An assessment of driving fitness in patients with visual impairment to understand the elevated risk of motor vehicle accidents

Colour vision restrictions for driving: an evidence-based perspective on regulations in ASEAN countries compared to other countries

Colour vision deficiency is an impairment in discriminating colours. Beyond occupational opportunities, colour vision-based restrictions may limit driving, which is a daily task for many people. This review aims to compare existing colour vision requirements for obtaining a driving license in southeast Asian countries to the rest of the world. Subsequently, to review existing published literature and provide evidence-based recommendations for future guidelines for colour-deficient drivers. Color vision requirements for obtaining a driving license vary widely amongst countries. While colour-deficient drivers may face mild challenges in driving, increased awareness and developing effective compensatory strategies could enable them to drive safely. The current evidence does not support a strict exclusion of all colour-deficient individuals from driving. Instead, emphasis is needed on screening to increase awareness and insight into their disability. Future studies should consider compensatory adaptive strategies that are specific for high-risk situations such as challenging driving conditions.

Vision rehabilitation in glaucoma patients

PURPOSE OF REVIEW

Vision rehabilitation services are important but underutilized resources for patients with glaucoma. Glaucoma and its impact on vision can affect patients' abilities to read and drive, two activities of daily living that are associated with quality of life and functional independence. In this review, we provide an overview of low vision, discuss barriers to vision rehabilitation, and outline various strategies and interventions to optimize visual function and quality of life in patients with glaucoma.

RECENT FINDINGS

Studies have shown that glaucoma negatively impacts reading, driving and overall quality of life. Decreased visual acuity, visual field loss and reduced contrast sensitivity play a role. Low vision services and interventions can help patients maximize visual function and improve their quality of life. Barriers to receiving these services exist at multiple levels and an increased awareness and integration into routine ophthalmic care are needed to deliver comprehensive care.

SUMMARY

Glaucoma is one of the leading causes of low vision. Ophthalmologists who treat glaucoma often tend to focus on objective measures to monitor progression and disease severity, but the functional impact of glaucoma should also be addressed. Low vision services can benefit patients, particularly for reading and driving, and should be considered as an essential component of patient care.

Influence of Vision on Drivers: A Pilot Study

Background: Driving is the main mode of transportation in many countries, and visual safety depends largely on good visual health. The objective of this study is to analyze the visual health of Spanish drivers; as well as analyze the difference between professional and non-professional drivers. Methods: A visual screening was carried out in Spanish drivers from all over Spain, in which the following tests were performed: monocular visual acuity in distance and near vision, visual field, stereopsis, contrast sensitivity, intraocular pressure and balance test binocular. Subsequently, a questionnaire was carried out on the patient’s driving data and ocular antecedents. Results: 74.5% of the drivers used glasses to drive, of which 61.5% used progressive glasses. However, 39.4% reported having difficulties seeing well. The mean visual acuity in the distance and near was 0.93 ± 0.13 and 0.94 ± 0.13, respectively. Significant differences have been found in accident risk based on visual acuity (p < 0.001). But no significant differences have been found in terms of visual field, stereopsis, contrast sensitivity, binocular balance and intraocular pressure (p > 0.05). Conclusion: Vision appears to play a key role in driving and a good visual assessment is recommended for early detection of visual problems that may affect road safety. A study with a larger sample size would be necessary to confirm the results of this pilot study.

Incidence of ocular and systemic diseases affecting visual function among state bus drivers

Purpose:

To evaluate the incidence of ocular and systemic disease affecting visual function among state transport corporation bus drivers in a south Indian district.

Methods:

This retrospective study analysed the records of all the drivers who presented to a south Indian tertiary-care eye hospital in 2019 for their mandatory annual ocular check-up. Details reviewed included demographic details; refraction; presence of systemic and ocular diseases with vision-threatening potential; presence of ocular conditions responsible for visual loss and the treatment administered.

Results:

3042 drivers (mean age, 47.0 ± 5.7 years) were evaluated. Visual function-threatening systemic diseases were present in 25.0% drivers, out of which diabetes mellitus (18.7%) was the most common pathology. The most common ocular problem was refractive error (45.0%). Visual function-threatening ocular diseases were present in 9.5% drivers. Diabetic retinopathy, visually-significant cataract, glaucoma and central serous chorioretinopathy were noted in 4.0%, 1.9%, 1.7% and 0.8% drivers. Surgical intervention was required in 2.2% drivers. Thirteen drivers were temporarily deemed unfit for driving heavy-weight vehicles.

Conclusion:

Several bus drivers suffer from vision-threatening systemic and ocular diseases. Some of them require surgical intervention to retain fitness. A complete ocular and systemic evaluation of diseases with vision-threatening potential should be performed at the time of renewal of the driving license. The drivers should be educated about the systemic diseases which can affect their driving skills and must be encouraged to seek medical help at an early stage.

Impact of binocular visual field loss on driving performance in glaucoma patients

AIM

To evaluate the driving performance in young and middle-aged Chinese glaucoma patients with mild to severe visual field loss compared to those without glaucoma by using a driving simulation test.

METHODS

Twenty-nine participants were included in this study: nine patients with glaucoma but pass the binocular Esterman visual field test, ten patients with glaucoma and fail the binocular Esterman visual field test, and ten age-matched healthy controls. A driving simulation test was designed as a frequency-based analysis of a lane-keeping task. The total performance error, the control-response amplitude and delay were calculated.

RESULTS

Esterman visual field test fail group showed the longest delay of control-response among three groups (P=0.02). And the delay in lane-keeping task was significantly associated with inferior field of better-eye (r=0.51, P=0.004) and integrated visual field (r=0.55, P=0.002).

CONCLUSION

Young and middle-aged glaucoma patients with binocular visual field loss suffered from a longer delay of response in driving simulation test, while inferior visual field having more impact than superior visual field.

Comparing Component-Based and Occupation-Based Interventions of a Person with Visual Deficits' Performance

This study aimed to compare the effectiveness of component-based, occupation-based, and a combined intervention for visual-scanning to improve occupational performance. This exploratory case study used a 55-year-old female, seven years post-stroke with visual field deficits, who completed a component-based intervention (Vision Coach), an occupation-based intervention (IADL activities that incorporated scanning tasks), and a combined intervention. The Assessment of Motor and Process Skills (AMPS) was completed prior to and after each intervention. Participant's data was compared between interventions and AMPS standardization sample, with observable improvements in motor skills and process skills. Visual-scanning training as a compensatory method appears to be effective for chronic visual field deficits post-stroke, particularly using component-based and occupation-based interventions in combination.

A New System for Assessing Visual Disability Using a Digital Visor

Background: Considering the lack of universally accepted visual requirements for driving and for defining various grades of visual disability, the aim of this study is to propose a new method that provides a numerical score resulting from a combined assessment of the visual field and visual acuity loss obtained using a digital technology visor. Methods: This study presents a new system for calculating the percentage of visual disability by combining binocular visual acuity and binocular visual field assessments. A new Global Vision Evaluation System digital technology visor uses standardized, reproducible criteria to produce well-defined, numerically expressed test results. Through a specific algorithm, the device produces a numerical value expressing the percentage of visual disability. Results: Eighty-six subjects with various types of visual impairment underwent visual acuity and visual field test examinations carried out employing both traditional methods and the new digital visor. The two methods provided homogeneously similar results regarding the positioning of the subjects on the visual disability scale. Conclusions: The new digital visor seems to be a valid method to ensure that visual disability assessments are more homogeneous and reliable, and that, consequently, the resources available for this purpose are more fairly distributed.

Being watched over by a conversation robot may enhance safety in simulated driving

INTRODUCTION

In an aging society that is more and more information-oriented, being able to replace human passengers' protective effects on vehicle drivers with those of social robots is both essential and promising. However, the effects of a social robot's presence on drivers have not yet been fully explored. Thus, using a driving simulator and a conversation robot, this experimental study had two main goals: (a) to find out whether social robots' anthropomorphic qualities (i.e., not the practical information the robot provides drivers) have protective effects by promoting attentive driving and alleviating crash risks; and (b) by what psychological processes such effects emerge.

METHOD

Participants were recruited from young (n = 38), the middle-aged (n = 39), and the elderly (n = 49) age groups. They were assigned to either the treatment group (simulated driving in a conversation robot's presence) or the control group (simulated driving alone), and their driving performance was measured. Mental states (peaceful, concentrating, and reflective) also were assessed in a post-driving questionnaire using our original scales.

RESULTS

Although the group of older participants did not experience protective effects (perhaps due to motion sickness), the young participants drove attentively, with the robot enhancing peace of mind. The protective effect was also observed among the middle-aged participants, and the verbal data analysis ascribed this to the robot's role of expressing sympathy, especially when the middle-aged drivers nearly had not-at-fault crashes, which caused them to be stressed. In conclusion, we discuss the practical implications of the results.

Measuring Disability in Glaucoma

BACKGROUND

Glaucomatous visual field loss can have far-reaching and debilitating consequences on an individual, affecting one's ability to perform many important tasks. Although assessment of glaucoma-related disability constitutes an important part of clinical care, there remains a lack of organized, detailed information on the most suitable methods to capture disability in glaucoma.

PURPOSE

This review details the available methods to measure glaucoma-related disability and highlights important findings from studies utilizing these various methods.

METHODS

The literature was reviewed to identify papers evaluating disability in glaucoma and findings were summarized by research methodology used and area of impairment.

RESULTS

Identified methods for capturing glaucoma-related disability included qualitative descriptions, glaucoma-specific quality of life questionnaires, vision-specific questionnaires, general health questionnaires, functional domain-specific questionnaires, evaluation of task performance, event assessment (ie, falls and motor vehicle accidents), and real-world behavior (ie, daily physical activity). Findings using these methods show a strong relationship between glaucoma and/or glaucoma severity and difficulties with reading, driving, mobility, and other tasks such as prehension and facial recognition. In addition, glaucoma has financial and psychological implications on the patient, and can affect caregivers in some cases as well.

CONCLUSIONS

A wide variety of research tools have been used to characterize the disability resulting from glaucoma. Together, these tools show that glaucoma affects many abilities which are important for independent living. Strengths and limitations of the various research techniques are discussed so that future studies may use the method(s) most suitable for answering the research question posed.

The Impact of Visual Field Loss on Driving Skills: A Systematic Narrative Review

Purpose

To review the evidence on the impact of visual field loss on skills required for driving.

Methods

A literature search was undertaken using a systematic approach. Papers within scope were identified by two independent reviewers, and papers were grouped into similar themes for discussion.

Key findings

Evidence suggests that both binocular and monocular visual field defects have a negative impact on driving skills. Both central and peripheral cause difficulties, but the degree of impact is dependent on the defect severity and compensation ability. Many factors that affect compensation to visual field loss and the effects of visual field loss on driving skills are discussed, including cognitive status, age and duration of visual field loss. In summary, in central visual field loss compensation, strategies include reduction of overall driving speed; whereas, in peripheral field loss, increased scanning is reported to aid adaptation.

Conclusions

For driving, there is evidence that complete and/or binocular visual field loss poses more of a difficulty than partial and/or monocular loss, and central defects cause more problems than peripheral defects. A lack of evidence exists concerning the impact of superior versus inferior defects. The level of peripheral vision loss that is incompatible with safe driving remains unknown, as compensation abilities vary widely between individuals. This review highlights a lack of evidence in relation to the impact of visual field loss on driving skills. Further research is required to strengthen the evidence to allow clinicians to better support people with visual field loss with driving advice.

Doctor, when can I drive? - Range of motion of the knee while driving a car

BACKGROUND

One of the most important activities of daily living is operating a motor vehicle. With increasing age the prevalence of musculoskeletal disorders such as knee osteoarthritis may interfere with an individual's ability to do so safely. Physicians are tasked with determining a patient's ability to drive and yet the necessary joint range of motion required for driving a car has not been characterized.

METHODS

The range of motion of the right and left knees was recorded using electrogoniometers in 20 healthy subjects while driving a car on three route types (a) city streets, b) country roads and c) highways). Special emphasis was placed on the left knee associated with changing a gear.

RESULTS

The range of motion while driving is 40-80° for the right and 20-85° flexion for the left knee. A significant difference was noted for each side (p < 0.01) with a higher flexion occurring in the left knee (p < 0.01). The average position of the knee while changing a gear (beginning, maximum, ending) was: right: 55°±10°, 62°±10°, 53°±10°; left: 67°±7°, 39°±8°, 66°±8° (mean flexion±standard deviation).

CONCLUSION

This study characterized the knee range of motion that occurs while driving a car. Our data suggests that common driving activities such as accelerating a vehicle or braking can be achieved with the right knee through a limited range of motion. The greater range of motion and the higher flexion of the left knee are mainly attributed to the gear changing. The present data may benefit physicians in their evaluation of driving capability.

Performance-based visual field testing for drivers with glaucoma: A pilot study

OBJECTIVE

Conventional visual field (VF) tests are limited in predicting on-road driving performance of individuals with glaucoma. We developed a new performance-based VF test in a driving simulator for individuals with glaucoma. The aim was to evaluate the psychometric properties of the newly developed test.

METHODS

In this pilot study, 17 drivers with glaucoma aged 65.24 ± 9.69 and 13 control drivers aged 61.27 ± 11.45 completed the performance-based VF task. Construct validity was determined by comparing performance on the new task with results on conventional visual and perimetry tests including Humphrey Visual Field Analyzer, Keystone Vision Screener, and Useful Field of View (UFOV). Concurrent validity was evaluated by comparing performance on the new task with on-road driving performance, scored using the Test Ride for Investigating Practical fitness-to-drive (TRIP). Ten individuals (7 with glaucoma and 3 controls) participated in the test-retest reliability assessment.

RESULTS

Drivers with glaucoma identified fewer symbols (P = .047) and took longer to respond to the symbols (P = .048) compared to controls. In the glaucoma group, correct responses on the performance-based VF test correlated strongly (r = -0.51, P = .046) with UFOV divided attention. Both glaucoma and control groups achieved submaximal to maximal scores on the TRIP (median [Q1-Q3], glaucoma: 193 [191-196]; controls: 196 [195-196]; P = .16). No strong correlations were found between scores on the performance-based VF test and on-road driving performance in glaucoma. The intraclass correlation coefficients ranged between 0.77 for response time and 0.92 for correct responses, indicating good to excellent test-retest reliability.

CONCLUSIONS

We established the construct validity and test-retest reliability of the performance-based VF test. Future studies should include a larger sample with more severe driving difficulties to demonstrate the concurrent validity between performance-based VF testing and on-road driving performance in glaucoma.

The effect of concentric constriction of the visual field to 10 and 15 degrees on simulated motor vehicle accidents

Purpose

Traffic accidents are associated with the visual function of drivers, as well as many other factors. Driving simulator systems have the advantage of controlling for traffic- and automobile-related conditions, and using pinhole glasses can control the degree of concentric concentration of the visual field. We evaluated the effect of concentric constriction of the visual field on automobile driving, using driving simulator tests.

Methods

Subjects meeting criteria for normal eyesight were included in the study. Pinhole glasses with variable aperture sizes were adjusted to mimic the conditions of concentric visual field constrictions of 10° and 15°, using a CLOCK CHART^®. The test contained 8 scenarios (2 oncoming right-turning cars and 6 jump-out events from the side).

Results

Eighty-eight subjects were included in the study; 37 (mean age = 52.9±15.8 years) subjects were assigned to the 15° group, and 51 (mean = 48.6±15.5 years) were assigned to the 10° group. For all 8 scenarios, the number of accidents was significantly higher among pinhole wearing subjects. The average number of all types of accidents per person was significantly higher in the pinhole 10° group (4.59±1.81) than the pinhole 15° group (3.68±1.49) (P = 0.032). The number of accidents associated with jump-out scenarios, in which a vehicle approaches from the side on a straight road with a good view, was significantly higher in the pinhole 10° group than in the pinhole 15° group.

Conclusions

Concentric constriction of the visual field was associated with increased number of traffic accidents. The simulation findings indicated that a visual field of 10° to 15° may be important for avoiding collisions in places where there is a straight road with a good view.

Glaucoma and quality of life: fall and driving risk

PURPOSE OF REVIEW

Numerous population-based studies suggest that glaucoma is an independent risk factor for falling and motor vehicle collisions, particularly for older adults. These adverse events lead to increased healthcare expenditures and decreased quality of life. Current research priorities, therefore, include identifying factors that predispose glaucoma patients to falling and unsafe driving, and developing screening strategies and targeted rehabilitation. The purpose of this article is to review recent studies that address these priorities.

RECENT FINDINGS

Studies continue to support that glaucoma patients, particularly those with advanced disease, have an increased risk of falling or unsafe driving. Risk factors, however, remain variable and include severity and location of visual field defects, contrast sensitivity, and performance on divided attention tasks. Such variability is likely because of the multifactorial nature of ambulating and driving and compensatory strategies used by patients.

SUMMARY

Falls and unsafe driving remain a serious public health issue for older adults with glaucoma. Ambulation and driving are complex tasks and there is no consensus yet, regarding the best methods for risk stratification and targeted interventions to increase safety. Therefore, comprehensive and individualized assessments are recommended to most effectively evaluate a patient's risk for falling or unsafe driving.

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma.

Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1), dynamic visual field condition (C2), and dynamic visual field condition with active driving (C3) using an interactive, desktop driving simulator. The number of correct responses (accuracy) and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions.

Results: Adding cognitive demand (C2 and C3) to the static visual field test (C1) adversely affected accuracy and response times, in both groups (p < 0.05). However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3) 3 (2–6.50) vs. controls: 2 (0.50–2.50); p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6) vs. controls: 1 (0.50–2); p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02).

Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Predicting Future Self-Reported Motor Vehicle Collisions in Subjects with Primary Open-Angle Glaucoma Using the Penalized Support Vector Machine Method

PURPOSE

We predict the likelihood of a future motor vehicle collision (MVC) from visual function data, attitudes to driving, and past MVC history using the penalized support vector machine (pSVM) in subjects with primary open-angle glaucoma (POAG).

METHODS

Patients with POAG were screened prospectively for eligibility and 185 were analyzed in this study. Self-reported MVCs of all participants were recorded for 3 years from the baseline using a survey questionnaire every 12 months. A binocular integrated visual field (IVF) was calculated for each patient by merging a patient's monocular Humphrey Field Analyzer (HFA) visual fields (VFs). The IVF was divided into six regions, based on eccentricity and the right or left hemifield, and the average of the total deviation (TD) values in each of these six areas was calculated. Then, the future MVCs were predicted using various variables, including age, sex, 63 variables of 52 TD values, mean of the TD values, visual acuities (VAs), six sector average TDs with (pred_{penSVM_all}) and without (pred_{penSVM_basic}) the attitudes in driving, and also past MVC history, using the pSVM method, applying the leave-one-out cross validation.

RESULTS

The relationship between pred_{penSVM_basic} and the future MVC approached significance (odds ratio = 1.15, [0.99-1.29], P = 0.064, logistic regression). A significant relationship was observed between pred_{penSVM_all} and the future MVC (odds ratio = 1.21, P = 0.0015).

CONCLUSIONS

It was useful to predict future MVCs in patients with POAG using visual function metrics, patients' attitudes to driving, and past MVC history, using the pSVM.

TRANSLATIONAL RELEVANCE

Careful consideration is needed when predicting future MVCs in POAG patients using visual function, and without driving attitude and MVC history.

Effect of glaucoma on eye movement patterns and laboratory-based hazard detection ability

Purpose

The mechanisms underlying the elevated crash rates of older drivers with glaucoma are poorly understood. A key driving skill is timely detection of hazards; however, the hazard detection ability of drivers with glaucoma has been largely unexplored. This study assessed the eye movement patterns and visual predictors of performance on a laboratory-based hazard detection task in older drivers with glaucoma.

Methods

Participants included 30 older drivers with glaucoma (71±7 years; average better-eye mean deviation (MD) = −3.1±3.2 dB; average worse-eye MD = −11.9±6.2 dB) and 25 age-matched controls (72±7 years). Visual acuity, contrast sensitivity, visual fields, useful field of view (UFoV; processing speeds), and motion sensitivity were assessed. Participants completed a computerised Hazard Perception Test (HPT) while their eye movements were recorded using a desk-mounted Tobii TX300 eye-tracking system. The HPT comprises a series of real-world traffic videos recorded from the driver’s perspective; participants responded to road hazards appearing in the videos, and hazard response times were determined.

Results

Participants with glaucoma exhibited an average of 0.42 seconds delay in hazard response time (p = 0.001), smaller saccades (p = 0.010), and delayed first fixation on hazards (p<0.001) compared to controls. Importantly, larger saccades were associated with faster hazard responses in the glaucoma group (p = 0.004), but not in the control group (p = 0.19). Across both groups, significant visual predictors of hazard response times included motion sensitivity, UFoV, and worse-eye MD (p<0.05).

Conclusions

Older drivers with glaucoma had delayed hazard response times compared to controls, with associated changes in eye movement patterns. The association between larger saccades and faster hazard response time in the glaucoma group may represent a compensatory behaviour to facilitate improved performance.

Eye-Tracking as a Tool to Evaluate Functional Ability in Everyday Tasks in Glaucoma

To date, few studies have investigated the eye movement patterns of individuals with glaucoma while they undertake everyday tasks in real-world settings. While some of these studies have reported possible compensatory gaze patterns in those with glaucoma who demonstrated good task performance despite their visual field loss, little is known about the complex interaction between field loss and visual scanning strategies and the impact on task performance and, consequently, on quality of life. We review existing approaches that have quantified the effect of glaucomatous visual field defects on the ability to undertake everyday activities through the use of eye movement analysis. Furthermore, we discuss current developments in eye-tracking technology and the potential for combining eye-tracking with virtual reality and advanced analytical approaches. Recent technological developments suggest that systems based on eye-tracking have the potential to assist individuals with glaucomatous loss to maintain or even improve their performance on everyday tasks and hence enhance their long-term quality of life. We discuss novel approaches for studying the visual search behavior of individuals with glaucoma that have the potential to assist individuals with glaucoma, through the use of personalized programs that take into consideration the individual characteristics of their remaining visual field and visual search behavior.

The role of specific visual subfields in collisions with oncoming cars during simulated driving in patients with advanced glaucoma

BACKGROUND/AIMS

To assess the role of specific visual subfields in collisions with oncoming cars during simulated driving in patients with advanced glaucoma.

METHODS

Normal subjects and patients with glaucoma with mean deviation <-12 dB in both eyes (Humphrey Field Analyzer 24-2 SITA-S program) used a driving simulator (DS; Honda Motor, Tokyo). Two scenarios in which oncoming cars turned right crossing the driver's path were chosen. We compared the binocular integrated visual field (IVF) in the patients who were involved in collisions and those who were not. We performed a multivariate logistic regression analysis; the dependent parameter was collision involvement, and the independent parameters were age, visual acuity and mean sensitivity of the IVF subfields.

RESULTS

The study included 43 normal subjects and 100 patients with advanced glaucoma. And, 5 of the 100 patients with advanced glaucoma experienced simulator sickness during the main test and were thus excluded. In total, 95 patients with advanced glaucoma and 43 normal subjects completed the main test of DS. Advanced glaucoma patients had significantly more collisions than normal patients in one or both DS scenarios (p<0.001). The patients with advanced glaucoma who were involved in collisions were older (p=0.050) and had worse visual acuity in the better eye (p<0.001) and had lower mean IVF sensitivity in the inferior hemifield, both 0°-12° and 13°-24° in comparison with who were not involved in collisions (p=0.012 and p=0.034). A logistic regression analysis revealed that collision involvement was significantly associated with decreased inferior IVF mean sensitivity from 13° to 24° (p=0.041), in addition to older age and lower visual acuity (p=0.018 and p<0.001).

CONCLUSIONS

Our data suggest that the inferior hemifield was associated with the incidence of motor vehicle collisions with oncoming cars in patients with advanced glaucoma.

Medical review licensing outcomes in drivers with visual field loss in Victoria, Australia

BACKGROUND

Good vision is essential for safe driving and studies have associated visual impairment with an increased crash risk. Currently, there is little information about the medical review of drivers with visual field loss. This study examines the prevalence of visual field loss among drivers referred for medical review in one Australian jurisdiction and investigates factors associated with licence outcome in this group.

METHODS

A random sample of 10,000 (31.25 per cent) medical review cases was extracted for analysis from the Victorian licensing authority. Files were screened for the presence of six visual field-related medical conditions. Data were captured on a range of variables, including referral source, age, gender, health status, crash history and licence outcome. Prevalence analyses were univariate and descriptive. Logistic regression was used to assess factors associated with licence outcomes in the visual field loss group.

RESULTS

Approximately 1.9 per cent of the 10,000 medical review cases screened had a visual field loss condition identified (n = 194). Among the visual field loss group, 57.2 per cent were permitted to continue driving (conditional/unconditional licence). Primary referral sources were the police, self-referrals and general medical practitioners. Key factors associated with licence test outcomes were visual field condition, age group, crash involvement and referral to the Driver Licensing Authority's Medical Advisors. Those who were younger had a crash involvement triggering referral and those who were referred to the Medical Advisors were more likely to have a positive licensing outcome.

CONCLUSION

The evidence base for making licensing decisions is complicated by the variable causes, patterns, progressions and measuring technologies for visual field loss. This study highlighted that the involvement of an expert medical advisory service in Victoria resulted in an increased likelihood that drivers with visual field loss will be allowed to continue driving. Further research is warranted to explore issues relating to severity of field loss and the capacity for compensation.

Glaucoma and Driving: On-Road Driving Characteristics

Purpose

To comprehensively investigate the types of driving errors and locations that are most problematic for older drivers with glaucoma compared to those without glaucoma using a standardized on-road assessment.

Methods

Participants included 75 drivers with glaucoma (mean = 73.2±6.0 years) with mild to moderate field loss (better-eye MD = -1.21 dB; worse-eye MD = -7.75 dB) and 70 age-matched controls without glaucoma (mean = 72.6 ± 5.0 years). On-road driving performance was assessed in a dual-brake vehicle by an occupational therapist using a standardized scoring system which assessed the types of driving errors and the locations where they were made and the number of critical errors that required an instructor intervention. Driving safety was rated on a 10-point scale. Self-reported driving ability and difficulties were recorded using the Driving Habits Questionnaire.

Results

Drivers with glaucoma were rated as significantly less safe, made more driving errors, and had almost double the rate of critical errors than those without glaucoma. Driving errors involved lane positioning and planning/approach, and were significantly more likely to occur at traffic lights and yield/give-way intersections. There were few between group differences in self-reported driving ability.

Conclusions

Older drivers with glaucoma with even mild to moderate field loss exhibit impairments in driving ability, particularly during complex driving situations that involve tactical problems with lane-position, planning ahead and observation. These results, together with the fact that these drivers self-report their driving to be relatively good, reinforce the need for evidence-based on-road assessments for evaluating driving fitness.

Ocular disease and driving

As the driving population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age-related prevalence of ocular disease. The increase in visual impairment in the driving population has a number of implications for driving outcomes. This review summarises current research regarding the impact of common ocular diseases on driving ability and safety, with particular focus on cataract, glaucoma, age-related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self-reported driving outcomes, driving performance (on-road and simulator-based) and various motor vehicle crash indices. Collectively, this review demonstrates that driving ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum driving safety and quality of life benefits.

A view on glaucoma--are we seeing it clearly?

Successful clinical management of glaucoma should not simply be about control of intraocular pressure, but must equate to correct decisions about intensifying treatment when patients are at risk of developing 'visual disability'. Yet little is known about what visual field defects, at different stages of glaucoma, specifically affect patients' abilities to perform everyday visual tasks. One way to do this is to measure patient performance in tasks in a lab setting. Another way is to ask patients themselves. The latter can be revealing and demystify views about how patients perceive the world. This short commentary highlights some of the current research in this area.

Predicting Risk of Motor Vehicle Collisions in Patients with Glaucoma: A Longitudinal Study

Purpose

To evaluate the ability of longitudinal Useful Field of View (UFOV) and simulated driving measurements to predict future occurrence of motor vehicle collision (MVC) in drivers with glaucoma.

Design

Prospective observational cohort study.

Participants

117 drivers with glaucoma followed for an average of 2.1 ± 0.5 years.

Methods

All subjects had standard automated perimetry (SAP), UFOV, driving simulator, and cognitive assessment obtained at baseline and every 6 months during follow-up. The driving simulator evaluated reaction times to high and low contrast peripheral divided attention stimuli presented while negotiating a winding country road, with central driving task performance assessed as “curve coherence”. Drivers with MVC during follow-up were identified from Department of Motor Vehicle records.

Main Outcome Measures

Survival models were used to evaluate the ability of driving simulator and UFOV to predict MVC over time, adjusting for potential confounding factors.

Results

Mean age at baseline was 64.5 ± 12.6 years. 11 of 117 (9.4%) drivers had a MVC during follow-up. In the multivariable models, low contrast reaction time was significantly predictive of MVC, with a hazard ratio (HR) of 2.19 per 1 SD slower reaction time (95% CI, 1.30 to 3.69; P = 0.003). UFOV divided attention was also significantly predictive of MVC with a HR of 1.98 per 1 SD worse (95% CI, 1.10 to 3.57; P = 0.022). Global SAP visual field indices in the better or worse eye were not predictive of MVC. The longitudinal model including driving simulator performance was a better predictor of MVC compared to UFOV (R² = 0.41 vs R² = 0.18).

Conclusions

Longitudinal divided attention metrics on the UFOV test and during simulated driving were significantly predictive of risk of MVC in glaucoma patients. These findings may help improve the understanding of factors associated with driving impairment related to glaucoma.