Validation of Simplified Visual Acuity Testing Protocols in Amyotrophic Lateral Sclerosis

Abstract

High- and low-contrast visual acuity (HCVA, LCVA) are potential quantitative markers of neurological dysfunction in amyotrophic lateral sclerosis (ALS). The complex nature and duration of gold standard (GS) protocols precludes widespread use in neurology settings. This study compares simplified to GS visual acuity (VA) protocols. Monocular HCVA and LCVA were measured in ALS ( = 10) and control ( = 4) subjects using six protocols, varying by two chart and three refraction methods. Intraclass correlation coefficients between simplified and GS protocols ranged from 0.83 to 0.98 (HCVA, excellent agreement) and 0.56 to 0.75 (LCVA, moderate agreement). Differences between LCVA and GS protocols exceeded test-retest reliability. Simplified HCVA protocols using LCD (liquid crystal display) tablet charts and/or pinhole correction produced valid measurements. None of the modified LCVA testing protocols produced valid measurements.

Use of the King-Devick Variable Color Contrast Sensitivity Chart to differentiate stages of age-related macular degeneration

“…Despite evidence supporting the usefulness of these contrast and colour vision screening tools in detecting and monitoring AMD severity, these assessments are time consuming and require specialised equipment and interpretation, making them difficult to implement in clinical practice. Previously studied in migraine headache, 14 Parkinson's disease 15 and amyotrophic lateral sclerosis, 16 the King-Devick Variable Color Contrast Sensitivity Chart (VCCSC) is an iOS platform application that is available on a portable mobile or tablet. Variable contrast levels as well as colour contrast presentations can be adjusted to allow simultaneous assessment of visual acuity, contrast sensitivity and colour vision.…”