Table 1

Outcome variables

  • A scoring algorithm developed for the NEI VFQ-25 for patients with chronic dry eye that assesses vision-related quality of life

  • Measures activity limitation (near activities, distance activities, peripheral vision, colour vision, driving, social functioning and six additional questions) and socioemotional impact (ocular pain, mental health, role difficulties and dependency)

  • Scores range from 0 to 100; a lower score indicates more activity limitations and socioemotional impact

  • Assesses five dimensions of health status: mobility, self-care, usual activities, pain/discomfort, anxiety/depression

  • Patient selects best response to describe health for the current day

  • Index score, using the UK time-trade-off methodology, can be calculated from the five items to calculate utilities

  • Measures ocular surface irritation over the past week

  • 12-item questionnaire with six typical symptoms (dryness, grittiness, stinging, tiredness, pain and itchiness) and subquestions for each symptom to identify the frequency and intensity of DED

  • Each item scored on a scale of 0 (no symptoms) to 6 (most frequent/most severe)

  • Total score: 0–72

  • Measures health-related productivity loss during work and regular activities (ie, percent activity impairment due to a problem, percent impairment while working due to a problem, percent overall work impairment due to a problem, percent work time missed due to a problem)

  • Scores reflect a percentage of impairment

    (0%–100%); higher numbers indicate greater impairment and less productivity

  • Assesses the impact of dry eye symptoms on aspects of a patient’s daily life (ie, emotional impact, daily activities, impact of work, satisfaction with treatment effectiveness, symptom bother, treatment-related bother)

  • Scores on each dimension range from 0 to 100; higher scores on the Dry Eye Impact on Daily Life module (ie, emotional impact, daily activities, and impact of work) indicate less impact; higher scores for symptom bother indicate greater bother due to symptoms; higher scores for satisfaction with treatment effectiveness indicate greater satisfaction; higher scores with treatment-related bother indicate less treatment-related bother

  • Quantifies severity and frequency of dry eye symptoms: frequency and intensity of eye discomfort and eye dryness; frequency of watery eyes

  • Total score: 0–22; score of >6 suggests dry eye;>12 indicates additional testing needed to exclude a diagnosis of Sjögren’s syndrome

  • Measures frequency and severity of ‘dryness, grittiness, or scratchiness’, ‘soreness or irritation’, ‘burning or watering’ and ‘eye fatigue’

  • Total score (0–28) and individual domain scores calculated

  • Higher score indicates more frequent and/or more severe symptoms

  • DED, dry eye disease; DEQ-5, 5-item Dry Eye Questionnaire; EQ-5D-5L, EuroQol 5 dimensions 5 levels; IDEEL, Impact of Dry Eye on Everyday Life; OCI, Ocular Comfort Index; SPEED, Standardised Patient Evaluation of Eye Dryness; NEI VFQ-25, 25-item National Eye Institute Visual Function Questionnaire; VFQ-28R, 28 item revised Visual Function Questionnaire; WPAI, Work Productivity and Activity Impairment.