Prevalence, associated risk factors; and patient and economic impact of multiple sensory impairment in a multi-ethnic elderly population in Singapore: the PIONEER study

BACKGROUND

To determine the prevalence, risk factors; and impact on patient health and economic outcomes across the laterality spectrum of multiple sensory impairment (MSI) in a multi-ethnic older Asian population.

METHODS

In this population-based study of Singaporeans aged ≥ 60 years, MSI was defined as concomitant vision (visual acuity > 0.3 logMAR), hearing (pure-tone air conduction average > 25 dB), and olfactory (score < 12 on the Sniffin' Sticks test) impairments across the spectrum of laterality (any, unilateral, combination [of unilateral and bilateral], and bilateral).

RESULTS

Among 2,057 participants (mean ± SD 72.2 ± 0.2 years; 53.1% female), the national census-adjusted prevalence rates of any, unilateral, combination, and bilateral MSI were 20.6%, 1.2%, 12.2%, and 7.2%, respectively. Older age, male gender, low socioeconomic status (SES), and smoking (all p < 0.05) were independently associated with higher likelihood of any MSI. Compared to those with no sensory loss, those with MSI had significantly decreased mobility (range 5.4%-9.2%), had poor functioning (OR range 3.25-3.45) and increased healthcare costs (range 4-6 folds) across the laterality spectrum. Additionally, bilateral MSI had a significant decrease in HRQoL (5.5%, p = 0.012).

CONCLUSIONS

MSI is a highly prevalent medical condition, with 1 in 5; and almost 1 in 10 community-dwelling older Asians having any and bilateral MSI, respectively, with a higher likelihood in men, smokers, and those with low SES. Critically, MSI has a substantial negative impact on patient health and economic outcomes across the laterality spectrum. Sensory testing is critical to detect and refer individuals with MSI for management to improve their functional independence and QoL.

Optical Coherence Tomography-Derived Measurements of the Optic Nerve Head Structure of Aboriginal and Torres Strait Islander Children

PRCIS

This study demonstrated significant differences in optic nerve head characteristics in Aboriginal and Torres Strait Islander children compared with non-Indigenous children, which has implications for glaucoma risk and diagnosis in Aboriginal and Torres Strait Islander populations.

PURPOSE

The purpose of this study was to examine the optic nerve head (ONH) characteristics of visually normal Aboriginal and Torres Strait Islander children and non-Indigenous Australian children.

MATERIALS AND METHODS

Spectral domain optical coherence tomography imaging was performed on the right eye of 95 Aboriginal and Torres Strait Islander children and 149 non-Indigenous Australian children (5-18 years). Horizontal and vertical line scans, centered on the ONH, were analyzed to determine the dimensions of the ONH (Bruch membrane opening diameter), optic cup diameter, Bruch membrane opening minimum rim width, and the peripapillary retinal nerve fiber layer thickness.

RESULTS

The vertical but not horizontal Bruch membrane opening diameter of Aboriginal and Torres Strait Islander children was significantly larger than non-Indigenous children (mean difference: 0.09 mm, P = 0.001). The horizontal (mean difference: 0.12 mm, P = 0.003) and vertical cup diameter (mean difference: 0.16 mm, P < 0.001) were also significantly larger in Aboriginal and Torres Strait Islander children, as were the horizontal and vertical cup-to-disc ratios (both P < 0.01). Aboriginal and Torres Strait Islander children also had a significantly thinner Bruch membrane opening minimum rim width in the superior, nasal, and temporal meridians (all P < 0.001). Peripapillary retinal nerve fiber layer thickness did not differ between groups.

CONCLUSIONS

Differences exist in the ONH structure between Aboriginal and Torres Strait Islander children and non-Indigenous children, which may have implications for the detection and monitoring of ocular disease in this population and highlights the need to extend this research to the adult population.

Hyperopia in schoolchildren: Investigating the impact on vision and determining appropriate methods for screening

INTRODUCTION

Hyperopia is associated with reduced vision and educational outcomes in schoolchildren. This study explored the impact of clinically significant hyperopia (≥+2.00 D) on visual function in schoolchildren and compared the ability of different screening tests (alone and in combination) to detect this level of hyperopia.

METHODS

Vision testing including monocular logMAR visual acuity (VA) measured to threshold (distance [DVA], near [NVA] and DVA through a plus lens [+2.50 D]), stereoacuity and cycloplegic autorefraction (tropicamide 1%) were undertaken on 263 schoolchildren (mean age: 11.76 years ± 3.38) in Queensland, Australia. Vision measures were compared between children with clinically significant hyperopia in at least one meridian (≥+2.00 D) and emmetropia/low hyperopia (>0.00 and <+2.00 D). Receiver operating curve (ROC) analysis was performed to identify optimal pass/fail criteria for each test and the diagnostic accuracy of individual and combinations of tests.

RESULTS

Thirty-two children had clinically significant hyperopia and 225 had emmetropia/low hyperopia. DVA and NVA were worse (p < 0.01), while the difference in DVA through a plus lens was less in children with clinically significant hyperopia (p < 0.01). ROC analysis for individual tests resulted in areas under the curve (AUCs) ranging from 0.65 to 0.85. Combining screening tests revealed that failing one or more of the following tests was most effective for detecting hyperopia: DVA, NVA and difference in DVA through a plus lens, resulting in a sensitivity and specificity of 72% and 81%, respectively.

CONCLUSION

Significant differences in visual function existed between schoolchildren with clinically significant hyperopia and emmetropia/low hyperopia. Combining measures of DVA and NVA and the difference in DVA through a plus lens demonstrated good discriminative ability for detecting clinically significant hyperopia in this population.

Effect of low luminance on face recognition in adults with central and peripheral vision loss

PURPOSE

To investigate the effect of low luminance on face recognition, specifically facial identity discrimination (FID) and facial expression recognition (FER), in adults with central vision loss (CVL) and peripheral vision loss (PVL) and to explore the association between clinical vision measures and low luminance FID and FER.

METHODS

Participants included 33 adults with CVL, 17 with PVL and 20 controls. FID and FER were assessed under photopic and low luminance conditions. For the FID task, 12 sets of three faces with neutral expressions were presented and participants asked to indicate the odd-face-out. For FER, 12 single faces were presented and participants asked to name the expression (neutral, happy or angry). Photopic and low luminance visual acuity (VA) and contrast sensitivity (CS) were recorded for all participants and for the PVL group, Humphrey Field Analyzer (HFA) 24-2 mean deviation (MD).

RESULTS

FID accuracy in CVL, and to a lesser extent PVL, was reduced under low compared with photopic luminance (mean reduction 20% and 8% respectively; p < 0.001). FER accuracy was reduced only in CVL (mean reduction 25%; p < 0.001). For both CVL and PVL, low luminance and photopic VA and CS were moderately to strongly correlated with low luminance FID (ρ = 0.61-0.77, p < 0.05). For PVL, better eye HFA 24-2 MD was moderately correlated with low luminance FID (ρ = 0.54, p = 0.02). Results were similar for low luminance FER. Together, photopic VA and CS explained 75% of the variance in low luminance FID, and photopic VA explained 61% of the variance in low luminance FER. Low luminance vision measures explained little additional variance.

CONCLUSION

Low luminance significantly reduced face recognition, particularly for adults with CVL. Worse VA and CS were associated with reduced face recognition. Clinically, photopic VA is a good predictor of face recognition under low luminance conditions.

The use of driver screening tools to predict self-reported crashes and incidents in older drivers

There is a clear need to identify older drivers at increased crash risk, without additional burden on the individual or licensing system. Brief off-road screening tools have been used to identify unsafe drivers and drivers at risk of losing their license. The aim of the current study was to evaluate and compare driver screening tools in predicting prospective self-reported crashes and incidents over 24 months in drivers aged 60 years and older. 525 drivers aged 63-96 years participated in the prospective Driving Aging Safety and Health (DASH) study, completing an on-road driving assessment and seven off-road screening tools (Multi-D battery, Useful Field of View, 14-Item Road Law, Drive Safe, Drive Safe Intersection, Maze Test, Hazard Perception Test (HPT)), along with monthly self-report diaries on crashes and incidents over a 24-month period. Over the 24 months, 22% of older drivers reported at least one crash, while 42% reported at least one significant incident (e.g., near miss). As expected, passing the on-road driving assessment was associated with a 55% [IRR 0.45, 95% CI 0.29-0.71] reduction in self-reported crashes adjusting for exposure (crash rate), but was not associated with reduced rate of a significant incident. For the off-road screening tools, poorer performance on the Multi-D test battery was associated with a 22% [IRR 1.22, 95% CI 1.08-1.37] increase in crash rate over 24 months. Meanwhile, all other off-road screening tools were not predictive of rates of crashes or incidents reported prospectively. The finding that only the Multi-D battery was predictive of increased crash rate, highlights the importance of accounting for age-related changes in vision, sensorimotor skills and cognition, as well as driving exposure, in older drivers when using off-road screening tools to assess future crash risk.

The relationship between central and mid-peripheral motion perception and the hazard perception test in younger and older adults

INTRODUCTION

Vision standards for driving are typically based on visual acuity, despite evidence that it is a poor predictor of driving safety and performance. However, visual motion perception is potentially relevant for driving, as the vehicle and surroundings are in motion. This study explored whether tests of central and mid-peripheral motion perception better predict performance on a hazard perception test (HPT), which is related to driving performance and crash risk, than visual acuity. Additionally, we explored whether age influences these associations, as healthy ageing impairs performance on some motion sensitivity tests.

METHODS

Sixty-five visually healthy drivers (35 younger, mean age: 25.5; SD 4.3 years; 30 older adults, mean age: 71.0; SD 5.4 years) underwent a computer-based HPT, plus four different motion sensitivity tests both centrally and at 15° eccentricity. Motion tests included minimum displacement to identify motion direction (Dmin ), contrast detection threshold for a drifting Gabor (motion contrast), coherence threshold for a translational global motion stimulus and direction discrimination for a biological motion stimulus in the presence of noise.

RESULTS

Overall, HPT reaction times were not significantly different between age groups (p = 0.40) nor were maximum HPT reaction times (p = 0.34). HPT response time was associated with motion contrast and Dmin centrally (r = 0.30, p = 0.02 and r = 0.28, p = 0.02, respectively) and with Dmin peripherally (r = 0.34, p = 0.005); these associations were not affected by age group. There was no significant association between binocular visual acuity and HPT response times (r = 0.02, p = 0.29).

CONCLUSIONS

Some measures of motion sensitivity in central and mid-peripheral vision were associated with HPT response times, whereas binocular visual acuity was not. Peripheral testing did not show an advantage over central testing for visually healthy older drivers. Our findings add to the growing body of evidence that the ability to detect small motion changes may have potential to identify unsafe road users.

Ocular biometry measures and their correlation with refractive error in Aboriginal and Torres Strait Islander children

CLINICAL RELEVANCE

The ocular biometry measures of the eye determine the refractive status, and while most refractive error develops during childhood, the ocular biometry measures of Aboriginal and Torres Strait Islander children have not previously been reported.

BACKGROUND

To investigate the ocular biometry of Aboriginal and Torres Strait Islander children, including measures important in determining refractive error and those which relate to the risk of ocular disease.

METHODS

Participants included 252 primary and secondary school children (Aboriginal and Torres Strait Islander: 101; non-Indigenous: 151), aged between 4 and 18 years. Habitual monocular distance visual acuity, cycloplegic autorefraction, and ocular optical biometry were measured in all participants and intraocular pressure measured in secondary school children using rebound tonometry.

RESULTS

The mean (±SD) spherical equivalent refractive error of Aboriginal and Torres Strait Islander children was significantly less hyperopic than non-Indigenous children (Aboriginal and Torres Strait Islander: +0.52 ± 0.80 D; non-Indigenous: +0.86 D ±0.58 D; p < 0.001). There were no differences in axial length or axial length/corneal radius ratio between the two groups, however the mean lens power of Aboriginal and Torres Strait Islander children was significantly greater than that of non-Indigenous children (Aboriginal and Torres Strait Islander: 23.62 D; non-Indigenous: 22.51 D; p < 0.001). Aboriginal and Torres Strait Islander children had a thinner central corneal thickness (Aboriginal and Torres Strait Islander: 534 ± 37 µm; non-Indigenous: 543 ± 35 µm; p = 0.04), and lower intraocular pressure compared with non-Indigenous children (Aboriginal and Torres Strait Islander: 14.7 ± 3.8 mmHg; non-Indigenous: 16.0 ± 3.7; p = 0.02).

CONCLUSION

Differences exist in the refractive error, lens power, central corneal thickness, and intraocular pressure of Aboriginal and Torres Strait Islander children compared to non-Indigenous Australian children which have potential implications for the development of refractive error and ocular disease later in life.

Prevalence of vision conditions in children in a very remote Australian community

CLINICAL RELEVANCE

Understanding the prevalence of vision conditions in a population is critical for determining the most appropriate strategies for detecting and correcting eye conditions in a community. This is particularly important in very remote regions where access to vision testing services is limited.

BACKGROUND

Although recent studies have provided detailed analyses of the prevalence of vision conditions in Aboriginal and/or Torres Strait Islander children in urban and regional areas of Australia, there is a paucity of research examining vision conditions in children in remote regions. Importantly, a significant proportion of the population in remote and very remote regions identify as Aboriginal and/or Torres Strait Islander people.

METHODS

Comprehensive eye examinations were provided to 193 primary school children in a very remote Australian region. Ninety eight percent of children identified as Aboriginal and/or Torres Strait Islander. The eye examination included measures of visual acuity, cycloplegic autorefraction, binocular vision and accommodative function, ocular health and colour vision. Previous history of eye examinations and refractive correction were assessed through parental questionnaire.

RESULTS

Although the average unaided vision in the population was good (mean: 0.02 ± 0.13 logMAR) and the prevalence of reduced unaided visual acuity (>0.3 logMAR in either eye) was low (4%), vision conditions were detected in 32% of children. The most common conditions were clinically significant refractive errors (18% of children) and binocular vision or accommodative disorders (16%). Of the total population of children tested, 10% had previously had an eye examination, and 2% were reported to have previously been prescribed spectacles.

CONCLUSIONS

In this population of children in a very remote Australian region, up to 1 in 3 children had a vision condition, with many of these conditions being uncorrected and undetected. These findings highlight the important need for additional resources to be made available to very remote communities for the detection and correction of vision conditions in childhood.

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.

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.

Concept Mapping to Identify Content for a Performance-Based Measure of Low Luminance Vision-Related Activities of Daily Living

Purpose

The purpose of this study was to identify low luminance activities of daily living (ADL) relevant to adults with vision impairment using a concept-mapping approach.

Methods

“Group concept mapping” was utilized to identify specific ADLs that persons with vision impairment find challenging under low light conditions. In the first “brainstorming” phase, 24 adults with vision impairment from a range of eye conditions (mean age = 73 years, SD = 14 years) and 26 international low vision experts (mean experience = 22, SD = 11 years) generated statements to the focus prompt, “Thinking as broadly as possible, generate a list of statements detailing specific day-to-day activities a person with vision impairment might find challenging under low light conditions, such as in a poorly lit room or outside at dusk.” In the second phase, participants sorted activities by similarity and rated the importance of each activity. Multidimensional scaling and hierarchical cluster analysis were applied to produce concept maps showing clusters of prioritized activities.

Results

One hundred thirteen unique ideas/activities were generated, rated and sorted. Eight clusters were identified (from highest to lowest importance): hazard detection and safety outside; social interactions; navigation; near reading; selfcare and safety at home; distance spotting; searching around the home; and cooking and cleaning.

Conclusions

The conceptual framework and low luminance ADLs identified (the most important being hazard detection and safety outside, and social interactions) provide a basis for developing a performance-based measure of low luminance visual function.

Translational Relevance

A performance-based measure of low luminance vision-related ADLs is required for comprehensively and objectively assessing efficacy of eye treatments and low vision rehabilitation outcomes in adults with vision impairment.

The Effects of Glare on the Perception of Visual Motion as a Function of Age

Purpose

The purpose of this study was to determine the impact of glare, that simulated the effects of oncoming vehicle headlights, and age on different aspects of motion perception in central and peripheral vision.

Methods

Twenty younger (mean age = 25 years, range = 20-32 years) and 20 older (mean age = 70 years, range = 60-79 years) visually healthy adults completed four visual motion tasks. Stimuli were presented centrally and at 15 degrees horizontal eccentricity for 2 viewing conditions: glare (continuous, off-axis) versus no glare. Motion tasks included minimum Gabor contrast required to discriminate direction of motion, translational global motion coherence, minimum duration of a Gabor to determine direction of motion (2 different size Gabors to determine spatial surround suppression), and biological motion detection in noise. Intraocular straylight was also measured (C-Quant).

Results

Older adults had increased intraocular straylight compared with younger adults (P < 0.001). There was no significant effect of glare on motion thresholds in either group for motion contrast (P = 0.47), translational global motion (P = 0.13), biological motion (P = 0.18), or spatial surround suppression of motion (P = 0.29). Older adults had elevated thresholds for motion contrast (P < 0.001), biological motion (P < 0.001), and differences in surround suppression of motion (P = 0.04), relative to the younger group, for both the glare and no-glare conditions.

Conclusions

Although older adults had elevated thresholds for some motion perception tasks, glare from a continuous off-axis light source did not further elevate these thresholds either in central or peripheral vision.

Translational Relevance

A glare source that simulated the effect of oncoming headlights, did not impact motion perception measures relevant to driving.

Retinal thickness in healthy Australian Aboriginal and Torres Strait Islander children

Background

Understanding normative retinal thickness characteristics is critical for diagnosis and monitoring of pathology, particularly in those predisposed to retinal disease. The macular retinal layer thickness of Australian Aboriginal and/or Torres Strait Islander children was examined using spectral-domain optical coherence tomography.

Methods

High-resolution macular optical coherence tomography imaging was performed on 100 Aboriginal and/or Torres Strait Islander children and 150 non-Indigenous visually healthy children aged 4–18 years. The imaging protocol included a 6-line radial scan centred on the fovea. Images were segmented using semi-automated software to derive thickness of the total retina, inner and outer retina, and individual retinal layers across the macular region. Repeated measures ANOVAs examined variations in thickness associated with retinal region, age, gender and Indigenous status.

Results

Retinal thickness showed significant topographical variations (p < 0.01), being thinnest in the foveal zone, and thickest in the parafovea. The retina of Aboriginal and/or Torres Strait Islander children was significantly thinner than non-Indigenous children in the foveal (p < 0.001), parafoveal (p = 0.002), and perifoveal zones (p = 0.01), with the greatest difference in the foveal zone (mean difference: 14.2 μm). Inner retinal thickness was also thinner in Aboriginal and/or Torres Strait Islander children compared to non-Indigenous children in the parafoveal zone (p < 0.001), and outer retinal thickness was thinner in the foveal (p < 0.001) and perifoveal zone (p < 0.001). Retinal thickness was also significantly greater in males than females (p < 0.001) and showed a statistically significant positive association with age (p = 0.01).

Conclusion

There are significant differences in macular retinal thickness between Aboriginal and/or Torres Strait Islander children and non-Indigenous children, which has implications for interpreting optical coherence tomography data and may relate to risk of macula disease in this population.

Visual Predictors of Postural Sway in Older Adults

Purpose

Accurate perception of body position relative to the environment through visual cues provides sensory input to the control of postural stability. This study explored which vision measures are most important for control of postural sway in older adults with a range of visual characteristics.

Methods

Participants included 421 older adults (mean age = 72.6 ± 6.1), 220 with vision impairment associated with a range of eye diseases and 201 with normal vision. Participants completed a series of vision, cognitive, and physical function tests. Postural sway was measured using an electronic forceplate (HUR Labs) on a foam surface with eyes open. Linear regression analysis identified the strongest visual predictors of postural sway, controlling for potential confounding factors, including cognitive and physical function.

Results

In univariate regression models, unadjusted and adjusted for age, all of the vision tests were significantly associated with postural sway (P < 0.05), with the strongest predictor being visual motion sensitivity (standardized regression coefficient, β = 0.340; age-adjusted β = 0.253). In multiple regression models, motion sensitivity (β = 0.187), integrated binocular visual fields (β = -0.109), and age (β = 0.234) were the only significant visual predictors of sway, adjusted for confounding factors, explaining 23% of the variance in postural sway.

Conclusions

Of the vision tests, visual motion perception and binocular visual fields were most strongly associated with postural stability in older adults with and without vision impairment.

Translational Relevance

Findings provide insight into the visual contributions to postural stability in older adults and have implications for falls risk assessment.

Low levels of refractive blur increase the risk of colour misperception of red train signals

Purpose

Red signals signify danger in a range of situations, including train operations. Importantly, misperception of a red signal as yellow can have serious safety implications. This study investigated the effects of lens blur on incorrect colour perception of red signals, which has been implicated in previous train crashes.

Methods

Participants included 15 young (26.6 ± 4.6 years) and 15 older (55.8 ± 3.1 years) visually normal adults. Red and yellow wayside train signals were simulated for two brightness levels (dim, bright) using a custom‐built projection system. The effect of blur (best‐corrected refraction [No Blur], +0.25 DS, +0.50 DS, +0.75 DS, +1.00 DS, +1.25 DS) on the number of incorrect colour perception responses of the signals was recorded. The order of conditions was randomised between participants.

Results

For incorrect responses to the red signal, there were significant main effects of blur (p < 0.001) and signal brightness (p < 0.001) and a significant interaction between blur and brightness (p < 0.001). The effects of blur were greater for the dim compared to the bright signals, with significantly higher colour misperceptions for the dim signal for +0.50 DS blur and higher, compared with No Blur. Colour misperceptions of the yellow signals were low compared with that of the red signals, with only +1.25 DS blur resulting in a significantly higher number of incorrect responses than No Blur (p < 0.001). There were no effects of age for the red or yellow colour misperceptions (p > 0.19).

Conclusions

Low levels of blur (+0.50 DS to +1.25 DS) resulted in a significant misperception of the red signals as orange‐yellow, particularly for dim signals. The findings have implications for vision testing and refractive correction of train drivers to minimise the possibility of colour misperception of red train signals.

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.

Low Light Exposure and Physical Activity in Older Adults With and Without Age-Related Macular Degeneration

Purpose

To investigate the extent of low light exposure and associated physical activity in older adults with and without age-related macular degeneration (AMD).

Methods

Light exposure (lux) and physical activity (counts per minute, CPM) were measured in 28 older adults (14 bilateral AMD and 14 normally sighted controls) using a wrist-worn actigraphy device (Actiwatch) for 7 days and nights. Exposure to low light levels (≤10 lux) and physical activity during waking hours were determined, as well as number of brief active periods during sleeping hours (e.g., going to the bathroom). Assessments included visual acuity and the Low Luminance Questionnaire (LLQ).

Results

No significant differences were found in low light exposure (39 ± 14% vs. 34 ± 10%) or physical activity (200 ± 82 CPM vs. 226 ± 55 CPM) during waking hours between the AMD and control group. However, the AMD group had more brief active periods during sleeping hours than controls (1.8 ± 1.3 vs. 1.1 ± 0.4; P = 0.007). Reduced physical activity under low light levels was significantly associated with lower LLQ scores (P = 0.012).

Conclusions

Exposure to low light levels and associated physical activity were similar in older adults with and without AMD. This has important implications for older adults with AMD, given the impact of low light levels on visual function and mobility, suggesting the need for including lighting advice in rehabilitation programs for this population.

Translational Relevance

Older adults with and without AMD spend over a third of waking hours under low light levels, which are an environmental falls hazard. Findings suggest the need for interventions to improve lighting levels for older adults.

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.

Longitudinal Impact of Vision Impairment on Concern About Falling in People With Age-Related Macular Degeneration

Purpose

To explore the longitudinal impact of central vision loss on concern about falling (CF), over a 12-month period, in people with age-related macular degeneration (AMD).

Methods

Participants included 60 community-dwelling older people (age, 79.7 ± 6.4 years) with central vision impairment due to AMD. Binocular high-contrast visual acuity, contrast sensitivity, and visual fields were assessed at baseline and at 12 months. CF was assessed at both time points using the Falls Efficacy Scale–International (FES-I). Sensorimotor function (sit to stand, knee extension, postural sway, and walking speed) and neuropsychological function (reaction time, symptoms of anxiety and depression) were also assessed at both time points using validated instruments. Falls data were collected using monthly diaries during the 12 months.

Results

CF increased by a small but significant amount over the 12-month follow-up (2.1 units; P = 0.01), with increasing prevalence of high levels of CF (FES-I score ≥ 23), from 48% at baseline to 65% at 12 months. Linear mixed models showed that reduced contrast sensitivity was significantly associated with increased concern about falling (P= 0.004), whereas declines in both visual acuity and contrast sensitivity during the follow-up period were associated with increases in CF over the 12-month follow-up (P = 0.041 and P = 0.054, respectively), independent of age, gender, falls history, or number of comorbidities.

Conclusions

Higher levels of CF are common in older people with AMD, and levels increase over time; this increase is associated with declines in both visual acuity and contrast sensitivity. These findings highlight the need for regular assessment of both visual acuity and contrast sensitivity to identify those at greatest risk of developing higher CF.

Translational Relevance

Routine assessment of visual acuity and contrast sensitivity in older people with AMD will assist in identifying those at risk of developing high CF.

Eye movement patterns and reading ability in children

PURPOSE

Eye movements are integral to the reading process. This study characterised the eye movement patterns of children differentiated by their reading ability, while completing a saccadic eye movement test with irregular target spacing (Development Eye Movement (DEM) test) using a novel eye movement classification algorithm.

METHODS

Participants included 196 Grade 2 Australian schoolchildren (mean age: 7.9 ± 0.3 years) who completed a computerised version of the DEM test, while their eye movements were recorded (Tobii TX300 eye-tracker). Children also completed a standardised reading comprehension test, which categorised them into below average and average or above reading ability groups. A novel eye movement classification algorithm was developed that considered the vertical and horizontal eye movements of each child.

RESULTS

Compared to children with average or above reading ability, the below average reading group displayed poor vertical eye movement control, demonstrated by a significantly greater proportion of interline eye movements (vertical eye movements away from the current line) (p < 0.001). Differences in horizontal eye movements were also observed, with below average readers demonstrating a smaller proportion of expected forward saccades (p < 0.001) (within-line forward saccades with horizontal amplitude between the minimum and maximum horizontal spacing between digits), while this group also displayed longer fixation durations (p = 0.001). The below average reading group demonstrated significantly poorer results on all standard DEM metrics than the average or above reading ability group: horizontal subtest time (p < 0.001), vertical subtest time (p = 0.004) and ratio (p = 0.004).

CONCLUSIONS

Children exhibiting below average reading ability were poorer at maintaining control of vertical (interline), as well as horizontal, eye movements compared to children with average or above reading ability. Future studies should explore the mechanisms underlying these differences, particularly in vertical eye movements, given that reading paragraphs (involving multiple lines of text) requires accurate eye movements in both the vertical and horizontal direction.

Left Turns by Older Drivers With Vision Impairment: A Naturalistic Driving Study

BACKGROUND AND OBJECTIVES

Older drivers are overrepresented in collisions at intersections while making left turns across oncoming traffic. Using naturalistic driving methods, we evaluated the association between vision impairment and their left-turn characteristics.

RESEARCH DESIGN AND METHODS

In this prospective, observational study, vision impairment as defined by visual acuity, contrast sensitivity, visual processing speed, visual field sensitivity, and motion perception was assessed in drivers ≥70 years old. Data acquisition systems were installed in their personal vehicles recording video and vehicle kinematics. Driving during everyday life was recorded for 6 months. Data analysts evaluated a temporal data window surrounding randomly selected left turns at 4-way intersections. Left-turn traversals and turning behavior were evaluated in terms of age-adjusted associations with vision impairment.

RESULTS

The sample consisted of 151 older drivers. The number of turns studied was 473; 265 turns were rated as unsafe traversals, and 201 as problematic turning behavior. Drivers with slowed visual processing speed and visual field impairment were less likely to exhibit unsafe traversals (p < .05); those with worse contrast sensitivity, slowed visual processing speed, and visual field impairment were less likely to exhibit problematic turning behavior (p < .05).

DISCUSSION AND IMPLICATIONS

Using naturalistic driving, our study suggests older drivers with vision impairment exhibit better performance in making left turns than those without deficits, which contradicts older driver studies on left turns using driving simulators and on-road driving evaluations. Our findings suggest more cautious and self-regulatory behavior, which are consistent with older visually impaired drivers' commonly expressed concerns about their driving difficulties.

Association between decision-making under risk conditions and on-road driving safety among older drivers

Objective: Despite theoretical models emphasizing the likely importance of adaptive decision-making to maintaining safety on the roads, there has been a lack of research investigating this topic. This exploratory study aimed to determine if decision-making under risk conditions, as measured by the Game of Dice Task (GDT), can explain additional variance in on-road driving safety beyond other well-validated predictors. Method: Two hundred and thirty-nine cognitively normal Australian drivers aged 65-96 completed demographic and health questionnaires, vision testing, a neurocognitive test battery assessing cognitive flexibility, cognitive interference, episodic memory, verbal working memory, verbal fluency, and visuospatial function, the GDT-a lab-based assessment of decision-making under risk conditions, validated off-road driver screening measures and an on-road driving assessment along a standard route in urban traffic conditions administered by a trained Occupational Therapist (OT). Results: The number of risky choices made, but not the number of strategy changes, across trials of the GDT independently predicted on-road safety ratings after controlling for visual acuity, cognitive test performance, and off-road driver screening measures, B = -.146, 95% CI [-.276 to -.016]. Conclusion: Overall, this study offers the first evidence that decision-making is related to older adults' on-road driving safety, and makes recommendations for future research exploring the contribution of decision-making to on-road safety. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Improving the safety of distracted pedestrians with in-ground flashing lights. A railway crossing field study

INTRODUCTION

Current signage at intersections is designed for attentive pedestrians who are looking ahead. Such signage may not be sufficient when distracted by smartphones. Illuminated in-ground LED lights at crossings are an innovative solution to alert distracted pedestrians.

METHOD

We conducted a field study at a railway crossing equipped with in-ground lights to assess whether distracted pedestrians (N = 34, Mean age 33.6 ± 8.6 years) could detect these lights and how this impacted on their visual scanning and crossing behaviour. This involved a 2 × 3 repeated measures design exploring the impact of the presence (treatment) or absence (control) of in-ground lights (treatment) at a crossing, and a distractor task presented through a mobile device (none, visual, and audio) on eye movements recorded using an eye tracker, and verbal reporting of when participants detected the lights.

RESULTS

Participants engaged in the distraction tasks as evidenced by their accuracy and reaction times in all conditions. With both the audio and visual distraction tasks, participants looked at the in-ground LEDs and detected their activation as accurately as when not distracted (95%). While most participants detected the lights at their activation, visual distraction resulted in 10% of the detections occurring as participants entered the rail corridor, suggesting effectiveness in gaining pedestrians' attention. Further, participants were significantly less likely to check for trains when visually distracted (70%), a 10% reduction compared to the no or audio distractor conditions (80% and 78% respectively). The introduction of the in-ground lights resulted in appropriate scanning of the rail tracks (77% and 78% for the visual and auditory distractor tasks respectively) similar to that of non-distracted participants for the crossing without lights (80%).

CONCLUSIONS

Our findings indicate that illuminated in-ground lights could be useful in attracting the attention of distracted pedestrians at railway level crossings, and possibly at other road intersections. Practical Applications: Illuminated in-ground lights can be installed at rail and road intersections with known pedestrian distraction as a countermeasure. Further research is necessary to understand their long-term effects.

Using retro-reflective cloth to enhance drivers' judgment of pedestrian walking direction at night-time

PURPOSE

Fatal pedestrian collisions are over-represented at night and poor conspicuity is believed to be a leading causative factor. Retro-reflective clothing enhances pedestrian conspicuity, particularly when placed in a biological motion or "biomotion" configuration. In this study, we explored how various retro-reflective clothing configurations affected the ability to judge the direction of a pedestrian walking across the road, which has important implications for collision avoidance.

METHODS

Participants included 21 young drivers (mean age 21.6 ± 2.0 years) with normal vision. A closed-road circuit was used to assess the accuracy of drivers' judgement of the direction of walking of a pedestrian at night-time wearing one of five different clothing configurations: four with retro-reflective materials placed in different locations (Biomotion, Legs + Torso, Torso Only, Legs Only), and a control wearing only black clothing (Street). Participants were seated in a stationary vehicle with low beam headlamps, 135 m from a pedestrian, who walked across the road from both sides, in different directions (towards the car, straight across the road, or away from the car). Outcome measures included drivers' response accuracy and confidence ratings for judging pedestrian walking direction.

RESULTS

Accuracy in judging pedestrian walking direction differed significantly across the clothing configurations (p < 0.001). Response accuracy was significantly higher for the Biomotion configuration (80% correct), compared to the other retro-reflective (Legs + Torso 64%; Torso Only 53%; Legs Only 50%) and Street configurations (33%). Similar trends were noted for confidence ratings across the clothing conditions, yet the relationship between confidence ratings and response accuracy within each clothing configurations was poor.

CONCLUSIONS

The use of retro-reflective clothing in a biomotion configuration facilitated the highest accuracy and confidence in drivers' judgment of pedestrian walking direction, compared to other configurations. These findings highlight the importance of using biomotion clothing for pedestrians at night, to not only facilitate drivers' earlier recognition of pedestrians, but also increase their accuracy in determining the walking direction of pedestrians as they cross the road. Practical applications: The use of clothing incorporating retro-reflective material in a biomotion configuration for pedestrians crossing roads at night provides enhanced cues for drivers regarding the presence and walking direction of pedestrians.

Naturalistic Driving Techniques and Association of Visual Risk Factors With At-Fault Crashes and Near Crashes by Older Drivers With Vision Impairment

Importance

Government motor vehicle crash reports used in the study of driver safety can be biased and incomplete. Naturalistic driving methods using in-vehicle instrumentation have been developed in recent years to objectively measure crashes and near crashes as they occur on the road using video and vehicle kinematic data.

Objective

To examine visual risk factors associated with at-fault crashes and near crashes among older drivers, most of whom have age-related eye conditions associated with vision impairment.

Design, Setting, and Participants

This prospective cohort study was conducted at an academic ophthalmology clinic from January 1, 2015, to November 10, 2018, among 154 adults 70 years of age or older who were legally licensed in Alabama and who reported currently driving at least 4 days per week; 137 of 151 participants (90.7%) had an age-related eye condition in at least 1 eye. Drivers participated in a baseline visual function assessment followed by installation of a data acquisition system recording multichannel synchronized video and vehicle kinematics in their personal vehicle. Drivers were instructed to drive for 6 months as they normally would during everyday life. Statistical analysis was performed from June 15 to September 15, 2020.

Main Outcomes and Measures

The rate of combined incident at-fault crashes and near crashes, defined by the number of events and the number of miles driven.

Results

The sample consisted of 154 drivers (85 men [55.2%]; mean [SD] age, 79.3 [5.1] years). Visual functions associated with crash and near-crash involvement included impaired contrast sensitivity (rate ratio [RR], 2.7; 95% CI, 1.3-5.5), moderate (RR, 2.3; 95% CI, 1.1-4.9) and severe (RR, 5.0; 95% CI, 2.2-11.7) slowing in visual processing speed, and elevated motion perception thresholds for a drifting grating (RR, 1.9; 95% CI, 1.1-3.5). Those with impaired peripheral visual field sensitivity had increased rates of crashes and near crashes (RR, 1.8; 95% CI, 1.0-3.3); however, this finding was not statistically significant (P = .07).

Conclusions and Relevance

With the use of naturalistic driving methods in which crashes and near crashes involving older drivers are objectively measured as they occur on the road, associations have been identified between impaired contrast sensitivity, slowed visual processing speed, and impaired motion perception and an increased rate of a combined total of at-fault crashes and near crashes.

The effect of low light levels on postural stability in older adults with age-related macular degeneration

PURPOSE

To investigate the effect of low light levels on postural stability in older adults with and without age-related macular degeneration (AMD).

METHODS

Participants included 28 older adults [14 with AMD (mean age ± S.D., 83.4 ± 6.7 years) and 14 controls with normal vision (74.6 ± 3.3 years)]. Postural stability was assessed with eyes open on both a firm and foam surface under four lighting conditions in a randomised order: photopic (~436 lux, vertically at the eye), sudden reduction to mesopic (~436 to ~1 lux), adapted mesopic (~1 lux) and adapted mesopic with a light emitting diode (LED) door frame lighting system (~1.3 lux), using the root mean square (RMS) of the centre of pressure measures derived from an electronic force plate in the anterior-posterior (AP) and medio-lateral (ML) directions. Visual function was assessed binocularly (visual acuity, contrast sensitivity and visual fields), physical function was assessed using standardised measures (sit-to-stand, grip strength and the timed walk test) and self-reported difficulties under low light levels were recorded using the Low Luminance Questionnaire. Data were analysed using linear mixed models.

RESULTS

For all participants, low light levels significantly increased postural sway on the foam surface in the AP (p = 0.01) but not ML (p = 0.80) direction, but had no effect on postural stability on the firm surface. On the foam surface, while AP-RMS sway was significantly greater in the sudden (p < 0.001) and adapted (p = 0.02) mesopic compared to the photopic condition, sway for the adapted mesopic with the LED lighting system was not significantly different to the photopic condition (p = 0.20). On the foam surface, AP-RMS (p = 0.02) and ML-RMS (p < 0.001) sway were significantly greater in the AMD compared to the control group. None of the measures of visual function was significantly associated with AP- or ML-RMS sway.

CONCLUSIONS

On the foam surface, low light levels significantly reduced postural stability in older adults with and without AMD, and postural stability was significantly reduced for the AMD group compared to controls, regardless of light level. Importantly, the LED lighting system reduced sway under mesopic conditions, which was not significantly greater than that measured under photopic conditions in either group. These findings have important implications for enhancing the visual environment for older adults with and without AMD to improve postural stability and reduce the risk of falls in low lighting environments.

The mental health and wellbeing survey of Australian optometrists

PURPOSE

To investigate the prevalence of mental health conditions and burnout among practising optometrists in Australia.

METHODS

A cross-sectional survey of registered practising Australian optometrists was undertaken over a three-week period from mid-November 2019. The survey comprised three well-established mental health scales (Kessler Psychological Distress Scale [K10], Depression Anxiety Stress Scales [DASS-21] and Maslach Burnout Inventory [MBI]) and an open-ended question inviting comments.

RESULTS

Five hundred and five respondents completed the K10, representing 8.8% of registered optometrists in Australia; 466 completed all three scales. Prevalence of moderate to severe psychological distress (K10 ≥ 25) was 30.7% (95% CI 26.7%-34.7%), with similar findings for depression and anxiety (DASS-21). Prevalence of high burnout, as indicated by MBI-GS exhaustion was 56.1% (95% CI 51.7%-60.4%), cynicism 57.1% (95% CI 52.7%-61.5%) and professional efficacy 23.1% (95% CI 19.4%-26.8%). Optometrists aged ≤ 30 years were 3.5 times more likely to report moderate to severe psychological distress compared to optometrists aged >30 years (OR = 3.54, P < 0.001, 95% CI 2.38-5.25). The most frequently mentioned work-related issues concerned retail pressures, workload and career dissatisfaction.

CONCLUSIONS

The rates of mental health conditions and burnout reported by practising Australian optometrists were high compared with the general population and other health professionals. Younger age and burnout were significant risk factors for psychological distress. Interventions are required to address these issues, particularly for younger optometrists, and could include workplace modifications and building resilience to improve personal mental wellbeing and ensure patient safety.

Impact of Amblyopia on Visual Attention and Visual Search in Children

Purpose

The purpose of this study was to compare binocular visual attention, visual processing speeds, and visuo-cognitive search ability in children with and without amblyopia and investigate the association of visual acuity and binocular function with these measures.

Methods

Participants included 20 children with amblyopia (mean age = 9.0 ± 1.2 years; 15 anisometropic and 5 strabismic) and 20 children with normal vision development (9.5 ± 1.7 years). Vision assessment included visual acuity (monocular and binocular) and binocular function (Worth 4 Dot and Randot Preschool Stereotest). Visual attention and processing speeds were assessed using the three subtests of the Useful Field of View (UFOV; central processing, divided attention, and selective attention). Visuo-cognitive search was measured using static and dynamic presentations of the Trail Making Tests (TMTs), parts A and B, with increasing levels of executive function demand. All children performed these tasks binocularly.

Results

Children with amblyopia demonstrated slower visual processing times on the UFOV (P = 0.04), and slower completion times on the TMT search tests (P = 0.014), compared to controls. TMT performance for children with amblyopia was also more negatively impacted with increasing executive function demands on the TMT part B, compared to controls (P = 0.005). Binocular visual acuity was associated with TMT (P = 0.006) and UFOV (P = 0.07) performance, but none of the other visual function measures were related to performance on these tasks.

Conclusions

Children with amblyopia exhibit deficits in higher-order visual processing skills, including visual attention and visual search, particularly with increasing executive function demands. These findings have implications for understanding the impact of amblyopia on everyday function in children.

Motion perception as a risk factor for motor vehicle collision involvement in drivers ≥ 70 years

PURPOSE

To evaluate the relationship between visual function and a five-year history of motor vehicle collision rates in older adults. Motion perception impairment was explored as a risk factor for motor vehicle collisions for the first time in this study.

MATERIALS AND METHODS

Participants were licensed drivers ≥70 years old enrolled in the Alabama VIP Older Driver Study who underwent functional assessments for motion perception, distance visual acuity, contrast sensitivity, visual field sensitivity, and visual processing speed. Participants were recruited based on their being patients in an ophthalmology clinic in the year prior to enrollment or had participated in an earlier driving study. Crash reports were obtained from the Alabama Law Enforcement Agency for the 5 years prior to enrollment and mileage estimated using the Driving Habits Questionnaire. Crude and age-adjusted rate ratios (RRs) and 95 % confidence intervals (95 % CIs) were calculated using Poisson regression.

RESULTS

159 participants enrolled with a mean age of 79 years. The age-adjusted crash rate was higher among those with worse motion perception (RR: 2.7, 95 % CI: 1.4-5.2), severe slowing in visual processing speed (RR: 3.6, 95 % CI: 1.5-8.5), and impaired peripheral visual field sensitivity (RR: 2.4, 95 % CI: 1.3-4.4).

CONCLUSIONS

Among a sample of older drivers, crash rates were higher for those with impaired motion perception, severely slowed visual processing speed, and impaired peripheral visual field sensitivity. The association between motion perception and crash risk in older drivers has not been previously reported. Prospective analysis of the Alabama VIP Older Driver Study will examine these risk factors for future collision involvement based on naturalistic driving data.

Hazard Perception in Older Drivers With Eye Disease

Purpose

Timely detection of hazards is a key driving skill; however, the hazard perception of drivers with eye disease and related visual changes and the visual predictors of hazard perception are poorly understood.

Methods

Participants included drivers aged 65 years and older with a range of eye diseases, including cataract, age-related maculopathy (AMD), and glaucoma (n = 99; mean age, 75.4 ± 6.4 years) and controls (n = 118; mean age, 72.2 ± 5.5 years). Visual performance was assessed using clinical measures (visual acuity, contrast sensitivity, visual fields) and non-clinical measures (useful field of view, motion sensitivity). Participants completed a computer-based hazard perception test (HPT) that has been related to driving performance and crash risk.

Results

Participants with eye disease exhibited a 0.73-second delay in HPT response times compared to controls (6.61 ± 1.62 seconds vs. 5.88 ± 1.38 seconds; age-adjusted P = 0.012). Participants with glaucoma exhibited significantly delayed responses compared to those with AMD (P = 0.038) and controls (P = 0.004). Poorer motion sensitivity (standardized β = 0.27; P < 0.001), visual acuity (β = 0.21; P = 0.002), and better-eye mean defect (β = –0.17; P = 0.009) were most strongly associated with delayed HPT responses. Motion sensitivity remained significantly associated with HPT responses, adjusted for visual acuity and visual fields.

Conclusions

HPT responses of older drivers with eye disease were delayed compared to controls and translate to an estimated 16-meter longer stopping distance when traveling at 80 km/hr. Decreased motion sensitivity was most strongly associated with delayed HPT responses.

Translational Relevance

HPT tests can provide insight into difficulties regarding road hazard detection of older drivers with eye disease and provide a potential avenue for interventions to improve road safety.

Motion perception at mesopic light levels: effects of physiological ageing and eccentricity

PURPOSE

To explore the differential effects of age and eccentricity on the perception of motion at photopic and mesopic light levels.

METHODS

Thirty-six visually normal participants (18 younger; mean age 25 years, range: 20-31) and (18 older; mean age 70 years, range: 60-79) underwent two testing sessions, one at photopic and one at mesopic light levels. In each session, motion perception was tested binocularly at two eccentricities (centrally, and peripherally at 15° rightwards and 5° superior to the horizontal) for four motion tasks: minimum contrast of a drifting Gabor to identify motion direction (motion contrast); translational global motion coherence; biological motion embedded in noise and the minimum duration of a high-contrast Gabor to determine the direction of motion, using two Gabor sizes to measure spatial surround suppression of motion.

RESULTS

There was a significant main effect of light condition (higher thresholds in mesopic) for motion contrast (p < 0.001), translational global motion (p = 0.001) and biological motion (p < 0.001); a significant main effect of age (higher thresholds in older adults) for motion contrast (p < 0.001) and biological motion (p = 0.04) and a significant main effect of eccentricity (higher thresholds peripherally) for motion contrast (p < 0.001) and biological motion (p < 0.001). Additionally, we found a significant three-way interaction between light levels, age and eccentricity for translational global motion (similar increase in mesopic thresholds centrally for both groups, but a much larger deterioration in older adult's peripheral mesopic thresholds, p = 0.02). Finally, we found a two-way interaction between light condition and eccentricity for translational global motion (higher values in central mesopic relative to peripheral photopic, p = 0.001) and for biological motion (higher values in peripheral mesopic relative to central photopic, p < 0.001).

CONCLUSIONS

For the majority of tasks assessed, motion perception was reduced in mesopic relative to photopic conditions, to a similar extent in both age groups. However, because some older adults exhibited elevated thresholds even under photopic conditions, particularly in the periphery, the ability to detect mesopic moving stimuli even at high contrast was markedly impaired in some individuals. Our results imply age-related differences in the detection of peripheral moving stimuli at night that might impact hazard avoidance and night driving ability.

High Rates of Uncorrected Vision Conditions among Schoolchildren in Rural Queensland, Australia

SIGNIFICANCE

This study is the first to report high rates of uncorrected vision conditions among Australian secondary schoolchildren living in a rural area and to comment on the rate of eye examinations undertaken on Australian Indigenous children. Uncorrected vision problems that continue throughout the school years have significant implications for children's quality of life and education.

PURPOSE

This study aimed to investigate the prevalence of uncorrected vision conditions among Australian schoolchildren.

METHODS

Participants included 280 students from rural primary and secondary schools (aged 4 to 18 years), of whom 40% identified as being of Aboriginal and/or Torres Strait Islander descent (Indigenous). All participants underwent an eye examination including measurements of monocular distance and near visual acuity, assessment of accommodative and vergence function, stereoacuity, color vision, and cycloplegic autorefraction. A parental questionnaire was used to determine whether the child had previously had his/her eyes examined.

RESULTS

The overall prevalence of uncorrected vision conditions in this population was 35%. The odds of previously having had an eye examination were 2.3× higher for non-Indigenous compared with Indigenous children despite both groups exhibiting high rates of uncorrected vision conditions (Indigenous, 31 [29%]; non-Indigenous, 66 [40%]; χ21 = 3.24, P = .07). Of the children who had significant refractive error (Indigenous, 23 [21%]; non-Indigenous, 49 [30%]; χ21 = 2.70, P = .10), 82% were uncorrected, and only 39% of Indigenous children and 54% of non-Indigenous children had previously had an eye examination.

CONCLUSIONS

These findings suggest that high rates of uncorrected vision conditions are present among Australian primary and secondary schoolchildren from a rural area and highlight that Indigenous children are much less likely to have had an eye examination. Understanding factors that affect the rate of eye examinations and compliance with spectacle correction must be addressed given the potential impact of these vision conditions.

Determinants of concern about falling in adults with age-related macular degeneration

PURPOSE

To investigate the prevalence and level of concern about falling (CF) among older people with vision impairment due to age-related macular degeneration (AMD) compared to a visually normal control group, and to identify determinants of CF for the AMD group.

METHODS

Participants included 133 older people: 77 with AMD (mean age = 80.5 ± 6.2 years), and 56 controls (mean age = 75.4 ± 5.3 years). Binocular visual acuity, contrast sensitivity and visual fields were measured, and CF was assessed using the Falls Efficacy Scale - International (FES-I). Data were also collected for sensorimotor function (postural sway, sit-to-stand, knee extensions, walking speed, proprioception), and neuropsychological function (reaction time, symptoms of anxiety and depression) using validated tests and scales.

RESULTS

Concern about falling scores were higher for AMD participants compared to control participants (mean ± S.D. 24.6 ± 8.0 vs 21.6 ± 5.7, p = 0.02, respectively), although these findings failed to reach significance when adjusted for age (p = 0.16). Among AMD participants, multivariable models showed that greater CF was associated with reduced contrast sensitivity (p = 0.02), slower sit-to-stand times (p < 0.001) and higher anxiety scores (p < 0.001); these factors explained 40% of the variance in CF (p < 0.01).

CONCLUSION

Levels of CF in older people with AMD were not found to be elevated by their disease status alone, but rather by the extent of vision loss. Levels of CF in those with AMD were associated with various visual, sensorimotor and neuropsychological factors. These findings will assist clinicians in identifying those at greatest risk of developing high CF and inform the design of future intervention programmes for this population.

Rationale and Methodology of The PopulatION HEalth and Eye Disease PRofile in Elderly Singaporeans Study [PIONEER]

To describe the rationale, design and methodology of a geographically-representative and population-based study investigating the epidemiology, impact, personal and economic burden of age-related eye diseases, declining visual and other sensory systems in Asians aged >60 years in Singapore.PIONEER (The PopulatION HEalth and Eye Disease PRofilE in Elderly Singaporeans Study) is currently a cross-sectional study targeting 3152 Chinese, Malay and Indian adults who are Singapore citizens or permanent residents aged 60 years and older living across Singapore. The study is intended to be longitudinal, with several waves of data planned to be collected in the future. The sampling frame consisted of 7000 names derived from age, gender and ethnicity-stratified random sampling of individuals >60 years. Selected individuals were invited via letters, home visits, and telephone calls for a clinical assessment at the Singapore Eye Research Institute. Individuals with limited mobility were examined in a custom-designed mobile eye clinic. Questionnaires were subsequently administered at participants' homes by trained interviewers in their preferred language. A total of 3,299 participants (from East, West, North and South Singapore) were approached from December 2017 to November 2019. Of these, 953 (28.5%) were deemed ineligible. Out of 2,346 eligible participants, 904 (38.5%) refused, and 1,442 (61.5%) attended our clinical testing protocol, giving an initial response rate of 61.5%. Of these, 1,170 (81%) were cognitively able to complete the questionnaire assessment. The mean age±SD of our participants was 73.8±8.6 years; n=798 (55.3%) were female; and 828 (57.4%) were of Chinese ethnicity. The findings from this study will allow a deeper understanding of the risk factors and impact of aging in Asian populations, particularly in relation to the visual function and other functional system.

Choroidal Thickness in Indigenous Australian Children

Purpose

This study aimed to examine the choroidal thickness profiles in visually normal Australian Indigenous children, given the important role of the choroid in refractive error and a range of ocular diseases.

Methods

Choroidal thickness was assessed across the central 5 mm macular region using enhanced depth imaging spectral domain optical coherence tomography, in 250 children enrolled in an elementary school and a secondary school in rural Queensland, Australia. One hundred (40%) of these children identified as Indigenous Australians.

Results

The subfoveal choroid was significantly thicker in Indigenous children (mean 369 ± 75 µm), compared to non-Indigenous children (355 ± 73 µm; P = 0.03). Subfoveal choroidal thickness was also significantly associated with age (β = +7.6, r² = 0.105, P = 0.003), and axial length (β = −19.9, r² = 0.030, P < 0.001). A significantly thicker choroid in Indigenous children was also found in analyses across the central 5 mm macular region (P = 0.008). A significant interaction between Indigenous status and meridian was observed (P = 0.007) with the largest differences between Indigenous and non-Indigenous children being in the nasal and inferonasal meridians.

Conclusions

This study establishes the normative characteristics of macular choroidal thickness in Indigenous Australian children and demonstrates a significantly thicker choroid compared to non-Indigenous children from the same geographic region. These results may have implications for our understanding of factors predisposing or protecting Australian Indigenous people from a range of conditions associated with choroidal thickness.

Translational Relevance

The significantly thicker choroid in Australian Indigenous children should be considered in clinical diagnoses and management of conditions associated with choroidal changes.

Effects of night-time bicycling visibility aids on vehicle passing distance

Bicycling at night is dangerous, with vehicle passing distances being a key concern, given that the main cause of night-time bicycling fatalities is from motorists hitting bicyclists from behind. However, little is known about vehicle passing distances at night or how they are affected by bicyclist visibility. This study assessed the impact of different bicyclist visibility configurations on vehicle passing distances at night-time. Fourteen licenced drivers with normal vision (age 24.2 ± 3.7 years) drove an experimental vehicle with low-beam headlights around a 1-km section of a closed-road circuit at night. Each lap involved passing two bicyclists displaying one of four visibility configurations: Control (red rear-facing light and reflector), Handlebars (control plus two red rear-facing lights on each handlebar), Helmet (control plus one red rear-facing light on the helmet), and Leg Retro-reflectors (control plus retro-reflective strips positioned on the knees and ankles). Participants were instructed to pass each bicyclist at a distance of 1-metre at a speed no greater than 50 km/hr, consistent with Queensland's Minimum Passing Distance rule. Participants completed eight laps, two for each configuration, in a randomised sequence. Passing distance was measured using a vehicle-mounted ultra-sonic sensor (ToughSonic14; Senix). Following each lap, participants rated the difficulty level in judging the 1-metre passing distance, as well as their estimated passing distance. Visibility configuration significantly affected passing distance (p = 0.001), with wider passing distances for the Handlebar configuration (1.54 ± 0.62 m), followed by the Helmet (1.51 ± 0.63 m), Leg Retro-reflectors (1.50 ± 0.62 m) which were all significantly greater than the Control (1.42 ± 0.57 m), but not significantly different from each other. There was also a significant effect of visibility configuration on difficulty rating (p = 0.035), with the Control rated as the most difficult, followed by Helmet, Handlebars and Leg Retro-reflectors. Overall, additional visibility aids resulted in wider vehicle passing distances, likely due to enhanced visual cues for drivers. The findings suggest that bicyclists should incorporate additional visibility aids to encourage safer passing distances of vehicles at night-time.

Experiences following cataract surgery - patient perspectives

PURPOSE

Most patients report being highly satisfied with the outcome of cataract surgery but there are variable reports regarding the impact of cataract surgery on some real-world activities, such as fall rates. We hypothesised that adaptations to changed refractive correction and visual function may cause difficulties in undertaking everyday activities for some patients and used a series of focus groups to explore this issue.

METHOD

Qualitative methods were used to explore patients' experiences of their vision following cataract surgery, including adaptation to vision changes and their post-surgical spectacle prescription. Twenty-six participants took part in five focus groups (Mean age = 68.2 ± 11.4 years), and the data were analysed using thematic analysis.

RESULTS

We identified three themes. 'Changes to Vision' explores participants' adaptation following cataract surgery. While several had problems with tasks relying on binocular vision, few found them bothersome and they resolved following second eye surgery. Participants described a trial and error approach to solving these problems rather than applying solutions suggested by their eyecare professionals. 'Prescription Restrictions' describes the long-term vision problems that pre-surgery myopic patients experienced as a consequence of becoming emmetropic following surgery and thus needing spectacles for reading and other close work activities, which they did not need before surgery. Very few reported that they had the information or time to make a decision regarding their post-operative correction. 'Information Needs' describes participant's responses to the post-surgical information they were given, and the unmet information need regarding when they can drive following surgery.

CONCLUSION

The findings highlight the need for clinicians to provide information on adaptation effects, assist patients to select the refractive outcome that best suits their lifestyle, and provide clear advice about when patients can start driving again. Patients need to be provided with better guidance from clinicians and prescribing guidelines for clinicians would be beneficial, particularly for the period between first- and second-eye surgery.

Older drivers' self-reported vision-related night-driving difficulties and night-driving performance

PURPOSE

To investigate associations between older drivers' perceived vision-related night-driving difficulties and night-time driving performance measured on a closed-road circuit.

METHODS

Participants included 26 older drivers (71.8 ± 6.3 years) who reported vision-related night-driving difficulties assessed with the vision and night driving questionnaire (VND-Q). High-contrast, photopic visual acuity (VA) and ratings of discomfort glare (de Boer scale) were also assessed. Night-time driving performance was measured on a closed-road circuit that involved recognition, hazard avoidance and lane-keeping tasks in the absence and presence of intermittent glare. Generalized linear mixed models investigated the relationship between VND-Q scores and overall driving performance scores, as well as with discomfort glare ratings and VA.

RESULTS

Greater levels of vision-related night-driving difficulties (VND-Q scores) were significantly associated with poorer night-driving performance (p = 0.003); the association was even stronger for driving performance in the presence of intermittent glare (p = 0.001). Reduced VA was associated with poorer night-driving performance (p = 0.022) but the association was weaker than for the VND-Q scores. In contrast, ratings of discomfort glare were not significantly associated with driving performance (p = 0.14).

CONCLUSION

The VND-Q was significantly associated with night-time driving performance and provides a useful instrument for assessing vision-related night-driving difficulties which can be incorporated into clinical vision assessments.

Differential aging effects in motion perception tasks for central and peripheral vision

The perception of motion is considered critical for performing everyday tasks, such as locomotion and driving, and relies on different levels of visual processing. However, it is unclear whether healthy aging differentially affects motion processing at specific levels of processing, or whether performance at central and peripheral spatial eccentricities is altered to the same extent. The aim of this study was to explore the effects of aging on hierarchically different components of motion processing: the minimum displacement of dots to perceive motion (Dmin), the minimum contrast and speed to determine the direction of motion, spatial surround suppression of motion, global motion coherence (translational and radial), and biological motion. We measured motion perception in both central vision and at 15° eccentricity, comparing performance in 20 older (60-79 years) and 20 younger (19-34 years) adults. Older adults had significantly elevated thresholds, relative to younger adults, for motion contrast, speed, Dmin, and biological motion. The differences between younger and older participants were of similar magnitude in central and peripheral vision, except for surround suppression of motion, which was weaker in central vision for the older group, but stronger in the periphery. Our findings demonstrate that the effects of aging are not uniform across all motion tasks. Whereas the performance of some tasks in the periphery can be predicted from the results in central vision, the effects of age on surround suppression of motion shows markedly different characteristics between central and peripheral vision.

Subjective Verticality Is Disrupted by Astigmatic Visual Distortion in Older People

Purpose

There is little research evidence to explain why older adults have more problems adapting to new spectacles incorporating astigmatic changes than younger adults. We tested the hypothesis that astigmatic lenses oriented obliquely would lead to errors in verticality perception that are greater for older than younger adults.

Methods

Participants included 12 young (mean ± SD age 25.1 ± 5.0 years) and 12 older (70.2 ± 6.3 years) adults with normal vision. Verticality perception was assessed using a computer-based subjective visual vertical (SVV) task, under static and dynamic (in the presence of a moving peripheral distractor) conditions and when viewing targets through the near refractive correction (control condition), and two forms of astigmatic lenses oriented in the vertical, horizontal, and oblique meridians.

Results

The older group demonstrated much greater dynamic SVV errors (e.g., 3.4° for the control condition) than the younger group (1.2°, P = 0.002), larger errors with vertical and horizontal astigmatic lenses (older group 4.1°and 5.2° for toric and magnifier lenses vs. younger group 1.2° and 1.4°, respectively, P < 0.001), and a larger influence of the oblique astigmatic lenses (older group 5.6° vs. younger group 2.1°, P<0.001).

Conclusions

Astigmatic lenses produced little or no errors in SVV in young adults, but large static and dynamic SVV errors in older adults. This indicates a greater reliance on visual input with increased age for SVV, and helps explain why oblique astigmatic refractive corrections can cause dizziness in older patients and why they report greater difficulties adapting to new spectacles with astigmatic changes.