Visual midline gauge validity and repeatability: Comparison to a current clinical method.

SIGNIFICANCE: Visual midline shifts are thought to occur post-stroke and be a risk factor for falls. This study investigates a new method for quantifying visual midline shifts, a first step toward developing greater understanding of visual midline shift. PURPOSE: This study standardized the parameters of a novel visual midline gauge, compared the results with the current clinical method, and presents normative data and repeatability of both methods. METHODS: Ninety-three participants without neurological or ocular problems were recruited in Canada and Hong Kong. In experiment 1, horizontal and vertical visual midlines were measured using the gauge for two speeds and two repositioning methods. In experiment 2, visual midline was measured for three distances using a target speed and repositioning method chosen based on the first experiment. Visual midlines were also measured using the current clinical method during both visits. RESULTS: There were no significant effects of age, speed, study location, or repositioning method on visual midline positions (all p>0.05). For the horizontal direction, measurements at 25 cm were different from those at 50 (p=0.03) and 100 cm (p=0.001). For the vertical direction, there was no such effect. The measurements were found to be repeatable to within approximately 3°. In both visits, there were significant correlations between measurements using the visual midline gauge and the clinical method for the vertical direction (all p<.001) but not for the horizontal direction (all p>0.05). CONCLUSIONS: The measurement of visual midline is tolerant of differences in target speed, testing method, and age of the participants, and the visual midline gauge measurements are repeatable.

Status of Vision and Eye Care Among Patients in Rehabilitation Hospital Units: A Cross-Sectional Study.

OBJECTIVES: The prevalence of vision disorders is high among geriatric and hospital inpatient populations, yet they often go undetected, resulting in consequences such as falls or prolonged recovery time. A needs assessment study was conducted to investigate levels of vision and the potential prevalence of unmanaged/undiagnosed ocular disorders among adult inpatients in a hospital-based rehabilitation unit. DESIGN: Cross-sectional study. SETTING & PARTICIPANTS: Inpatient rehabilitation units of an acute care hospital system in Ontario, Canada. Adults (n = 112) in a hospital inpatient rehabilitation unit participated from October 2018 to February 2019. METHODS: Participants were surveyed regarding their demographic, ocular, and medical data and spectacle wear. Visual acuity, contrast sensitivity, visual fields, and stereoacuity plus the spectacle condition were directly assessed. RESULTS: The majority (75%) were found to have reduced habitual vision while in hospital. Nearly 60% of participants reported at least some difficulty reading a newspaper or distinguishing a face or were "not happy with their vision." This was despite 80% of participants reporting that they had an eye care practitioner and 70% that they had an eye examination within the last 2 years. More than half (51.8%) of the participants received the recommendation to follow up with their eye care practitioner on discharge from the hospital. CONCLUSIONS AND IMPLICATIONS: Reduced vision and vision disorders has a high prevalence among hospital patients in rehabilitation units and should be evaluated at or soon after hospital intake. By incorporating vision screening tools, necessary precautions may be taken to avoid possible falls and promote recovery.

Visual Functions, Seatbelt Usage, Speed, and Alcohol Consumption Standards for Driving and Their Impact on Road Traffic Accidents.

Purpose:  The incidence of road traffic accidents (RTAs) is dramatically increasing worldwide. Consequently, driving and licensing authorities have instituted strict rules and regulations, such as vision standards, restrictions on drunk driving, seat belt usage, and speeding, for driving safety. This study aimed to summarize the global visual standards for driving license issuing and renewal and investigate the effect of driving safety laws on RTA-related death rates in different countries. Methods:  The study gathered data on visual standards for driving licenses from reliable sources and extracted enforcement scores (drunk driving, seat belt usage, and speeding) and RTA-related death rates from the World Health Organization status report on road safety. The Wilcoxon test explored the association between visual standards and RTA-related death rates, while the Kruskal-Wallis test analyzed the relationship between visual functions and death rates, as well as driving safety enforcement scores and RTA-related death rates. Results:  The analysis was conducted on 71 countries and 50 states within the United States out of the 193 countries listed by the United Nations. It was found that 116 countries and states required a minimum VA range of 6/6-6/18, while 91 countries and states mandated a similar range for one-eyed drivers. VF testing for driving licenses was necessary in 77 countries and states. No significant association was observed between VA or VF testing and RTA-related death rates. However, countries that conducted more visual function tests demonstrated lower rates of RTA-related fatalities. Furthermore, RTA-related death rates were significantly associated with speeding, drunk driving, and seat belt laws. Conclusion: Implementing clear policies regarding vision requirements, maintaining strict rules, and promoting law enforcement on speeding, drunk driving, and seat belt usage are crucial for improving road safety. These measures should be prioritized by driving and licensing authorities worldwide to mitigate the escalating incidence of RTAs.

Classification in Para skiing: do better performing skiers have better visual functions?

Introduction: Currently, Paralympic skiers with vision impairment are allocated to classes based only on their better eye static visual acuity and visual field diameter. These studies were conducted to investigate whether a broad range of visual functions were different among groups of skiers with different levels of skiing performance. Methods: Static and dynamic visual acuities, contrast sensitivity, light and glare sensitivity, glare recovery, motion perception, and visual field were assessed binocularly in elite Para nordic (n = 26) and Para alpine skiers (n = 15) at 3 international Paralympic events. Skiing performances were calculated using modified skiing points systems based on skiers' raw race times. Clusters of skiers with similar performances were identified in each sport, and their vision and non-vision variables were compared. Results: Skiers in the best performing Para nordic clusters (1 and 2) had better static visual acuities (p = 0.041) and larger visual fields (p = 0.004) compared to cluster 3. In Para alpine slalom (p = 0.019), giant slalom (p = 0.019), and Super-G (p = 0.039) the average static visual acuities among the better performing clusters were significantly better compared to the worst performing cluster. In slalom, the cluster with better performance also had a significantly larger visual field (p = 0.038). In downhill, the better performance cluster demonstrated better dynamic visual acuity (p = 0.029). Discussion: Clusters with better performing skiers appear to have better visual function in both sports. The results of this study would suggest that Para nordic and Para alpine skiers with light perception or no light perception vision should be in one class and that the skiers with quantifiable static VA should be in a different class.

Do Impairments in Visual Functions Affect Skiing Performance?

Nordic and alpine skiing-related visual tasks such as identifying hill contours, slope characteristics, and snow conditions increase demands on contrast processing and other visual functions. Prospective observational studies were conducted to assess the relationships between skiing performance and a broad range of visual functions in nordic and alpine skiers with vision impairments. The study hypothesized that contrast sensitivity (CS), visual acuity (VA), and visual field (VF) would be predictive of skiing performance. Binocular static VA, CS, light sensitivity, glare sensitivity, glare recovery, dynamic VA, translational and radial motion perception, and VF were assessed in elite Para nordic (n = 26) and Para alpine (n = 15) skiers. Skiing performance was assessed based on skiers' raw race times. Performance on the visual function tests was compared with skiing performances using Kendall's correlations (with and without Bonferroni-Holm corrections) and linear multivariable regressions (p < 0.05 considered significant). None of the vision variables were significantly correlated with performance in Para nordic or Para alpine skiing after Bonferroni-Holm corrections were applied. Before applying the corrections, VF extent (ρ = -0.37, p = 0.011), and static VA (ρ = 0.26, p = 0.066) demonstrated the strongest correlations with Para nordic skiing performance; in Para alpine skiing, static VA and CS demonstrated the strongest correlations with downhill (static VA: ρ = 0.54, p = 0.046, CS: ρ = -0.50, p = 0.06), super G (static VA: ρ = 0.50, p = 0.007, CS: ρ = -0.51, p = 0.017), and giant slalom (static VA: ρ = 0.57, p = 0.01, CS: ρ = -0.46, p = 0.017) performance. Dynamic VA and VF were significantly associated with downhill (ρ = 0.593, p = 0.04) and slalom (ρ = -0.49, p = 0.013) performances, respectively. Static VA was a significant predictor of giant slalom [(F(3,11) = 24.71, p < 0.001), and R of 0.87], super G [(F(3,9) = 17.34, p = 0.002), and R of 0.85], and slalom [(F(3,11) = 11.8, p = 0.002), and R of 0.80] performance, but CS and VF were not. Interestingly, static VA and CS were highly correlated in both Para nordic (ρ = -0.60, p < 0.001) and Para alpine (ρ = -0.80, p < 0.001) skiers. Of the vision variables, only static VA and VF were associated with skiing performance and should be included as the in Para nordic and Para alpine classifications. The strong correlations between static VA and CS in these skiers with vision impairment may have masked relationships between CS and skiing performance.

Exploration of the minimum visual disability criteria for Para nordic and Para alpine skiing using simulated vision impairments.

The International Paralympic Committee Classification Code requires sports to develop evidence-based, sports-specific classification systems. This project aimed to determine the minimum eligibility criteria for Para nordic and Para alpine skiing by simulating vision impairments and measuring the impact of the impairments on performance in twenty-two nordic (28.09 ± 9.68 years; 16 male) and eleven alpine (37.91 ± 18.9 years, 11 male) able-sighted skiers. Eight visual acuity (VA)/contrast sensitivity (CS) (Cambridge Simulation Glasses, University of Cambridge) and six visual field (VF) impairments (bespoke goggles; University of Waterloo) were simulated. VA, CS and VF were measured in each participant before they completed an on-snow session, skiing short competition-style courses with each of the 14 simulated impairments in a randomized order. Clear goggle (no impairment) trials were used as controls. Receiver Operating Characteristic (ROC) and decision tree analyses were conducted to determine the optimum VA, CS and VF cut-offs for classifying performance based on differences from baseline in real time. Moderate impairments in VA, CS and VF negatively affect skiing performance. The recommended cut-off criteria based on both analyses were VA ≥0.90 logMAR and ≤48% VF extent for nordic and VA of ≥0.60 logMAR and VF extent of ≤59.0% for alpine.

Relationship of Contrast Sensitivity Measured Using Quick Contrast Sensitivity Function With Other Visual Functions in a Low Vision Population.

Purpose: Contrast sensitivity (CS) is predictive of various aspects of an individual's functional vision, such as recognizing faces and driving. Currently available CS charts are limited in terms of the spatial frequencies they can test and/or the contrast resolution of the targets they present. The traditional methods for measuring full CS functions (CSFs) are time consuming. The purpose of this study was to examine the feasibility of using the quick CSF method in a low vision population and to assess the relationships of CS with other visual functions, which can contribute to the understanding of the functional vision. Methods: Static visual acuity, dynamic visual acuity, CS, global motion perception thresholds, and visual field were measured binocularly in 53 individuals with low vision. The number of participants who could complete each assessment was used to assess feasibility. The relationships between CS and other visual functions were assessed using linear regressions and multiple regressions. Results: The quick CSF was quantifiable in 34 participants of the 42 with quantifiable visual acuities. The area under the log CSF-the summary statistic of CSF-was significantly correlated with static visual acuity and dynamic visual acuity (r = -0.79 and r = -0.63, respectively; P < 0.001). Conclusions: The qCSF is capable of measuring CS in a wide range of visual impairment severities. area under the log CSF only correlates with measures of visual acuity.