Increased visual and cognitive demands emphasize the importance of meeting visual needs at all distances while driving

The complex relation between visual complaints and decline in visual, visuoperceptual and cognitive functions in people with multiple sclerosis

People with multiple sclerosis (pwMS) report many different visual complaints, but not all of them are well understood. Decline in visual, visuoperceptual and cognitive functions do occur in pwMS, but it is unclear to what extend those help us understand visual complaints. The purpose of this cross-sectional study was to explore the relation between visual complaints and decline in visual, visuoperceptual and cognitive functions, to optimize care for pwMS. Visual, visuoperceptual and cognitive functions of 68 pwMS with visual complaints and 37 pwMS with no or minimal visual complaints were assessed. The frequency of functional decline was compared between the two groups and correlations were calculated between visual complaints and the assessed functions. Decline in several functions occurred more frequently in pwMS with visual complaints. Visual complaints may be an indication of declined visual or cognitive functioning. However, as most correlations were not significant or weak, we cannot infer that visual complaints are directly related to functions. The relationship may be indirect and more complex. Future research could focus on the overarching cognitive capacity that may contribute to visual complaints. Further research into these and other explanations for visual complaints could help us to provide appropriate care for pwMS.

Post-coronavirus disease 2019 functional impairments, limitations, and restrictions: A prospective cohort study based on the international classification of functioning, disability, and health

Background

Current knowledge regarding coronavirus disease 2019 (COVID-19) is constantly evolving, and the long-term functional impairments, limitations, and restrictions have not yet been well established.

Objective

to evaluate the impact of post-COVID condition on the human functioning through the International Classification of Functioning, Disability and Health (ICF) classification.

Methods

This is a prospective cohort study with 53 individuals with post-COVID condition at 3 time points: 0 to 3 (baseline), 3 to 6, and 6-12 months (follow-up). Outcomes were organized in dichotomous variable: No impairment (0); presence of impairment (≥1) in body function, structure, activities, and participation domains according to the ICF checklist. Chi-square test was used to determine the differences of 3 time points, and association with persistent symptoms.

Results

A statistically significant difference was observed between the periods, with greater disabilities at 6-12 than at 0-3 months in mental, sensory, pain, and movement-related functions; cardiovascular, immunological, and respiratory systems. In terms of activity and participation, a greater limitation at 6-12 months was observed than at 0-3 months in learning and applying knowledge, general tasks, and mobility. In the domain of interpersonal interactions and relationships, there was a statistically significant difference between the 6-12 and 3-6 months groups. Associations between COVID-19 symptoms and ICF components at the first follow-up were: anosmia and dysgeusia with weight maintenance, fatigue and irritability with pain, brain fog with watching and listening, walking difficulty with pain, and headache with pain, watching, and listening. At the second follow-up were: anosmia and dysgeusia with energy and drive functions, attention, memory, and emotional functions; dizziness with watching and listening; fatigue with emotional function, pain, undertaking multiple tasks, lifting and carrying objects, and driving; irritability with energy and drive, emotional function, undertaking multiple tasks, lifting and carrying objects, and walking; walking difficulty with energy and driving, emotional function, respiration, muscle power, cardiovascular system, undertaking multiple tasks, lifting and carrying objects, and walking; and headache with emotional function, watching, and listening.

Conclusions

Individuals with COVID-19 persistent symptoms showed impairments in structure and function, activity limitations, and participation restrictions during the 1-year follow-up period.

Big Data analysis of vision screening standards used to evaluate fitness to drive

PURPOSE

Visual acuity assessment is the most commonly performed vision screening method for drivers. The standards and repeat assessment intervals used, however, are arbitrary, lack an evidence base and are highly variable across different countries. This study utilises the power of Big Data to provide evidence-based recommendations for standardised driver vision screening.

METHODS

Anonymised electronic medical record data was gathered from 40 Irish optometry practices comprising 81,184 unique patients. A Kaplan-Meier Survival (KMS) analysis was used to determine the effect of increasing age and time since screening on the likelihood of passing the visual acuity standard for driving. A logistic function was fit to assess the effect of varying the minimum visual acuity standard required to drive on the screening pass rate within the population.

RESULTS

The likelihood of failing repeat screening increased as a function of time since initial screening for all age groups (χ²=1447, df =6, p < 0.001), with older patients most affected. Rescreening intervals for individuals who initially met the vision standard unaided reduced as a function of age. Using an 80% survivability threshold, intervals ranged from every eight years for drivers under 50, reducing to every two years for those aged over 80. Rescreening intervals for drivers requiring optical correction to meet the standard, also decreased with age. Approximately 1% of individuals are excluded from driving using a 0.3 logMAR visual acuity standard with correction.

CONCLUSION

Visual acuity-based screening should take place at regular intervals for all drivers, not just those over 70. Re-screening intervals should be based on age, with shorter intervals for older drivers due to the combined effect of age and time on the likelihood of passing the driving visual acuity standards. The most commonly used standard of 0.3 logMAR results in a minimal number of potential drivers being excluded from driving.

The effect of mental load on psychophysical and visual evoked potential visual acuity

PURPOSE

Under real-world conditions, tasks dependent on visual acuity may need to be performed in the presence of a mental load arising from concurrent, non-visual tasks. Therefore, measuring visual acuity concurrently with mentally demanding tasks may reflect a patient's vision more accurately. This study was designed to evaluate the impact of task-induced mental load on high contrast visual acuity, as measured using a letter chart and estimated via sweep visual evoked potentials (sweep VEP).

METHODS

Visual acuity was determined using the Freiburg Vision Test, and also using sweep VEP tested stepwise, from coarse to fine, over 13 spatial frequencies, in 31 healthy participants (aged 22.4 ± 3.6 years). Recordings were repeated while participants concurrently performed an auditory 2-back task. Mental load of the n-back task was confirmed through subjective ratings.

RESULTS

Visual acuity determined with the Freiburg Vision Test worsened from -0.02 ± 0.12 to 0.04 ± 0.15 logMAR under mental load (p = 0.03). Visual acuities estimated by sweep VEPs worsened from 0.38 ± 0.1 to 0.47 ± 0.1 logMAR (p < 0.001). While the slope of the VEP amplitude versus spatial frequency function steepened significantly with mental load (p = 0.01), VEP noise levels were not significantly affected (p = 0.07).

CONCLUSION

Visual acuity reduces significantly with a concurrent task that produces mental load. At least part of this reduction appears to be related to alterations in responses within the visual cortex, rather than being purely attributable to higher-level distraction effects.