; P < .0001). Similar significant mean CS reductions of 0.17 ± 0.12 (P < .0001) and 0.14 ± 0.12 log units (P < .0001) were produced in response to FLS and refractive blur, respectively (approximately 1 triplet).

CONCLUSIONS

Forward light scatter and refractive blur contributed to an increased size of the disk halo produced by a glare source in similar proportion. Although defocus blur has a substantial effect on LCVA, a loss of more than 1 line of LCVA after best refractive correction would be indicative of FLS.

Bioptic Telescope Use and Driving Patterns of Drivers with Age-Related Macular Degeneration

Purpose

To investigate the telescope use and driving patterns of bioptic drivers with age-related macular degeneration (AMD).

Methods

A questionnaire addressing telescope use and driving patterns was administered by telephone interview to three groups of bioptic drivers: AMD (n = 31; median 76 years); non-AMD first licensed with a bioptic (n = 38; 53 years); and non-AMD first licensed without a bioptic (n = 47; 37 years). Driving patterns of bioptic AMD drivers were also compared with those of normal vision (NV) drivers (n = 36; 74 years) and nonbioptic AMD drivers (n = 34; 79 years).

Results

Bioptic usage patterns of AMD drivers did not differ from those of the younger bioptic drivers and greater visual difficulty without the bioptic was strongly correlated with greater bioptic helpfulness. Bioptic AMD drivers were more likely to report avoidance of night driving than the age-similar NV drivers (P = 0.06). However, they reported less difficulty than the nonbioptic AMD drivers in all driving situations (P ≤ 0.02). Weekly mileages of bioptic AMD drivers were lower than those of the younger bioptic drivers (P < 0.001), but not the NV group (P = 0.54), and were higher than those of the nonbioptic AMD group (P < 0.001).

Conclusions

Our results suggest that bioptic telescopes met the visual demands of drivers with AMD and that those drivers had relatively unrestricted driving habits.

Translational Relevance

Licensure with a bioptic telescope may prolong driving of older adults with AMD; however, objective measures of bioptic use, driving performance, and safety are needed.

Road safety in an aging population: risk factors, assessment, interventions, and future directions

With the number of older drivers projected to increase by up to 70% over the next 20 years, preventing injury resulting from crashes involving older drivers is a significant concern for both policy-makers and clinicians. While the total number of fatal crashes per annum has steadily decreased since 2005 in Australia, the rate of fatalities has demonstrated an upward trend since 2010 in drivers aged 65 years and above (8.5 per 100,000), such that it is now on par with the fatality rate in drivers aged 17-25 years (8.0 per 100,000) (Austroads, 2015). Similar statistics are reported for the United States (NHTSA, 2012), implying there is a need for better identification of those older drivers who are unsafe and implementation of strategies that can enhance mobility while maximizing road safety.

Mature Driver Laws and State Predictors of Motor Vehicle Crash Fatality Rates Among the Elderly: A Cross-sectional Ecological Study

OBJECTIVE

State-level data have indicated that motor vehicle crash (MVC) fatality rates among the elderly vary widely across states. To date, the majority of states have implemented mature driver laws, which often require more frequent license renewals, in-person renewal, and vision testing for drivers above a certain age. We sought to evaluate the impact of mature driver laws on states' MVC fatality rates among the elderly while examining other state-level determinants of MVC-related deaths.

METHODS

We performed a cross-sectional ecological study and modeled state MVC fatality rates for the population over age 65 as a function of state transportation policies and demographic, health system, population health, travel, and climate characteristics using a general linear model. Principal component analysis was used to reduce dimensionality of the data and overcome multicollinearity of state predictor variables.

RESULTS

Higher average temperature, higher gas prices, and a greater number of emergency medicine physicians to population size were significantly associated with lower MVC fatality rates. Positive predictors of MVC fatality rates were percentage of population overweight or obese and percentage with college degree over the age of 65. Having any restriction on elderly drivers was associated with a higher MVC fatality rate and no individual component of mature driver laws (shortened renewal cycle, in-person renewal, and vision testing) was significantly associated with lower fatality MVC rates for adults over 65.

CONCLUSIONS

Mature driver laws are not associated with lower state MVC fatality rates among the elderly.

Older drivers and rapid deceleration events: Salisbury Eye Evaluation Driving Study

Drivers who rapidly change speed while driving may be more at risk for a crash. We sought to determine the relationship of demographic, vision, and cognitive variables with episodes of rapid decelerations during five days of normal driving in a cohort of older drivers. In the Salisbury Eye Evaluation Driving Study, 1425 older drivers aged 67-87 were recruited from the Maryland Motor Vehicle Administration's rolls for licensees in Salisbury, Maryland. Participants had several measures of vision tested: visual acuity, contrast sensitivity, visual fields, and the attentional visual field. Participants were also tested for various domains of cognitive function including executive function, attention, psychomotor speed, and visual search. A custom created driving monitoring system (DMS) was used to capture rapid deceleration events (RDEs), defined as at least 350 milli-g deceleration, during a five day period of monitoring. The rate of RDE per mile driven was modeled using a negative binomial regression model with an offset of the logarithm of the number of miles driven. We found that 30% of older drivers had one or more RDE during a five day period, and of those, about 1/3 had four or more. The rate of RDE per mile driven was highest for those drivers driving<59 miles during the 5-day period of monitoring. However, older drivers with RDE's were more likely to have better scores in cognitive tests of psychomotor speed and visual search, and have faster brake reaction time. Further, greater average speed and maximum speed per driving segment was protective against RDE events. In conclusion, contrary to our hypothesis, older drivers who perform rapid decelerations tend to be more "fit", with better measures of vision and cognition compared to those who do not have events of rapid deceleration.

Visual fitness of public vehicle drivers in southeast of iran

BACKGROUND

Although visual impairment of drivers is a very important risk factor for car accident, a few published papers have explored this issue in Iran. This study aims to evaluate the visual fitness of public vehicle drivers in Kerman province, southeast of Iran.

METHODS

A total of 4,003 public vehicle drivers were examined by one ophthalmologist for visual fitness in Kerman province between January 2009 and June 2010. Data are presented as Mean±SD or percentage, and with 95% confidence intervals (CIs). Pearson Chi-square and McNemmar tests along with crude odds ratio (OR) were used to compare vision deficit between groups.

RESULTS

Almost 361 drivers (9.0%; 95% CI: 8.1-9.9) had insufficient vision to drive public vehicles before the refractive errors (RE) correction and this number, was reduced to 68 drivers (1.7%; 95% CI: 1.3-2.1) after the correction. A number of them including 200 drivers (5.0%; 95% CI: 4.3-5.7) had insufficient vision to drive personal vehicles before the correction and this was reduced to 30 thereafter (0.8%; 95% CI: 0.5-1.0). We also found out that the vision status got worse with aging, and RE was the most prevalent cause of sight defects.

CONCLUSION

It seems that visual fitness of public vehicle drivers is a point of real concerns which might somewhat explain the high rate of car accidents in Iran.

Prevalence of impairment of visual function in European drivers

PURPOSE

This study aimed to investigate the prevalence of impairment of visual function amongst European drivers.

METHODS

A total of 2422 drivers from five European countries underwent a battery of visual function tests, including tests for visual acuity (VA), visual field (VF), contrast sensitivity, straylight (glare sensitivity) and useful field of view (UFOV). Subjects belonged to the following age categories: 45-54 years; 55-64 years; 65-74 years, and ≥ 75 years. A group of subjects aged 20-30 years served as a reference group. Results were compared with current standards for the visual function of drivers in the EU.

RESULTS

Visual acuity in 0.5% of the younger group and 5.3% of the eldest group was below the standard required for driving. Visual acuity after proper refraction adhered to the standard in the majority of cases. Visual field results were below standard or questionable in 2.7% and 2.4%, respectively, of subjects in the eldest group. In this eldest group, impaired contrast sensitivity was present in 6.3%, increased glare sensitivity in 29.5% and impaired UFOV in 21.6% of subjects, but, as there are no standards for these criteria, the exact level of prevalence depends on the definition of impairment.

CONCLUSIONS

Prevalences of impairment of visual functions that are not included in current standards (particularly contrast sensitivity and glare sensitivity) are much higher than prevalences of functions that are included (VA and VF).

International vision requirements for driver licensing and disability pensions: using a milestone approach in characterization of progressive eye disease

Objective

Low vision that causes forfeiture of driver’s licenses and collection of disability pension benefits can lead to negative psychosocial and economic consequences. The purpose of this study was to review the requirements for holding a driver’s license and rules for obtaining a disability pension due to low vision. Results highlight the possibility of using a milestone approach to describe progressive eye disease.

Methods

Government and research reports, websites, and journal articles were evaluated to review rules and requirements in Germany, Spain, Italy, France, the UK, and the US.

Results

Visual acuity limits are present in all driver’s license regulations. In most countries, the visual acuity limit is 0.5. Visual field limits are included in some driver’s license regulations. In Europe, binocular visual field requirements typically follow the European Union standard of ≥120°. In the US, the visual field requirements are typically between 110° and 140°. Some countries distinguish between being partially sighted and blind in the definition of legal blindness, and in others there is only one limit.

Conclusions

Loss of driving privileges could be used as a milestone to monitor progressive eye disease. Forfeiture could be standardized as a best-corrected visual acuity of <0.5 or visual field of <120°, which is consistent in most countries. However, requirements to receive disability pensions were too variable to standardize as milestones in progressive eye disease. Implementation of the World Health Organization criteria for low vision and blindness would help to establish better comparability between countries.

Comparison of the visual function index to the Snellen Visual Acuity Test in predicting older adult self-restricted driving

OBJECTIVE

In this observational study, a modified version of the Visual Function Index (VF-14) and the Snellen Visual Acuity Test were compared in how well they correlated with self-restricted driving habits in older adults. The VF-14 was originally designed to assess vision in cataract patients; however, in this study, a modified version (mVF-14) was evaluated as a tool for predicting self-restricted driving in older drivers.

METHODS

During a 3-month period, 151 drivers over the age of 65 were screened at the local senior center. In addition to the Snellen Visual Acuity Test and mVF-14, each participant was given a questionnaire about their driving habits, previously used in self-restriction studies.

RESULTS

Out of 151 total participants, 134 were included and 7 nondrivers and 10 subjects who did not complete all questionnaires were excluded. One hundred one participants exhibited normal visual acuity of 20/40 or better (75%), and 110 scored over 90 on the mVF-14 (82%). Spearman's rank sum correlation coefficient was used to analyze the data and showed significant negative correlation of the mVF-14 and Snellen with self-restricted driving. Individuals with normal vision (20/40 or better on the Snellen eye test) had both high and low mVF-14 scores.

CONCLUSIONS

The study shows that poor vision, as indicated by the Snellen scale and low mVF-14 scores, correlates to self-imposed driving limitations. The mVF-14 showed further distinctions of self-restriction between individuals in the same Snellen Visual Acuity category. Therefore, using the mVF-14 in addition to the Snellen Visual Acuity Test can be helpful to further differentiate visual ability within older drivers who appear to have normal vision.

The crash involvement of older drivers is associated with their hazard perception latencies

Hazard perception in driving is the one of the few driving-specific skills associated with crash involvement. However, this relationship has only been examined in studies where the majority of individuals were younger than 65. We present the first data revealing an association between hazard perception and self-reported crash involvement in drivers aged 65 and over. In a sample of 271 drivers, we found that individuals whose mean response time to traffic hazards was slower than 6.68 s [the receiver operating characteristic (ROC) curve derived pass mark for the test] were 2.32 times [95% confidence interval (CI), 1.46, 3.22) more likely to have been involved in a self-reported crash within the previous 5 years than those with faster response times. This likelihood ratio became 2.37 (95% CI, 1.49, 3.28) when driving exposure was controlled for. As a comparison, individuals who failed a test of useful field of view were 2.70 (95% CI, 1.44, 4.44) times more likely to crash than those who passed. The hazard perception test and the useful field of view measure accounted for separate variance in crash involvement. These findings indicate that hazard perception testing and training could be potentially useful for road safety interventions for this age group.

Visual function survey of commercial intercity vehicle drivers in Ilorin, Nigeria

OBJECTIVE

To determine the prevalence of visual impairment among commercial intercity vehicle drivers (CIVDs) in Ilorin, Nigeria.

DESIGN

A cross-sectional descriptive study.

PARTICIPANTS

Among the estimated 450 drivers operating in 5 motor parks for CIVDs in Ilorin, 399 drivers participated in the study.

METHODS

A structured questionnaire was administered at the motor parks to consecutive and consenting drivers, and basic ocular examinations were done.

RESULTS

Using the Federal Road Safety Commission's requirement for commercial drivers in Nigeria, the prevalence of drivers with inadequate visual acuity (VA) was determined to be 11.5%, and 3.3% had monocular blindness. The prevalence of abnormal colour vision and visual field loss was 4.3% and 5.5%, respectively. There was no statistically significant relationship between visual impairment (VA and visual fields) and involvement in road traffic accidents (p > 0.05). Uncorrected refractive error, cataract, and glaucoma were the commonest causes of visual defects. Three hundred thirty-seven drivers (84.5%) did not have their eyes tested at first licensing and 370 drivers (92.7%) did not have testing at least once during renewals.

CONCLUSIONS

A significant number of CIVDs in Ilorin are operating with VA that is far below the expected for their class of licence, and another unacceptably high percentage did not undergo any form of ocular examination prior to obtaining their driving licence. There is a need for renewed efforts to enforce a compulsory basic ocular examination for all prospective commercial drivers, and to ensure that the visual requirement for driving is met.

Fall incidence in a population of elderly persons in Nigeria

BACKGROUND

Falls are a common public health problem amongst the elderly in many communities. There is a need for information on the causes as well as the impact of this preventable risk on health among the elderly in sub-Saharan Africa.

OBJECTIVE

To examine the prevalence and factors associated with falls among a population of elderly persons in Nigeria.

METHODS

A multi-stage stratified sampling of households was implemented to select persons aged 65 years and older in the south-western and north-central parts of Nigeria (n = 2,096). Respondents were asked about the occurrence, number, and consequences of falls in the previous 12 months. They were also assessed for the presence of vision impairment, chronic pain and medical conditions.

RESULTS

Falls were reported by 23% (n = 482) of the sample. Females (24.0%) were more likely than males (17.9%) to report falls. Respondents with chronic pain conditions, especially those with arthritis, and those with insomnia were at increased risk for falls. Among fallers, females were more likely than males to sustain injuries, including fractures (45.0 vs. 30.1%; p = 0.001). Persons with near vision impairment were less prone to serious falls with injuries than those with no visual impairment (p < 0.05).

CONCLUSION

Falls are an important health problem among elderly Nigerians. A fall prevention program must have a particular focus on females, those with chronic pain conditions and those experiencing insomnia.